Ocorrência de protófitas em ruminantes e suínos domésticos ainda não descritos no Brasil

Abstract

THE OCCURRENCE OF HITHERTO UNDESCRIBED PROTOPHYTAL PATHOGENS IN DOMESTIC RUMINANTS AND PIGS IN BRAZIL. C.W.G. LOPES, M.Sc. Thesis presented to the Universidade Federal Rural do Rio de Janeiro, July, 1976. Past studies on the fauna of the New World have shown that the continent Oceania and island Madagascar were devoid of any artyodactiline species while the Americas a harboured a substantial assortment of indigenous wild artyodactiline species. The urge to create favourable conditions for imigrants in newly discovered continents made it necessary to introduce domestic animals from the Old World for the production of a regular supply of milk, beef, mutton and pork. The export of animal products was restricted to wool and hides. This was the position of the animal husbandry 40 until refrigerated ocean shipping was introduced. This gave a tremendous impetus to the extension of the stock industry and also to the export of meat and meat products. The present total domestic artyodactiline world population of each especies, their numbers in the Old World and New World are presented in tabular form. The importation of breeding stock was accompanied by certain hazards, the seriousness of which was only recognized several decades later. North America abtained its breeding stock from north western Europe for the temperate zone while cattle form the Mediterranean region were destined for the state of Texas and North Mexico. In doing so the cattle from the latter region introduced Texas fever and its vector Boophilus annulatus into the North America. Farmers sustained severe losses. Smith & Kilborne (1893) identified the causal agent as Babesia bigemina and the same time showed that its vector is B. annulatus ,the first arthopod to be stablished as a vector of a protozoon blood parasite. This vector also transmitted Anaplasma marginale but its identity was only established two decades later by Theiler (1910). For the development of the cattle industry in the tropical regions of Oceania, Madagascar, Southern Mexico, Central and South America Zebu cattle from Asia were introduced. These cattle which harboured the tick B. microplus reached their destination by devious routes. This readily adaptable vector soon spread far afield in the new habitats and caused severe economic losses by transmitting B. biqemina, B. argentina and A. marginale to the growing number of the bovine population. Surveys in the Old World for the possible existence of other blood parasites revealed that sheep and goats harbour, Anaplasma ovis and Eperythrozoon ovis, cattle E. wenyoni and pigs E. suis while in the United States of America E. parvum was added to the list of protophytal microorganims. The known world distribution of the abovement-mentioned pathogens are listed in a series of tables. Up to the present no attempts had been made to establish any of the Eperythrozoon spp. and A. ovis in Brazil. Splenectomy of artyodactiline animals previously exposed to tick and bloodsucking insect infestations in the State of Rio de Janeiro revealed that the parasitic relapses in the sheep were those to A. ovis and E. ovis in cattle E. wenyoni, in pigs to E. parvum. An attempt to ascertain a possible E. suis infection by the subinoculation of blood from slaugtered pigs from the State of Paraná into a esplenectomized and an entire pig gave negative results. It is generally accepted that E. wenyoni and E. parvum usually produce a benign disease. The degree of the pathogenicity of A. ovis, E. ovis and E. suis varies from very mild to severe and sometimes terminates fatally. The behaviour of both these parasites under Brazilian 42 conditions still needs to be determined.