|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1992 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1991 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1990 : ¥700,000 (Direct Cost : ¥700,000)
Nine strains of Aedes albopictus (subgenus Stegomyia) and 11 strains of Aedes togoi (subgenus Finlaya) were tested for their susceptibility to Brugia pahangi, using Mongolian jirds (Meriones unguiculatus) infected with these filarial worms. Microfilaremea in bloods of the jirds used in most of experiments was 100-130 mf/10mu1. The 9 mosquito strains used of Ae. albopictus originated from Thailand, Malaysia, and Japan, and all showed zero % susceptibility to this filarial species. The 11 strains of Ae. togoi used were collected from Canada, Thailand, Taiwan and Japan. The susceptibility of these strains to the filarial worms was as follows : the Canadian strain 48%, the Thai 75%, the Taipei(Taiwan)-100 %, the Soya(Hokkaido) 92%, the Miyako(Iwate) 53%, the Oga(Akita) 47%, the Sado(Nigata) 60%, the Nagasaki 66%, the Tsushima(Nagasaki) 33%, the ru mutant 60%, and another sru mutant 72%. The selection experiments either for or against the susceptibility to B. pahangi were conducted on only the Ae. togoi strains, since all the Ae. albopictus strains showed no susceptibility to this filarial species. The sru strain which had been selected for the susceptibility for 3 to 5 generations exhibited 90 to 95% susceptibility. On the other hand, the 4 strains (Oga, Miyako, Sado and Tsushima) that had been selected against the susceptibility for 3 to 7 generations showed various levels of the susceptibility. The Oga strain fluctuated in the susceptibility levels at each generation of selection, but after 6 to 7 generation of selection this strain showed lowered levels of 10 to 29% from 47% susceptibility of the parental generation. From these results it seems that a polygenic mechanism is involved in this filarial susceptibility of Ae. togoi. One of these genetic factor is likely to be located in between the malic enzyme (Me) and sex loci on linkage groupe I, as indicatad by the data from cross experiments.