Human Diseases Flashcards
Airborne Viruses
Chickenpox, Shingles, Influenza, Measles, Mumps, Respiratory Syncytial Virus, Rubella, SARS, Smallpox.
Chickenpox
(Varicella-Zoster Virus). DNA virus.
Airborne; human reservoir
Shingles
(Herpes Zoster). Reactivated chickenpox.
Treatment: acyclovir, antivirals
Influenza
RNA virus.
Airborne; various animal reservoirs.
Secondary infections common (pneumonia)
Treatment: inactivated virus vaccine, symptomatic therapy
Antigenicity constantly changing due to antigenic drift (accumulation of mutations in a geographic area) and shift (reassortment of genomes when two strains infect the same cell).
Influenza Subtypes
Hemagglutinin (HA) and Neuraminidase (NA). Each is a membrane surface protein that function in viral attachment and virulence.
Measles
(Rubeola). RNA Virus.
Airborne; causes subacute sclerosing panencephalitis which is a progressive degeneration of the CNS.
Treatment: symptomatic therapy, MMR vaccine
Mumps
RNA virus.
Airborne; can cause meningitis and orchitis (testes inflamm.)
Treatment: symptomatic therapy, MMR vaccine
Respiratory Syncytial Virus
RNA (-) virus.
Airborne or contact; dangerous for children; causes cold-like symptoms which may progress into bronchitis/pneumonia.
Treatment: inhaled ribavirin, RSV immune-globulin
Rubella
(German Measles). Enveloped RNA virus.
Airborne; causes mild rash; congenital version is bad for pregnancy, can lead to fetal death.
Treatment: MMR vaccine
Severe Acute Respiratory Syndrome
(SARS-associated coronavirus).
Airborne; can be fatal, dry cough, often pneumonia.
Treatment: none approved
Smallpox
(Variola). Linear dsDNA virus.
Airborne or contact; causes rash and high fever.
Smallpox Erradication
Made possible because:
Humans are only reservoir, there are no asymptomatic carriers, the disease has obvious clinical features, and has a short infectivity period
Arthropod-borne Viruses
From blood-sucking arthropods. West Nile Fever.
West Nile Fever
(Encephalitis). RNA virus.
Arthropod-borne; causes fever, rash, possible encephalitis (inflamed brain).
Direct Contact Viruses
Via touching, sex, etc. AIDS/HIV, Cold Sores, Common Cold, Genital Herpes, Mononucleosis, Viral Hepatitis, Warts, Viral Gastroenteritis, Poliomyelitis.
HIV
RNA retrovirus.
Direct contact; can develop into AIDS (last stage) and compromise the host immune system. Course of disease is monitored by Th cell count (below 200/uL is AIDS)
Treatment: No cure, drug cocktails often used
HIV Life Cycle
Virion has a protein spike (gp120) that attaches to CD4+ cells. Reverse transcriptase then transcribes the RNA into dsDNA which is then integrated into the host as a provirus. Can remain latent or direct synthesis of new viruses that are released via budding.
HIV Stages
Acute: few weeks after infection; mild illness; virus replicates throughout body.
Asymptomatic (latent): 6 months-10years; virus is latent, but still replicating.
Chronic Symptomatic: can last for years, virus still replicating, CD4+ count drops significantly, opportunistic pathogens emerge.
AIDS: immune system no longer viable, CD4+ count below 200/uL or 14%.
HIV Drugs
Nucleoside RT Inhibitors (AZT)
Nonnucleoside RT Inhibitors
Protease Inhibitors
Fusion Inhibitors (prevent HIV entry into cells)
Berlin Patient
Only person ever cured of HIV. Received a stem cell transplant from a donor with the CCR5 delta32 mutation (CCR5 is a co-receptor for HIV).
Cold Sores
(Herpes simplex virus 1, HSV-1). Enveloped dsDNA virus.
Direct contact; infect epithelium around mouth, can be active or latent.
Treatment: acyclovir, antivirals, no vaccine
Common Cold
(Rhinoviruses). ssRNA viruses.
Airborne or direct contact
Treatment: symptomatic therapy
Genital Herpes
(HSV-2). Linear, enveloped dsDNA virus.
Direct contact; common STD, can be active or latent
Treatment: acyclovir, antivirals, no vaccine
Mononucleosis
(Epstein-Barr virus, Herpes). Enveloped dsDNA virus.
Direct contact; infects B cells and causes enlarged lymph nodes, flu-like symptoms; lasts 1-6 weeks.
Treatment: symptomatic therapy