A field trial with etofenprox (OMS 3002) as a residual insecticide against malaria vectors, in Tanjung Bunga district, east Flores, Indonesia.

An operational trial of Vectron (Etofenprox, OMS 3002) was conducted in East Flores Regency, Nusa Tenggara Timur Province. The compound (Etofenprox 10EW) was applied as indoor residual spray and as an impregnation treatment for bednets in two separate areas. Dosage in both cases was 0.2 g/m2. A third area, designated as control, was untreated. In bioassay tests, bamboo surfaces gave 100% mortality for 150-160 days post spray, while wooden surfaces and treated bednets both gave complete mortality for at least 120 days. Malaria cases monitored by successive malariometric surveys showed steady declines in positivity rates, particularly in children.

Scrub typhus survey of Biak and Owi islands: ectoparasites of small mammals and rickettsial isolations.

A survey of smnall mammals and their ectoparasites was conducted on the islands of Biak and Owi, Indonesia, in August 1976. Two species of chiggers known to serve as vectors of scrub typhus were found: Leptotrombidium (Leptotrombidium) deliense from Rattus exulans, R. ruber, and R. r. septicus; L. (L.) flectcheri from R. exulans, R. leucopus and R. r. septicus. Rickettsia tsutsugamushi was isolated from the spleens of R. exulans and R. r. septicus. The favored ecotype of the chigger and rat hosts of R. tsutsugamushi appeared to be coarse, low-lying native vegetation on a porous coralline soil. These and similar nearby coral islands should be considered high risk areas for scrub typhus.

New hosts of Breinlia booliati with observations on its distribution in Southeast Asia.

Breinlia booliati Singh & Ho, 1973 first described from Peninsular Malaysia has been shown to infect a large range of murids ranging in distribution from southern Thailand, Peninsular Malaysia, Sarawak to Ciloto, Indonesia. Probably further work will reveal a greater host range as well as its geographical distribution. The vectors involved in its transmission need to be elucidated.

Studies on the susceptibility of a large urban population of Aedes aegypti to infection with dengue viruses.

A large urban population of Aedes aegypti in Jakarta, Indonesia was studied for one year to determine whether it was homogeneous in terms of susceptibility to dengue viruses and whether seasonal changes in susceptibility to dengue viruses occurred. Mosquitoes from several districts in Jakarta showed a low but homogeneous susceptibility to dengue 2 virus from November 1975 to April 1976. In June 1976, increased susceptibility to dengue 2 virus was observed among some of the subpopulations of Ae. aegypti, and higher infection rates and increased variation were observed among these mosquitoes during the rest of the study period. Correlation with confirmed DHF cases in Jakarta was discussed.