Laboratory infection and release of Spiroplasma (Entomoplasmatales: Spiroplasmataceae) from horse flies (Diptera: Tabanidae).

Naturally-infected Tabanus gladiator and T. sulcifrons (from Georgia, USA) were restrained and fed 10% sucrose to determine the exit points of Spiroplasma from them. The flies were allowed to feed for 24 h, and the resulting oral and anal specks were cultured in M1D broth. Spiroplasmas were isolated from 21 of 51 oral specks, but not from 23 anal specks deposited on plastic. In contrast, when anal specks were deposited in a sucrose solution, 9 of 28 anal specks in sucrose yielded spiroplasma cultures. T. lineola and T. longiusculus were offered a culture of Spiroplasma strain EC-1 on a stewed raisin or in 5% sucrose in the form of a hanging drop. After 4 days, the minced abdominal viscera of each fly were incubated in M1D broth and 25 of 32 tabanids yielded cultures of Spiroplasma.