zoonotic viral dz Flashcards
list the zoonotic viruses
rabies, hantavirus, filovirus, arenavirus, paramyxovirus, arbovirus, HIV, influenza, SARS-CoV and MERS-CoV
Which zoonotic viruses transmit from animals to humans but do not exhibit human to human
transmission under natural conditionsWhich zoonotic viruses transmit from animals to humans but do not exhibit human to human
transmission under natural conditions
Rabies virus, Sin Nombre virus, West Nile virus
Which zoonotic viruses Transmit from animals to humans and can cause limited cycles of human to human transmission
Lassa fever virus, Machupo virus, Ebola virus, Marburg virus, Nipah virus, Monkeypox virus
Which zoonotic viruses Originated or persist in animals but can cause self-sustaining chains of
transmission in humans (human to human OR vector to human)Which zoonotic viruses Originated or persist in animals but can cause self-sustaining chains of
transmission in humans (human to human OR vector to human)
influenza, SARS, HIV, yellow fever, Dengue,
main source of rabies transmission
dogs (worldwide) and bats/ skunks in colorado. 30-50% occur in children living in poverty. Also occurs in racoons, bats, skunks, foxes. Transmission via bite or mucosal contamination with infectious material (saliva). Each host harbors a unique rabies virus variant
rabies virus structure
rhabdoviridae lyssavirus- Bullet-shaped virion. non-segmented negative-strand RNA genome (12 kb). lipid envelope. Post-exposure prophylaxis is effective against all strains
of Rabies virusrhabdoviridae lyssavirus- Bullet-shaped virion. non-segmented negative-strand RNA genome (12 kb). lipid envelope. Post-exposure prophylaxis is effective against all strains
of Rabies virus
Rabies clinical
Incubation: 1-3 months (can be up to 1 year). Furious (encephalitic) form (80%): Difficulty swallowing, Hydrophobia (Terror and excitation with spasm of inspiratory muscles, larynx, and pharynx precipitated by attempts to drink),
Episodes of hallucination, Hypersalivation,Brain stem dysfunction-coma-death. Paralytic form (20%): Lack of major features of furious form, Quadriparesis, Multiple organ failure-deathIncubation: 1-3 months (can be up to 1 year). Furious (encephalitic) form (80%): Difficulty swallowing, Hydrophobia (Terror and excitation with spasm of inspiratory muscles, larynx, and pharynx precipitated by attempts to drink),
Episodes of hallucination, Hypersalivation,Brain stem dysfunction-coma-death. Paralytic form (20%): Lack of major features of furious form, Quadriparesis, Multiple organ failure-death
rabies pathogenesis
virus replicates at site of wound > infects neurons innvervating site of wound > retrograde spread through axons (no viremia) > replication in motor neurons and local dorsal root ganglia > centrifugal spread along nerves to salivary glands, skin, cornea > sx develop
rabies diagnosis
Detect rabies virus antigen or RNA in serum, CSF, saliva, skin sample from neck (check animal brains if animal is available). Can use direct fluorescence assay, RT-PCR, ELISA. Negri bodies eosinophilic inclusion bodies of virus particles in the cytoplasm of infected neurons) are seen upon autopsy
rabies post exposure prophylaxis
Immediately wash with soap and water. 1. Human rabies virus immunoglobulin (HRIG): Passive-immunization around area of wound—neutralize virus no later than 7 days after first vaccine dose. 2. Rabies virus vaccine (4 dose vaccine schedule): Inactivated vaccine. Administered IM at different site than HRIG. Additional doses at days 3, 7, and 14
rabies prevention
mass vaccination of dogs is cheaper than PEP
Hantavirus structure and transmission
Segmented (3), negative sense, ssRNA genome.
diseases caused by hantavirus
Hemorrhagic fever with renal syndrome (HFRS) and Hantavirus pulmonary syndrome (HPS)
Hantavirus transmission
Chronically infected rodents (absence of overt disease) transmit from rodent to rodent via scratching, biting. Human infection primarily due to exposure to aerosols of rodent urine. Mucus membrane contact and skin breaches are also consideration.
What is the main hantavirus in North America and what is the disease it causes
Sin Nombre virus- causes hantavirus pulmonary syndrome
Hantavirus pulmonary syndrome prodrome clinical sx/ labs
prodrome: fever, chills, myalgia for 3-7 days. Then pain in legs and back. Presence of productive cough at onset of illness is NOT consistent with HPS. Laboratory findings: Low platelet count, Neutrophilia, Elevated LDH and AST. Rodent exposure
Hantavirus pulmonary syndrome disease progression
Transition from prodrome to respiratory failure is rapid: 12-24 hours. Tachypnea, Tachycardia
Pulmonary edema and inflammation, Crackles or rales on lung examination. Hypotension and shock. In severe cases, patients require intubation and mechanical ventilation. Death due to respiratory failure, shock, and myocardial dysfunction
HPS treatment
limited to supportive care, respiratory support, blood oxygenation if severe.
Hemorrhagic fever with renal syndrome
influenza-like symptoms for 1 week (high fever, headache, malaise, chills). This phase is followed by a hypotensive phase characterized by thrombocytopenia and petechial hemorrhage. Approx. 10-15% of patients exhibit shock and renal failure contributes to over half all deaths
Filoviruses structure
Two genera: ebolavirus and Marburgvirus. Non-segmented negative-sense RNA genome. Bacilliform to filamentous morphology, Nucleocapsid (viral proteins + -RNA genome), Matrix protein, Envelope (derived from host PM), Membrane glycoprotein
filoviruses transmission
spread among animals (bats, apes) can then spread to humans. Human to human spread then occurs via contact btw bodily fluids (blood, urine, saliva, etc). Virus can enter via cuts or abrasions, or mucus membranes. Droplet transmission possible, but not airborne
droplet vs airborne transmission
In the droplet route, the pathogen falls to the ground in large droplets. The pathogen doesn’t make it very far away from the source of the fluid. In the airborne route, a virus can travel more than 30 feet in tiny droplets and can stay in the air for minutes or hours
Where do most filovirus outbreaks occur
remote regions of central Africa
Ebola early sx
2-21 days after exposure: fever, headache, fatigue, diarrhea, vomiting, weakness, stomach pain, unexplained bleeding, joint/ muscle aches
Ebola treatment
IV fluids/ electrolyte balance, maintain oxygen status and BP, treat infections if they occur
Henipavirus - family, diseases,
new genus within the family Paramyxoviridae (Mumps, Measles, RSV). Causes respiratory and neurological complications. High pathogenicity in humans, low in pigs, subclinical in bats
What factors contributed to emergence of Nipah virus
Pig farming, fruiting failure of forest trees (drough conditions, forest fires), forest fruit bats migrated to orchards and pig farms
HIV-1 vs HIV-2
HIV-1: pandemic virus. HIV-2: restricted to W. Africa
