Veterinary Science and Microbiology

VSC438 Ecology of Infectious Disease

Viruses

Dr. Jim Collins

 

Rodent Reservoirs: Hemorrhagic Fevers, Hantaviruses, and ?

 

Topics

Viral Hemorrhagic fevers

            Arenaviruses, Filoviruses, some Flaviviruses, and Bunyaviruses

All are RNA viruses that have evolved stable relationships with their rodent

or insect hosts

Geographic delineation of the viruses. Why?

Severe disease in dead (!)-end hosts

Biological Safety levels 1,2 3, 4.

Ecological niche and prevention of transmission to humans

Disease in humans: What causes hemorrhage?

Changes in the rodent reservoir

            Numbers, movement, behavior

Bolivian Hemorrhagic Fever and Karl Johnson of MARU, 1962-3

“Field Investigation”

 

 

Questions

1. With examples, describe the role of rodents in viral hemorrhagic fevers of humans.

2. Define “rodent zoonosis”

3. Using examples of the viruses discussed in this class (all lectures), describe the many ways human disease either evolved and\or continues to occur within this paradigm:

            Animal à  Animal à Human à  Human

4. Does this paradigm describe “evolutionary transmission”, as we have discussed it in classs?

 

Case: THIS is where Hanta comes from:

Hantavirus Pulmonary Syndrome – Vermont

A 61-year-old previously healthy Vermont resident was hospitalized with respiratory failure requiring ventilation., profound hypoxemia, and low blood pressure. Subsequent chest radiographs revealed bilateral edema consistent with acute respiratory distress syndrome ARDS. During the 2 months preceding hospitalization the patient had cleaned a mouse nest from a woodpile, observed mice in the basement, and trapped 2 mice under the kitchen counters. During an onsite investigation conducted by the Vermont Department of Health, mice droppings were observed under the kitchen counter and in the cellar. The wildlife services program of the U.S.D.A. trapped rodents near patient's house: 46 rodents were captured, including 6 deer mice, 13 white-footed mice, 21 woodland jumping mice, one meadow jumping mouse, four chipmunks, and one vole. These rodents were tested serologically at CDC for hantavirus antibodies and 2 of 5 deer mice were positive; all other rodents were negative.