Department of Veterinary Medicine, University of Bari, Valenzano, Bari, Italy.
Philadelphia Zoo, Philadelphia, PA, USA.
Parasit Vectors. 2023 Mar 6;16(1):87. doi: 10.1186/s13071-023-05708-1.
The Asian elephant (Elephas maximus), which is an endangered species, harbors several parasites. Among the ectoparasites that it harbors, ear mites of the genus Loxanoetus have the potential to cause external otitis, an inflammation that may also be associated with the presence of other microorganisms. We assessed the relationships between ear mites, nematodes, yeast, bacterial rods, and cocci sampled from the ears of captive Asian elephants in Thailand. In addition, we discuss the possibility that dust-bathing behavior may be triggered by ear mite infestation, and that this in turn may lead to contamination of the ears with soil microorganisms.
Legally owned captive Asian elephants (n = 64) were sampled. Ear swabs were individually collected from both ears and microscopically examined for the presence of mites, nematodes, yeast, bacterial rods, cocci, and host cells. Mites and nematodes were identified to species level using morphological and molecular methods.
Loxanoetus lenae mites were present in 43.8% (n = 28/64) of the animals (19 animals with mites in one ear and nine animals with mites in both ears). Nematodes of the genus Panagrolaimus were detected in 23.4% (n = 15/64) of the animals (10 with nematodes in one ear and five with nematodes in both ears). In adult elephants (Fisher's exact test, P = 0.0278) and female elephants (Fisher's exact test, P = 0.0107), the presence of nematodes in both ears was significantly associated with the presence of mites. In addition, higher categorical burdens of nematodes were also significantly associated with the presence of mites (Fisher's exact test, P = 0.0234) and epithelial cells (Fisher's exact test, P = 0.0108), and marginally significantly associated with bacterial cocci (Fisher's exact test, P = 0.0499).
The presence of L. lenae mites in the ear canals of the Asian elephants was significantly associated with the occurrence of other microorganisms, such as soil nematodes, bacteria and yeasts. The presence of mites in their ears may increase the dust-bathing behavior of elephants which, if confirmed, represents a further paradigmatic example of a parasitic infestation affecting animal behavior.
亚洲象（Elephas maximus）是一种濒危物种，体内有多种寄生虫。在其携带的外寄生虫中，耳螨属的耳螨有可能引起外耳炎，这种炎症也可能与其他微生物的存在有关。我们评估了来自泰国圈养亚洲象耳朵的耳螨、线虫、酵母、杆菌和球菌之间的关系。此外，我们还讨论了耳螨感染可能引发象尘土浴行为，而这种行为反过来又可能导致耳朵被土壤微生物污染的可能性。
对合法拥有的圈养亚洲象（n=64）进行采样。从每只耳朵中单独采集耳拭子，并在显微镜下检查是否存在螨虫、线虫、酵母、杆菌、球菌和宿主细胞。使用形态学和分子方法鉴定螨虫和线虫的种类。
43.8%（n=28/64）的动物（19 只动物一只耳朵中有螨虫，9 只动物两只耳朵中有螨虫）中存在 Loxanoetus lenae 螨虫。23.4%（n=15/64）的动物（10 只动物一只耳朵中有线虫，5 只动物两只耳朵中有线虫）中检测到 Panagrolaimus 属线虫。在成年大象（Fisher 精确检验，P=0.0278）和雌性大象（Fisher 精确检验，P=0.0107）中，双侧耳朵中存在线虫与存在螨虫显著相关。此外，线虫的分类负担较高也与螨虫（Fisher 精确检验，P=0.0234）和上皮细胞（Fisher 精确检验，P=0.0108）的存在显著相关，与细菌球菌（Fisher 精确检验，P=0.0499）的存在也有边缘显著相关。
亚洲象耳道中 L. lenae 螨虫的存在与其他微生物的存在显著相关，如土壤线虫、细菌和酵母。螨虫在耳朵中的存在可能会增加大象的尘土浴行为，如果得到证实，这将代表寄生虫感染影响动物行为的又一个典范例子。
