Filarial hydrocele: a neglected condition of a neglected tropical disease.

Filarial hydrocele is the most common chronic manifestation of lymphatic filariasis (LF) and poses a major public health burden to several filarial endemic countries. This review highlights the socio-economic impact of the disease, the role of the immune system in hydrocele development, current diagnostic approaches, and the control and management of filarial hydrocele. In the quest to facilitate the global effort to eliminate filarial hydrocele as a neglected tropical disease, a more comprehensive understanding of the mechanisms underlying the pathogenesis and development of the condition is important. In general, success has been achieved using annual treatment with ivermectin, but much remains to be done, particularly with late-stage infected individuals where surgery remains the only option. Studies have successfully demonstrated that inhibition of embryogenesis in adult female worms occurs after weeks of tetracycline treatment. Even more intriguing was the observation that the Wolbachia endosymbionts potently induce proinflammatory cytokines such as tumor necrosis factors (TNFs) and vascular endothelial growth factors (VEGFs), which are crucial for the development of filarial hydrocele. Furthermore, reports from human studies show that doxycycline treatment significantly ameliorates filarial hydrocele and markedly reverses early-stage filarial hydrocele. However, with the enormous challenges that face LF elimination such as global funding, logistics, civil wars, and drug resistance, a more relentless and collective approach from local governments as well as other stakeholders is needed to accelerate the fight against filarial hydrocele if the goal to eliminate it by 2020 is be to achieved.