SEROLOGICAL EVIDENCE OF EXPOSURE TO Anaplasma phagocytophilum IN HORSES FROM THE RIO DE JANEIRO STATE MOUNTED POLICE BRED IN THE URBAN ZONE

AbstractAnaplasma phagocytophilum is an emergent hemoparasite in regions where ticks are regularly found. In order to investigate the rate of anti-A. phagocytophilum antibody in horses of the Mounted Police of Rio de Janeiro state and therefore the presence of this agent, 41 horses from the Cavalry Squadron (CS) and 50 from the Regiment of Mounted Police (RMP) were selected. For the serologic diagnosis the Indirect Fluorescent Antibody test was performed. In the present work, among 91 equine sera samples anti-A. phagocytophilum antibodies, with titer ≥ 1:80, were detected in 11 animals (12%), being five (5%) from males and six (7%) females, with no statistical difference. The adult animals with ages varying between five and 14 years presented the highest rate of positive reaction, although antibodies were detected in animals of all ages. We did not observe statistic differences in relation to the presence of anti-A. phagocytophilum antibodies among the animals bred in the CS and RMP. The presence of anti-A.phagocytophilim antibodies in horses of the Mounted Police with no clinical signs is indicative that the parasite is present in the enzootic form among the horses of the urban area. The circulation of the parasite among the animals is not dependent of the presence of tick infestations.

摘要
嗜吞噬细胞无形体（Anaplasma phagocytophilum）是蜱虫高发区域的新发血液寄生虫。为探究里约热内卢州骑警队马匹的抗嗜吞噬细胞无形体抗体阳性率，进而明确该病原体的流行现状，本研究选取了来自骑兵中队（CS）的41匹马与骑警团（RMP）的50匹马作为受试对象。本研究采用间接荧光抗体试验开展血清学诊断。
在91份马血清样本中，共检出11匹（12%）受试马匹的抗嗜吞噬细胞无形体抗体滴度≥1:80，其中公马5匹（占比5%）、母马6匹（占比7%），性别间未呈现统计学差异。年龄介于5至14岁的成年马匹阳性率最高，但所有年龄段的受试马匹均检出该抗体。骑兵中队与骑警团饲养的马匹之间，抗嗜吞噬细胞无形体抗体的检出率未存在统计学差异。
本研究中，无临床症状的骑警队马匹检出抗嗜吞噬细胞无形体抗体，提示该寄生虫以地方流行性形式存在于城市区域的马群中。该寄生虫在马群中的循环传播与蜱虫侵扰并无关联。