ReovirusNaked, dsRNA and linear- 10-12 segments Coltivirus – Colorado tick fever Rotavirus – #1 cause of fatal diarrhea in children. Less common due to vaccination.
CalicivirusesNaked, ⊕ single-stranded and linear Norovirus – viral gastroenteritis with vomiting, watery diarrea.
FlavivirusEnveloped, ⊕ single-stranded and linear HCVYellow fevera – Liver, kidney, heart, and GI (black vomit) damageDenguea – Break bone fever (rash, muscle and joint pain), reinfection can result in ...
TogavirusEnveloped, ⊕ ssRNA and linear Rubella – German measles (erythematous rash begins on face, progresses to torso)Eastern and Western equine encephalitisaChikungunya virusa
CoronavirusesEnveloped, ⊕ single-stranded and linear "Common cold", SARS, MERS
OrthomyxovirusesEnveloped, Θ single-stranded and linear- 8 segments Influenza virus
RhabdovirusesEnveloped, Θ single-stranded and linear Rabies
BunyavirusesEnveloped, ⊝ single-stranded and circular RNA- 3 segments California encephalitisaSandfly/Rift Valley feversaCrimean-Congo hemorrhagic feveraHantavirus – transmission by rodent excrement, hemorrhagic ...
RhinovirusA picornavirus (naked, ⊕ ssRNA) - Cause of common cold- >100 serologic types- Acid labile – destroyed by stomach acid, therefore, does not infect the GI tract (unlike other picornaviruses)
Yellow fever virusA flavivirus (enveloped, ⊕ ssRNA)- Arbovirus, transmitted by Aedes mosquito- Reservoir: Monkeys- Endemic in South America and Sub-Saharan Africa Symptoms:1. High fever, headaches, chills, aching ...
RotavirusA segmented dsRNA (reovirus). - Most important global cause of infantile gastroenteritis.- Major cause of acute diarrhea in the US during winter, especially in day care centers, kindergartens. - Villous ...
Influenza virusOrthomyxovirus (enveloped, ⊝ ssRNA with 8 segments)- Contain hemagglutinin (binds sialic acid and promotes viral entry)- Contain neuraminidase (promotes progeny virion release) - Patients at risk for ...
Rubella virusTogavirus (enveloped, ⊕ ssRNA) Causes rubella, once known as German 3-day measles. Presentation:- Low-grade fever- Postauricular and nuchal lymphadenopathy- Arthralgias- Fine, maculopapular, confluent ...
ParamyxovirusesEnveloped, ⊝ ssRNA, non-segmented Parainfluenza – croup (seal-like barking cough)Mumps, MeaslesRSV – bronchiolitis in babies - All contain surface F (fusion) protein, which causes respiratory ...
Croup (acute laryngotracheobronchitis)Caused by parainfluenza viruses, which are paramyxoviruses (enveloped, ⊝ ssRNA).- Peak incidence: 6 months to 3 years- Most common in fall and winter Virus membrane contains hemagglutinin (binds sialic ...
Measles (rubeola) virusParamyxovirus (enveloped, ⊝ ssRNA) - Prodromal fever with cough, coryza (inflammation of nasal mucosal), conjunctivitis, light sensitivity- Eventually Koplik spots (bright red spots with blue-white ...
MumpsParamyxovirus (enveloped, ⊝ ssRNA)- Uncommon due to effectiveness of MMR vaccine Symptoms:- Parotitis- Orchitis (inflammation of testes)- Aseptic meningitis- Pancreatitis- Can cause sterility
Rabies virusRhabdovirus (bullet-shapped virus, enveloped, ⊝ ssRNA, helical)- Infection more commonly from bat, raccoon, and skunk bites (US) and dogs (worldwide).- Aerosol transmission (eg, bat caves) also possible. ...
Prions- conversion of a α-helical protein termed prion protein (PrPc) to a β-pleated form (PrPsc), which is transmissible via CNS-related tissue (iatrogenic CJD) or food contaminated by BSE-infected animal ...
PoxvirusEnveloped, dsDNA and linear (largest DNA virus) - Smallpox eradicated world wide by use of the live-attenuated vaccine- Cowpox ("milkmaid blisters")- Molluscum contagiosum – flesh-colored papule with ...
HepadnavirusEnveloped, partially dsDNA and circular HBV: - Acute or chronic hepatitis- Not a retrovirus but has reverse transcriptase
AdenovirusNaked, dsDNA and linear - Febrile pharyngitis – sore throat- Acute hemorrhagic cystitis – mostly boys age 5-15- Pneumonia- Conjunctivitis – "pink eye"- Gastroenteritis- Myocarditis Prevention: live, ...
PapillomavirusNaked, dsDNA and circular HPV – warts (serotypes 1, 2, 6, 11), CIN, cervical cancer (most commonly 16, 18)- Infects basal layer of the skin and mucous membranes- Malignancy may result: E6 and E7 inhibit ...
ParvovirusNaked, ssDNA and linear (smallest DNA virus)- Attaches to P antigen on RBCs B19 virus - Aplastic crisis in sickle cell disease- "Slapped cheek" rash in children (erythema infectiosum, or fifth disease)- ...
PolyomavirusNaked, dsDNA and circular - JC virus – progressive multifocal leukoencephalopathy (PML) in HIV- BK virus – transplant patients, commonly targets kidney. Occurs in ~5% of all kidney transplants patients. ...
Herpes simplex virus-1Enveloped, DS and linear Route: Respiratory secretions, saliva - Gingivostomatitis- Keratoconjunctivitis- Herpes labialis- Herpetic whitlow on finger- Temperal lobe encephalitis- Esophagitis- Erythema ...
Herpes simplex virus-2Enveloped, DS and linear Route: Sexual contact, perinatal - Herpes genitalis- Neonatal herpes - Viral meningitis more common with HSV-2 than with HSV-1. - Tzanck smear looks for multinucleated giant cells ...
Varicella-Zoster virus (HHV-3)Enveloped, DS and linear Route: Respiratory secretions - Varicella-zoster (chickenpox, shingles), encephalitis, pneumonia- Most common complication of shingles is post-herpetic neuralgia. - Latent in ...
Cytomegalovirus (HHV-5)Enveloped, DS and linear Route: Congenital transfusion, sexual contact, saliva, urine, transplant- Uses integrins to cause infection - Mononucleosis (⊝ Monospot) in immunocompetent patients- Infection ...
Human herpes viruses 6 and 7Enveloped, DS and linear Route: Saliva Roseola infantum (exanthem subitum):- High fevers for several days- Can cause seizures- Followed by diffuse macular rash - HHV-7 – less common cause of roseola
Human herpesvirus 8Enveloped, DS and linear Route: Sexual contactSite of latency: B cells, glandular epithelial cells Kaposi sarcoma (neoplasm of endothelial cells)- Seen in HIV/AIDS and transplant patients- Dark/violaceous ...
RNA virusesReovirus (DS): Rotavirus - cause of fatal diarrhea in children Picornavirus- Poliovirus- Echovirus - aseptic meningitis- Rhinovirus - "common cold"- Coxsackievirus - aseptic meningitis; herpangina; hand, ...
Ebola virusFilovirus (enveloped, ⊝ ssRNA)- Transmission requires direct contact with bodily fluids, fomites (including dead bodies), bats or primates (apes/monkeys); high incidence of nosocomial infection.- Targets ...
Zika virusFlavivirus (enveloped, ⊕ single-stranded)- Transmitted by Aedes mosquito.- Sexual or vertical transmission possible.- Outbreaks more common in tropical and subtropical climates. Presentation:- Conjunctivitis- ...
Hepatitis serologic markersAnti-HAV (IgM) – Best test to detect acute hepatitis A.Anti-HAV (IgG) – Indicates prior HAV infection and/or prior vaccination; protects against reinfectino. HBsAg – Indicates HBV infection.Anti-HBs ...
HIVDiploid genome (2 molecules of RNA). 3 structural genes:- env (gp120 and gp41): envelope glycoproteins→ gp120 – attachment to CD4+ T cell→ gp41 – fusion and entry- gag (p24 and p17): capsid ...
HIV diagnosisPresumptive diagnosis made with HIV-1/2 Ag/Ab immunoassays. - These immunoassays detect viral p24 Ag capsid protein and IgG Abs to HIV-1/2. Very high sensitivity/specificity.- ⊕ tests are confirmed ...
Common diseases of HIV-positive adultsCD4+ count <500mm3:- Candida albicans – oral thrush- EBV – oral hairy leukoplakia- HHV-8 – Kaposi sarcoma (lymphocytic inflammation)- HPV – squamous cell carcinoma, commonly of anus or cervix ...
Viral geneticsRecombination: Exchange of genes between 2 chromosomes by crossing over within regions of base sequence homology. Reassortment: When viruses with segmented genomes (eg, influenza virus) exchange genetic ...
DNA virus characteristicsAre HHAPPPy viruses: Hepadna, Herpes, Adeno, Pox, Parvo, Papilloma, Polyoma. All DNA viruses have dsDNA except Parvoviridae (ssDNA). All are linear except papilloma and polyoma (circular, supercoiled) ...
RNA virus characteristicsAll RNA viruses have ssRNA except Reoviridae (dsRNA). All replicate in the cytoplasm (except retrovirus and influenza virus). (+) stranded RNA viruses: I went to a retro (retrovirus) toga (togavirus) ...
Viral envelopesGenerally, enveloped viruses acquire their envelopes from plasma membrane when they exit the cell. Exceptions include herpesviruses, which acquire their envelopes from nuclear membrane. Naked viruses ...
HSV identification- Viral culture for skin/genitalia - CSF PCR for herpes encephalitis - Tzanck test – a smear of an opened skin vesicle to detect multinucleated giant cells commonly seen in HSV-1, HSV-2, and VZV infection. ...
Receptors used by virusesCMV – Integrins (heparan sulfate) EBV – CD21 HIV – CD4, CXCR4, CCR5 Parvovirus B19 – P antigen on RBCs Rabies – Nicotinic AChR Rhinovirus – ICAM-1
RetrovirusesEnveloped, ⊕ ssRNA- 2 copies- Have reverse transcriptase HTLV (icosahedral) – T-cell leukemiaHIV (complex and conical) – AIDS
ArenavirusesEnveloped, ⊕ and ⊝ single stranded and circular RNA- 2 segments LCMV – lymphocytic choriomeningitis virusLassa fever encephalitis – spread by rodents