Step 1 - Micro 5

denniskwinn's version from 2015-04-25 16:10


Question Answer
Typhoid fever causebacteria salmonella typhi
Typhus caused bybacteria Rickettsia prowazekii (epidemic), Rickettsia typhi (endemic), Rickettsia tsutsugamush (scrub)
Chlamydia trachomatisbacteria causes STD
Treponemaa spirochete - causes syphillis (pallidum) or yaws (pertenue)
Trichomonas vaginalisProtozoan -causes STD
TrypanosomaProtozoan - causes chaga’s disease (cruzi) or african sleeping sickness
ToxoplasmaProtozoan - causes a ToRCH infection
Trichinella spiralisNematode in undercooked meat
Taenia soliumTapeworm larvae (intestinal infection) or eggs (neurocysticercosis) in pork


Question Answer
Naked icosahedral viral structureNucleocapsid on outside, nucleic acid on inside
Enveloped icosahedral viral structureNucleic acid inside, Capid then Lipid bilayer and surface protein on outside
Enveloped helical viral structureNucleic acid and nucleocapsid protein surrounded by matrix or core protein with lipid bilayer and surface protein
Viral recombinationExchange of genes b/w 2 chromosomes by crossing over within regions of significant base sequence homology
Viral reassortmentWhen viruses with segmented genomes exchange segments - high frequency recombination cause of worldwide flu pandemics
Viral complementationWhen 1 of 2 viruses that infect the cell has a mutation that results in a nonfunctional protein. Nonmutated virus “complements” the mutated one by making a functional protein that serves both viruses
Viral phenotypic mixingOccurs with simultaneous infection of a cell with 2 viruses. Virus can be coated with surface protein of virus B - type B protein coat determines the infectivity of the phenotypically mixed virus. The progeny from this infection have a type A coat form the type A genetic material
Live attenuated viral vaccinesinduce humoral and CMI but have reverted to virulence on rare occasions - killed vaccines only activate humoral immunity. Live don’t need boosters
Viruses with live attenuated vaccinessmallpos, yellow fever, chickenpox, Sabin’s polio, MMR -
MMRmeasles, mumps, rubella - only live attenuated vaccine that can be given to HIV-positive patients
Killed viral vaccinesRabies, influenze, Salk polia, HAV vaccines
Recombinant viral vaccinesHBV, HPV
DNA viral genomesAll DNA viruses are ds except parvo, all linear except papilloma, polyoma, hepadnaviruses(circular)
RNA viral genomes all ss except Reoviridae -
Naked viral genome infectivityPurifiec nucleic acids of most dsDNA and + strand ssRNA viruses are infections. . Naked nucleic acids of - strand ssRNA and dsRNA viruses are not infectious - they require enzymes contained in the complete virion
Virus ploidyall viruses are haploid except retroviruses (2 identical ssRNA molecules)
DNA viral replicationin the nucleus (except poxvirus)
RNA viral replicationin the cytoplasm (except influenze virus and retroviruses)
Naked viruses Calcivirus, Picornavirus, Reovirus, Parvovirus, Adenovirus, Papilloma, Polyoma - Naked, CPR and PAPP smear
Enveloped virusesusually acquire their envelopes from plasma membrane when they exit from cell - exceptions = herpesviruses - envelope from nuclear membrane
DNA enveloped virusesHerpesvirus (HSV 1, 2, VZV, CMV, EBV) HBV, smallpox
DNA nucleocapsid virusesAdenovirus, papillomaviruses, parvovirus
RNA enveloped viruseInfluenza virus, parainfluenza virus, RSV, measles, mumps, rubella, rabies, HTLV, HIV
RNA nucleocapsidEnteroviruses (poliovirus, coxsackievirus, echovirus, HAV), rhinovirus, reovirus (rotavirus)
DNA virusesHHAPPPPy (Hepadna, Herpes, Adeno, Pox, Parvo, Papilloma, Polyoma
DNA virus characteristics1. Are double stranded (except parvo) 2. Are linear (except papilloma and polyoma and hepadna) 3. Are icosahedral (except pox) 4. Replicate in the nucleus (except pox)
HSV-11.Herpesvirus 2. DS linear DNA viruses 3. Enveloped 4. Transmitted via Resp secretions, saliva 5. Gingivostomatitis, keratoconjunctivitis, temporal lobe encephalitis (most common cause of sporadic encephalitis in the United states) - herpes labialis
HSV-21.Herpesvirus 2. DS linear DNA viruses 3. Enveloped 4. Spread by sexual contact, perinatal 5. Herpes genitalis, neonatal herpes
VZV (HHV-3)1.Herpesvirus 2. DS linear DNA viruses 3. Enveloped 4. Spread by respiratory secretions 5. Chickenpox, zoster shingles, encephalitis, pneumonia
EBV (HHV-4)1.Herpesvirus 2. DS linear DNA viruses 3. Enveloped 4. Spread by respiratory secretions, saliva 5. Mononucleosis, Burkitt’s lymphoma, nasopharyngeal carcinoma
CMV (HHV-5)1.Herpesvirus 2. DS linear DNA viruses 3. Enveloped 4. Spread by transfusion, sexual contact, saliva, urine, transplant, congenital 5. Infection in immunosuppressed patients, especially transplant recipients - congenital defects, mononucleosis, infected cells have characterisic owl’s eye appearance
HHV-61.Herpesvirus 2. DS linear DNA viruses 3. Enveloped 4. Spread not determined 5. Roseola (exanthem subitum) - high fevers for several days that can cause seizures followed by diffuse macular rash
HHV-71.Herpesvirus 2. DS linear DNA viruses 3. Enveloped 4. Lots of types 5. Clinically insignificant (included only to complete family)
HHV-81.Herpesvirus 2. DS linear DNA viruses 3. Enveloped 4. Spread by sexual contact 5. Kaposi’s sarcoma - associated herpesvirus (KSHV)
Hepadinavirus1. HBV 2. Enveloped 3. Dsdna-partial circular 4. Acute or chronic hepatitis, 5. vaccine available - use has increased - not a retrovirus but has reverse transcriptase
Adenovirus1. Linear DSdna 2. Not enveloped 3. Febrile pharyngits - sore throat 4. Pneumonia 5. Conjunctivitis (watery pink eye)
Parvovirus1. Linear SSdna 2. Not enveloped 3. B19 Virus - aplastic crises in sickle cell disease, “slapped cheeks” rash - erythema infectiosum (fifth disease), RBC destruction in fetus leads to hydrops fetalis and death
Papillomavirus1. Circular DSdna 2. Not enveloped 3. HPV -warts, CIN, cervical cancer
Polyomavirus1. Circular DSdna 2. No envelope 3. JC- progressive multifocal leukoencephalopathy (PML) in HIV
Poxvirus1. Linear DSdna (largest) 2. Enveloped 3. Smallpox (eradicated) , Vaccinia (cowpox), Molluseum contagiosum
HSV identificationTzanck test - a smear of an opened skin vesicle to detect multinucleated giant cells. Used to assay for HSV-1, 2 and VZV. Infected cells also have intranuclear Cowdry A inclusions - - Tzanck heavens I don’t have herpes
EBV1. A herpesvirus - can cause mono 2. Infects B cells 3. Fever, hepatosplenomegaly, pharyngitis, lymphadenopathy (especially posterior cervical nodes) 4. Peak incidence 15-20 years of age. 5. Abnormal circulating cytotoxic T cells (atypical lymphocytes) 6. Assoc w/ Hodgkins, endemic Burkitt’s, nasopharyngeal carcinoma. 7.Most common during peak kissing years 8. Positive monospot test, heterophil antibodies detected by agglutination of sheep RBCs
Reoviruses1. No envelope 2. DS linear RNA 10-12 segments 3. Double Icosahedral 2. Reovirus = Colorado tick feer, Rotavirus - #1 cause of fatal diarrhea in children
Picornaviruses1. No envelope 2. SS+ linear RNA 3. Icosahedral capsule 4. Many types: Polio, Echo, Rhino, Coxsackie, HAV
Hepevirus1. No envelope 2. SS+linear RNA 3. Icosahedral capsid 4. HEV
Calciviruses1. No envelope 2. SS+linear RNA 3. Icosahedral capsid 4. Norwalk virus -viral gastroenteritis
Flaviviruses1. Enveloped 2. SS+linear RNA 3. Icosahedral capsid 4. HCV, Yellow fever, Dengue, St. Louis encephalitis, West nile virue
Togaviruses1. Enveloped 2. SS+linear RNA 3. Icosahedral capsule 4. Rubella (german measles), Eastern equine encephalitis, Western equine encephalitis
Retroviruse1. Enveloped 2. SS+linear RNA 3. Icosahedral capsule 4. Have reverse transcriptase 5. HIV, HTLV
Coronaviruses1. Enveloped 2. SS+linear RNA 3. Helical capsule 4. Common cold and SARS
Orthomyxoviruses1. Enveloped 2. SS-linear 3. Helical capsule 4. Influenza virus
Paramyxoviruses1. Enveloped 2. SS- linear nonsegmented 3. Helical capsule 4. Parainfluenza -croup, RSV, Mumps
Rhabdoviruse1. Enveloped 2. SS - linear RNA 3. Helical capsule 4. Rabies
Filoviruses1. Enveloped 2. SS - linear RNA 3. Helical capsule 4. Ebola/Marburg hemorrhagic fever - often fatal
Arenaviruses1. Enveloped 2. SS - circular 3. Helical capsule 4. LCMV - lymphocytic choriomeningitis virus, Lassa fever encephalitis - spread by mice
Bunyaviruses1. Enveloped 2. SS - circular RNA 3. Helical capsule 4. California encephalitis, Sandfly/Rift valley fevers, Crimean-Congo hemorrhagic fever, Hantavirus - hemorrhagic fever pneumonia
Deltavirus1. Enveloped 2. SS - circular RNA 3. Helical capsule 4. HDV
Negative stranded virusesThey have to bring polymerase to make a positive strand - include: Arenavirus, Bunya, Paramyxo, orthomyxo, Filo, Rhabdo
Segmented viruses 1. All RNA 2. Bunya, Ortho, Arena, Reo (BOAR), Influenzae too - can undergo reassortment that causes antigenic shift
Picornavirus1. Small RNA virus 2. Polio, Echo, Rhino, Coxsackie, HAV 3. RNA translated into 1 large polypeptide that is cleaved by proteases into functional viral proteins 4. Can cause aseptic viral meningitis
Rhinovirus1. Picornavirus 2. Nonenveloped RNA 3. Cause of common cold 4. >100 serotypes
Yellow fever virus1. Flavivirus (also arbo) 2. Transmitted by Aedes mosquitos 3. Monkey and human reservoir 4. High fever, black vomitus, jaundice 5. Councilman bodies (acidophilic inclusions) may be seen in liver
Rotavirus1. Segmented dsRNA reovirus 2. Most important global cause of infantile gastroenteritis 3. Major cause of acute diarrhea in US during winter 4. Villous destruction ↓ absorption of Na+ and water 5. ROTA= right out the anus
Orthomyxovirus1. Enveloped 2. ssRNA with segmented genome 3. Hemaglutinin (promotes viral entry) 4. Neuraminidase (promotes progeny release) 5. World wide flu epidemics - Patient at risk for fatal bacterial superinfection
Influenza genetic shift1. Leads to pandemic 2. Reassortment of viral genome
Influenza genetic drift1. Minor (antigenic drift) changes based on random mutation 2. Leads to epidemic
Rubella virus1. Togavirus - 2. Causes 3 day (german) measles 3. Fever, lymphadenopathy, arthralgias, fine truncal rash. 4. Causes mild disease in children but serious congenital disease (a TORCH disease)
Paramyxovirus1. Disease in children 2. Parainfluenza (croup), mumps, measles, RSV 2. All contain surface F(fusion) protein which causes resp epithelial cells to fuse and form multinuclear cells 3. Palivizumab is used in RSV to neutralize F protein
Rubeola1. Paramyxovirus 2. Causes measles 3. Koplik (red with blue-white center) spots on buccal mucosa are diagnostic 4. SSPE (years later), encephalitis, giant cell pneumonia (rarely, in immunosuppressed) 5. Rash spreads from head to toe - do not confuse with roseola 6. 3 Cs of measles = cough, Coryza, Conjunctivitis
Mumps virus1. Paramyxovirus 2. Parotitis, Orchitis (testes inflammation), aseptic meningitis 3. Can cause sterility (esp after puberty)
Rabies virus1. Negri bodies (cytoplasmic inclusion in neurons) 2. Bullet shaped capsid 3. Long incubation period (wks to mos) allowing immunization after exposure 4. Fever, malaise→agitation, photophobia, hydrophobia→paralysis, coma→death 5. Travels to CNS by retrograde up axons
Arboviruses1. Transmitted by arthropods (mosquitos, ticks) 2. Dengue fever, yellow fever, hemorrhagic shock syndrome
HAV1. RNA picornavirus 2. Primarily fecal-oral 3. Short incubation (3 weeks) 4. No carriers
HBV1. DNA hepadnavirus 2. Primarily parenteral, sexual and maternal-fetal routes 3. Long incubation (3 months) 4. Has carriers 5. Cellular RNA poly transcribes RNA from DNA template, reverse transcriptase transcribes DNA genome from RNA intermediate 6. Virion enzyme is DNA-dependent DNA polymerase
HCV1. RNA flavivirus 2. Transmitted primarily via blood 3. Common cause of post transfusion hep and hep among IV drug users 4. Chronic, Cirrhosis, Carcinoma, Carriers
HDV1. Defective virus requires HBsAg as its envelope. 2. HDV can coinfect w/HBV or superinfect (worse prognosis)
HEV1. RNA hepevirus 2. Transmitted enterically, causes water-borne epidemics 3. High mortality in pregnant women
IgG HAVab indicatesprior infection of HAV - protective against reinfection
IgM HAVab indicatesactive HAV
HBsAg indicatescarrier state for HBV w/continued presence
HBsAb indicatesimmunity to hep B
HBcAgAntigen associated with core of HBV
HBcAbIgM indicated recent disease, IgG signifies chronic
HBeAga different antigenic determinant in HBV core - important indicator of active viral replication = transmissibility
HBeAbindicates low transmissibility
ALT>AST in hepatitis =Viral hep
AST>ALT in hepatitis =alcoholic hepatitis
Draw out table and time course page 173,174173, 174