Tristeza parasitária bovina (revisão de literatura).

Abstract

The tick fever is a complex of diseases including diseases caused by protozoa of the genus Babesia and Rickettsia of the genus Anaplasma . It is important to know these diseases in its various aspects , as this information is important for the treatment and establishment of control measures and prophylaxis . The objective of this work was to present a review of literature about epidemiological, etiological , clinical, pathological , prophylactic and therapeutic of these diseases. The transmission of the causative agents of tick fever is possible from biological transmission by ticks R. (Boophilus ) microplus , hematophagous insects , contaminated needles and surgical instruments. Epidemiological studies of the tick fever classified the regions as free areas, due to the absence of the vector, areas of enzootic instability,where there are frequent outbreaks due to variations in the population of vectors and antibodies in animals and endemic areas, where due to the presence of ticks throughout year typically do not occur clinical cases in native animals. In relation of the pathogenesis the information from the literature show that B. bigemina parasites most frequently red blood cells from the peripheral circulation, while B. bovis is found in capillaries of the central organs . B. bigemina is able to trigger a mechanism that causes damage on cells and tissues. The Babesia bovis causes massive hemolysis , and the rapid course of the disease is due primarily to the hypotensive shock caused by the parasite catabolites. In anaplasmosis once inside the cell Anaplasma divides by binary fission and infect other red blood cells . The infected erythrocytes are phagocytosed by the reticulo endothelial system. The course of anaplasmosis is faster than babesiosis , the animal may lead to death within 24 hours. Acute infection with Babesia spp. and A. marginale have clinical signs as fever, pale mucous membranes, tachypnea, tachycardia, anemia, jaundice (more common in intense and anaplasmosis ), hemoglobinuria (in babesiosis), stopped or reduced rumination, anorexia and prostration . In babesiosis by B. bovis , the most virulent of the three agents , neurological symptoms as incoordination, followed by posterior paralysis, mania, convulsions and coma are observed. The laboratory diagnosis, through the identification of the agent and assessment of hematocrit, becomes extremely important for disease confirmation and realization of specific treatment. Tick fever should be differentiated from all disease of cattle in which the red color of the urine is a major clinical manifestations including leptospirosis, copper poisoning, , enzootic hematuria, hemoglobinuria puerperal and bacillary hemoglobinuria. Tick fever must also be differentiated of rabies because of the infection with B. bovis that leads to neurological symptoms. Other diseases such as trypanosomiasis and gastrointestinal parasites that occur with signs of weakness, anemia and prostration should also be differentiated from tick fever Poisoning by plants like Cassia occidentalis and Pteridium aquilinum and Brachiaria radicans with tick fever is done with drugs with effect babesicida ( derived from diamidina ) anaplasmicida ( tetracycline ) and double acting ( imidocarb and associations of diamidina with oxytetracycline ). The control of these diseases must be done through management measures appropriate to the epidemiology of the agents tick fever in the region. To control the tick fever can still be used techniques like premonition , chemoprophylaxis or vaccination. In the State of Paraiba recent research has shown that outbreaks occur at the end of the rainy season and most outbreaks are caused by Anaplasma marginale. Outbreaks are caused by the introduction of animals from endemic areas and occur in areas where the presence of tick during the rainy season and these are combated inadequately. It is conclude that is tick fever a serious disease of frequent occurrence in Brazil and in the semiarid region and need to have their pathogenesis and clinical signs well known to be readily diagnosed and combated effectively. Furthermore it was found that the knowledge of the epidemiology of the diseases in this region is important for the proper establishment of prophylactic measures.