Integrity
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Zoonotic Diseases
(Francis' disease, deer-fly fever, rabbit fever, O'Hara disease) AGENT- Francisella tularensis, a small pleomorphic, gram-negative, nonmotile rod or coccobacillus that can survive several weeks in the external environment. RESERVOIR AND INCIDENCECommon often fatal septicemic disease of rabbits, squirrels, muskrats, deer, bull snakes, sheep, wild rodents, cats and dogs. Major reservoirs are RABBITS, TICKS, MUSKRATS. Has been reported in NHP's at an urban zoo. Natural infection in laboratory animals and zoonotic transmission from them has NOT been reported. TRANSMISSION:Handling tissue of infected animals (direct contact with UNBROKEN skin is sufficient). Reported human infections due to a cat bite and scratch and a NHP bite also reported. transmitted by biting insects inhalation, ingestion DISEASE IN ANIMALS:Clinical signs usually occur alongside heavy infestation with ticks, and include sudden high fever, anorexia and stiffness, eventually leading to prostration and death. In sheep, pregnant ewes may abort. Affected dogs have soft nodular swellings under the skin. Miliary foci of necrosis occur in the liver, spleen and lymph nodes. Severe lesions in the lung involve widespread consolidation with edema and pleurisy. DISEASE IN MAN:Fever, headache, and nausea begin suddenly, and a local lesion-a papule-develops and soon ulcerates. Regional lymph nodes may become enlarged and tender and may suppurate. The local lesion may be on the skin of an extremity (ulceroglandular disease) or in the eye. Pleuropulmonary disease may develop from hematogenous spread or may be primary after inhalation. Following ingestion of infected meat or water, an enteric (typhoidal) form may be manifested by enteritis, stupor, and delirium. In any type of involvement, the spleen may be enlarged and tender and there may be nonspecific rashes, myalgias, and prostration. A case fatality rate of 5-10% mainly from the typhoidal or pulmonary form exists. DIAGNOSIS:Culture (requires specialized laboratory and dangerous, therefore, not recommended) A positive agglutination test (>1:80) develops in the second week after infection and may persist for several years. TREATMENT IN MAN:Streptomycin + tetracycline. Chloramphenicol may be substituted for tetracycline. PREVENTION\CONTROL:Wear impervious gloves while handling animals or tissues cook the meat of wild rabbits and rodents thoroughly vaccine available for high risk personnel avoid bites of flies, mosquitoes, and ticks and avoid drinking, bathing, swimming in untreated water in endemic areas. |