Lecture 23

• arthropod-borne diseases

  vector: mosquito

  all caused by family: Flaviviridae

  enveloped, positive ssRNA
• Zika virus

  discovered 1947

  symptoms: fever, rash, joint pain, red eyes

  most people infected: no symptoms

  during pregnancy: linked to microcephaly (and other brain defects)

  transmission: mosquito, sexual, pregnant woman to fetus, blood transfusion
• direct contact diseases

  common cold

  mono

  warts

  AIDS

  ebola
• common cold

  causes: rhinovirus (major), corona, adenoviruses
• rhinovirus

  positive ssRNA, naked, icosahedral

  >100 different serotypes
• mononucleosis

  Epstein-barr virus (Herpesviridae)

  transmited via saliva

  • initially entering and replicating in throat epithelial cells
  • then infects B cells, can become latent

  receptor: MHC2

  cancer: Burkitt lymphoma (B cell)
• downey cells

  enlarged T cels, responding to infected B cells

  Mono

  A) lymphocyte

  B) nucleus

  
• warts

  human papillomaviruses (HPV)

  naked, DNA

  genital warts: most common sexually transmitted disease in US

  some strains oncogenic, cervical cancer
• gardasil vaccine - warts

  virus like particle (VLP) vaccine

  capsid, no genome, noninfectious
• ebola outbreak, west africa

  as of august 2015

  total cases: suspected, probable and confirmed = 27,860

  total deaths: 12,281
• warts - tumor suppressor protein

  p53 protein, controls cell cycle and apoptosis

  HPV protein: early 6 (E6) targets p53 destruction
• ebola hemorrhagic fever


  RNA, filamentous, enveloped

  family: Filoviridae

  viral proteins block interferon, clot blood
• ebola transmission

  direct contact with blood or body fluids of infected symptomatic person

  evidence for zoonotic: fruit bats, primates

  
• food and water borne disease

  gastroenteritis: inflammation of stomach and intestine

  major causes:

  • rotavirus
  • norovirus
  • naked, RNA viruses
  • fecal oral transmission, also person to person
  • on cruise ships

  
• poliovirus

  enterovirus, RNA genome

  stable in food, water (ingested)

  multiples in throat and intestinal cells

  targets motor nerve cells in spinal cord (paralysis)

  vaccines: salk - in US (killed), sabin (live, oral)

  80% of the worlds population now live in polio free areas
• viral zoonotic disease

  75% of infectious diseases originate with animals

  currently 7.9 billion people on the planet
• rabies

  animals: multiples in salivary glands

  • bullet shaped, enveloped, RNA

  humans: tropism - for muscle and neuronal cells

  • spreads via CNS to brain - paralysis
  • 2-16 week incubation period
  • preexposure vaccination (kill)
  • slow disease progression allows postexposure vaccination

  
• pathogenesis events following inoculation of rabies virus by an animal bite

  viruses move by hijacking the neurons own transport pathways moving on microtubule tracks using dyenin and kinesin motor proteins