MICROBIOLOGY & IMMUNOLOGY
MICRO: Virology
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| -?-(d) Parvovirus | B19 virus—aplastic crises in sickle cell disease, "slapped cheeks" rash—erythema infectiosum (5th disease), hydrops fetalis |
| -?-(b) Herpesviruses | HSV-1; HSV-2; VZV; EBV; CMV; HHV-6; HHV-7; HHV-8 |
| -?-(c) Adenovirus | Febrile pharyngitis—sore throat; pneumonia; conjunctivitis |
| -?-(f) Poxvirus | Smallpox, although eradicated, could be used in germ warfare vaccinia—cowpox ("milkmaid's blisters"); molluscum contagiosum |
| -?-(a) Hapadnavirus | HBV; acute or chronic hepatitis; vaccine available—use has increased tremendously; not a retrovirus but has reverse transcriptase |
| -?-(e) Papovavirus | HPV—warts, CIN, cervical cancer; JC—progressive multifocal leukoencephalopathy: (PML) in HIV |
| (a) Hapadnavirus (b) Herpesviruses (c) Adenovirus (d) Parvovirus (e) Papovavirus (f) Poxvirus | |
| -?-(n) Deltavirus | HDV |
| -?-(a) Picornaviruses | Poliovirus—polio-Salk/Sabin vaccines—IPV/OPV; echovirus—aseptic meningitis; rhinovirus—"common cold"; coxsackievirus—aseptic meningitis herpangina—febrile pharyngitis, hand foot mouth disease, myocaritis; HAV—acute viral hepatitis |
| -?-(b) Caliciviruses | HEV; Norwalk virus—viral gastroenteritis |
| -?-(l) Arenaviruses | LCV—lymphocytic choriomeningitis; meningitis—spread by mice |
| -?-(c) Reoviruses | Colorado tick fever; rotavirus—#1 cause of fatal diarrhea in children |
| -?-(k) Coronaviruses | "Common cold" |
| -?-(i) Rhabdoviruses | Rabies |
| -?-(d) Flaviviruses | HCV; yellow fever, dengue, St Louis encephalitis; West Nile virus |
| -?-(h) Paramyxoviruses | Parainfluenza—croup; RSV—bronchiolitis in babies, Rx—riboflavin; measles; mumps |
| -?-(e) Togaviruses | Rubella; Eastern equine encephalitis; Western equine encephalitis |
| -?-(f) Retroviruses | Have reverse transcriptase; HIV—AIDS; HTLV—T-cell leukemia |
| -?-(g) Orthomyxoviruses | Influenza virus |
| -?-(m) Bunyaviruses | California encephalitis; sandfly/Rift Valley fevers; Crimean-Congo hemorrhagic fever;Hantavirus-hemorrhagic fever, pneumonia |
| -?-(j) Filoviruses | Ebola/Marburg hemorrhagic fever—often fatal |
| (a) Picornaviruses (b) Caliciviruses (c) Reoviruses (d) Flaviviruses (e) Togaviruses (f) Retroviruses (g) Orthomyxoviruses (h) Paramyxoviruses (i) Rhabdoviruses (j) Filoviruses (k) Coronaviruses (l) Arenaviruses (m) Bunyaviruses (n) Deltavirus | |
Regarding general rules covering all DNA viruses:
What does the acronym HHAPPPy stand for? -?-Hepadna, Herpes, Adeno, Pox, Parvo, Papova
These are characteristics of DNA viruses: -?-double -stranded; l -?-linear; i -?-iscosahedral; replicate in the -?-nucleus.
Generally, enveloped viruses acquire their envelopes from
-?-plasma membrane
when they exit from cell.
Exceptions are -?-herpesviruses
which acquire envelopes from nuclear membrane.
All viruses are haploid except -?-retroviruses, which have 2 identical ssRNA molecules.
| -?-(a) recombination | Exchange of genes between 2 chromosomes by crossing over within regions of significant base sequence homology |
| -?-(c) complementation | When 1 of 2 viruses that infect the cell has a mutation that results in a nonfunctional protein |
| -?-(d) phenotype mixing | Genome of virus A can be coated with the surface proteins of virus B |
| -?-(b) reassortment | When viruses with segmented genomes exchange segments |
| (a) recombination (b) reassortment (c) complementation (d) phenotype mixing | |
| -?-(a) DNA enveloped viruses | Herpesviruses, HBV, smallpox virus |
| -?-(d) RNA nucleocapsid viruses | Enteroviruses, rhivovirus, reovirus |
| -?-(b) DNA nucleocapsid viruses | Adenovirus, papillomarivurses, parvovirus |
| -?-(c) RNA enveloped viruses | Influenza virus, RSV, mumps, HIV |
| (a) DNA enveloped viruses (b) DNA nucleocapsid viruses (c) RNA enveloped viruses (d) RNA nucleocapsid viruses | |
Genetic -?-shift is the reassortment of viral genome and genetic -?-drift refers to minor changes based on random mutation.
In the U.S., rabies, which has a long incubation period and causes fatal encephalitis with seizures & hydrophobia, is more commonly caused by -?-bat, -?-raccoon and -?-skunk bites than from dog bites.
| Virus | Diseases | Route of transmission |
|---|---|---|
| HSV-1 | -?-Gingivostomatitis, keratoconjunctivitis, temporal lobe encephalitis, herpes labialis | Respiratory secretions, saliva |
| HSV-2 | -?-Herpes genitalis, neonatial herpes | Sexual contact, perinated |
| VZV | -?-Varicella-zoster (shingles), encephalitis, pneumonia | Respiratory secretions |
| EBV | Infectious mononucleosis, Burkitt's | -?-Respiratory secretions, saliva |
| CMV | Congenital infection, monomucleosis, pneumonia | -?-Congenital, transfusion, sexual contact, saliva, urine, transplant |
| HHV-8 | Kaposi's sarcoma (HIV patients) | -?-Sexual contact |
-?-Tzanck test is used to assay for HSV-1, HSV-2, and VZV.
Hepatitis transmission:
-?-(a) HAV
primarily transmitted by fecal-oral route; HBV primarily transmitted by
-?-(b) parenteral, sexual & maternal-fetal routes;
-?-(c) HCV
primarily transmitted via blood & resembles HBV in its course & severity; and,
-?-(d) HEV
transmitted enterically & causes water-bourne epidemics.
| -?-(e) HBcAb | An indicator of recent disease |
| -?-(b) HBsAg | Continued presence indicates carrier state |
| -?-(a) IgM HAVAb | Best test to detect active hepatitis A |
| -?-(c) HBsAb | Provides immunity to hepatitis B |
| -?-(g) HBeAb | Indicates low transmissibility |
| -?-(d) HBcAg | Associated with core of HBV |
| -?-(f) HBeAg | Important indicator of transmissibility |
| (a) IgM HAVAb (b) HBsAg (c) HBsAb (d) HBcAg (e) HBcAb (f) HBeAg (g) HBeAb | |
For HIV diagnosis, the presumptive diagnosis is made with -?-ELISA and confirmed with -?-Western blot assay; -?-HIV PCR/viral load tests are increasingly popular and allow physician to monitor the effect of drug therapy on viral load.
| -?-(b) viral | HSV, VZV, CMV, PML |
| -?-(d) protozoan | toxoplasmosis, cryptosporidiosis |
| -?-(a) bacterial | tuberculosis, Mycobacterium avium-intracellulare complex |
| -?-(c) fungal | thrush, cryptococcosis, histoplasmosis, pneumocystis pneumonia |
| (a) bacterial (b) viral (c) fungal (d) protozoan | |