Humans and viruses I and II
Professor Robert Siegel
Autumn + Winter 2008
Central European Encephalitis Virus (CEEV); Murray Valley Encephalitis Virus (MVEV);
TT Virus; Sabia Virus (Brazilian Hemorrhagic Fever)
Central European Encephalitis Virus (CEEV)
Description: CEEV is a tick-borne encephalitis of group B arboviruses. It is classified under the Flaviviridae family and flavivirus genus. Mosquito-borne and tick-borne flaviviruses evolved via a common ancestral line but diverged from nonvector borne viruses in the hepacivirus and pestivirus genera.
Power: One of the more notable infectious diseases in Europe, the former Soviet Union, and Asia. Several thousand cases are reported annually, but many other cases go unreported.
Attacks: Transmitted by the tick, Ixodes ricinus, which is both vector and reservoir of CEEV. Also transmitted by ingesting infected goat, sheep, or cow milk. Vertical transmission from infected mother to fetus can also occur.
Outcome: Infection usually presents as mild influenza-type illness or as benign aseptic meningitis. Fever is often biphasic, and there may be severe headache and neck rigidity, with transient paralysis of the limbs, shoulders or sometimes the respiratory musculature. A few patients are left with residual paralysis. Fatal meningoencephalitis occurs in up to 5 percent of patients.
Speed: Incubation period is 7 to 14 days. The convalescent period can be long.
Vaccines: An inactivated TBE (tick-borne encephalitis) vaccine is available in Europe and Russia. However, adverse vaccine-reactions in children limit the utility of the product.
Behavioral: During the months from April to November when cases of CEE are highest, those with recreational or occupational exposure to rural areas should wear long pants—and other protective clothing—to prevent tick exposure. Insect repellants can also ward off ticks.
Treatment: There is no specific drug therapy, just supportive care based on syndrome severity. Anti-inflammatory drugs like corticosteroids may be considered under certain circumstances to alleviate symptoms. Intubation and ventilatory support may be necessary.
Game Action: Take a hike and contract CEEV. Sit out a turn.
One Liner: Don’t go near ticks, fear encephalitis, and you’re in the clear—no CEEV!
Murray Valley Encephalitis Virus (MVEV)
Description: A mosquito-borne encephalitis. Is classified under the Flaviviridae family (formerly Togaviridae) and flavivirus genus. Mosquito-borne and tick-borne flaviviruses evolved via a common ancestral line but diverged from nonvector borne viruses in the hepacivirus and pestivirus genera.
Power: An infectious disease recognized in parts of Australia, New Zealand, and New Guinea. Can infect humans, wild birds (main reservoir), and other mammals.
Attacks: Transmission via bite of infected Culex annulirostris mosquito.
Outcome: Involves brain and spinal cord meninges, headache, high fever, nuchal rigidity, neurologic signs, stupor, coma, spastic quadriplegia, convulsions and paralysis including respiratory, and progressive CNS damage. Progresses rapidly in infants who experience a fatality rate up to 60 percent.
Speed: Incubation period 5 to 15 days.
Vaccines: No vaccine is currently available.
Behavioral: Use of bed nets; insecticides; protective clothing; anything else to avoid mosquito bites.
Treatment: No specific treatment; supportive care
Game Action: Contract MVEV in the Outback. Barely escape. Go back two squares.
One Liner: Watch for Culex, don’t catch MVEV!
Description: TT virus (TTV) named after the initials of the patient in whom virus was first discovered. Part of the Circoviridae family.
Power: Wide spread throughout world and can be present in 50 to 95 percent of healthy individuals—highest frequencies in South America, Central Africa, and Papua New Guinea
Attacks: Large arsenal of attacks: parenteral transmission through blood and blood products; fecal-oral transmission; sexual transmission; and vertical transmission.
Outcome: Liver disease and hepatitis (fulminant and chronic)—but no clear-cut evidence that TT virus directly causes hepatitis.
Speed: Infection largely persistent
Vaccines: No vaccine
Behavioral: Screening blood for TT virus before transfusions; safe sex practices; avoid alcohol and fatty foods
Treatment: Usual hepatitis B and C treatments: antivirals, Interferon Alpha, Lamivudine, Baraclude, Ribavirin
Game Action: Each player is stormed by TTV; each player donates $100 to TTV research.
One Liner: TTV everywhere you can see!
Indian Journal of Medical Research, TT Viruses: How much do we Know? Priya Abraham.<http://findarticles.com/p/articles/mi_qa3867/is_200507/ai_n15347943>
Sabia Virus (Brazilian Hemorrhagic Fever)
Description: Of the Arenaviridae family and arenavirus genus, Sabia virus is a lethal robovirus. A biocontainment level BSL-4 agent. The genome is 7400 nucleotides (RNA) and is multipartite, each segment in a separate nucleocapsid and the nucleocapsids surrounded by one envelope. Virus codes for a RNA-dependent RNA polymerase.
Power: Has a mortality rate of about 1 in 3; hemorrhagic fever is common and morbidity is high.
Attacks: Virus has an enzootic life cycle and is occasionally transmitted from rodents to humans or other vertebrates. Human infection is thus incidental to the natural cycle and occurs when an individual comes in contact with excretions of infected rodents—via ingestion of contaminated food, direct contact between exposed cuts and feces, and inhalation of aerosolized excretions. Parenteral transmission between humans is also possible if one individual is infected.
Outcome: Symptoms include fever, malaise, vomiting, pronounced sore throat, mucosal and gastrointestinal bleeding, bleeding gums, edema, hypotension, and shock. Death comes to 1 in 3 infected individuals.
Speed: SABV has an incubation period of 7-14 days. Initial signs and symptoms are often indistinguishable from other viral diseases—such as yellow fever. Swift diagnosis is needed, though death sometimes occurs before antibodies can even be detected.
Vaccines: No licensed vaccine yet, mainly because the virus is very rare.
Behavioral Defenses: Avoid rodent droppings by preventing rodents access to interior of home; avoid sweeping floor without a surgical mask if rodent feces are likely; avoid pitching tents or sleeping bags near rodent-infested areas.
Treatments: Ribavirin is the most effective treatment. Fluid intake is also important to compensate for vascular leakage and edema.
Game action: Fall prey to an extremely rare and deadly virus; go back to start.
One Liner: Mind rodents and Sabia will respond in kind.
Sources - <http://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/arena.htm>