Role of laboratory animals in the transmission of zoonoses

Laboratory and experimental animals can be infected by many pathogenic agents, of which man is susceptible. Sometimes infection can be symptomless in the animals (e. g. monkey B virus, Lassa-virus infection) but most of the diseases show cyclic course, during which the agents are spread into the environment through different excreta and man can be indirectly infected. On this basis, most of the diseases can be classified as orthozoonosis, when the infectious agent get into humans'body through oral, dermal or aerogenic ways (Hanta-, Pox-, lymphocytic choriomeningitis virus, Lassa, Hepatitis A virus, Chlamydia psittaci, Salmonella etc.). Other agents (bunyaviruses, rickettsias) are transmitted through vectors (cyclozoonoses), and there are diseases where the agents get into the organism through the lesions of the skin (e. g. tularaemia, leptospirosis). Laboratory zoonoses manifest usually in the same or similar clinical signs in animals and humans (e. g. monkey pox, encephalomyocarditis, hepatitis A) but there are such that cause different signs (e. g. chlamydiosis). Certain microorganisms may cause different clinical forms according to geographical region (hemorrhagic fever with renal syndrome, endemic nephropathy, pulmonary syndrome). Conditions of the prevention of zoonoses transmitted by laboratory animals are the knowledge about the characteristics of the agents, early detection of clinical signs and keeping the rules relating to work health and to biosafety of laboratories.