Viruses

1. Enteroviruses
   1. Polio, coxsackie, echovirus, enterovirus 70, Hepatitis A

      Anotações:

      • All are stable around pH 3-9. Replicate at 37 degrees celsius and use ICAM-1 cell surface receptors. Peak during summer and fall. Humans only host.
   2. Rhinovirus

      Anotações:

      • Labile at pH 3. Prefers 33-35 degrees celcius, in the nasal mucosa. Uses ICAM-1 receptors and peak during winter and spring

1. Norwalk virus

1. Rotavirus
2. Coltivirus
   1. Replication

      Anotações:

      • Enters cell by endocytosis. Capsid is partially removed from genome in endolysosome but never fully exposed in order to prevent activation of antiviral state.
   2. Pathogenesis

      Anotações:

      • Infects erythroid precursor cells without damaging them and replicates in bone marrow, heart, lungs, lymph nodes, and spleen. This way the virus remains in the mature cells and is protected from the host. On the other hand, infection of cells of the small vessels will cause hemorrhaging
   3. Vector/reservoir

      Anotações:

      • Vector is the wood tick  and reservoir is the golden mantled ground squirrel.
   4. Disease

      Anotações:

      • Colorado tick fever

1. Coronaviridae

1. Flaviridae
   1. Diseases
      1. Encephalitis

         Anotações:

         • Fever, stiff neck, vomiting, headache
         1. West Nile Virus

            Anotações:

            • For differential, exclude HSV-1
         2. St. Louis
         3. Powassan
      2. Dengue Fever

         Anotações:

         • Caused by Dengue virus. Low grade fever for 1-3 days, headaches, Eye, bone, and muscle pain as well as itchy rash. Dengue hemmorhagic fever is due to the second serotype of virus and can lead to a sever complication called dengue shock syndrome
         1. Similarity to Chickunguya

            Anotações:

            • Both virus are transmitted by the same mosquito and show similar clinical symptoms and since they circulate around the same area, can co-infect. However, dengue fever is more likely to cause neutropenia and thrombocytopenia while chinkungaya is more likely to cause lymphopenia. Important to rule out dengue because proper management of dengue can improve symptoms
      3. Yellow fever

         Anotações:

         • Caused by yellow fever virus. Hemmorhagic fever with high fatality- usually in about 5 days. Causes degeneration of the liver with jaundice. Causes kidney, heart, and GI damage Treatment: vaccine available. also control of vector
      4. Hepatitis C Virus
   2. Diagnoses/Prevention

      Anotações:

      • Look for IgM and IgG bodies. Mosquito control is the best prevention
2. Togaviridae
   1. Rubella Virus
   2. Alpha virus

      Anotações:

      • Causes encephalitis and is arthropod borne. Has a bird mosquito life cycle which is important and can expand to horses and humans which are dead end hosts. Lytic infection in bird and persistent in mesquitos
      1. Syndromes
         1. Encephalitis

            Anotações:

            • Found in North and South America, carribeans
         2. Fever with arthritis, myalgia, and rash

            Anotações:

            • Found in Asia and Africa with the Aedes mesquito as vector and the Chikungya strain of the virus
      2. Pathogenesis

         Anotações:

         • Bite causes primary viremia (FLU), then spreads to capillary endothelial cells, macrophages, monocytes, and RE cells causing RASH. Secondary viremia follows next and can cause damage to the brain, muscles, and joints. However, if antibodies are present, secondary viremia does not occur.
      3. Diagnosis

         Anotações:

         • Diagnose serologically by looking for IgM or IgG. usually a 4-fold rise in the antibodies is diagnostic

1. Retroviridae
   1. Spumaretrovirinae
      1. Spuma virus

         Anotações:

         • Animal and human diseases
   2. Orthoretrovirinae
      1. animal pathogens
         1. Alpha, beta, gama, epsilon retrovirus
      2. Human and animal pathogens
         1. HTLV (deltaretrovirus) and HIV (Lentivirus)

1. Hepatitis Virus D

Anotações:

• Virus replication: Requires mitotically active cells Prefers erythroid precursor cells= anemia Attaches to erythrocyte P antigen

Anotações:

• All cause latent infections reactivated by environmental and host factors

1. HSV-1, 2
2. VZV
3. EBV
4. CMV
5. HHV-6,7,8

1. Hepatitis B Virus

1. Replication process

   Anotações:

   • 1) Cellular enzymes come and remove outer membrane 2) Early transcription uncoating enzyme 3) uncoating enzyme unwraps genome 4) delayed early transcripts produce DNA polymerase 5) Virions released via cellular villi
2. Molluscum Contagiosum, small pox, vaccinia