Loa loa: development to the infective stage in an American deerfly, Chrysops atlanticus

Chrysops atlanticus Pechuman, an American species collected along the Mississippi Gulf Coast, was found to support the development of the microfilaria of Loa loa to the infective stage. Development took place in the fat-body of the fly and required 9-10 days in flies maintained at 80 deg F and 60-80% R.H. The site of development and pattern of morphogenesis of the parasite in C. atlanticus was virtually identical to that described in natural African vectors [cf. RAE/B 50, p. 169]. The development of large numbers of L. loa to the infective stage took place without apparent ill effects on the fly. Two uninfected patas monkeys each were given 75 third-stage larvae obtained from experimentally infected C. atlanticus. Both animals developed patent infections in approximately 5 months, clearly demonstrating that the entire life-cycle of L. loa can be maintained in the laboratory outside the endemic areas.