The impact of permethrin impregnated bednets on the malaria vector Anopheles maculatus (Diptera: Culicidae) in aboriginal villages of Pos Betau Pahang, Malaysia.

The effect of permethrin impregnated bednets on Anopheles maculatus Theobald was studied in four villages in Pos Betau, Pahang, Malaysia from August 1990 to July 1992. Collections of mosquitos were carried out indoors and outdoors from 1900 to 0700 hours. All mosquitos were dissected for sporozoites and parity. In May 1991 two villages received bednets impregnated with permethrin at 0.5 g/m2 and two villages received placebo bednets. There was a significant difference in the sporozoite and parous rates between the treated and control villages after the distribution of bednets (p < 0.05). There was no significant difference in the bites/man/night of An. maculatus between the pre and post treatment periods in the control villages. However there was a significant difference in bites/man/night between pre and post treatment in the treated villages (p < 0.001).

Endemic goiter in the Lemanak and Ai river villages of Sarawak.

In a survey of 974 villagers (408 males, 566 females; ages = 11-82 years) of the Ai (n = 496; 212 males, 284 females) and Lemanak (n = 478; 196 males, 282 females) rivers in the district of Lubuk Antu in Sarawak's Sri Aman Division during July 1993, goiter was found in 31.8% of the subjects. The goiter prevalence was higher in the more interior Ai river area than in the Lemanak river area (36.9% vs 26.5%). In females aged 15 years and above, the goiter prevalence was 75.4% and 49.1%, respectively, in the Ai and Lemanak river areas. The difference in goiter prevalence between the two areas was related to the degree of iodine deficiency in the two areas. The median urinary iodine excretion in the Ai river villagers was 22.1 micrograms/l compared to 72.9 micrograms/l in the Lemanak river villagers (p < 0.0001). Goitrous subjects tended to have lower urinary iodine concentration than non-goitrous subjects. In the males, smoking of tobacco was associated with a two-fold increase in goiter frequency. Despite on-going distribution of iodized salt by the medical and health services in the State, only 23% of the 135 salt samples obtained from the households in the areas contained detectable iodine.

Fluoride studies in Malaysia.

Twenty-four-hour urine samples and whole deciduous teeth from fluoridated (0.71 ppm) and non-fluoridated (0.14 ppm) areas together with some selected local food items were analysed for their fluoride content. The mean values for urinary fluoride were 0.90 ppm or 0.77 mg per day for the fluoridated area and 0.50 ppm or 0.52 mg per day for the non-fluoridated area. Assuming that half of all the fluoride ingested is excreted in the urine, this study suggests that the average daily fluoride intakes by adults in the fluoridated and non-fluoridated areas were about 1.5 mg and 1 mg respectively. The mean fluoride content of non-carious deciduous teeth from the fluoridated area was 416.89 ppm compared to 178.45 ppm in the low fluoride area.