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75 Cards in this Set
- Front
- Back
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Caspids
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Icosahedral symmetry caspids: Many polypeptide chains come together for form protein subunit called capsomer. Capsomers form equilateral triangles, put 20 triangles together to form icosahedron.
Helical symmetry caspids: Capsomers are bound to RNA (always RNA b/c only RNA viruses are helical) & coiled into helical nucleoprotein caspid. Most assume spherical shape except Rhabdovirus that assumes bullet shape. |
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DNA Viruses, characteristics & rules
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HHAPPPy
Herpes Hepadna Adeno Parvo Papova Pox Most are double stranded, Icosahedral & replicate in Nucleus 2 exceptions 1) Parvoviridae is single strand DNA 2) Pox has complicated dsDNA coding hundreds of proteins & not icosahedral capsid but Pox. Also, POX in a BOX replicates in cytoplasm Parvo, Adeno & Papova are naked |
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RNA viruses
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Most are single stranded, eveloped, show helical capsid symmetry, & replicate in cytoplasm
Exceptions: 1) Reoviridae are doule stranded 2) Three non enveloped Picorna, Calici, & Reoviridae 3) Six do not have helical symmetry: Picorna, Calici, Reo, Toga, Flavi are icosahedral while Rhabdo is bullet shape. 4) Picorna, Calici, Toga, Flavi, Corona, Retro are +RNA 5) Orthomyxo & Retro replicate in nucleus |
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4 steps of viral reproduction
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1) Adsorption & penetration
2) Uncoating of virus 3) Synthesis of viral products & inhibition of host cell synthesis of products 4) Release of virions from host cell by lysis or budding |
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Adsorption & Penetration
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Viral particle binds to host cell membrane & instead of injecting DNA like bacteriophage, Viruses are completely internalized, capsid & nucleic acid. Internalization via endocytosis or fusion of virion envelope with host cell membrane.
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Viral transcription, translation, & replication
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+ RNA must use host ribosomes to undergo transcription to make RNA dependent RNA polymerase & Structural proteins. + RNA makes - RNA then back to + RNA for assembly.
-RNA must carry viral RNA dependent RNA polymerase to make positive strand copy to translate into viral proteins. DNA viruses are complex & has phases Immediate early & early: transcribes proteins used for DNA replication & further transcription Late transcription: Transcribes mRNA encoding structural proteins |
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Viral assembly & Release
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Naked viruses exit via lysis or exocytosis
Enveloped viruses exit via budding through golgi, nuclear memb, or cytoplasmic membrane to tear off a piece of host lipid bilayer membrane. |
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Viral host cell outcome
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1) Cell Death
2) Transformation into cancer cell through oncogene activation 3) Latent infection - virus surviving in latent state 4) Chronic slow infection - cause disease after many years |
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2 viral families & their members that have similar structures & ability to adsorb to glycoprotein receptors on uper respiratory tract.
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Orthomyxovirus:
Influenza virus that Causes ORdinary flu Paramyxoviruses: PARAde of diseases Parainfluenza virus Respiratory syncytial virus Mumps Measles (Rubeola) |
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Orthomyxoviridae Virion structure & Pathogenesis
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Negative stranded RNA virus with 2 distinct glycoproteins: Hemagluttinin & Neuraminidase anchored by M protein
HA - Binds to host Sialic acid receptors present on surface of erythrocytes & upper respiratory cell membranes. Causes heme-agglutination & fusion with upper respiratory cells. Thus, HA is needed for adsorption. NA - Cleaves Neuraminic acid, a integral part of mucin, to expose sialic acid beneath for HA binding. Also cleaves sialic acid for new virions to be released. |
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Influenza epidemiology
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Has 3 types A,B,& C. A infects humans & mammals like birds & swine. B & C only infect humans.
Requires NA & HA to undergo antigenic drift to cause epidemics & antigenic shift to cause pandemics & infect people other than children who have never been exposed. |
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Influenza complications
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Lowers host defenses to expose to secondary bacterial infections like Staph A, Strep Pneumoniae, Haemophilus Influenza
Giving kids asprin for influenza or varicella can cause Severe brain & liver disease called Reye's syndrome. Don't give kids asprin, give tylenol. |
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Influenza treatment
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Grown in mass quantities in chick embryos & then inactivated, purified, & given as vaccines.
Live attenuated virus can be given as a nasal spray to people from 5-49. Called cold-adapted influenza vaccine-trivalent. (CAIV-T) |
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Paramyxoviridae organisms, structure, & general characteristics
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Parainfluenza, Respiratory Synctial virus, Mumps, Measles
Structure is similar to orthomyxoviridae except: 1) These (-) RNA viruses are single stranded rather than segmented 2) HA & NA are part of same glycoprotein spike 3) Possess fusion (F) protein to cause host cells to form multinucleated giant cells Think lungs - All adsorb to & replicate in upper respiratory tract. Parainfluenza & Respiratory synctial can cause lower respiratory infections(Pneumonia) in children & upper respiratory infections (Bad Colds) in adults. Think Kids - Most infections occur in children Think Viremia - Results in dissemination to distant sites after reproduction in upper respiratory tract. Mumps can infect parotid & testes, Measles can cause fever, Mumps & Measles can cause encephalitis. |
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Parainfluenza virus
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- Causes upper respiratory infection in adults ranging from rhinitis, pharyngitis, & sinus congestion
- Can cause pneumonia in kids, elderly & immunocompromised |
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Croup
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Parainfluenza infection of larynx & other upper respiratory structures in children. Swelling rpoduces stridor & barking cough.
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RSV
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Respiratory Synctial Virus
- Number 1 cause of pneumonia in children. - Has F protein that causes formation of multinucleated giant cells (Synctial cells) - Lacks both HA and NA |
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Mumps symptoms & vaccine
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Replicates in upper respiratory tract & regional lymph nodes to spread via blood to many organs especially parotid gland & testes
- Can result in meningitis & encephalitis - Vaccination with live attenuated virus via MMR. |
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Rubeola symptoms, Complications, & Vaccine
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aka Measles
- Highly contagious & has 10 day incubation before development of rash - Prodrome develops before rash & pt suffers from conjunctivitis, photophobia, high fevers, cough, rhinitis - Koplik spots develop a day or 2 before rash & present with small red based lesions with white & blue centers in mouth. -Maculopapular flat to slightly bumpy rash spreads from forehead down & hits feet by day 3. Then it clears also from forehead down by day 6. Complications - Can disseminate to many organ systems & damage lungs, eyes, heart, & encephalitis. - Measles during pregnancy has 20% chance of spontaneous abortion & premature delivery. - Subacute sclerosing panencephalitis(SSPE) - form of encephalitis caused by measles & follows many years after measles infection. Vaccinate via live attenuated measles virus in MMR. |
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The 6 hepatitis viruses & some characteristics
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RNA are ACDEG while DNA is B
- A and E are transmitted fecal oral while BCD are through parenteral contact |
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Viral Hepatitis
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Acute viral hepatitis Can be caused by all types. Sudden with mild to severe course followed by complete resolution. Begin with fever, fatigue, muscle/joint aches, cough, jaundice. Release of AST, ALT, GGT, & alkaline phosphatase which help establish diagnosis of hepatitis.
Chronic viral hepatitis can have prolonged course and caused by BCD the parenteral viruses. Hard to diagnose |
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HAV Family, Transmission, disease process, Serology, vaccination
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Part of the Picorna virus family, thus is Naked, Icosahedra, +ssRNA.
Transmitted via Fecal Oral route via poor hand washing, fecally contaminated drunking water, close contact like day care etc. - 15-40 day incubation followed by acute hepatitis. Young children frequently affected. - Will stimulate IgM & then IgG. IgG indicates old infection & no active disease. Antibodies last indefinitely. Inactivated Hepatitis A vaccine is recommended for adults at high risk of HAV infection. |
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HBV family, transmission, Structure, Disease process, Complications, Serology, Vaccine
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Hepadna virus - Double stranded circular DNA, Enveloped, Icosahedral
- Present in all human body fluids & transmitted parenterally - Intact HBV is called DANE particle that can be broken up to HBsAg which is composed of envelope & some caspids. HBcAg which is the viral core. While both are antigenic, only antibodies against HBsAg are protective. During active infection, soluble component of core is released as HBeAg & is marker for active disease in highly infectious state. Injuries are due to cell mediated immune attach on HBV. Can damage hepatocytes as well as skin, kidney & joint damage. Can cause: 1) Acute hepatitis 2) Fulminant acute hepatitis with severe rapid destruction of liver 3) Chronic hepatitis a) Asymptomatic carrier - never develop HBsAg & become asymptomatic carriers b) Chronic-persisitent hepatitis - low grade smoldering hepatitis c) Chronic active hepatits - Acute hepatitis state that continue without normal recovery 4) Coinfection with HDV Complications: Cirrhosis & Primary hepatocellular carcinoma Serology - HBsAg = active disease anti-HBsAg = Immune, cured IgM anti HBcAg = Acute IgG anti HBcAg = Chronic HBeAg = High infectivity anti - HBeAg = low infectivity Vaccinate via recombinant vaccine. gene coding for HBsAg is cloned in yeast & used to produce mass quantities of HBsAg to be used as vaccine. |
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HDV transmission & disease
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Transmitted parenterally & can only replicate with help of HBV.
1) Coinfection - HBV & HDV are both infected parenterally. HBsAg will protect against both, ending infection. 2) Superinfection - Persone with chronic HBV is infected with HDV causing higher incidence of fulminant hepatitis, cirrhosis & greater mortality. |
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HCV family, disease, diagnosis
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- Part of Flavivirus family & is thus enveloped icosahedral +ssRNA.
- Incubation for 6-12 wks, acute infection usually asymptomatic but up to 85% will develop chronic hepatitis & 20% of those will develop cirrhosis Diagnose via testing for anti-HCV antibodies |
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HEV
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Similar to HAV & is also transmitted via fecal oral. Endemic to Asia, India, Africa, & Central America
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HGV
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Also a flavivirus, transmissible by transfusion & parenteral. Not shown to cause liver disease
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The 3 big concepts unique to retroviridae
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Retro - Carries reverse transcriptase, an RNA dependent DNA polymerase to convert the RNA to DNA. Has unique sticky ends that incorporate into host genome.
Grow - Can activate proto-oncogenes for malignancy Blow - Cytotoxic to certain cells & blow them up. HIV blows up T helper cells. |
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Acute & Non acute transforming viruses
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Acute - Carry intact oncogenes which are integrated into host DNA to cause malignant transformation.
- Some oncogenes are so long that most acute transforming viruses lost their own DNA & became defective acute transforming viruses & require a coinfecting virus to cause cancer. Non-acute transforming viruses activate host cell proto-oncogenes by integrating viral DNA into key regulatory area. Has room for full genome. |
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HTLV-I
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Human T-cell Leukemia virus
- First human retrovirus discovered linked to paralytic disease that occurs in the tropics called Tropical spastic paraparesis. Also induces Leukemia in Caribbean & Japan. |
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HIV-2 & SIV
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HIV-2 causes disease similar to AIDS in western Africa & has 40% sequence hemology to HIV-1.
SIV causes aids like disease in primates & shares homology with HIV-2 |
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HIV Structure
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- Spherical enveloped virus with central cylindrical nucleocapsid.
1) 2 Identical +ssRNA associated with nucleocapsid proteins bound to RNA & 3 essential retroviral enzymes Protease, Reverse Transcriptase, & Integrase. 2) Surrounding RNA dimer is the Capsid Proteins. Major caspid protein is p24. Can be measured in serum to detect early HIV infection 3) Rest has same structure as influenza with matrix proteins binding glycoproteins gp120 & gp41. |
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HIV Genome
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All retroviruses possess in their genome, Long Terminal Repeats (LTR) Gag, Pol & Env genes
LTR - Sticky ends recognized by integrase for incorporation into host genome. Also has promotor function that enhance viral DNA transcription. gag - encodes for proteins inside envelope including Nucleocapsids, p24, & Matrix proteins. Pol - Encodes vital protease, integrase & reverse transcriptase. Protease is neccesary to cleave gag & pol from precursor Env - Codes for ENVelope proteins that form glycoprotein spikes gp120 & gp41 that combine to gp160 to bind to CD4 receptors on T cells. Regulatory proteins Tat - encodes viral TrAnsacTivator protein that activates transcription of viral genome. Rev - Revs up viral activity by binding to viral gene to decrease splicing & thus increase reading of gag, pol, & env Nef - Function is uncertain but nef deficient HIV-1 do not develop AIDS. |
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HIV heterogenicity
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Has hypervariable regions in areas encoding gp120 & even reverse transcriptase. highest error rates but occurs in multiples of 3 to preserve reading frame.
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HIV Transmission
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Spread by Parenteral routh via
Sex: Women are 20x more likely than men to attract Blood transfusion: whole blood, concentrated RBC, platelets, WBC, clotting factors & plasma. All except gamma-globulin. 3) IV drugs 4) Transplacental - 30% transmission to fetus via tranplacental, delivery & perinatally 5) Needle stick - 0.03% chance 6) Not spread my mosquito bites or casual contact. No evidence of spread via saliva, urine, tears, or sweat. |
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HIV Cell infection
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gp160 binds to CD4 receptors on T helper cells, macrophages, monocytes & dendritic cells. Requires coreceptor CCR5 or CXCR4.
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HIV disease course
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Following infection, HIV can replicate immediately to result in rapid progression to AIDS or there can be a chronic latent course. Former is most common pattern in 3 stages
1) Acute viral illness with fever, malaise, lymphadenopathy develops in 80% after 1 month. HIV specific immune response results, & HIV hides in nodes & peripheral blood. 2) Clinical latency - Median of 8 years while CD4 counts decrease by 60/microLiter/yr 3) AIDS - defined as CD4 less than 200 with HIV. Death occurs within 2 years. |
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Mechanism of T cell death & Clinical significances
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HIV creates gp160 which inserts into CD4 cytoplasmic membrane. New HIV virus will exit cell and pick up envelope at gp160 site.
1) May bind to adjacent CD4 receptor as it is leaving cell to tear & destroy CD4 cell. 2) gp160 in infected cells can bind up to 500 uninfected cells to form multinucleated giant cells. Virus can infect more cells without going into blood. 3) Gp160 can mark cell for cytotoxic T cell destruction. - Polyclonal activation of B cells results in hypergammaglobulinemia & diminished response to other pathogens - May hide & replicate in monocytes & macrophages. & can ride them into CNS. |
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HIV Direct viral illness & Malignancies
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Constitutional illness - Night sweats, fever, wasting syndrome.
Neurological damage - Most HIV pts suffer from neurological dysfunction ranging from encephalopathy resulting in AIDS-Dimentia complex, to Meningitis. Malignancies - High incidence of B cell lymphoma often presenting as brain mass. Half of B cell lymphomas contain EBV. Kaposi's sarcoma, most of which occur in homosexual men & appears to have HHV-8 as cofactor. Red to purple leisions or nodules all over body. |
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HIV diagnosis
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Following infection, Viral RNA & Antigens such as p24 can be detected in blood within weeks. 3-6 weeks later ELISA can detect antibodies with 99.5% sensitivity. If positive do again, if still positive run western blot. WB is positive if it has bands to 2HIV gene products p24, gp41, gp120
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Herpesviridae viruses & generalities
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HSV1&2, VZV, Cytomegalovirus, EBV, Human herpesvirus 6(Roseola)
1) All develop latent state 2) Subtype Alpha HSV-1, HSV-2, & Varicella-zoster cause multinucleated giant synctial cells with intranuclear inclusion bodies 3) Herpesviridae are held at bay by cell mediated immune response |
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HSV 1 & 2 Transmission & Diseases
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Transmission via direct inoculation of muco-cutaneous surfaces.
NEWDKGG Depending on Host immune status, may include: 1) Gingivostomatitis - Painful swollen gums, fevers, vesicles on areas of skin where viral entry occured. 2) Genital herpes - May be caused by HSV1 or 2. Fever, headache, vaginal discharge, blisters & ulcers. 3) Herpetic keratitis - Most common infectious cause of blindness in US. 4) Neonatal herpes - Transplacental causing congenital defects or abortion. Can also aquire during delivery 5) Herpetic Whitlow - HSV infection of finger which becomes hot red & swollen 6) Disseminated herpes - Immunocompromised can develop HSV infection of liver, lung, GI 7) Encephalitis - HSV-1 is most common cause of viral encephalitis. Sudden onset of fever & focal neurological abnormalities |
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VZV diseases & vaccine
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Varicella - Infects respiratory tract of children usually during winter & spring & replicates for 2 week incubation. Then comes fever, malaise, headache with rash. Varicella rash starts on face & trunk spreading to entire body including mucous membranes. Multiple vesicles arise in patches with lesions at diff stages. All scab in 1 wk.
Zoster - Following stressed state or lowered cell-mediated immunity, latent varicella-zoster virus in sensory ganglion infects peripheral nerves causing burning painful skin lesions. Live attenuated virus vaccine. Can administer zoster immune globulin within days of exposure. |
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CMV characteristics, diseases, diagnosis
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Cytomegalovirus, So named because infected cells become swollen, & with other herpesviridae, multinucleated giant cells & intranuclear inclusion bodies are present.
1) Asymptomatic 2) Congenital CMV - One of the TORCHES. Most common viral cause of mental retardation, microcephaly, deafness, seizures. If reactivation occurs during pregnancy, fetus will be infected 3) Cytomegalovirus mononucleosis - Causes Mononucleosis in young adults similar to that by EBV 4) Can reactivate in immunocompromised & cause retinitis, pneumonia, disseminated infection & even death. Marrow transplant = CMV pneumonia, AIDS = CMV Retinitis Diagnose via - buffy coat, antigen is detected during replication, PCR |
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EBV diseases
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Epstein-Barr Virus - Another herpesviridae that causes Mononucleosis & Burkitt's lymphoma via transformation.
Mono - EBV infects human B cells by binding to C3d receptor. Transforms cell to proliferate. Some cells will be activated by EBV & cells will lyse with viral release. Transformed cancer cells then suddenly disappear with resolution of illness. Burkitt's lymphoma - EBV found in cancer cells of Burkitt's lymphoma, a B-cell lymphoma affecting children in central africa. Translocation activates oncogene. Latent EBV can be reactivated during immunosuppression |
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Mononucleosis disease & diagnosis
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"kissing disease" of young adults.
Develop fever, chills, sweats, headache, & painful pharyngitis. Enlarged lymph nodes as B cells multiply with large spleens. Diagnose via atypical lymphocytes on blood smear & heterophile antibody which is antibody against that cross reacts & agglutinates sheep RBC. Used for rapid Monospot test. |
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HHV8
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Human herpes virus 8 - Appears to cause Kaposi's sarcoma in AIDS pts.
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Poxviridae
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Double Enveloped dsDNA virus that lives in a box & replicates in cytoplasm. Has complex DNA genome that codes for hundreds of proteins & carries many of its own enzymes.
Causes Smallpox |
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Smallpox transmission, disease, vaccine
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Caused by Poxviridae
Eradicated in 1977, used to be highly contagious & transmitted via respiratory tract only to humans. Disease in which 30% died & rest were scarred for life. Molluscum Contagiosum - small 1-2mm white bumps with central dimple that develop centrifugally. Vaccine containg vaccinia virus, an antivirulent form of poxviridae. |
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Papova
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dsDNA, Naked, Icosahedral virus.
Papilloma - Warts & Cervical Cancer Polyoma - Human BK & JC VA - simian vacuolating virus does not cause disease in humans |
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Papilloma virus diseases & vaccination
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Warts - Many strains that have tropism to squamous epithelial cells. Cause common, genital & laryngeal warts. Benign hyperproliferation of keratinized squamous epithelium that goes away in 1-2 yrs.
Cervical cancer - Cervical dysplasia & carcinoma are associated with sexual activity & previous exposure to HPV types 16 & 18. Diagnose via PAP smear to look for dysplasia & vaccinate against types 16&18 for cervical cancer & types 6&11 for genital warts. |
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Polyomavirus
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2 viruses BK & JC, both of which are uniquitous & infect worldwide at early age.
BK Polyomavirus - Ubiquitous & causes mild or asymptomatic infection in children JC polyomavirus - Similar to BK but causes opportunistic infection in immunocompromised called Progressive Multifocal Leukoencephalopathy (PML). White matter damage with memory loss, poor speech, & Incoordination. |
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Adenovirus
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Causes upper respiratory tract
- Can result in rhinitis, conjunctivis, sore throat, cough, may progress to pneumonia |
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Parvoviridae
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Smallest icosahedral naked ssDNA virus.
Causes childhood disease called erythema infectiosum characterized by fever & slapped face rash on cheeks. |
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HHV-6
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Roseola
Causes Exanthema subitum with 3 day fever & rash. Affects most of kids before age 2 |
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Arboviruses
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Togaviridae, Flaviviridae, & Bunyaviridae. Except Rubivirus of Togaviridae & Hentavirus of Bunyaviridae are not arthropod borne.
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Picornaviridae
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Large group of enteroviruses including Rhinovirus, poliovirus, coxsackie A & B, echovirus, & new enterovirus.
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Viruses that cause common cold
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Rhinovirus & Coronaviridae which causes SARS.
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Viruses that cause diarrhea
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Rotavirus & Caliciviridae which includes Norwalk virus.
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Viruses that cause hemorrhagic fever & are potential bioweapons.
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Filoviridae - Ebola & Marburg viruses
Arenaviridae - Such as Lassa Fever virus |
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Togaviridae classification, members, diseases & vaccine
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An Arbovirus, two members infect humans
Alpha viruses - mosquitoborne & infects Horses, Birds & humans to cause encephalitis, fever, headache, neurologic deficits. Western equine encephalitis in western US & Canada, Eastern equine encephalitis, Venezuelan equine encephalitis in southern US down to South America Rubivirus - Although a togavirus, Rubivirus is not an arbovirus. Transmitted via respiratory secretions, only infects humans & causes rubella which is mild febrile disease with 3 day rash. However, causes congenital defects during first trimester. 1) Heart: Patent ductus, IV septal defects, PA stenosis etc 2) Eyes - Cataracts, chorioretinitis etc 3) CNS - Mental retardation, microcephaly, deafness Vaccination via MMR live attenuated Rubivirus. Not given to pregnant women. |
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Flaviviridae classification, & diseases
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An Arbovirus similar in morphology to Togaviridae & also cause encephalitis. Spread by mosquitos that infects humans & birds
St. Louis encephalitis - Second leading cause of epidemic viral encephalitis. Accounts for many cases a year. Yellow fever - Made famous by panama canal project. Hepatitis with jaundice, fever, nausea, vomiting, & backache a week after exposure. Dengue fever - Mosquito-borne febrile disease mainly occurring in tropics, but also SW USA & Mexican border. Causes severe backpain, muscle & joint pain with severe headache. Serotype 2 dengue fever will cause Dengue hemorrhagic fever, shock & death. West Nile Virus |
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West Nile Virus family, transmission, symptoms, diagnosis
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Part of Flavivirus & Transmitted by a mosquito bite. Very deadly to horses & birds.
Most pts are asymptomatic however, can have headache, maculopapular rash followed by fatigue, weakness. -Some develop neuroinvasive disease such as aseptic meningitis, frank encephalitis, decreased consciousness, or paralysis. Diagnose via culture, Serum IgM & IgG against WNV, CSF IgM vs WNV, or 4x increase in serum antibody titers. |
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Bunyaviridae
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An Arbovirus that causes diseases characterized by fever & encephalitis such as California encephalitis & Rift Valley fever.
Hantavirus pulmonary syndrome - Has non-arthropod vector. Carried by rodent vector & caused influenza like illness followed by sudden respiratory failure. Previously only associated with hemorrhagic fever with renal failure in Asia & Europe. Pts present with high fever, muscle aches, cough, nausea & vomiting. Rapid heart & respiratory rate. Disrupted lung capillary permeability results in pulmondary edema. Diagnose via IgM and IgG against Sin Nombre Virus |
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Picornaviridae family, genra & subgroups
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Includes Enteroviruses & Rhinovirus
Enteroviruses - Poliovirus, Coxsakie A & B, Echovirus, New enteroviruses Rhinovirus causes common cold |
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Poliovirus family, transmission, & disease
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One of the enteroviruses of Picornaviridae
- Transmitted via fecal oral & initially replicates in tonsils & peyer's patches, allowing for respiratory transmission. Then crosses BBB to anterior horn. 3 Stages 1) Mild illness with fever 2) Aseptic meningitis - Fever & Meningismus with recovery in 1 wk 3) Paralytic poliomyelitis - Destroys presynaptic motor neurons in anterior horn as well as post synaptic motor neurons exiting horn. Can result in loss of leg, arm, paraplegia, or quadriplegia & even respiratory failure. These serious events occur in those older than 15. |
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Polio vaccine
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Salk - Formalin inactivated polio vaccine
Sabin - oral attenuated polio vaccine, with viruses that replicates & sheds in feces but does not cause paralytic poliomyelitis. Supplants wild type poluivirus with attenuated type. - Oral, stimulates both IgG & Secretory IgA, & attenuated virus can be transmitted to contacts to result in secondary immunity in others. Sabin was totally replaced by Salk in 2000 |
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Coxsackie A, B, Echoviruses & New Enteroviruses
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All members of the Picornaviridae & have many similar symptoms
1) Asymptomatic or mild fever 2) Respiratory symptoms 3) Rashes 4) Aseptic meningitis - Enteroviruses are most common cause of non bacterial meningitis in US. Coxsakie A - Causes paralysis & death of mice with muscle necrosis. - Herpangina - a self limiting fever, sore throat, small red vesicles over back of throat -Hand foot mouth syndrome - common acute illness in children with fever, oral vesicles & small tender lesions on hands, feet, buttocks Coxsakie B - Causes less severe infection in mice. - Pleurodynia - fever, headache, pleuritic pain - Myocarditis/Pericarditis - Infection & inflammation of myocardium & pericardial membrane. Can result in chest pain, arrhythmia, cardiac failure. |
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Coronavirus transmission, symptoms, diagnosis
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Causes SARS
- Transmission via respiratory droplets in mucous membrane. - 2-10 day incubation, then present with fevers, myalgias, chills, then later developed dry cough, chest pain, & dyspnea. Diagnose via Reverse transcriptase PCR from viral RNA in respiratory secretions, feces, urine or lung biopsy. |
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Caliciviridae characteristics & diseases
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Primarily infects young kids & is indistinguishable from rotavirus gastroenteritis. Fever, abdominal pain & diarrhea after 1-2 day incubation. Resolution after 4-7 days.
Norwalk virus - Can occur in adults. Occured in Norwalk Ohio. Norovirus - aka Norwalk Like virus that is major cause of diarrheal outbreaks on cruise ships or after Hurricane Katrina. |
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Rotavirus disease & vaccine
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Member of Reovirus. & Major cause of infant mortality worldwide from diarrhea.
- Live attenuated vaccine called RotaShield was launched in US but withdrawn due to Intussusception where small intesting collapses inward where distal SI slides into proximal SI. |
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Rhabdoviridae transmission, disease, diagnosis, treatment
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Rabies is only member that affects humans but can also affect any warm-blooded animals such as dogs, cats, skunks, coyotes, foxes, bats etc serving as reservoir.
- After infection, virus replicates at wound site for days then migrates slowly up nerve axons to CNS causing fatal encephalitis. 1) Prodrome - nonspecific symptoms of fever, headache, sore throat, painfully sensitive nerves at healed wound site. 2) Acute encephalitis - hyperactivity & agitation leading to confusion, meningismus & even seizures. 3) Classic brainstem encephalitis - Cause cranial nerve dysfunction with painful pharyngeal contractions & swalloing liquids. Foaming of mouth 4) Death occurs after respiratory center dysfunction - Forms Negri bodies in brain cells. - When bitten or licked by possibly rabid animal, aggresively clean wound with soap & water. Capture or destroy animal & look for Negri bodies. If person is positive, must give passive immunization followed by 5 injections of killed rabies virus vaccine. |
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Filoviridae members, transmission, disease
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Ebola & Marburg viruses
- Transmission via contact with bodily fluids or possible airborne transmission. - Acute viral hemorrhagic fever with fever, diarrhea, weakness, dysphagia, hiccups & bleeding |
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ArenaViridae members & disease
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Include Lassa Fever virus & 4 south American Hemorrhagic fever viruses.
- Produces disease slower in onset but similar manifestations of Filoviridae infection. Fever, diarrhea, weakness, dysphagia, bleeding. However, unlike Filoviridae, Arenaviridae infection is treatable. |
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Rift Valley Fever
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Part of Bunyaviridae & Yellow fever virus of Flaviviridae. Also causes hemorrhagic fever.
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