Infecção natural por hemoparasitos em bezerros submetidos à quimio-profilaxia aos 30 dias de idade

Abstract

RESUMOOs carrapatos causam danos aos seus hospedeiros tanto pela ação espoliadora e ingestão de sangue quanto pela transmissão de agentes patogênicos, sendo também responsáveis por elevados gastos com produtos carrapaticidas, mão-de-obra e equipamentos para o controle (CORDOVÉS, 1997 The tick-borne disease (TBD) brings great damages to cattle breeding. The most important etiologic agents are Babesia bigemina, B. bovis and Anaplasma marginale, being the tick Boophilus microplus the main vector. This work reports the occurrence of natural infection by hemoparasites of TBD in 36 calves with high ticks natural infestation submitted to chemoprophylaxis with 30 days year-old. The blood smears from animals of different ages were analized and were found B. bigemina (33.3%), B. bovis (11.1%) and A. marginale (13.9%). Six animals had clinical symptoms (16.7%) and one dead (2.8%). The number of clinical cases ocurred in consequence of an association of factors as high infestation of ticks and low passive immunity in period that calves had not developed enough active immunity.

Detection of antibodies against Babesia bovis and Babesia bigemina in calves from the region of Araguaína, State of Tocantins, Brazil

“…In a situation of enzootic stability, calves are infected in the early months of life and are protected by colostral antibodies (passive immunity), thus enabling the development of active immunity without presenting clinical disease (KESSLER et al, 1983). However, a study of calves of 1 to 50 days of age concluded that under conditions of high tick infestation high morbidity and mortality can occur even in the period of protection by colostral antibodies (SILVA et al, 2007).…”

“…Other locations were considered areas of instability, such as the States of Rondonia and Acre in northern Brazil (BRITO et al, 2007) and Londrina in the State of Parana (VIDOTTO et al, 1997). The Greater Metropolitan area of Rio de Janeiro was considered an area of stability for B. bovis (SILVA et al, 2007) and of instability for B. bigemina (SOUZA et al, 2000).…”

“…The clinical signs of the disease are fever, anemia, anorexia, lethargy, ataxia, tachypnea, hemoglobinuria, and muscle tremors (GUGLIELMONE, 1995;SOARES et al, 2000;SILVA et al, 2007;SINGH et al, 2009). The economic importance of this disease is due to the high animal morbidity and mortality especially among calves, and to its effects on weight gain and milk production, leading to the use of costly disease control and prevention measures (MARTINS et al, 1996;GRISI et al, 2002;BARROS et al, 2005).…”

Assessing different chemoprophylactic protocols against bovine tick-borne diseases and their influence on the weight gain of calves

“…Nonetheless, some authors recommend the use of enrofloxacin for the treatment of anaplasmosis (FACURY-FILHO et al, 2012), but this drug has shown little effect in several studies (ATIF et al, 2012;COETZEE et al, 2006). While in Brazil the recommended dose against anaplasmosis is up to 20 mg Kg -1 of long acting oxytetracycline in a sigle application (FACURY-FILHO et al, 2012;SILVA et al, 2007), other countries use the drug in doses as low as 7 mg Kg -1 (ORTIZ et al, 2012). In this light, we believe that not only subclinical, but even mild cases of anaplosmosis could be treated with the dose used in this study (6.7 mg Kg -1 ), allowing full productive recuperation.…”

Babesiose cerebral em bezerros

“…No presente estudo, chama a atenção que a babesiose cerebral foi observada na forma de surto, com mortalidade de 100% dos bezerros afetados, no período do outono. Altas taxas de mortalidade pela doença em bezerros nos primeiros meses de vida é raramente descrita na literatura (Trindade et al 2011), sendo na maioria das vezes poucos casos isolados de mortalidade por B. bovis em bezerros nas primeiras semanas de vida (Kessler et al 1983, Bracarense et al 2001, Silva et al 2007, Santarosa et al 2013, Moreira et al 2015.…”