Coutinho Maria Teresa Zanatta, Bueno Lilian Lacerda, Sterzik Annelise, Fujiwara Ricardo Toshio, Botelho Jose Ramiro, De Maria Mario, Genaro Odair, Linardi Pedro Marcos
Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Caixa Postal 486, Avenida Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, Minas Gerais, CEP 31270-901, Brazil.
Vet Parasitol. 2005 Mar 10;128(1-2):149-55. doi: 10.1016/j.vetpar.2004.11.011. Epub 2004 Dec 21.
The vectorial competence of the tick Rhipicephalus sanguineus is discussed in relation to the epidemiology of canine visceral leishmaniasis, taking into account its strict association with dogs and the low indices of natural infection presented by its known vector, the phlebotomine sand fly Lutzomyia longipalpis. In order to evaluate natural infection by Leishmania chagasi and the infectivity of these parasites in the tick, 39 specimens (6 females, 11 males and 22 nymphs) of R. sanguineus were removed from 21 dogs showing diverse symptoms of zoonotic visceral leishmaniasis (ZVL). Six ticks (15.4%) gave positive results for the genus Leishmania using the PCR technique. To determine the infectivity of the parasites, 36 hamsters were inoculated orally and peritoneally with macerates of ticks removed from nine dogs symptomatic for visceral leishmaniasis. After 6 months the hamsters were sacrificed and necropsied. Serum was removed for IFAT, as well as spleen and liver fragments to make imprint smears and for PCR. Eight (88.9%) of these dogs presented ticks that were infective for 14 hamsters (41.2%), 12 (85.7%) of them infected peritoneally and two (14.3%) orally. PCR revealed 27 smears (40.9%) to be positive, 20 (62.5%) of them infected peritoneally and seven (20.6%) orally. IFAT showed 14 positive animals (41.2%). Based on these findings, we suggest that the vectorial capacity of R. sanguineus for L. chagasi should be evaluated further, opening new perspectives in the epidemiology of ZVL.
考虑到血红扇头蜱与犬类的紧密关联以及其已知传播媒介——长须罗蛉的自然感染率较低，本文探讨了血红扇头蜱的媒介能力与犬内脏利什曼病流行病学的关系。为了评估恰加斯利什曼原虫的自然感染情况以及这些寄生虫在蜱中的感染性，从21只表现出多种人兽共患内脏利什曼病（ZVL）症状的犬身上采集了39只血红扇头蜱标本（6只雌性、11只雄性和22只若虫）。使用PCR技术，6只蜱（15.4%）检测出利什曼原虫属呈阳性。为了确定寄生虫的感染性，对36只仓鼠进行了口服和腹腔接种，接种物为从9只患有内脏利什曼病症状的犬身上采集的蜱的匀浆。6个月后，对仓鼠实施安乐死并进行尸检。采集血清用于间接荧光抗体试验（IFAT），同时采集脾脏和肝脏组织碎片制作印片涂片并进行PCR检测。其中8只（88.9%）犬身上的蜱对14只仓鼠（41.2%）具有感染性，其中12只（85.7%）通过腹腔感染，2只（14.3%）通过口服感染。PCR检测显示27份涂片（40.9%）呈阳性，其中20份（62.5%）通过腹腔感染，7份（20.6%）通过口服感染。IFAT检测显示14只动物呈阳性（41.2%）。基于这些发现，我们建议进一步评估血红扇头蜱对恰加斯利什曼原虫的媒介能力，这为ZVL的流行病学研究开辟了新的视角。
