Viscerotropic/Neurotropic viral dz

-blood, liver, spleen, intestines (Lg and Sm)

• -Yellow fever
• -Dengue fever
• -Mononucleosis
• -Hepatitis
• -CMV
• -HIV
• -Viral gastroenteritis
• -Viral fevers

• Flaviviridae
• RNA virus
• -arbovirus = arthropod-borne (mosquito)

• -injected into bloodstream and infects liver
• -fever, bleeding gums, bloody stool, jaundice
• -high mortality rate = internal bleeding

Vaccine available

• Dengue Fever
• Flaviviridae

-temperature fluctuations

• Flaviviridae
• RNA virus
• mosquito transmission

-replicates in platelets and WBCs

• -Sharp pain in muscles and joints
• -high fever; sweats
• -Breakbone/Saddleback fever

Vaccine NOT available

Aedes aegypti

Aedes albopicticus (Dengue)

• Hemorrhagic fever
• -skin rash
• -severe vomitting
• -shock

• Herpesviridae
• Epstein-Barr virus

• -contact with saliva; several months in saliva
• -targets B-lymphocytes in lymph nodes and spleen

• -swollen glands
• -fever
• -sore throat
• -damaged B cells

Downey cells: damaged B-lymphocytes with vacuolated and granulated cytoplasm

• Heterophile anitbody: Ab's react w/antigens from other species
• -Paul-Bunnell Test: pt's serum agglutinates RBCs of horse and sheep
• (also called Monospot Slide Test)

Burkitt's lymphoma- cancer/tumor of tissue in the jaw

Chronic fatigue syndrome

• Picornaviridae
• HAV

• -Inflammatory disease of Liver
• -anorexia
• -N/V
• -Jaundice

• -short-incubation
• -fecal-contaminated food/water transmission

-Immunity results from full recovery

• Hepadnaviridae
• HBV

• Fatigue
• Anorexia
• Dark urine (RBCs lysed)
• Clay-colored stools
• Jaundice
• Taste change- smokers develop distaste for cigarettes

• -long-incubation
• -Contact w/body fluids transmission

*more infectious than HIV

• Hepatocarcinoma
• -later in life, possibly triggered by stress/immunity

Body fluids:

• -nonsterile tatooing
• -contaminated needles
• -nonsterile dental tools
• -sexually transmitted

• Flaviviridae
• HCV

• Slow liver damage and cirrhosis
• -Contaminated tatooing, drug users, organ transplants

• Alpha Interferon
• Ribivirin

• Hepatitis C
• Yellow fever
• Dengue fever
• West Nile encephalitis

several viruses:

• Rotavirus (most common)
• Norovirus
• Cocksackie virus
• Echovirus
• Hep A

• Colorado tick fever
• Reoviridae
• Bunyaviridae: Sandfly fever, Rift Valley fever

• Arenaviridae (Lassa fever)
• Marburg and Ebola
• Filoviridae

• -cause capillaries to burst
• massive bleeding = death

• Arenaviridae
• RNA virus

rodents/rats = reservoir

Bunyaviridae

• -Fever
• -Acute renal failure
• -Respiratory failure

-airborne viral particles from dried urine/feces of rodents (deer mice)

Herpesviridae

• -can produce serious birth defects
• -primary infection usually asymptomatic
• -owl eyes CPE in nucleus of neuron soma

-transmitted with saliva, breast milk, sex, blood

• -elderly
• -immunocompromised
• -AIDS pts--> 1/3 aquire CMV-retinitis

• Retroviridae
• Human immunodefiency virus (HIV)

• -retrovirus = reverse transcriptase
• -provirus = dsDNA from mRNA enters chromosome

-AIDS = clinical manisfestation of HIV infection

• Cellular targets:
• -T helper lymphocytes
• -Monocytes
• -Macrophages
• -Microglia

gp120 and gp41 = proteins of peplomers in envelope

peplomer spikes

• gp120 = attachment proteins; attaches to CD4 receptors
• gp41 = fusion protein

• gag - viral capsid proteins
• pol - reverse transcriptase

LTR- long terminal repeat

LTR-->gag-->pol

• -coreceptor of T-helper cells (TCR)
• -CD4 amplifies signal generated by TCR by recruiting enzyme lyrosine kinase lck

-lck- activates molecules involved in signaling cascade of activated Tcell (cytokines!)

-CD4 recognizes MHC Class II

CD4 = primary receptor used by HIV-1 to gain entry

• -attached to CD4 with gp120 in envelope
• -binding causes conformational change of gp120--> allows HIV-1 to bind to chemokine recptors CCR5 and CXCR4

-gp41 structural change--> HIV inserts into host cell and outer membrane of virus fuses w/cell membrane

AIDS = < 200 CD4 T-cells

4-8wks after exposure = asymptomatic or mild flu-like

• Opportunistic infections:
• Karposi's sarcoma
• cervical cancers
• lymphomas
• CMV-retinitis
• any bacterial disease

• 1. Western Blot for HIV proteins
• 2. ELISA test for Ab against HIV

• 1. Reverse transcriptase inhibitors
• -drugs act as nucleotide analogs; stop transcription
• -Lamivudine, AZT, ddI, ddC

• 2. Protease inhibitors
• -Invirase, Indinavir, Ritonavir

HAART- drug combinations

highly active antiretroviral therapy; not a cure

• 1. Reverse transcriptase inhibitors
• 2. Protease inhibitors

Retroviruses mutate very rapidly:

reverse transcriptase has no corrective functions

• Rabies- Rhabdoviridae
• Polio- Picornaviridae
• West nile- Flaviviridae
• Lymphocytic chloriomeningitis

• Rhabdoviridae
• bullet-shaped
• -transmission via saliva
• -disease depends on viral load the human receives
• -incubation = 6d-1yr

• Fever
• HA
• Tension paralysis
• hydrophobia
• -very deadly

gamma-gobulin

Picornaviridae

• -contaminated food/water
• -meningitis
• -medulla infection = bulbar polio
• -upper body nerves affected--> mild to severe Upper body paralysis

Vaccine: Salk's, Sabin's

formaldehyde inactivated vaccine

attentuated oral vaccine

Flaviviridae

• -transmitted via mosquito bite (Culex mosquito on birds)
• -can develop encephalitis and meningitis

vaccine for horses NOT humans

Culex mosquito vector from birds

Arenaviridae

• -exposure to rodent feces
• -mild-influenza s/s
• -fever
• -malaise
• -HA