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56 Cards in this Set
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Rhinoviruses
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(RNA virus; picornavirus; SS + linear; icosahedral; no envelope)
1. Acid-labile • Gastric acidity kills the virus 2. Over 100 serotypes • Vaccine is unlikely 3. Transmission a. RESPIRATORY droplets are deposited onto surfaces and fingers transport the virus to the eyes and nose #1 way to PREVENT COLD Importance of washing the hands b. Person-to-person via aerosol of respiratory droplets 4. MCC OF THE COMMON COLD |
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coxsackie virus
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(RNA virus; picornavirus; SS + linear; icosahedral; no envelope)
• Primarily fecal-oral 2. Herpangina a. Fever, pharyngitis b. Pharynx/soft palate have vesicles/ulcers surrounded by erythema PAINFUL ULCERS c. Tender cervical adenopathy 3. Hand-foot-mouth disease a. Febrile disease that primarily occurs in young children b. Vesicular rash on hands, feet, and in the mouth a. MCC of MYOCARDITIS AND PERICARDITIS, inc CK/MB troponins; do PCR b. Fever, chest pain with friction rub ; Relieved by leaning forward; signs of congestive heart failure c. Myocardial biopsy • Demonstrates muscle necrosis and a lymphocytic infiltrate d. May progress to congestive (dilated) cardiomyopathy 5. Type 1 diabetes mellitus ***In HLA DR3/DR4 patients, it may infect and destroy the b-islet cells ("insulitis") leading to diabetes mellitus 6. Viral (aseptic) meningitis a. MCC of viral meningitis b. Mainly occurs in the summer 7. Pleurodynia (Bornholm's disease, acute chest syndrome) • Fever with pleuritic chest pain (infects pleura) |
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MCC of the common cold
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rhinovirus
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viruses causing the common cold
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rhino #1 • Coronaviruses, adenoviruses, influenza C virus, coxsackie viruses
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polio
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RNA virus; picornavirus; SS + linear; icosahedral; no envelope)
1. Infection most often occurs in summer months; Fecal-oral route 3. Replicates in neurons of ANT HORN CELL DESTRUCTION 4. Many also infect neurons in brain stem, Bulbar poliomyelitis with respiratory paralysis 5. Infections- Mild to non-paralytic to paralytic 6. Post-polio syndrome a. Occurs years after acute illness, b. Deterioration of residual function of previously affected muscles , c. Cause of deterioration unknown 7. Live, attenuated vaccine (Sabin) and killed vaccine (SALK-KILLED)-a. Give killed vaccine to children in the following circumstances: ****(1) Non-immunized patients are in the family (e.g., elderly); (2) Patient is immunocompromised (e.g., HIV positive); b. Live vaccine currently preferred (1) Strongly induces secretory IgA and IgA in the GI tract , • Not true of SALK , (2) Danger that attenuated virus may become more virulent , • Danger of infecting immunocompromised patients |
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SARS
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(RNA virus; coronavirus; SS + linear; helical; enveloped)
1. Infects lower respiratory tract and then spreads systemically 2. First transmitted to humans through contact with masked palm CIVETS (China) and then from human-to-human contact through respiratory secretions (e.g., hospitals, families). 3. One-third of patients improve and the infection resolves • Others develop severe respiratory infection and nearly 10% die. 4. ***Diagnose with viral detection by PCR or detection of antibodies |
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influenza
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(RNA virus; orthomyxovirus; SS – linear; helical; enveloped)
a. HEMAGGLUTININS bind to cell surface receptors (neuraminic acid and sialic acid) to initiate infection b. NEURAMIDASE dissolves mucus and releases virus from infected cells c. Antigen shifts -(1) Major mutation in hemagglutinins or neuraminidase by rearrangement of RNA segments; (2) Requires a new vaccine; d. Antigen drifts (1) Minor mutations (2) Does not require a new vaccine e. Transmission-(1) Airborne respiratory droplets (2) Primarily occurs in winter months 2. Influenza a. Influenza A-• Responsible for worldwide epidemics (pandemics) b. Influenza B-• Causes major outbreaks c. Influenza C-• Mild respiratory infections d. Fever, headache, retroorbital pain, myalgias, pneumonia e. Association with Reye syndrome if aspirin is taken f. ****Mortality often due to superinfection of Staphylococcus aureus of a pre-existing influenza pneumonia g. Zanamivir, oseltamivir -(1) Neuraminidase inhibitors that prevent the release of viruses from infected cells (2) Amantadine and rimantadine are no longer recommended due to high levels of resistance h. Vaccination (1) Killed, egg-based vaccine against influenza A and B (2) Vaccine has weak antigenicity (3) Vaccinate people > 65 yrs old and people with chronic diseases (lung, liver, respiratory) (4) Increased incidence of Guillain-Barre syndrome*** |
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MCC of viral meningitis
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cocksackie virus
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MCC of myocarditis and pericarditis
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cocksackie virus
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RSV
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MCC of pneumonia and bronchiolitis (wheezing) in infants
2. Hand washing and use of gloves prevents nosocomial outbreaks in nurseries 3. Fusion protein causes cells to fuse producing multinucleated giant cells 4. Causes otitis media in older children 5. Infections primarily occur in winter 6. Rapid diagnosis by detection of antigen in nasopharyngeal wash 7. Rx: use of ribavirin has no proven beneficial effect 8. Passive immunization: palivizumab (monoclonal antibody) reduces hospitalization rates between November and April |
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MCC of pneumonia and chronchiolitis (wheezing in infants)
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RSV
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parainfluenza
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(RNA virus; paramyxovirus; SS – linear; helical; enveloped)
BRONCHIOLITIS IN INFANTS, INSPIRATORY STRIDER (also HI), STEEPLE SIGN; CAUSE OF COMMON COLD IN ADULTS a. Multinucleated giant cells in respiratory epithelium • Hallmark of viral fusion protein b. Wheezing 2. Croup (laryngotracheobronchitis) a. Major cause of croup b. Occurs in 3 mth to 5 year age bracket c. Fever, brassy cough, intermittent inspiratory stridor, and signs of respiratory distress d. Anterior x-rays of the neck (1) Tracheal narrowing (site of obstruction) from swelling of the tissue (2) Called "steeple sign" e. Cold water humidifiers and aerosolized racemic epinephrine are recommended f. Differential for inspiratory stridor includes • Croup, acute epiglottitis (H. influenzae), foreign body 3. Cause of common cold in adults |
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mumps
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(RNA virus; paramyxovirus; SS – linear; helical; enveloped)
INC AMYLASE NORMAL LIPASE (PANCREATIS NORMALLY INC LIPASE); DEC GLUCOSE, T1DM, MENINGOENCEPHALITIS 1. Bilateral parotitis -• Increased amylase, normal lipase 2. Unilateral orchitis 3. Infertility uncommon, unless it is bilateral 4. Meningoencephalitis a. Common complication • Self-limited b. CSF findings • Mononuclear cells, increased protein, decreased glucose (unusual for a virus) 5. Oophoritis (abdominal pain) 6. Pancreatitis (pain radiates into back) 7. Type 1 diabetes mellitus in HLA Dr3/Dr4 individuals 8. Live attenuated vaccine • Measles/mumps/rubella |
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rubeola
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RNA virus; paramyxovirus; SS – linear; helical; enveloped)
NOT TERATOGENEIC, 3C'S COUGH CORYZA CONJUNCTIVITY; KOPLIK'S SPOTS THEN RASH CENTRIFUGAL; GIANT CELL-WARTHIN-FINKELDEY MULTINUCLEATED GIANT CELLS; ACUTE APPENDICITIS IN CHILDRREN FROM MMR VACCINE OR POST VIRAL INFECTION 1. RNA paramyxovirus 2. Vaccination has reduced the incidence of rubeola 3. Prodrome • Fever, cough, coryza (runny nose), conjunctivitis 4. Koplik spots develop on the buccal mucosa. • Koplik spots white spots overlying an erythematous base 5. Maculopapular rash develops after Koplik spots disappears a. Cytotoxic T cell damage of endothelial cells containing the virus b. Typically begins on the head and then to the trunk and extremities c. Tends to become confluent on face and trunk but discrete on extremities 6. Complications a. Giant cell pneumonia • Warthin-Finkeldey multinucleated giant cells b. Acute appendicitis in children c. Otitis media d. Encephalitis • Before immunization, it was a common cause of death in measles e. Not teratogenic f. Prevented through vaccinations (1) Live, attenuated vaccine (2) Usually mixed with mumps and rubella (MMR) (3) Usually given at 15 months of age (4) If given before, IgG antibodies from mother can neutralize the virus regular measles |
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rubella
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german measles, 3 day measles
RNA virus; togavirus; SS + linear; icosahedral; enveloped) rash 3 days cephalocaudal NOT confluent, PAINFUL POSTAURICULAR LAD, POLYARTHRITIS IN ADULTS; TORCH-PDA, SENSORINEURAL HEARING LOSS 1. Transmission a. Respiratory droplets b. Vertical transmission (transplacental) 2. Vaccination has reduced incidence 3. Incubation 14-21 days • Initial site of infection is nasopharynx 4. Prodrome • Fever, malaise 5. Maculopapular rash lasts 3 days a. Pinkish, red maculopapular eruption b. Begins first at hairline and rapidly spreads cephalocaudally. c. Unlike rubeola, the macules and papules are discrete and do not become confluent d. Fades in 3 days 6. Painful postauricular adenopathy • Characteristic finding 7. Polyarthritis (immunocomplex) common in adults not children 8. Congenital rubella a. Neonatal disease more severe if contracted in first trimester • Embryonic phase of development b. Patent ductus arteriosus c. Cataracts d. Mental retardation e. Sensorineural hearing loss • MC complication f. Neonates shed virus for months • Newborns must be isolated 9. Prevent through vaccination |
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infections assoc w/ T1DM
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cocksackie and mumps
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POST auricular LAD
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rubella
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preauricular LAD
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adenovirus conjunctivitis
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rabies
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ACH RECEPTOR, AXONAL TRANSPORT, PARESTHESIAS, HYDROPHOBIA, ENCEPHALITIS, NEGRI BODIES IN PURKINJE CELL
Raccoon MCC in United States; • Raccoon > bats > skunks (midwest); c. Dog MCC in WW; d. Bats another common cause (aerosolized in saliva) 2. Viral receptor is Ach Rc a. Initially replicates at site of the bite b. Moves by axonal transport to the CNS c. After CNS replication, it migrates to the saliva d. Animal transmits virus when in the agitated state (encephalitis stage) 3. Incubation period 2 weeks to months 4. Prodrome • Fever, paresthesias in and around the wound site 5. Hydrophobia a. Due to spasms of throat muscles when swallowing b. Followed by flaccid paralysis 6. Encephalitis a. Death of neurons b. Eosinophilic intracytoplasmic inclusions called Negri bodies c. Seizures, coma, death 7. Rx a. Wash wound site (quaternary ammonium compound) b. Give passive immunization (immune globulin) mostly into wound site (where virus initially replicates) c. Give active immunization (human diploid vaccine) RNA virus; rhabdovirus; SS – linear; helical; enveloped) |
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LCV
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MOUSE URINE, MENINGOENCEPHALITIS
slum areas • Food or water contaminated with mouse urine/feces 2. Meningoencephalitis a. Combination of nuchal rigidity and mental status abnormalities (encephalitis) b. Permanent neurological damage in > 25% with encephalitis c. CSF findings • Increased protein, lymphocyte infiltrate, normal to decreased glucose (RNA virus; arenavirus; SS – circular; helical; enveloped) |
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hantavirus
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RNA virus; bunyavirus; SS – circular; helical; enveloped)
1. Transmission • Rodents (inhalation of urine/feces of deer mice) in Southwestern United States 2. Hantavirus pulmonary syndrome a. ARDS, hemorrhage, renal failure b. Laboratory • Viral RNA in lung tissue (PCR test) c. High mortality d. Rx • Ribavirin has been used but with questionable effectiveness |
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eastern equine virus
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arbovirus!!! WORST encephaltis
RNA virus; togavirus; SS + linear; icosahedral; enveloped) (1) Transmission by mosquito (2) Reservoir of virus (a) Wild-birds (b) Humans and horses are dead end hosts (3) Most severe encephalitis |
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western equine virus
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arbovirus encephaltis
RNA virus; togavirus; SS + linear; icosahedral; enveloped) (1) Transmission by mosquito (2) Reservoir of virus (a) Wild-birds (b) Humans and horses are dead end hosts |
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st louis virus
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arbovirus, encephaltis
(RNA virus; flavivirus; SS + linear; icosahedral; enveloped) (1) Transmission by mosquito (2) Reservoir of virus (a) Wild-birds (especially English sparrows) (b) Humans are dead end hosts |
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yellow fever virus
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arbovirus, fulminant hepatitis; COUNCILMAN BODIES, zone 2 hepatitis, RF
(RNA virus; flavivirus; SS + linear; icosahedral; enveloped) (1) Transmission by Aedes aegypti mosquitoes (2) Reservoir monkeys (3) Responsible for many deaths in construction of the Panama canal (4) Jaundice • Midzonal hepatic necrosis ("Councilman bodies", apoptosis of hepatocytes) (5) Renal failure® upper GI hemorrhage and shock leading to death (6) Live attenuated vaccine available |
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dengue virus
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arbovirus,
(RNA virus; flavivirus; SS + linear; icosahedral; enveloped) (1) Transmission by Aedes aegypti mosquitoes (2) Reservoir monkeys (3) Dengue hemorrhagic fever • Common cause of fatality to U.S. troops in Southeast Asia (4) Classic dengue (breakbone fever) (a) Initial influenza-like syndrome® (b) Severe muscle and joint pains® (c) Lymphadenopathy, rash, leukopenia (d) Usually recover |
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colorado tick fever virus
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arbovirus
(RNA virus; reovirus; DS linear; icosahedral; no envelope) (1) Transmission • Wood tick Dermacentor andersoni (same vector as RMSF), which feeds on rodents (reservoir) (2) Biphasic fever pattern (a) Fever for 24 hrs® no fever for 2-3 days® fever 2-4 days and subsides (b) This fever pattern is not present in RMSF (3) Encephalitis, retroorbital pain, severe myalgia, ~10% have a rash (similar to RMSF) |
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west nile virus
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arbovirus; TQ, MC CROWS
(RNA virus; flavivirus; SS + linear; icosahedral; enveloped) (1) Transmission by mosquitoes (2) Reservoir birds (a) Crows and other birds are spreading the disease from New York to the west coast (b) Crows and other birds often die from the disease (3) Encephalitis can be fatal |
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rotavirus
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(RNA virus; reovirus; DS linear; icosahedral; no envelope)
1. Transmission • Fecal-oral 2. Gastroenteritis a. *****MCC of diarrhea in children during winter months b. Damages ion transport pump in small intestinal cells c. **Secretory diarrhea with absence of blood and inflammation d. **Rotazyme test (ELISA) of stool • Detects virus in stool e. Pedialyte replacement • Hypotonic salt solution f. Live, oral attenuated vaccine highly effective in preventing infection • Small risk for INTUSSCEPTION RISK (causes hyperplasia of Peyer's patches) dance's sign --oblong mass; |
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norwalk virus
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(RNA virus; calicivirus; SS + linear; icosahedral; no envelope)
DRUGS AGINST PREOTEASE AND REV TRANSCRIPTSE 1. Transmission a. Fecal-oral b. Often afflicts people on cruise ships 2. Gastroenteritis a. MCC of gastroenteritis in adults • Uncommon in children b. Nausea, vomiting, diarrhea that resolves in 12-24 hrs • Occasionally can be fatal |
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retroviruses in general
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(RNA virus; retrovirus; SS + linear; icosahedral; enveloped)
HIV-1 MC in US, 2-developing countries, HTLV reverse transcritpase, integrated; CD4 T HIV IS CYTOLYTIC HTLV IS NOT |
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HIV
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attaches to gp120 to cd4 cells-->lose CMi
env gp120/41; pol-reverse trancriptase/integrase; gag-p24 (viral load biphasic) blood, semen, breat milk has HIV can not enter intact skin mucosa; MC acquired ID ww; >75% STD, IVDA 2nd MCC acute HIV-mononculeosis like 3-6 wks; latent >500, in follicular dnedritic cells (resecroir in sinuses of LN; also macs 2-10 years early symptomatic 200-500, gen LAD, hairy leukoplaskia EBV, ral candida, shuingles not neoplastic AIDS <200, P. jiroveic MC, systemic candida, burkitt's EBV, primary CNS lymphoma EBV kaposi's HHV-8; cervica SCC lungs MC involved; kidneys focal segmental glomerulosclerosis; AIDS-dementia multinuc giant cells; crytococcus, cMV retintis, toxopalsmsoois elisa gp120; west- gp120or 160; p24 and gp41; HIV viral lod PCR pregnant women w/ AIDS place on azidothyrmidien reverse transcritase inhibitor AZT SALK, HBV, influenza vaccine, Hib, pneumococca, MMR (only liver permitted) tx w/ rev transcriptase inhibitors and protease inhibitors |
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HTLV
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(RNA virus; retrovirus; SS + linear; icosahedral; enveloped)
a. Transmission • Same as HIV except for transplacental disease b. HTLV leukemia/lymphoma (1) Infects CD4 T helper cells (2) TAX protein product enhances IL-2 (T cell growth factor) causing uncontrolled growth leading to cancer (3) Lymphadenopathy, hepatosplenomegaly, lytic bone lesions (hypercalcemia), skin invasion (4) ELISA tests, Western blot assay, PCR to detect RNA or DNA are available |
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MCC diarrhea in children
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rotavirus, secretory
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MCC of gastroenteritis in adults
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norwalk virus
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ebola
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virus (RNA virus; filovirus; SS - linear; helical; enveloped)
1. Transmission • Usually from secondary transmission in the hospital from patient blood or secretions 2. Named after a river in Zaire 3. Hemorrhagic fever a. Hemorrhagic fever b. DIC, shock, hemorrhage from severe thrombocytopenia c. Mortality almost 100% |
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herpes virus in general
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Characteristics
a. Viruses (1) HSV-1 and -2: giant cells produced (2) Varicella-zoster virus: giant cells produced (3) Epstein Barr virus (EBV) (4) Cytomegalovirus (CMV): giant cells produced (5) Human herpesvirus 6 (HHV) 6 (6) HHV 8 (Kaposi's sarcoma-associated herpesvirus) b. Latency site for Varicella-zoster • Cranial or thoracic sensory ganglia c. Latency site for EBV • B lymphocytes d. Latency site for CMV • ? Circulating lymphocytes and/or epithelial cells e. Latency site for HHV 6 • T and B cells f. Latency site for HHV 8 • Uncertain g. Latency site for HSV-1 and -2 (1) HSV-1 in cranial sensory ganglia (e.g., trigeminal nerve) (2) HSV-2 in lumbar or sacral sensory ganglia |
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HSV-1
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(DNA virus; herpesvirus [HHV-1]; DS – linear; enveloped)
a. Transmission (1) Saliva or direct contact with virus in vesicle (2) CMI important in limiting the virus b. Keratoconjunctivitis with corneal ulcers (1) Dendritic (root-like) ulcers noted with fluorescein staining (2) Recurrences may lead to permanent scarring (3) Rx with trifluridine eye drops c. Gingivostomatitis (1) Usually occurs in children < 5 yrs old (2) Primary (first) infection (3) Systemic signs of fever and painful cervical lymphadenopathy (4) Painful vesicles usually develop on the lips, gingiva, oropharyngeal mucosa (5) Rx: acyclovir d. Herpes labialis (fever blisters, cold sores) (1) Recurrent HSV (2) Nonsystemic and involves mucocutaneous junction of the lips/nose: recurs in the same site (3) Reactivated by stress, sunlight, menses (4) Tzanck prep • Multinucleated squamous cell with red intranuclear inclusions (5) Rx: acyclovir e. Encephalitis (1) Hemorrhagic necrosis of temporal lobes (2) PCR of spinal fluid detects HSV-1 DNA (3) Rx: acyclovir f. Herpetic whitlow (1) Traumatic implantation of the virus into the finger or hand (2) Painful pustular lesion (3) Commonly occurs in dentists g. Disseminated infection in immunocompromised patients • Esophagus, lungs h. Kaposi's varicelliform eruption • HSV 1 infection superimposed on a previous dermatitis, usually in an immunodeficient person i. Bell’s palsy • Rx: no Rx or acyclovir with or without prednisone |
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HSV-2
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(DNA virus; herpesvirus [HHV-2]; DS – linear; enveloped)
a. Transmission (1) Sexual contact (2) Vertical transmission (contact with secretions containing virus) (3) Cell mediated immunity important in limiting the virus b. Genital herpes (1) Locations • Penis, vulva, vagina, cervix (erosive cervicitis), anus (proctitis, common in homosexuals) (2) Vesicles heal within 3 wks and may recur every 4-6 wks • Called recurrent herpes (3) Rx: acyclovir (others- famciclovir, valacyclovir) (a) Shortens the duration and reduces the extent of shedding of the virus (not a cure) (b) Rx for initial infection and recurrences c. Infection during pregnancy (1) Viral shedding may occur without visible lesions (2) In the presence of viral shedding, babies must be delivered by Cesarean section d. Neonatal herpes (1) Contracted by contact of the baby with genital secretions within the vaginal vault (vertical transmission) (2) ~3 to 10% of newborns actually contract neonatal herpes when exposed to the virus • Greater chance with primary infection (3) Vesicular lesions appear within 2-10 days after birth (4) Local (eyes, mouth, conjunctiva) or disseminated disease involving any organ in the body (5) If left untreated, ~70% will develop disseminated disease or encephalitis and 70% of these will die or suffer permanent neurologic sequelae e. Viral meningitis • Mild, self-limited disease, unlike encephalitis |
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EBV
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(DNA virus; herpesvirus [HHV-4]; DS – linear; enveloped)
a. Infectious mononucleosis (1) Transmission by saliva (2) Infects B cells via CD21 receptor • Remains latent in B cells (3) Malaise, exudative pharyngitis, painful generalized adenopathy, hepatosplenomegaly (4) Ampicillin induces a rash (5) Laboratory findings (a) Atypical lymphocytosis • Usually more than 20% of the total WBC count • Atypical lymphocytes are antigenically stimulated T cells (b) Positive heterophil antibody test • Initial screening test • Detects IgM antibodies against horse (most common), sheep, and bovine RBCs • Sensitivity 87%, specificity 91% (c) Antiviral capsid antigen (VCA) • High sensitivity and specificity • Develops early in the infection • Persists for life (d) Anti-early antigen (EA) • Increased with chronic infections (e) Anti-Epstein Barr nuclear antigen (EBNA) • High sensitivity and specificity • Develops late in the infection • Persists for life (f) Increased transaminases (g) Total bilirubin usually normal (h) Anti-i cold autoimmune hemolytic anemia b. Burkitt's lymphoma (1) B cell lymphoma with t(8;14) (2) Involves paraortic lymph nodes in children (jaw in Africa) c. Nasopharyngeal carcinoma d. Hairy leukoplakia • Glossitis of tongue in pre-AIDS e. Primary CNS lymphoma in AIDS f. Mixed cellularity Hodgkin's lymphoma |
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CMV
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DNA virus; herpesvirus [HHV-5]; DS – linear; enveloped)
a. Transmission (1) Vertical • Transplacental (MC), cervical secretions, or breast milk (2) Saliva • MC method in children (3) Sexual • Semen and cervical secretions (4) Blood transfusions • MC infection transmitted by blood transfusion (5) Transplantation • Particularly kidney and bone marrow transplants b. Enlarged cells with prominent basophilic intranuclear inclusions ("owl eyes") (1) Cells are hypertrophied (2) Multinucleated giant cells may be present c. Laboratory (1) Urine is the best culture medium (2) MC overall antibody in the United States d. Heterophile negative mononucleosis (1) Unlike infectious mononucleosis (a) No pharyngitis (b) No cervical adenopathy (c) No positive heterophile antibody test (2) Similar to infectious mononucleosis (a) Atypical lymphocytosis (b) Splenomegaly (c) Fever, lethargy e. Systemic infections in immunocompromised patients (1) Bone marrow transplants • CMV pneumonitis has an 85% mortality (2) AIDS patients when CD4 T helper count is < 50 cells/mm3 (a) Colon (MC site) • Diarrhea • Rx options: ganciclovir; foscarnet; valganciclovir (b) Esophagus • Odynophagia • Rx options: ganciclovir; foscarnet; valganciclovir (c) Biliary tract • MCC cholecystitis (d) Pancreas • MCC pancreatitis (e) CMV retinitis • MCC of blindness in AIDS • Rx options: ganciclovir; foscarnet f. Congenital infection (1) MC in-utero viral infection (2) Part of the TORCH complex (3) Majority are asymptomatic: 8590% (4) Transmission • Primarily transplacental (5) Bilateral sensorineural hearing loss MC complication (6) Psychomotor retardation (7) Periventricular calcification (8) Rx of congenital CMV • Ganciclovir is the first choice, foscarnet, if ganciclovir does not work |
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HHV-6
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(DNA virus; herpesvirus [HHV-6]; DS – linear; enveloped)
a. Cause of roseola (exanthem subitum) b. High fever, febrile convulsions, fever subsides and rash occurs c. White ring around red spots is a characteristic finding |
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HHV-8
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Cause of Kaposi’s sarcoma in AIDS
• Protein produced inactivates RB suppressor gene b. Transmitted sexually or by transplantation (e.g., kidney) c. Infects B cells and produces a malignant lymphoma |
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VZV
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(DNA virus; herpesvirus [HHV-3]; DS – linear; enveloped)
a. Varicella (chickenpox) (1) Vesicles at different stages of development • Papules to vesicles to pustules to crusted lesions (2) Positive Tzanck prep with multinucleated squamous cells containing eosinophilic inclusions (3) Self-limited cerebellitis • Ataxia, vertigo, nystagmus (4) Pneumonia • Can be very severe (5) Association with Reye syndrome if patient takes aspiring (6) Vaccine (a) Live, attenuated (b) One dose for children 1-12 yrs old (7) Rx adolescents, young adults only: acyclovir b. Varicella zoster (shingles) (1) Latent in cranial (trigeminal nerve distribution, outer ear for VIII) or thoracic sensory ganglia (2) Painful vesicular rash follows sensory dermatomes (3) Rx: valacyclovir, famciclovir, or acyclovir with or without prednisone |
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adenovirus
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(DNA virus; DS – linear; no envelope)
1. Transmission • Fecal-oral, respiratory droplet, direct inoculation 2. Pharyngoconjunctival fever • Painful preauricular nodes ("viral pink-eye") 3. MC viral cause of hemorrhagic cystitis 4. Gastroenteritis in children < 2 yrs old • Commonly preceding infection that precipitates acute appendicitis 5. Pneumonia in children and young adults • Rx in severe pneumonia cidofovir |
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papilloma virus
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DNA virus; herpesvirus [HHV-1]; DS – circular; no envelope)
1. Transmission • Sexual, skin to skin contact 2. Carcinogenesis of papillomaviruses (in papovavirus family) related to gene products E6 and E7 a. E6 gene product inactivates the TP53 suppressor gene b. E7 gene product inactivates the RB suppressor gene 3. Infect squamous epithelium and produce koilocytosis • Vacuolated cells with pyknotic nuclei 4. Condyloma acuminata a. Venereal warts (most common STD) • HPV 6, 11 b. Located in moist areas in the anogenital region and on the cervix • Fern-like appearance c. Usually flat on the cervix d. Confused with condyloma latum in secondary syphilis • Same location, but usually flat rather than fern-like e. Rx options • Topical podophyllin, a-interferon 2b injection, topical imiquimod (Aldara) cream f. Vaccine available 6. Squamous cell carcinoma a. HPV types 16 (MC), 18 b. MCC of squamous cancer of vulva, vagina, cervix c. Penis d. Anus in homosexuals e. New vaccine decreases risk for cancer (tumor vaccine) 7. Common warts • Verruca vulgaris |
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papovavirus
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JC virus
) (DNA virus; polyomavirus; DS – circular; no envelope) 1. Conventional slow virus encephalitis • JC virus infects oligodendrocytes 2. Causes progressive multifocal leukoencephalopathy (PML) a. Fatal demyelinating disease b. Primarily occurs in immunocompromised host (e.g., AIDS) c. Diagnosis • PCR assay of spinal fluid or brain tissue |
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poxvirus
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DNA virus [largest DNA virus]; DS – linear; enveloped)
1. Smallpox (variola) a. Only disease that has been eradicated from the earth (1) Eradication is due to vaccination (2) Potential use for terrorism b. Transmission (1) Respiratory droplet, fomites, person-to-person (2) Incubation 7-17 days c. Unlike varicella (chickenpox) the vesicles are well synchronized (same stage of development) • Vesicles develop into pustules, which rupture and produce scabs d. Vesicles cover the skin and mucous membranes • Palms and soles involved (not true of varicella) e. Vesicles rupture and leave pock marks with permanent scarring 2. Vaccinia a. Iatrogenic disease produced by the inoculation of poxvirus into the skin to induce immunity against smallpox b. Generalized vaccinia occurs in immunodeficient patients or in those with preexisting skin lesions (e.g. eczema) 3. Molluscum contagiosum a. Transmission • Personal contact with lesions, common in children and immunosuppressed people b. Nodular lesions with umbilicated centers containing granular material (molluscum bodies) c. Lesions spontaneously resolve after a few months |
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parvovirus
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B19
) (DNA virus [smallest DNA virus]; SS – linear; no envelope) 1. Transmission • Respiratory, vertical (transplacental) 2. Erythema infectiosum (fifth disease) a. Infects endothelial cells; also forms immunocomplexes with IgG or IgM b. Bright red rash on the face "slapped face appearance" c. Rash on body, runny nose, mild fever d. Arthritis (1) Complication that is more common with female adults than children (2) Immunocomplexes of virus with IgG or IgM 3. Aplastic anemia and pure RBC aplasia a. Complicates chronic hemolytic anemias (sickle cell disease, hereditary spherocytosis) b. Replicates in stem cells not mature cells c. Intranuclear inclusions d. Rx: intravenous immunoglobulin 4. Pregnant woman a. Infection during first trimester may result in a spontaneous abortion b. Infection during second trimester produces hydrops fetalis (severe hemolytic anemia leading to heart failure) |
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HAV
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f/o, food/feces, child care, traveler's hepatitis, vaccine; antiIgM active; IgG inactive protective
A-asymp, acute, alone (no carrers) picornavirus No carrier state or chronic hepatitis Virus is not cytolytic; cytotoxic T cells kill infected cells Children are the most affected group Common in day care centers, eating raw oysters, travelers to developing countries, jails, male homosexuals Anti-HAV-IgM indicates active infection. (2) Anti-HAV-IgG indicates recovery from infection or vaccination (protective antibody). (3) Vaccine (a) Active immunization (b) Inactivated HAV (c) Recommended for travelers to foreign countries and children attending day care centers (4) Immune serum globulin: passive immunization Anti-HAV-IgM indicates active infection. (2) Anti-HAV-IgG indicates recovery from infection or vaccination (protective antibody). (3) Vaccine (a) Active immunization (b) Inactivated HAV (c) Recommended for travelers to foreign countries and children attending day care centers (4) Immune serum globulin: passive immunization MC hepatitis to present with jaundice Second most common hepatitis |
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HBV
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Transmission parenteral, sexual, vertical (blood contamination, breast feeding)
Most common hepatitis in United States Carrier state; chronic hepatitis (10% if immunocompetent) Serum sickness prodrome (5-10%): vasculitis (polyarteritis nodosa), polyarthritis, membranous glomerulopathy Rx: a-interferon used for treatment; reverse transcriptase inhibitors useful Most common infection post-accidental needle stick Increased incidence of hepatocellular carcinoma (postnecrotic cirrhosis precursor lesion) (1) Hepatitis B surface antigen (HBsAg) (a) Appears within 2–8 weeks • First marker of infection (b) Persists up to 4 months in acute hepatitis and greater than 6 months in chronic HBV (2) Hepatitis B e antigen (HBeAg) and HBV-DNA (a) Infective particles • Appear after HBsAg and disappear before HBsAg. (b) If present greater than 6 months in conjunction with HBsAg indicates an infective chronic carrier. (3) Anti-HBV core antibody IgM (anti-HBc-IgM) (a) Nonprotective antibody • Remains positive for maximum of 6 months before conversion to anti-HBc-IgG (b) Persists during "window phase" or "serologic gap" when HBsAg, HBV DNA, and HBeAg are absent (4) Anti-HBV surface antibody (anti-HBs) (a) Protective antibody (b) Only marker of immunization after HBV vaccination (5) Chronic HBV (a) Persistence of HBsAg greater than 6 months (b) "Healthy chronic carrier" • Presence of HBsAg and anti-HBc-IgG but absence of infective particles (DNA and e antigen) (c) Infective chronic carrier • Presence of HBsAg and infective particles (DNA and e antigen) and anti-HBc-IgG • Increased risk for development of cirrhosis and hepatocellular carcinoma • Rx options: adefovir; entecavir; interferon alfa-2b; lamivudine (6) Vaccine (a) Active immunization (b) Recombinant DNA (c) All newborns and adolescents, health care personnel, IV drug abusers, patients receiving multiple transfusions (d) Benefits of vaccination • Decrease risk for developing hepatitis B and D • Decrease risk for developing hepatocellular carcinoma (tumor vaccine) (7) Hyperimmune globulin (a) Passive immunization • Contains surface antibody (b) Accidental needle stick from patient with HBsAg positive blood or newborn born to HBsAg positive woman • Should receive vaccine and hyperimmune globulin at different sites |
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HCV
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• Transmission parenteral, ? sexual
Carrier state; chronic hepatitis (> 70%) Virus is not cytolytic; cytotoxic T cells kill infected cells Least likely viral hepatitis to develop jaundice Associated with post-transfusion hepatitis (uncommon now due to nuclear testing), type I membranoproliferative glomerulonephritis, alcohol excess, mixed cryoglobulinemia, postnecrotic cirrhosis (MC indication for liver transplant in United States) Increased incidence of hepatocellular carcinoma (incidence increases if alcohol excess also present; postnecrotic cirrhosis precursor lesion) (1) ELISA test does not distinguish IgG from IgM antibodies or whether the disease is acute, chronic, or resolved (2) No protective antibodies (3) Recombinant immunoblot assay (RIBA) is ordered if ELISA test is positive (4) Positive RIBA • Order PCR to detect viral RNA (5) Rx options for chronic HCV: • Either alfa 2a or 2b; ribavirin |
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HDV
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parenteral sexual
Carrier state; chronic hepatitis: less likely with coinfection (HBV + HDV at same time) than superinfection (HBV first, then HDV) Defective virus that requires hepatitis B surface antigen to replicate HDV is cytolytic and kills all hepatocytes containing HBsAg (fulminant hepatitis); some infected cells killed by cytotoxic T cells. Rx: a-interferon Presence of anti-HDV-IgM indicates active infection (2) No protective antibodies (3) Delta antigen (internal core protein of RNA genome) assay |
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HEV
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f/o waterborne
No carrier state or chronic hepatitis; occurs in developing countries (Asia, Africa, India, Mexico) (1) Presence of anti-HEV-IgM indicates active infection (2) Anti-HEV-IgG indicates recovery (protective antibody) Z. |
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HGV
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parenteral
Role in producing liver disease is under investigation |
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creutzfeldt jacob disease
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Due to prions (contain infectious proteins devoid of RNA or DNA).
a. Infective prions have misfolded proteins b. Cannot be killed with standard sterilization techniques c. Kill neurons (? apoptosis), produce spongiform change (unknown mechanism) 2. Transmission a. Corneal transplantation b. Contact with human brains (neurosurgeons, neuropathologist) c. Use of improperly sterilized cortical electrodes d. Ingestion of tissues from cattle with bovine spongiform encephalopathy ("mad cow" disease) 3. Brains have "bubble and holes" spongiform change in the cerebral cortex 4. Death occurs within 1 year |
