Laboratory and semi-field evaluation of Mosquito Dunks against Aedes aegypti and Aedes albopictus larvae (Diptera: Culicidae).

Laboratory bioassays and semi-field studies were conducted on the efficacy and longevity of Mosquito Dunks (7,000 ITU/mg Bti) in order to determine the concentration-response relationship and the effectiveness on the potency of the Bti product against Aedes mosquito species based on the WHO protocol standard methods and to determine the longevity of release for this product against Ae. aegypti mosquito larvae in water storage containers. This bio-potency study with the late 3rd instar larvae of Ae. aegypti and Ae. albopictus was carried out according to WHO standard protocols. The six concentrations of the Bti product used in each test were replicated 4 times with 25 mosquito larvae. Probit analysis was then used to determine the LC50 and LC95 which was equated with dosages of 1.02 and 1.86 ppm for Ae. aegypti; and 0.39 and 0.84 ppm for Ae. albopictus, which reveals a potency of 382.95 and 303.74 ITU/mg, respectively. The semi-field evaluation of this product in 200-liter earthen jars against 3rd instar larvae of Ae. aegypti showed satisfactory control of greater than 80% at 11 weeks post-treatment.

Soil analysis around anopheline breeding habitats in north-western Thailand.

The epidemiology of malaria is largely dependent on its vector habitat. Each species of Anopheles larvae has a specific habitat requirement for its development. Anopheline mosquitoes are common throughout Thailand and utilize a wide variety of habitats. The dominant malaria vectors in Thailand are An. dirus, An. maculatus, and An. minimus. The relationship between soil chemical components and the particular species of anopheline in their specific aquatic habitats was studied from September 2002 to July 2003 at Ban Khun Huay, Ban Pa Dae, and Ban Tham Seau in the Mae Sot district, Tak Province, Thailand. Mapping of each habitat was performed using a Global Positioning System unit. A total count of 2,130 laboratory reared adult Anopheles were collected from 138 habitats categorized into 11 different types identified into 18 species from larval sampling in three villages. An. dirus, An. maculatus, and An. minimus were found 5.26%, 10.70%, and 55.31%, respectively, along with other minor species. Drainage and/or season seemed to be associated with the presence of An. dirus, An. maculatus, An. minimus, An. jamesii, An. sawadwongporni, and An. peditaeniatus. Chemical tests: pH, aluminum, magnesium, calcium, and ferric iron showed some associations with the presence of Anopheles. Only drainage was found to be a parameter associated with the presence of An. minimus.

Cost-effectiveness in establishing hemophilia carrier detection and prenatal diagnosis services in a developing country with limited health resources.

The cost-effectiveness of carrier detection and prenatal diagnosis for hemophilia at the International Hemophilia Training Center, Bangkok, Thailand was studied. From 1991 to 2002, 209 females from 124 families with hemophilia A and B were included. There were 180 hemophilia A carriers and 29 hemophilia B carriers which could be classified into 78 obligate and 131 possible carriers. The phenotypic analysis for possible carriers involved the determination of levels of factor VIII or IX clotting activity (FVIII:C, FIX:C) and the ratio of FVIII:C and von Willebrand factor antigen. The result revealed that 49 females (37.4%) were diagnosed as carriers, 65 females (49.6%) were normal and 17 females (13%) were undetermined. Additional genotypic analysis was provided to 46 families with 74 females with obligate, proven or undetermined carriers within the reproductive life. The polymorphisms associated with factor VIII and IX genes were used including Bcl I for the factor VIII gene and combined use of Mse I, Sal I, Nru I, Hha I and Dde I for the factor IX gene. The informative rate was 59.4% (44/74). Consequently, 12 prenatal diagnoses for fetus at risk were performed. Sex determination was initially determined and followed by the diagnosis of hemophilia through informative gene tracking and/or the measurement of fetal levels of FVIII:C or FIX:C. The result revealed that 3 male fetuses were affected. The total cost of carrier detection and prenatal diagnosis that the families had to pay in the government hospital was 238,600 Baht (US dollars 5,965). It was compared to the estimated cost of minimal replacement therapy using lyophilized cryoprecipitate for the survival time of 30 years in one patient with hemophilia of 1,012,500 Baht (US dollars 25,312.5). The cost of prevention was much less than the replacement therapy. In conclusion, it is cost-effective to establish the service for carrier detection and prenatal diagnosis for hemophilia especially in developing countries with limited health resources.

Nutritional support in pediatric patients undergoing bone marrow transplantation.

BACKGROUND: Children undergoing bone marrow transplantation (BMT) are prone to develop severe gastrointestinal (GI) complications and metabolic imbalance which consequently impair their nutritional status. Nutritional support is an important adjunctive treatment during BMT. OBJECTIVE: To assess GI complications, metabolic complications and nutritional outcome of children undergoing BMT with nutritional support intervention. METHOD: Retrospective study of 20 children (median age 6.8 years, 11 males) undergoing BMT at Ramathibodi Hospital from March 1995 to July 2000 was conducted. Their medical records were reviewed. RESULTS: The patients underwent autologous (n = 9) and allogenic BMT (n = 11). Median z-scores of weight for age, height for age and weight for height were 0.06 +/- 1.93, -0.55 +/- 1.18 and 0.48 +/- 1.94, respectively. Nineteen patients had vomiting for 9.8 +/- 5.5 days. Eighteen patients developed diarrhea for 9.6 +/- 7.2 days. The durations of vomiting and diarrhea, as a percentage of total hospital days, were 33.5 +/- 16.3 per cent and 30.4 +/- 17.0 per cent, respectively. There were no differences between the patients with autologous and allogenic BMT regarding these durations. All patients needed enteral and/or parenteral nutrition support for 21.0 +/- 7.7 days except for one patient who could take adequate oral intake. The duration of enteral nutrition support was not significantly different between the groups but the duration of parenteral nutrition support was significantly longer in the allogenic group. Metabolic complications were hypokalemia, hypophosphatemia and one case of arrhythmia secondary to hypomagnesemia. All patients developed febrile neutropenia but none developed catheter-related sepsis. The length of hospital stay was 30.5 +/- 10.2 days. The median z-score of weight for height on the day of discharge was 1.08 +/- 2.03. CONCLUSION: Children undergoing BMT usually have GI symptoms of vomiting, diarrhea and mucositis as well as metabolic imbalances such as hypokalemia, hypophosphatemia and hypomagnesemia. Despite these complications, their nutritional status could be restored by proper nutritional support.