Micro 2 final

• 5 different viruses causing liver disease
• viruses are resistant to low pH, organic solvents and detergents

• picornavirus
• causes infectious hepatitis

• fecal-oral transmission
• 40-50% of total hep cases
• only 1 HAV serotype
• humans are the only resovoir, mainly children

• intestines-> blood-> liver
• 15-40 day incubation -> symptoms (fever, jaundice, headache, vomitting, liver inflammation, pain)
• 99% complete recover in 8-12 weeks

• sanitation
• chlorinate water
• killed virus vaccine for at risk individuals

• hepadnavirus (DNA)
• serup hep
• HBV virons called Dane particles
• eight subtypes

• partial dsDNA genome
• enters blood, finishes dsDNA
• mRNA-> reverse transcriptase-> DNA-> RNA degrades leaving partial dsDNA

spread by body fluids, injections, and pregnancy

• 50-180 day incubation
• symptoms: jaundice, fatigue, pain, decreased appetite, nausea, vomitting, joint pain
• 2% fatality rate
• strong cell mediated immunity = self-limitting
• weak immunity= chronic hepatitis

• avoid blood
• active immunizations made in yeast
• passive immunizations of immune globulin

flavivirus-> causes non-A, non-B hep

• reservoirs= human and chimps
• causes post transfusion hep
• transmission via body fluids
• male-> female > male -> male

• blood-> hepatocytes
• persistant infection= chronic disease
• 6-7 week incubation -> symptoms (jaundice, pain, nausea, dark urine)
• virus cleared 15-25% of the time in 4-6 months

ribavirin and interferon- removes HCV RNA from blood 70% of the time

• cant code for surface protein-> HBV helper virus
• intravenous drug useres are #1 infected, then sex
• must be aquired with HBV or in someone who already has HBV

• small, round, +SS RNA, naked
• enteric non-a, non-b hep
• fecal-oral transmission
• not usually person to person

• 16-60 day incubation
• jaundice, malaise, pain, nausea
• no chronic infection

• orthomyxovirus family cuasing acute infection
• enveloped, ss RNA of 8 fragments
• internal antigens are type specific

• influenza A- humans and animals
• influenza B- humans only
• influenza C- humans only

A or B, B is usually a milder form

external antigens (HA and NA) are strain specific and have much variation

• from mutation
• takes years for major change

• reassortment of influenza A antigens
• little immunity= apidemic/pandemic
• 16 HA and 9 NA found in ducks

• aerosols from person to person
• 24-48 hour incubation
• fatalities in the elderly and children

• croup in kids
• primary influenza virus pneumonia
• secondary bacterial infection

• respiratroy cells die causing decreased ciliary clearance
• symptoms: fever, myalgia, headache, ocular symptoms, dry cough, nasal discharge

Reye's syndrome- causes encephalitis in children, fatal 40% of the time, associated with asprin!

• amantadine- virus cant attach to cells
• relenza and timiflue- no new virons realeased

• new annual vaccine against suspected strains
• short-lived protection

• complication of influenza vaccine
• body attacks its nerves
• happens 1/1,000,000 vaccinations

• small, spherical, naked, +RNA
• respiratory and GI

• fecal-oral transmission
• infect oral-pharyngeal mucosa and lymph tissue
• usually asymptomatic

• poliomyelitis
• coxsackie virus
• echovirus

• asymptomatic
• abortive
• non-paralytic
• paralytic

• 90% of infections
• occurs when restriced to the GI tract

• 5% of infected individuals
• fever in 1 week
• general malaise with vomitting, headache, sorethroat

• aseptic meningitis- virus in brain and meningies, stiff neck, vomitting
• spontaneous recovery

• 4 days after symptoms, virus from blood-> anterior horn -> motor cortex
• different amounts of paralysis depending on areas of infection

virus no longer present but further loss of affected muscles

• for polio
• formalin-killed wild-type virus injection
• good humoral immunity
• prevents virus from entering neurons

• for polio
• live virus given orally
• grows in gut, cant migrate to meurons
• causes humoral and cell mediated response

• usually incorrectly diagnosed
• type A and Type B

• herpangina
• hand, foot and mouth disease
• hemorrhagic conjunctivitis
• aseptic meningitis

• internal symptoms
• localized internal lesions
• meningitis, fever, and rashes
• pleurodynia - the devils grip
• myocarditis and pericarditis

• fecal oral transmission
• similar to polio

human orphan virus

• aeptic meningitis
• repiratory infection
• gastroenteritis
• skin rash
• fever

• can cause the common cold (1/3 of all colds)
• 100+ serotypes

• aerosol transmission and fomites
• infects the upper respiratory tract

• symptoms: discharge/blocked nasal passages, sneezing, sore throat
• IgA in nasal secretions (#1), IgG in blood
• immunity against particular serotype lasts 1-2 years

• enveloped
• causes common cold and SARS

• atypical pneumonia
• person to person contact by aerosols
• hand washing to prevent
• days 2-7= dry cough
• develops into pneumonia

• non enveloped
• cause rotavirus

• 600,000-850,000 deaths/year
• infects middle and upper intestinal villi= cell dysfunction and death causing watery diarrhea leading to dehydration and death

• bullet shaped
• causes rabies

• asia, africa, and the americas
• transmitted by animal bite thru saliva
• human to human transmission by corneal transplants

• binds to N or Ms cells via nicotinic Ach r/cs (remains 1 week - years, 30 day average)
• nerves-> dorsal root ganglia/spinal cord-> brain-> encephalitis
• prodone: itching, pain, fever, headach, GI
• post-prodome: behavioral changes, hydrophobia (50%), seizures/hallucinations, then comatose, respiratory paralysis, death

• Furious form: aggitation and aggresion followed by depression, paralysis and death
• Dumb form: lethargic, depressed, and death

negri bodies (eosinophilic inclussions of aggregates of nuclocapsids in neurons)

• vaccine
• post-exposure prophylaxis
• inactivated vaccine
• HRIG (human rabies immunogolbulin) with vaccine
• possibe preventative vaccine

Arthropod Borne

• equine encephalitis virus
• west nile virus
• yellow fever
• Dengue fever
• Dengue hemorrhagic fever

• family togavirdae
• resovoir: birds, small mammles, horses
• transmission: mosquitoes
• humans: dead end host with mild flue symptoms, more severe in children

• family flavivirdae
• no symptoms in 75% of cases and mount immune attack

• resovoir: birds
• transmission: mosquitoes

• symptoms: fever, ehadache, body aches, nausea, vomiting
• 1/150 develop severe meningeoencephalitis

• family flavivirda
• africa and south america
• transmission: mosquitoes

• possible liver, kidney, and heart involvment
• GI hemorrhage= bloody vomit
• jaundice
• delerium, seizures, coma
• 5% mortality

american army surgeon, proved mosquito transmission of yellow fever

• no treatment
• eradicate mosquitoes
• vaccine, live attenuated. 1 dose lasts 10 years

• family flavivrdae
• caused by 4 different arboviruses
• tropic and subtropic mosquitoes
• self-limiting, uncomfortable but not fatal

• family flavivridae
• occurs when someone with immunity to 1 type of dengue is infected with another type

• benyavirdae
• filoviruses

• enveloped
• 250+
• most are arthropod borne causing persistant non-lethal infections

• targets primates
• viral hemorrhagic fevers: massive bleeding from every orafice
• endemic to Africa
• host: fruit bat?
• 2 viruses: ebola, marburg

• enveoloped
• reverse transvriptase
• viral DNA into host DNA

• oncoviruses (HTLV-1 and 2)
• Lentiviruses (HIV-1 and 2)

• oncovirus
• 1 in 25 infected develop cancer
• transmission: sex, blood, baby

• oncovirus
• uncommon
• hairy t cell leukemia

• SIV
• HIV-1
• HIV-2

• affect primates
• 18 SIVs infecting 20 primates
• possible cause of HIV

• chimps
• most like HIV-1
• chimps to humans?

• sooty mangabey
• most like HIV-2

• 2 genetically and antigenetically different types
• HIV-1: current pandemic
• HIV-2: west africa

• 3 groups: M, N, and O
• M group has 11 subtypes: A-K

M-B

• transmitted best by MSM and blood
• infects rectal mucosa

• in africa
• transmitted heterosexually
• infects langerhans cells in vagina, cervix, and penis

• 1986
• causes AIDS more slowly than HIV-1

• HIV-1: west africa from SIV cpz to humans
• earliest HIV case in Congo in 1959

HIV is an injustly maligned by-stander that is not the cause of the disease (AIDS)

• 1. virtually all AIDS patients have HIV
• 2. HIV isolated from virtually all AIDS patients and seropositive individules with early and late stage disease
• 3. Accidentiliy HIV infected health care workers get AIDS
• 4. HIV isolated from these people

HIV from simians to humans via oral polio vaccin in Africa in 1950s

• enveloped
• cone shapped capsid
• Gp 120 interacts with CD4 r/c on T cells

• reverse transcriptase: RNA to dsDNA
• intigrase: dsDNA into host chromosome
• Protease: cleaves -pol and -gag

• western countries: type M-B via MSM
• asia/africa: type M-C via heterosexuals
• 1/3 infected are women and commercial sex workers

• blood transfusion- 1985 screen for antibodies, 1992 ELISA
• at risk: hemophiliacs, IV drug users, needle stick accidents

• occupational
• mother to child via birth or milk
• not transmitted by saliva, mosquitoes, or ticks

• sexual transmission: infects langerhans cells
• spreads to lymph causing primary viremia (most infectious stage)
• CD4 cells: memory cells-> active easily infected by HIV-1, die in a few days
• -> resting cells act as resovior

• 1. primary viremia
• 2. primary symptoms
• 3. individual variation
• 4. adapted immune response
• 5. latent phase
• 6. dynamic equilibrium
• 7. second phase of decay
• 8. onset of AIDS

• lots of cells infected
• high titer in blood (days 4-11)

• flue-like or asymptomatic
• fever, night sweats
• 6 days- 6 months after infection

• rate of immune cell depletion varies
• genetic difference in r/cs

• cytotoxic T-lymphocytes
• antibody production

• cellular latency
• clinical latency= not AIDS right away

6-9 months b/t infected cells, viral replication and CD4 production

loss of latent CD4

• 1 year-15 years after infection
• T4 cells below 200, immune activity drops
• AIDS: onset of HIV-associated oportunistic infections

• infected person does not test positive with western blot or ELISA even though they have a high titer and symptoms
• could last for 6 months

• little early variation in single patient
• later infection shows variability due to: selective immune response and high mutation rate
• mutation resulting in evolution of SI HIV
• syncytia of CD$ cells, better at transfering virus

uses CCR-5 and CXCR-4-co-r/cs to infect multiple cell types

• viral (HHV 8) kaposi's sarcoma
• hodgkins lymphoma
• b cell lymphoma (burketts)
• HPV cancers- anogenital

• AIDS= 58 million worldwide
• 90% in developing countries
• AIDS increasing in females
• 70% of HIV people live in sub-Saharan Africa

• HIV-PCR: # of particles in blood
• ELISA and western blot: antibody titer

• HAART: triple drug therapy
• reverse transcriptase inhibitors
• protease inhibitors

GOAL: provide sterilizing immunity, acts agains free virus and HIV infected cells

• retrovirus: RT and RNA polymerase 2 lead to rapid polymorphism, vaccine would likely not effect all strains
• dont know how HIV leads to CD4 depeletion
• No good animal models: chimps dont develop AIDS