Current insecticide susceptibility status of Malaysian Anopheles maculatus Theobald to malathion, permethrin, DDT and deltamethrin.

Chemical insecticides are still considered as important control agents for malaria vector control. However, prolonged use of these chemicals may select mosquito vectors for resistance. In this study, susceptibility status of adult Anopheles maculatus collected from 9 localities in peninsular Malaysia, viz., Jeli, Temerloh, Pos Banun, Senderut, Jeram Kedah, Segamat, Kota Tinggi, Kluang and Pos Lenjang were determined using the standard WHO bioassay method in which the adult mosquitoes were exposed to standard insecticide impregnated papers malathion, permethrin, DDT and deltamethrin--at pre-determined diagnostic dosage. Deltamethrin was most effective insecticide among the four insecticides tested, with the LT50 of 29.53 min, compared to malathion (31.67 min), DDT (47.76 min) and permethrin (48.01 min). The effect of all insecticides on the laboratory strain was greater (with all insecticides demonstrated LT50 < 1 hour) than the field strains (deltamethrin 32.7, malathion 53.0, permethrin 62.0, DDT 67.4 min). An. maculatus exhibited low degree of resistance to all test insecticides, indicating that these chemical insecticides are still effective in the control of malaria vector.

Cognitive impairment among the elderly Malays living in rural Malaysia.

Cognitive impairment is a common psychiatric problem among the elderly. The objective of the study was to determine the prevalence of cognitive impairment among the elderly Malays living in a rural community in north Malaysia. A cross sectional study was conducted among the elderly population of 22 villages in north Malaysia. Elderly cognitive assessment questionnaire was used to determine the cognition status. Analysis was done using SPSS version 13. The prevalence of cognitive impairment among the older adults in these villages was 11% (n=46). There was an increasing prevalence of cognitive impairment with increasing age (p < 0.05). Being unmarried (OR 2.31), unemployed (OR 2.74) and living alone (OR 2.32) were significantly associated with the risk of being cognitively impairment. Being unemployed (OR 2.29) was a significant predictor variable for cognitive impairment. Similar to other studies conducted in Malaysia the prevalence of cognitive impairment was high.

Antibody to Pseudomonas pseudomallei exotoxin in sheep exposed to natural infection.

Specific antibody to Pseudomonas pseudomallei exotoxin was detected in sheep sera exposed to natural infection. An enzyme-linked immunosorbent assay (ELISA) was used. Serum antitoxin was present in 49.3% of sera obtained from a flock of sheep naturally exposed to P. pseudomallei infection. Among these sera, 17.0% gave titers of 10,000. In contrast, serum antitoxin was present in only 6.0% of sera collected from sheep kept on a melioidosis-free farm. The ELISA reactivity of all positive sera could be completely absorbed with purified P. pseudomallei exotoxin. Similarly, preincubation of the exotoxin-coated wells with specific antiserum inhibited the ELISA reactivity of sheep sera. The results indicate that exotoxin is produced in vivo during infection by P. pseudomallei.