The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, Centre for Animal Science, St. Lucia, Queensland 4072, Australia.
The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, Centre for Animal Science, St. Lucia, Queensland 4072, Australia.
Vet Parasitol. 2022 May;305:109715. doi: 10.1016/j.vetpar.2022.109715. Epub 2022 May 7.
Buffalo flies (Haematobia irritans exigua) are ectoparasites of major animal health and production concern in north Australian beef herds. Skin lesions associated with buffalo fly infestation, cause hide damage and welfare issues and are manifested as dermatitis or ulcerated areas found most commonly near the medial canthus of the eye, along the lateral and ventral neck and on the abdomen. Buffalo flies can transmit a nematode, Stephanofilaria sp., which has been considered the main aetiological agent for buffalo fly lesions, but the role of nematodes in the development of the lesions has not been defined. To investigate the geographical distribution of Stephanofilaria, swabs were taken from the surface of lesions and buffalo flies were netted from the backs of beef cattle from 20 properties located in northern, central and southern Queensland. Swabs and buffalo flies were then tested for the presence of Stephanofilaria by qPCR. In northern and central Queensland, all properties except one, tested positive for the presence of Stephanofilaria in either buffalo flies or swabs, or in both. The infection rate varied amongst sites ranging from 0% to 100% in lesions and 0-34% in female buffalo flies. No nematodes were found in male buffalo flies. In contrast, none of the 66 lesion swabs or 1220 buffalo flies collected from southern Queensland tested positive for Stephanofilaria infection despite the frequent occurrence of lesions in the herds from which samples were collected. These findings suggest that infection with Stephanofilaria, although frequently detected, is not essential for the development of buffalo fly lesions and other factors may contribute to the initiation of lesions. This study also confirmed the potential for using surface swabs as a quicker and less invasive means of sampling lesions than dermal biopsies when testing for the presence of Stephanofilaria by qPCR, but further studies will be required to estimate the sensitivity of this technique. Understanding the pathogenesis of buffalo fly lesions will aid the development of optimal treatment and control strategies.
水牛蝇（Haematobia irritans exigua）是北澳肉牛群中主要的动物健康和生产关注的外寄生虫。与水牛蝇侵扰相关的皮肤损伤会导致皮革损坏和福利问题，并表现为最常见于眼睛内眦、沿颈部外侧和腹侧以及腹部的皮炎或溃疡性区域。水牛蝇可以传播一种线虫，即 Stephanofilaria sp.，它被认为是导致水牛蝇损伤的主要病因，但线虫在损伤发展中的作用尚未确定。为了研究 Stephanofilaria 的地理分布，从病变表面采集拭子，并从北昆士兰、中昆士兰和南昆士兰的 20 个农场的肉牛背部捕捉水牛蝇。然后通过 qPCR 测试拭子和水牛蝇中是否存在 Stephanofilaria。在北昆士兰和中昆士兰，除了一个农场外，所有农场的水牛蝇或拭子中都检测到了 Stephanofilaria 的存在，或者两者都有。感染率在不同地点之间存在差异，病变中的感染率从 0%到 100%不等，雌性水牛蝇中的感染率从 0%到 34%不等。在雄性水牛蝇中未发现线虫。相比之下，尽管从收集样本的牛群中经常发现病变，但来自南昆士兰的 66 个病变拭子或 1220 只水牛蝇中均未检测到 Stephanofilaria 感染。这些发现表明，尽管 Stephanofilaria 经常被检测到，但它并不是水牛蝇损伤发展的必要条件，其他因素可能会导致损伤的发生。本研究还证实，当使用 qPCR 测试 Stephanofilaria 时，与皮肤活检相比，表面拭子是一种更快、侵入性更小的病变采样方法，但需要进一步研究来估计这种技术的敏感性。了解水牛蝇损伤的发病机制将有助于制定最佳的治疗和控制策略。
