Figure-1.

Life cycle of zoonotic Brugia pahangi. The parasite develops enzootic cycle of B. pahangi by which domestic cat or dog acquires the infection through mosquito-borne transmission ①-⑦. Transmission occurs when female adult of Armigeres subalbatus as a principal vector can transmit L₃ infective stage ⑦ to susceptible cat or dog during taking blood meal ①. An infected cat or dog frequently exposed to infective bites can develop the adult worm infection ② and later microfilaremia ③. The complete cycle of transmission occurs when microfilariae are transmitted to susceptible female adult of Ar. subalbatus ⑤ that takes another blood meal from infected cat or dog ④. Microfilariae can develop further juvenile stages by exsheathment in midgut ⑤, and later L₁ in hemolymph to L₂ in thorax ⑥ to L₃ in proboscis as infective stage ⑦. The parasite can also develop epizootic cycle of transmission ⑨ by which susceptible children acquires the accidental infection through Ar. subalbatus borne transmission ⑧. The childhood infection can undergo this epizootic B. pahangi by a single-step spillover ⑧. Meanwhile a spillback or human to human transmission of epizootic B. pahangi ⑩ remains unclear. [Source: Graphic illustration created by A. Bhumiratana].