ZOONOSES
1. Zoonoses are human diseases acquired from or transmitted to any other vertebrate animal. Zoonotic diseases are common in currently developing countries throughout the world and constitute, with starvation, the major threat to human health. More than 150 such diseases are known.
2. Zoonoses may be separated into four principal types, depending on the mechanisms of transmission and epidemiology. One type includes the direct zoonoses, such as rabies and brucellosis, which are maintained in nature by one vertebrate species. The transmission cycle of the cyclozoonoses, of which tapeworm infections are an example, requires at least two different vertebrate species. Both vertebrate and invertebrate animals are required as intermediate hosts in the transmission to humans of metazoonoses.
3. Most animals that serve as reservoirs for zoonoses are domesticated and wild animals with which man commonly associates. People in occupations such as veterinary medicine and public health, therefore, have a greater exposure to zoonoses than do those in occupations less closely concerned with animals.
4. In addition to the numerous human diseases spread by contact with the parasitic worm helminth and by contact with arthropods, many diseases are transmitted by the bites and venom of certain animals; poisonous or diseased food animals also transmit diseases. Dog bites may seriously injure tissues and also can transmit bacterial infections and rabies. The bite of a diseased rat may transmit diseases to man, including plague, salmonellosis, leptospirosis and rat-bite fevers. Cat-scratch disease may be transmitted through cat bites, and the deadly herpes B virus can spread by monkey bites. The bites of venomous snakes and fish account for considerable human discomfort and death. Poisonous wild animals inadvertently used for food include animals harbouring the anthrax bacillus and those containing the causative agents of salmonellosis, trichinosis, ect. The flesh of various types of fish is toxic to man.
(Encyclopedia Britannica) Определите, является ли утверждение:
Two vertebrate species participate in the transmission cycle.
Варианты ответов:
1. в тексте нет информации
2. ложным
3. истинным
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