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303 Cards in this Set
- Front
- Back
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what are the six DNA viruses we studied?
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Poxviridae
Parvoviruses Papilloma Hepadenaviridae Herpesviridae Adenoviridae |
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which is the only single stranded DNA virus?
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Parvoviridae
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oropharyngeal--often asymptomatic, fever, pharyngitis, vesicular lesions, gingivostomatitis, lymphadenopathy, recurrent disease may present as "fever blisters"
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Herpesviridae: HSV I/II
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keratoconjuctivitis--corneal ulcers, vesicular lesions on eyelids, significant cause of corneal blindness
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Herpesviridae: HSV I/II
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genital-vesicular ulcerative lesions of penis, cervix, vulva, vagina, may be associated with dysuria (painful urination), lymphadenopathy
recurrences are common and often asymptomatic in women |
Herpesviridae: HSV I/II
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Encephalitis--fever, headache, vomiting, seizures, paralysis, high fatality rate
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Herpesviridae: HSV I/II
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neonatal form usually has three variations: cutaneous, encepalitis, disseminated with mortality rate up to 80%
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Herpesviridae: HSV I/II
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entrance through mucosal cells or break in skin that causes cytolytic reaction, necrosis of tissue with imflammatory response
latency in neuronal cells may spontaneously reactivate |
Herpesviridae: HSV I/II
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Tzanck Test (cytology) used, but has poor sensitivity and specificity
specimens: throat, CSF, stool, vesicular fluid |
Herpesviridae: HSV I/II
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worldwide, up to 90% of adults have Ab
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Herpesviridae: HSV I/II
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infectious mononucleosis--malaise, myalgia, fever, abnormal liver function, lymphocytosis
congenital cns involvement, growth retardation, hepatospelenomegaly, microcephaly, retinitis can be fatal TORCH testing |
CMV
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entrance through epithelial causes cytomegalic reaction with slow spread to multi organ
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CMV
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viral shedding in oral cavity and urine
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CMV
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Herpesviridae Family
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HSV I/II
VZV Epstein Barr CMV |
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General Characterisitics of Herpesviridae Family Viruses
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wide spectrum of diseases
latency significant large icosahedral (150-200nm) ds genome enveloped encodes >100 viral specific proteins short or long growth cycle cell tropism related to latency: neuronal cells, lymphoid tissue, specific organ cell (kidney) |
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viral replication process
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viral envelope fuses with host cell
nucleocapsid tansported into nucleus uncoating transcription of viral DNA replication viral specific proteins generated (and some enzymes) cycles range from short (18hrs for HSV) to (70 hrs for CMV) |
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infectious mononucleosis--malaise, fatigue, fever, headache, sore throat, lymphadenopathy
burkitts lymphoma--tumor of b cells nasopharyngeal carcinoma |
EBV
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infected through salivary contact
targets epithelial cells of pharynx and salivary glands and eventually infecting B cells |
EBV
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chickenpox--malaise, fever, centripetal vesicular rash that lasts five days
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Varicella
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shingles--severe pain in concentrated area of skin (trunk, head, neck) followed by crop of vesicles (dollar sized)
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Zoster
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primary infection through mucosal cells of upper respiratory tract or conjunctiva which then migrated to local lymph nodes, spreads systemically and seeds liver and spleen
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VZ
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viremia involves infection of monocytes which deposit in skin and form vesicles
sensory nerve cells are location of latency reactivation may be triggered |
VZ
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Acyclovir (up to 72 hrs) and VZIG (used prophylactically) as treatment
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VZ
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worldwide, incidence of 20% for those over the age of 50
vaccine is available |
VZ
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common warts, laryngeal papilloma, veneral warts, plantar warts
transmitted directly, sexually or during birth(laryngeal) |
HPV
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infects cells of basal layer of epithelial cells (highly tropic for epithelial)
viral dna exists as episome (can replicate free in the cytoplasm (has a different number of copies) or can be inserted into the main bacterial chromosome and replicate with the chromosome) in non-cancerous cells but integrated into host cell DNA in cancerous cells |
HPV
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High risk of cancer associated with to specific strains (#16 and 18)
but there are over 100 types overall |
HPV
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does NOT grow in cell culture, PCR-based assay is used along with histological exam of tissue
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HPV
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Podophyllin or salicylic acid topically, surgical removal, cryotherapy (freeze and destroy cells)
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HPV
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20 million cases in the US
12 million cases of cervical cancer vaccine is available |
HPV
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General Characteristics of Poxviridae Family Viruses
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small pox, vaccinia
enter through mucosal cells of upper respiratory tract and enters blood stream (viremia) via lymph and RES mouth lesions develop cytoplasmic inclusions form followed by ballooning degeneration of coalescing cells and scarring |
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Two Poxviridae:
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Small Pox
Vaccinia |
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virus that causes small pox
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Variola
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small pox symptoms
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high fever, malaise, headache, prostration, centrifugal rash (macular>papular>vesicular>pustular)
30% fatality rate |
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vaccinia: 3 presentations
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occular
generalized (40% fatality) encephalitis (40% fatality) |
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only DNA virus whose replication takes place in the cytoplasm
cytoplasmic inclusion bodies are viral "factories" |
poxviridae
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1980-only disease to be successfully eradicated
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Poxviridae
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used as "vector" vaccine for some animal diseases such as rabies
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vaccinia
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viral agent that causes Erythema Infectiosum (5th disease)
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Parvoviridae (Human Parvovirus B19)
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clinical presentation of erythema infectiosum
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rash--"slapped cheek"
joint involvement in adults |
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3 Presentations of Parvovirus
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Erythema Infectiosum
Aplastic crisis Hydrops Fetalis (fluid build up in newborn) |
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acquired via respiratory route, targtets immature erythroid cells, affects bone marrow or liver(fetal cases)
cell death results in anemia neutralizing Ab formed (defends cell from Ag or infectious body by inhibiting or neutralizing any effect it has biologically) |
Parvovirus
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highly tropic for erythroid cell lines
binds to blood group P Ag on cell surface and is translocated to nucleus heavily dependent on host cell functions and enzymes cytolytic |
Parvovirus
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Icosahedral, , small, simple, no envelope
*SS DNA, replicates in nucleus |
Parvovirus
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does NOT grow in cell culture, use of serology IgM assay for diagnosis
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Parvovirus
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Family of Picornaviridae Characteristics
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small RNA virions
two major grouping: enterovirus and rhino virus wide range of disease: CNS, Cardiac, Respiratory, Rash, Gen. Disease all ssRNA with exception of Reoviridae which is dsRNA no envelope replicated in cytoplasm |
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replicative cycle of picornaviridae:
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virion attaches to specific host cell receptors
binding triggers release of viral RNA into cell translation of viral RNA results in production of replication proteins and viral coat proteins RNA Polymerase produces complementary RNA (neg. sense) which serves as template for new viral genome (positive sense) viral assembly viral release upon host cell disintegration 5-10hr cycle |
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Two Major Categories of RNA Viruses
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Picornaviridae
Calciviridae |
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virus that causes Norwalk Agent:
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Norovirus
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clinical presentation of norvirus
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gastroenteritis: rapid onset, diarrhea, nausea, vomitting, fever, ab cramps, headache, malaise
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properties of Norovirus / Calciviridae
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icosahedral
ssRNA non-enveloped replicates in cytoplasm |
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orally introduced
low ID of about 10 viral particles multiplication occurs in cells of small intesting little else is understood about pathogenesis |
Norovirus Initiation
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EM of stool sample
requires high viral load direction detection using EIA, Ag, PCR |
Norovirus Diagnostic
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most common cause of viral gastroenteritis in adults
more associated with outbreaks that sporadic disease cases 23 million cases/yr in the US associated with restaurants, long term care facilities, schools, cruises |
Norovirus Epidemiology
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mild disease begins with fever, headache, malaise, nausea, vomiting, constipation and sore throat
may progress to aseptic meningitis that includes stiff neck and back pain flaccid paralysis may ensue (infantile paralysis specifically associated) |
Poliovirus Clinical Presentation
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orally introduced, multiplication may initiate in lymphoid tissue (tonsil's, peyer's patches)
viremia ensues in presence of circulating Ab continues to be shed for weeks neuronal cells infected via blood stream spinal cord and brain both may be affected myocarditis on occasion |
Polio Initation
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virus isolation in monkey cell lines
specimens taken from throat or feces CPE develops in 3-5 days ID through neutralization assays serology used to show 4-fold rise in Ab to virus |
Polio Diagnostic procedures
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Salk vaccine
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injection of inactivated (dead) poliovirus
more commonly used today eventhough its not the more effective vaccine, herd immunity and the possibility of the oral attenuated strain to reactivate makes it less risky |
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Sabin vaccine
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orally taken, attenuated poliovirus
discontinued use |
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properties of Norovirus / Calciviridae
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icosahedral
ssRNA non-enveloped replicates in cytoplasm |
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orally introduced
low ID of about 10 viral particles multiplication occurs in cells of small intesting little else is understood about pathogenesis |
Norovirus Initiation
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EM of stool sample
requires high viral load direction detection using EIA, Ag, PCR |
Norovirus Diagnostic
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most common cause of viral gastroenteritis in adults
more associated with outbreaks that sporadic disease cases 23 million cases/yr in the US associated with restaurants, long term care facilities, schools, cruises |
Norovirus Epidemiology
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mild disease begins with fever, headache, malaise, nausea, vomiting, constipation and sore throat
may progress to aseptic meningitis that includes stiff neck and back pain flaccid paralysis may ensue (infantile paralysis specifically associated) |
Poliovirus Clinical Presentation
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orally introduced, multiplication may initiate in lymphoid tissue (tonsil's, peyer's patches)
viremia ensues in presence of circulating Ab continues to be shed for weeks neuronal cells infected via blood stream spinal cord and brain both may be affected myocarditis on occasion |
Polio Initation
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virus isolation in monkey cell lines
specimens taken from throat or feces CPE develops in 3-5 days ID through neutralization assays serology used to show 4-fold rise in Ab to virus |
Polio Diagnostic procedures
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vaccines developed in 1950s by Salk and Sabin
eliminated from western hemisphere in 1994 and current target for worldwide eradication occurs in all ages but more common in children |
Epidemiology of Polio
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Salk vaccine
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injection of inactivated (dead) poliovirus
more commonly used today eventhough its not the more effective vaccine, herd immunity and the possibility of the oral attenuated strain to reactivate makes it less risky |
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Sabin vaccine
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orally taken, attenuated poliovirus
discontinued use |
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aseptic meningitis (A&B): fever, malaise, headache, nausea, paresis
herpangina (A): febrile pharyngitis with vesicular lesions hand, foot and mouth disease (A): pharyngeal ulcerations coupled with vesicular rash on soles and palms pleurodynia (B): fever and stabbing chest pain myocarditis (B): acute inflammation of heart present in adults and children but more severe in children cold-like disease (A&B): rhinitis, congestion |
clinical presentaiton of Coxsackie Virus (A and B)
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orally introduced, multiplication initiates in throat and gut, spread via circulatory system, virus shed for weeks
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initiation of coxsackie virus
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virus isolation in newborn mice or cell cutlure using throat swab, nasal secretion, fecal specimen, CSF
CPE develops within 6-12 days (slower than polio) NO Vaccine, worldwide, common in summer and fall |
diagnostic procedure for Coxsackie
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bronchiolitis or pneumonia in children
acute hemorrhagic conjunctivitis aseptic meningitis or encephalitis (similar to coxsackie) |
Enterovirus (3 Clinical Presentations)
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no vaccine, worldwide spread, human reservoir, waterborne, short incubation for hemorrhagic conjunctivitis of only a day
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epidemiology of Enterovirus
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common cold: sneezing, lacrimation, pharyngitis, malaise, chills, bronchitis
may be clinically indistinguishable from similar condition caused by members of same family of viruses |
clinical presentation of Rhinovirus
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enters via respiratory tract, replicates in cells of nasal mucosa, symptoms related to host response
+100 serotypes adults avg 1-2 a year |
Initiation of Rhinovirus
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rapid onset, jaundice in prodromal stage, but not always present
fever, malaise, anorexia, nausea, ab discomfort |
Clinical Presentation of Hep A
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Hep strains A, B, C, EBV, Yellow fever, CMV, HSV, Rubella and some enteroviruses
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General Hepatitis can be caused by...
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orally introduced, multiplication in cells lining alimentary tract, transcytosis brings virus to blood stream, spreads to hepatocytes
passed in bile and feces |
initiation of Hep A
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widespread, outbreaks associated with families, institutions, camps, daycares, mililtary
fecal-oral spread raw oysters or clams anicteric cases more common in kids 1/3 US adults have Ab Human Immunoglobulin vaccination |
epidemiology of Hep A
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mild exanthem (breakout) : malaise, fever, morbilliform rash that begins on face and spreads to abs and extremities
lasts less than 3 days congenital syndrome: 85% of infants when mother is + in 1st trimester-->hearing loss, cardiac and neurologic abnormalities, cataracts and death |
two clinical presentations of Rubella
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enters via mucosa of upper respiratory tract, replicates, cervical lymph invasion, viremia, rash associated with immune response
may remain in nasopharynx for weeks |
initation of rubella
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specifc IgG used for pre-natal screening
detection of IgM indicative of current infection HI, viral neutralization, EIA, latex agglutination |
diagnostic procedures for Rubella
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no specific treatment but immune globulin has been used for pregnant women exposed to confirmed cases
termination of pregnancy has been considered in some cases |
Rubella Treatment
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vaccine released in 1969
disease still exists worldwide with about 100,00 cases/yr indigenous cases eliminated in the US with last major epidemic in 1963 w/ 10,000 fetal deaths, 2000 neonatal, 20,000 total cases |
Rubella Epidemiology
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Three Viral Encephalitides
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Eastern Equine Encephalitis
Venezuelan Equine Encephalitis Western Equine Encephalitis |
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most asymptomatic, may prevent with fever, headache, aseptic meningitis
severe form of encephalitis that has acute onset, headache, high fever, altered mental state, tremors, convulsions |
clinical presentations of Viral Encephalitides
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transmitted by mosquitoes, virus replicates in local lymph, enters blood stream
different agents have different tropisms: monocytes, liver, neuronal unknown mechanism used to cross BBB |
initiation of EEE, VEE, WEE
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geographically distributed
vaccines available for horses bird reservoir highest mortality of EEE 60% then VEE 25% and WEE 5% |
epidemiology of Viral Encephalitides
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acute, febrile, intense headache, myalgia, arthralgia, retro-orbital pain, anorexia, nausea, vomitting, rash
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clinical presentation of flavivirus, Dengue Fever
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another name for Dengue Fever
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Break Bone Fever
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transmitted by mosquitoes, replication in regional lymph, viremia
targets muscle and connective tissue |
Dengue Fever
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Dengue Fever belongs to what major group of RNA viruses?
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Flaviviridae
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found in tropics
50 million cases/yr risk of most severe hemorrhagic <0.2% vaccines in development human reservoir |
Epidemiology of Dengue Fever
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mild case of fever, aseptic meningitis
encephalitis characterized by acute onset, headache, high fever, altered mental state, tremors, convulsions |
clinical presentation of SLE (St Louis Encephalitis)
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SLE belongs to what family of RNA Viruses?
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Flaviviridae
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introduced via mosquito bite, replication in regional lymph, viremia, targets nerve cells
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initiation of SLE
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most common cause of epidemic viral encephalitis in US
incidence has waned with vector control bird reservoir |
St Louis Encephalitis
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febrile illness: fever, myalgia, headache, malaise, arthralgia
encephalitis |
West Nile Fever Virus (WNV)
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what broad family of RNA Viruses does WNV belong to?
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Flaviviridae
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introduced by mosquito, replication in lymph, viremia, targets various cells
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initiation of WNV
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first seen in US in 1999, now worldwide
bird reservoir, first seen in corvids vector one of several genera of mosquito |
epidemiology of WNV
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febrile illness with sudden onset, fever, chillds, headache, backache, myalgia, nausea, vomitting
"period of intoxication" 15% of cases serious with high fever, jaundice, hematemesis, renal dysfunction, mortality of 30% |
clinical presentation of Yellow Fever Virus
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Yellow Fever Virus belongs to what family of RNA Viruses?
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Flaviviridae
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introduced by mosquito, replication in regional lymph, viremia, localizes in liver, spleen, kidney
systemic disease results in necrosis of liver, kidney, petechiae (minor hemorrhage), myocardial damage |
initiation of Yellow Fever
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monitored close in endemic countries where Aedes mosquito present
vaccine required for entry to some countries 200,000/yr incidence with 30,000 deaths/yr |
Yellow Fever
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insidious onset, anorexia, ab discomfort, nausea, vomitting, jaundice (<30%)
90% asymptomatic 60-70% go to chronicity 50% of chronic--> cirrhosis or cancer |
Hep C
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blood borne acquisition, tropism for liver, less than 1/2 resolve after mild disease
most go on to long term infection of hepatocytes which leads to increased liver enzymes, deterioration of liver function chronicity related to balance between virus replication and host immune response |
Hep C
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Ribavirin and Interferon treatment
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Hep C
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180 million currently infected
3-4 mill more cases/year contracted via IDU, transfusions, STI human reservoir no screening test existed until 1992 2 month incubation |
Hep C Epidemiology
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malaise, fever, headache, sore throat, nausea, vomiting, diarrhea, myalgia
80% asymptomatic more severe during pregnancy w/ 80% fetal loss severe cases: shock, pleural effusion (build up liquid between lungs and chest cavity), hemorrhage, seizures deafness may result as a complication |
clinical presentation of Lassa Fever virus
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what family of RNA viruses is Lassa Fever in?
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Arenaviridae
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acquired via aersol of rodent excreta
involvement of macrophages, local lymph, hematogenous spread, affecting all organs may lead to capillary leakage and shock transmissible human-human |
Lassa Fever Initiation
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isolation requires BSL-4 due to ability to spread as aerosol particles
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Lassa Fever Diagnostics
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Ribvirin treatment
ongoing work towards vaccine seen in W. Africa wild rodent reservoir (mice and rats) 1% fatality |
epidemiology of Lassa Fever
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many subclinical cases
acute manifested as meningitis may appear "flu-like" with fever, chills, malaise, weakness, headache, sore throat rarely develops into encephalitis |
Clinical presentation of LCM (Lymphocytic Choriomeningitis)
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transmitted in urine, saliva, excreta of mice
may spread to meninges cell-mediated response of host exacerbates disease |
initiation of LCM
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IgM in CSF or serum must be distinguished from other meningitis or encephalitis syndromes
virus isolation may be done via intracerebral inoculation of mice |
LCM
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what broad family of RNA viruses is LCM part of?
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Arenaviridae
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seen widely in EU and Americas
house mouse reservoir no evidence of human-human transmission |
epidemiology of LCM
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afebrile "common cold" considered harmless
a unique strain can cause severe acute respiratory syndrome (SARS) that includes fever, chills, malaise, headache, dizziness, cough, shortness of breath and may require ventilation 10% fatality |
Clinical Presentation of Coronavirus
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high species specificity
tropism for epithelial cells of respiratory tract SARS agent may represent jumping the "species barrier" |
initiation of Coronavirus
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causes 20% of all colds worldwide
Ab found in >90% adults concept of "super spreaders" |
Epidemiology of Coronavirus
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severe, acute with fever, malaise, myalgia, headache, vomiting, diarrhea, rash
most severe may progress to hemorrhagic disease with hepatic and renal involvement leading to organ failure and death |
clinical presentation of Ebola Virus
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What broad group of RNA viruses is Ebola in?
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Filoviridae
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highly virulent tropism for endothelial cells, macrophages and hepatocytes
high virus titers in all major organs 90% mortality |
initation of Ebola
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BSL-4 required
seen in Central and West Africa 1976 first recognized (Hot Zone-written by Preston) non-human primates and bats as reservoir |
Ebola Epidemiology
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chills, headache, cough, fever, myalgia, malaise, anorexia
complications associated with age, debilitating disease, pregnancy 2ndary pneumonai may develop, frequently related to bacterial disease |
Influenza A clinical presentation
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spread via airborne droplets
tropism for respiratory epithelial cells, then spreads to adjacent cells, causing cell death and desquamation edema and mononuclear infiltration systemic effects related to cytokine action |
initiation of influenza A
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diagnosis difficult b/c very similar to many other diseases
virus isolation for detection done in embryonated eggs, cell culture, FA used with shell vial culture HI and EIA neutralization assays good for specificity but not always available serological interpretation complicated by anamnestic responses |
Diagnostic Procedures for Influenza A
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Influenza Typing
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antigenic variability
HA, NA and matrix proteins Ags all influenza type designation Nomenclature: type/origin/strain/year/H&N type |
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Amantadine
Vaccines: inactive, live (attenuated), need to be changed annually for max efficacy contraindications/risks: allergies, Guillan Barre Syndrome |
Treatment and Prevention of Influenza A
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annual outbreaks with predictable pattern
5million cases/yr with 500,000 deaths Ag drift and shift species variation, genetic recombination pandemic risk |
Epidemiology of Influenza A
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clinical variation by age and type
infants and children: Croup-like illness (difficulty breathing accompanied by barking cough) of bronchitis, bronchiolitis, pneumonia, fever, rhinitis, pharyngitis, otitis media adults: laryngitis, rhinitis |
clinical presentation of Parainfluenza
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spread via respiratory route, localized in upper resp tract
4 types type 3 excreted longer and therefore more communicable IgE production may contribute to severity |
initiation of Parainfluenza
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common cause of serious respiratory illness in infants and children (2nd only to RSV)
widespread in close settings like daycares |
Parainfluenza
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clinical variation with age
infants and children: acute, febrile, with enlarged salivary glands (parotitis) adults: fever, malaise, anorexia complications: meningitis, orchitis (swelling of testicles) |
clinical presentation of mumps
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what broad family of RNA viruses is Mumps in?
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Paramyxoviridae
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spread via resp. route, localized in nasal passages and upper resp.
viremia followed by involvement of parotid glands virus shed in saliva, may spread to visceral organs, esp kidneys |
initiation of mumps
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CPE shows syncytia
detection using hemadsorption inhibition IgM lasts 60 days so not a good indicator of time of infection |
diagnostic procedures for Mumps
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live, attenuated vaccine available
current incidence in US <500/yr worldwide low mortality of 3/10,000, which is usually only associated with encephalitic form |
epidemiology of Mumps
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acute, highly communicable with fever, conjunctivitis, coryza (inflamation of mucous membranes associated with cold), cough, koplik spots (prodromal), rash that begins on face
more severe in infants and adults less severe in children infectious during prodromal stage |
clinical presentation of measles
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spread via resp route, localized in upper resp tract, spread to regional lymph, viremic spread through RES, secreted in tears, nasal secretions, urine, blood
rash from cell-mediated immunity to infected cell in capillaries encephalitis potential complication sub acute sclerosing panencephalitis is a fatal sequela rarely seen |
initiation of measles
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what RNA family is measels in?
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Paramyxoviridae
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CPE shows giant cells and intracytoplasmic inclusions
slow growth in cell culture |
Measles Diagnostic
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live attenuated vaccine available (<500 cases/yr currently in US)
very low ID 5% mortality still an issue in developing nations herd immunity atypical measles (altered expression that occurs in individually incompletely vaccinated) |
epidemiology of Measles
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primarily infects children
ranges from subclinical to cold to pneumonia otitis media (inflammation or infection of middle ear) is common complication hospitalizes 2/100 infants fatal for 1/100 infants hospitalized |
clinical presentation of RSV (Respiratory Synctial Virus)
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spread via respiratory route, localized in nasopharynx, spread to lower resp tract, viremia rare
risk to infants due to their small air passages |
initiation of RSV
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no vaccine
worldwide spread major cause of pediatric respiratory disease reinfection may occur but with less serious symptoms |
Epidemiology of RSV
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diarrhea, fever, ab pain, vomitting, dehydration
loss of electrolytes can be fatal in infants and young children symptoms in adults are mild to none |
Clinical Presentation of Rotavirus
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viral attachment to cells in villi of small intestine, multiply in cells and disrupt transport and absorption of glucose and sodium
infected cells sloughed off into intestine and shed in stool with very high titers seen in stool specimens that may persist for two weeks |
initiation of Rotavirus
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fastidious virus (only infects a few cells productively)
cell culture NOT used |
diagnostic Rotavirus
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supportive treatment and replacement of electrolytes
vaccine withdrawn from use due to association with intussusception (serious intestinal disorder) |
Treatment of Rotavirus
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most important cause of gastroenteritis in children worldwide
5 billion cases/yr 5 million deaths/yr outbreaks more common in winter fecal-oral spread |
Epidemiology of Rotavirus
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fever, myalgia, headache, nausea, vomiting
fever normally diphasic |
clinical presentation of Colorado Tick Fever Virus
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spread via tick bite
viremia, blood cells infected, disease is self limited |
initiation of colorado tick fever
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seen in western US and Canada (where ticks are)
small mammals are reservoirs rarely fatal no specific treatment |
epidemiology of Colorado tick fever
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cause of adult T-cell Leukemia
most common in Japan likely acquired via breast milk latency up to 50yrs |
Clinical Presentation of HTLV (Human T-Lymphocytic Virus)
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first described as AIDS
now called HIV Infection with stages 1-3 |
Original Name for HIV
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fatigue, rash, headache, nausea, night sweats (may occur 3-6 weeks after infection)
immunosuppresion: opportunist infections may advance: PCP, candidiasis, kaposi's sarcoma very slow progression blood borne acquistion, viremia w/ seeding lymphoid organs, T helper lymphocytes (CD-4) are target cells CD-4 count drops, viral load increases and individuals succumb to opportunistic infections and other effects of immunosuppression |
Clinical Presentation and initiation of HIV
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Diagnosis via serology: Ab detection
EIA screening test followed by confirmatory WB test western blot requires standard for interpretation of viral load Ab to p24 and gp41/gp120/gp16 problem with "window", testing used is influenced by prevalence of disease PCR now used more routinely |
Diagnostic procedures for HIV
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CD-4 count: <200 cells/uL
viral load used to monitor treatment and disease progression Antiretrovirals: NRTI, NNRTI, PI, fusion inhibitor, chemokine co-receptor antagonist, nucleoside inhibitors, HAART (highly active antiretroviral therapy), combo of antiretrovirals usually involved two NRTIs and a PI (Nucleoside analog reverse-transcriptase inhibitors) (Protease Inhibitor) treatment reduces changes of selecting drug resistant strains supresses viral replication but does NOT cure |
Treatment for HIV
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incubation of 2-3 months to display Ab
1-15 yrs to progress to stage 3 of infection recognized in 1981, isolated in '83 and test released in '85 disproportion demographic spread worldwide route of transmission varies by population HIV prevention efforts: PEPFAR, Global Fund (president's emergency plan for aids relief) |
Epidemiology of AIDS
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Seoul Virus/Hantaan Virus
Sin Nombre Virus |
Hantavirus
two major agents: |
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hemorrhagic fever with renal syndrome (HFRS): acute onset, lower back pain, five stages: febrile, hypotensive, oliguric, diuretic, convalescent (gradual recovery)
Hantavirus pulmonary syndrome (HPS): fever, myalgia, GI complaints, respiratory distress, hypotension |
clinical presentation of Hantavirus
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pathogenesis not well understood, acquired through inhalation of virus in rodent excreta
causes increased permeability of capillaries in target organs can cause lifelong infections of rodents without evidence of disease |
initiation of Hantavirus
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Ribavirin treatment
rodent control for prevention mortality of 30% HFRF: SE Asia, afflicted soldiers during korean war, caused by field rodents HPS (sin nombre) : western hemisphere, major outbreak in 1993 in US, caused by door mice |
Treatment and Epidemiology of Hantavirus
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bullet shaped virus, caused acute fulminant (sudden) encephalitis
three phases: prodromal phase of malaise, anorexia, headache, photophobia, nausea, sore throat, fever acute neurologic phase of nervousness, apprehension, hallucinations, hydrophobia, seizures coma and death from respiratory failure |
clinical presentation of Rabies
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enters via circulatory sys, reaches cells of muscular or connective tissue where it multiplies, enters nerves via neuromuscular junctions, spreads throughout nervous system and localizes to salivary glands, spreading to multiple organs
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initiation of Rabies virus
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viral isolation/detection in suckling mice or hamsters via intracerebral inoculation
direct observation involves DFA of brain an cerebellus PCR used in humans serology employs rapid fluorescent foci inhibition test |
diagnostics of Rabies
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animal control
vaccination of domestic and wild animals pre-exposure prophylaxis post-exposure: RIG and Vaccination |
treatment and prevention of Rabies
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3-4 week incubation or up to a year
WW, enzootic in domestic and wild animals 15mill treated each year post-exposure most occur in children under 15 exposed to dog bites dogs, skunks, raccoons, bats are reservoirs |
epidemiology of Rabies
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Characteristics of Arboviruses
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ecological, NOT taxonomic grouping
include togaviridae and flavaviridae (which then include Rubella, EEE, VEE, WEE, Dengue, SLE, WNV, Yellow fever) vectors: mosquitoes (Aedes, anopheles, culex), ticks, sand flies lipid containing envelope ether sensitive positive sense RNA, ss "bud" through host cell membrane replication in cytoplasm febrile diseases w/ or w/out rash, encephalitis, hemorrhagic fever |
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Arenaviridae Broad Characteristics
Lassa Virus LCM |
pleiomorphic viral particle
segmented RNA genome envelope replication in cytoplasm encapsilates host cell ribosomes does NOT cause CPE rodent-borne |
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Coronaviridae Broad Characteristics
Corona virus SARS coronavirus |
pleiomorphic (spherical)
RNA genome enveloped rep in cytoplasm |
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Filoviridae Broad Characteristics:
Ebola |
Pleiomorphic (long filamentous)
RNA genome enveloped rep in cytoplasm |
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Orthomyxoviridae (Influenza A) Broad Characteristics
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pleiomorphic (spherical)
segmented RNA genome contain HA & NA Ags on surface replicate in nucleus* small size |
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Paramyxoviridae Broad Characteristics:
Parainfluenza Mumps Measles RSV |
non segmented RNA genome
stable antigens larger size replication in cytoplasm |
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Reoviridae Broad Characteristics
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icosahedral
double capsid ds RNA genome* no envelope rep in cytoplasm: hemagglutinin on viral surface attaches to host cell receptors, penetration followed by uncoating w/in lysosomes, bring in all enzymes for transcription, assemblye in cytoplasmic inclusion bodies reovirus is lytic |
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Retroviridae Broad Characteristics
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spherical
enveloped ss RNA genome contains reverse transcriptase replication involves cytoplasm AND nucleus: adsorbs to specific receptors on host cell, viral RNA transcribed into DNA in cytoplasm, DNA then migrated into nucleus and is integrated as provirus which may exist quiescently. when host cell is activated, provirus is transcribed by host cell RNA polymerase, virus particles mature and emerge via budding |
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Bunyaviridae Broad Characterisitics
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spherical or pleiomorphic
segmented RNA genome enveloped rep in cytoplasm transmitted by arthropods: ticks, mosquitoes some rodent-borne |
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Rhabdoviridae Broad Characteristics
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bullet shaped
ss RNA genome enveloped rep in cytoplasm |
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respiratory: cough, congestion, fever, sore throat, pneumonia
eye-pharyngoconjunctival fever "swimming pool conjuctivitis", epidemic conjunctivitis gastrointestinal: infantile gastroenteritis, diarrhea other: hemorrhagic cystitis, adenovirus hepatitis |
clinical presentations of Adenovirus
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infects epithelial cells ONLY
ususally doesnt spread beyond regional lymph nodes may persist as latent virus in adenoids and tonsils cytopathic effect: enlargement, rounding |
initiation of Adenovirus
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replicative cycle: attachment, penetration, uncoating and assembly in cell nucleus
24 hr infectious cycle 100,000 virus particles per cell |
Replicative cycle of Adenovirus
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icosahedral
ds DNA has protein "fibers" replicated in nucleus narrow host range 50 serotypes (<1/3 responsible for human disease) |
properties of Adenovirus
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stool, throat, urine, conjunctiva, rectal specimens
CPE: rounding, clustering, immunofluorescence, neutralization, HI CF to measure Ab to group Ag neutralization using patient serum |
diagnostics for Adenovirus
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no treatment available
worldwide fecal-oral and direct contact many subclinical cases ~1 week incubation young children and millitary at greater risk |
Epidemiology of Adenovirus
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insidious onset, elevated liver enzymes, jaundice, serum sickness-like syndrome of fever, rash, polyarteritis nodosa (arteries swollen and damaged)
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clinical presentation of Hep B (Hepadenaviridae)
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infects hepatocytes, localized areas of liver necrosis
damage is reversible upon recovery chronic hep associated with HDV co-infection hepatocellular carcinoma in 1% |
initiation of Hep B
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final assembly occurs outside of nucleus but all other steps the same as adenovirus
major proteins: HBsAg and HBcAg replicated in nucleus through RNA intermediate different types within host range |
replicative cycle of Hep B
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interferon, antivirals directed at replication, surgery (transplantation)
bloodborne, STI, transfusion associated vaccine available |
epidemiology and treatment of Hep B
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e.nana
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intestinal amoeba, non pathogen
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p.falciparum
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worst malaria, blood sporozoa, anopheles vector
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i. butschlii
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intestinal amoeba, non pathogen
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ascaris
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nematode, roundworm, largest, lung development, mammilated egg
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d. latum
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cestode, tapeworm, copepod--fish, ingested, infectious cercaria
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s.mansoni
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trematode, bloodfluke, blood vessels and liver sinuses, feeds on RBCs, penetrates skin when wading in water
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hookworm
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new and old world, nematode, attaches to intestinal wall and directly feeds on contents leading to anemia and protein deficiency
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tick
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arthropod, arachnida, babesia vector, 4 pairs of legs
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g.lamblia
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fecal-oral, contam H2O, steatorrhea
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enterobius vermicularis
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pinworm, nematode, most common, perianal itch, daycares, fecal-oral
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babesia
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tick-borne, maltese cross, blood sporozoa
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p.ovale
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blood sporozoa, anopheles
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trypanosoma
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hemoflagellate, infectious trypomastigote, Tsetse fly or reduvid bug
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d. fragilis
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intestinal flagellate with no visible flagella, no cyst, associated with enterobius eggs
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p. malariae
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blood sporozoa, troph basket, schizont merozoites, anopheles vector
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cryptosporidium
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common intestinal parasite, appease of ghost cells, contam H2o or food
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e. hystolytica
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intestinal amoeba, ingested RBCs are diagnostic, fecal-oral, amebiasis--dysentery
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chilomastix mesnili
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pear shaped troph (pyriform?), intestinal flagellate, fecal-oral or contam h2o, very resistant cyst, lives in cecum/colon
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p.vivax
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malaria, enopheles, blood sporozoan
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e. hartmani
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intestinal amoeba, non pathogen
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b.hominis
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only cyst form seen, intestinal flagellate, 6 peripheral nuclei
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trichuris
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whipworm, rectal prolapse, nematode, fecal-oral, helminthic therapy, cecum and colon, 1 yrs, 3,000-20,000 eggs/day
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hymenolepis
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cestode, infected beetle 2nd host, humans and rodents 1st, scolex, dwarf tapeworm, proglottids, infectious cysticercoid
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s.japonicum
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penetrated skin while wading, blood fluke, trematode, snail host
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nematodes
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roundworms:
enterobius trichuris ascaris necatur + ancylostoma |
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cestodes
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tapeworms:
h. nana (dwarf) d. latus (broadfish) |
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trematodes
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flukes:
s. mansoni s. japonicum s. haematobium SNAIL host |
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ectoparasites
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arachnids:
ticks( ixodes), mites (sarcoptes), spiders insecta: flies, mosquitoes, fleas, lice, bugs |
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pork/beef tapeworm
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taeniasis
(saginata--cow>solium--pork) |
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hydatid cyst disease
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echinococcosis, tissue cestode
dog host |
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oriental liver fluke
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clonochiasis
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cholangiocarcinoma, ascites, china, snail host
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clonorchiasis
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fascioliasis
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trematode, liver and lung fluke, aquatic plants, snail host
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paragonimiasis
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lung fluke, crab, crayfish host, snail host, S.America, SE Aseia, Africa
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snail fever
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schistosomiasis, penetration, 2 sexes,
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itch mite
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scabies
arthropod, arachnida, |
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head, body lice
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pediculosis
arthropod, insecta |
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phthiriasis
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public lice, crabs
arthropod, insecta |
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bedbugs
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arthropod, insecta
dont need humans for life cycle |
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string test
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giardiasis diagnostic test
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largest water borne outbreak in 1993 in milwauke
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cryptosporidiosis
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PAM
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clinical presentation of naegleriasis (non-intestinal amoeba)
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trichomoniasis
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fairly common infection of GU tract, urethritis, vaginitis, may coexist with gonorrhea
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toxoplasmosis
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coccidia, primary infection during pregnancy leads to fetal retinitis, brain disease and liver damage
TORCH test fatal for immunocompromised (AIDS) associated with domestic cats |
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african sleeping sickness
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trypanosomiasis, tsetse fly, painful chancre,
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american chagas disease
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trypanosoma cruzi, reduvid bug, inflammation of eye, mexico, central and south america
less common than similar african sleeping sickness |
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oriental sore espundia
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mucocutaneous leishmaniasis, female sand fly, macule at site of bite, erosion of nasal septum, montenegro skin test, marsupials, rodents, dogs
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visceral (kala-azar)
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leishmania donovani, fatal untreated, fox, jackals reservoir
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babesia co-spread with
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lymes disease, tick bite, zoonotic
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strongylodiasis
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parthenogenic female
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barrel, rectal, whip
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trichuriasis
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blood and tissue nematodes
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filariasis, onchocerciasis, dracunculiasis, toxocariasis, trichinellosis
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elephantiasis
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assoicated with filariasis, mosquito transmission
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river blindness
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female black fly, onchocerciasis
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guinea worm
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near eradication
dracunculiasis blister on foot develops when nematode tries to leave the host infective copepods ingested |
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toxocariasis
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visceral larva migrans, multiple granulomatous lesions, dog reservoir
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trichinellosis
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tissue nematode, undercooked pork, muscle invasion, edema, myalgia, human acts as paratenic host (not necessary)
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number of fungal species that cause human disease
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400
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characteristics of fungi
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contain true nucleus
lack chlorophyll reproduce asexually through sporulation heterotrophic |
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to distinguish candida albicans from other species:
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carb assimilation test
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cause of tinea pedis
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epidermophyton, trichophyton
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blastomyces dermatiditis classic characteristic
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broad-based budding cells
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treatments for fungal diseases
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ampho B and itroconazole
nystatin and griseofulvin trimethoprim-sulfamethoxazole |
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pneumocystis jiroveci
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does not grow in cell culture
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individuals who are genetically predisposed to type I hypersensitivity reactions are:
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Atopic
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paracoccidioides brasiliensis
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causes south american blastomycosis
lesions in oral cavity cross reacts with coccidiodes immitis and histoplasma capsulatum with skin testing |
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causative agent of chronic granulomatous, fungal disease of the lung that survives inside macrophages
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histoplasma capsulatum
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valley fever
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coccidiomycosis
symptoms flu like dissemination involves skin, joints, meninges labs work under BSC |
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fungus that are known to be inhibited by inhibitory substances normally found in selective fungal media
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cryptococcus neoformans
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fungi are capable of causing:
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infection, allergy, toxemia
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cell walls of fungi contain
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chitin
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dermatophytoses are characterized as:
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high prevalence, low pathogenicity
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mycetoma is characterized by:
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draining sinuses that contain granules (intertwined hyphae)
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blastomycosis most commonly seen in:
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ohio and mississippi river valleys
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coccidioides immitis seen in vivo in:
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spherules and edospores
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most common mycotic pulmonary disease in US
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Histoplasmosis
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best specimen for PCP is:
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induced sputum
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very few mycotic agents are reportable
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true
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fungi are part of normal flora in humans
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true
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aflatoxin is produced by
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aspergillus fumigatus
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asexual fungal spore
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conidium
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smooth, without hair
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glabrous
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spindle-shaped
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fusiform
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cheese-like consistency
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caseating
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colorless or transparent
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hyaline
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hyphal cross wall
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septum
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shortness of breath
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dyspnea
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easily broken
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friable
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alternating between yeast and mold form is called
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dimorphic
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mass of hyphae that form body of fungus
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mycellium
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allergic bronchopulmonary aspergillosis left untreated may lead to
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fibrosis of lung tissue
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protein for use in skin testing of coccidiomycosis
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spherules
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chromoblastomycosis characterized by
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verrucosa nodules on feet and legs
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early 1980s PCP was fairly common in immunocompromised, who were also infected with
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AIDS
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specialized, thick-walled spore that can be induced on certain media with candida albicans
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chlamydospore
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histoplasmosis
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fungal, one of most common, only one that could be found in VT, associated with pigeon droppings, characteristic "river boat pilot's wheel", inhalation of conidia, affect immunocompromised, river valleys, dimorphic and treated with itraconazole
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types of fungi
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mildew, mold, mushrooms, rust, yeast, smuts
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systemic mycoses
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usually reportable
caused by dimorphic fungi geographically limited agents exist in nature inhalation normal route of entry--most severe not generally communicable pyrogranulomatous responses clinically similar to TB |
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opportunistic mycoses
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difficult to treat
high mortality present in those with compromised immunity endo or exogenous respiratory, CNS, Angioinvasive, cutaneous |
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considered the "imperfect fungi" for only having an asexual stage
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deuteromycetes
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coccidia have
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both sex and asex cycles
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amebic dysentery caused by
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entamoeba hystolytica
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giardia lamblia is...
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weakly pathogenic and attacks the small intestine
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infective and diagnostic stage of crypto
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oocyst
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only effective way to protect water against crypto
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filter
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naegleriasis
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naegleria fowleri, PAM is most severe form, trophs seen in CSF or brain tissue
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trichomoniasis
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ranges from asymptomatic to vaginitis with profuse foul discharge
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pregnant women dont wat to get toxoplasmosis because
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fetus could be at risk for brain damage due to hydrocephaly
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multiple presentations of leishmaniasis
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kala-azar (visceral leishmaniasis)
oriental sore (cutaneous) espundia (mucosal) |
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more severe form of sleeping sickness
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caused by trypanosoma bucei rhodesiense
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flu like symptoms of babesia include
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muscle aches and malaise
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