Changes of liver functions after albendazole treatment in human gnathostomiasis.

Ninety-eight out-patients of the Hospital for Tropical Diseases, Bangkok with clinical diagnosis of cutaneous gnathostomiasis were studied. All patients were treated with albendazole at a dosage of 400 mg (two tablets) twice daily for 14 days. They were seen periodically on day 0, day 14, day 28, day 195 and 1 year after treatment with laboratory investigations for any side effects of the treatment. There was a statistically significant increase of total protein, albumin, alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values when comparing the different periods. The abnormal results are clearly indicated in AST and ALT values (liver enzyme) especially on day 14 both male and female patients had highest levels. No significant association with time was found in ALP value.

Risk factors for chronic diseases among road sweepers in Bangkok.

The nutritional and health status of road sweepers in Bangkok was investigated. Fifty-seven males and one hundred thirty-four females from 10 districts were selected for the study. The districts were sampled as cluster at random. From each district selected about 50% of road sweepers volunteered to participate in the investigation. Through questionnaires the age, marital status, place of origin, drinking and smoking habits were assessed. Anthropometric measurements, blood pressure and the lipid profile of these subjects were determined. According to a physical check-up and X-rays taken, all individuals investigated were apparently healthy. The age of the study group varied between 26 and 57 years. The median for the males was 47 years and for the females 37.5 years. Almost all the road sweepers were married. Smoking and alcohol drinking was widespread. Over- and undernutrition was found among the group investigated. 26.3% of the males and 1.5% of the females were undernourished. According to their systolic values, 15.8% of the males and 6.7% of the females were suffering from hypertension, and 38.6% of the males and 15.7% of the females had hypertension according to their diastolic values. 58.2% of the females and 29.3% of the males were overnourished. 57.9% of the males and 59.7% of the females had cholesterol levels above 200 mg/dl. Pathological values of LDL cholesterol were determined in 26.3% of the males and 28.4% of the females. The habit of consuming tonic drinks was widespread among the workers. The study concluded that behavior risk factors are highly prevalent in the group of workers belonging to the lower socio-economic class. Further investigations are presently being undertaken to study the after-effects of air pollution among this group of workers. The results will be subsequently reported in future publications.

A brief survey of phlebotomine sandflies in Thailand.

Sandflies were found in widely scattered localities in Thailand in varied numbers. Daytime resting places for the adults included caves, termite hills, abandoned houses, ancient stone sanctuaries, air-raid shelters, tree hollows, loose bark of dead standing trees and rock crevices. Of fifteen species, P. major major, P. teshi, S. anodontis, S. gemmea, S. hodgsoni hodgsoni, S. perturbans, S. punjabensis and N. vietnamensis were here recorded for the first time in Thailand. P. argentipes and P. major major are interesting in view of their potential as disease vectors.

Lipid composition of serum lipoprotein in opisthorchiasis.

Lipid composition (i.e. total cholesterol, free cholesterol, cholesteryl ester, triglycerides and phospholipids) in the individual serum lipoprotein fractions (i.e. high-density lipoprotein, low-density lipoprotein and very low-density lipoprotein) were studied in 24 healthy controls and 18 opisthorchiasis patients admitted to the Bangkok Hospital for Tropical Diseases, Faculty of Tropical Medicine. The two groups were similar in age range, sex ration and anthropometric data. Other background data such as blood pressure and alcohol consumption, were also similar in the two groups. All the patients had the habit of eating raw or half-cooked fish. Abnormalities of high-density lipoprotein content in the opisthorchiasis group showed as low cholesterol and cholesteryl ester concentrations but with high triglyceride concentrations. These may result from disturbance of the synthesis of nascent disk high-density lipoprotein or the removal of lipid content in lipoproteins.

Investigation of malaria sporozoites by immunoradiometric assay.

Two-site immunoradiometric assay (IRMA) (Zavala et al., 1982) using monoclonal antibodies to P. falciparum and P. vivax was applied to detect sporozoites in laboratory-maintained An. dirus and also mosquitoes collected from endemic areas of malaria in Thailand. Study in P. falciparum infected mosquitoes revealed that the circumsporozoite (CS) antigen was first found in the abdominal portion on day 10 post-infection, while it could be observed in the salivary glands from day 15 onwards. The head-thorax portion of wild-caught mosquitoes were investigated by IRMA compared with the dissection technique. The results showed that none of the mosquitoes collected from Phrae was positive for malaria. The mosquitoes collected from Chantaburi showed 4 out of 1243 An. dirus that were positive for P. falciparum by IRMA, with sporozoites ranging from 207 to 3875. Among 3123 An. minimus collected from Kanchanaburi, 3 were positive by IRMA, 2 for P. falciparum and one P. vivax with sporozoites found in head-thorax portion were 1880, 2380 and 1026 respectively. Not a single sporozoite was found in the mosquitoes collected from these areas by the dissection technique. However 7 out of 1219 An. minimus from Kanchanaburi were found to possess undeveloped oocysts in the stomach wall. It is evident that the IRMA is efficient, convenient and suitable for the investigation of sporozoites in this region. The application of this technique in further epidemiological study of malaria is in progress.

A small scale field trial with Temephos (Abate) for the control of four species of Mansonia (Mansonioides) (Diptera: Culicidae) in Thailand.

A 60-week control experiment with Temephos (Abate) against a largely isolated population of Mansonia annulata, Ma. annulifera, Ma. indiana and Ma. uniformis was carried out in a pool of 1.2 ha area and average depth of over 2 m in southern Thailand. Floating paper tea bags containing 24 g of 1% Abate sand granules were applied in two rounds at a density of 1 bag 4 m-2. Each round consisted of five applications at intervals of 13 days. During the application rounds mosquito larvae disappeared completely from the pool. This apparent effect of Abate was confirmed by bioassays made with pool water and larvae of Culex quinquefasciatus. Inactivation of Abate was linear during one week, with a slope of 5.8% per day. Adult densities dropped during the application rounds and, over a period of 48 weeks, were 78-85% less than during the corresponding time of the preceding reference year. The annual pattern of adult abundance that normally shows distinct seasonal peaks was strongly altered, although meterological data were comparable to the reference year.

Studies on oviposition characteristics of Mansonia (Mansonioides) mosquitoes in southern Thailand.

Oviposition characteristics of Mansonia (Mansonioides) mosquitoes were studied to assess future possibilities for their control. Special emphasis was given to the study of the factors, especially the host plant species, which guide the gravid females towards the oviposition site. Initially, egg dispersal throughout the breeding place was assessed by comparing egg densities between so-called areas of 100-200 m2, each characterized by reasonable homogeneity in its flora. Some of these areas were preferred by gravid females, indicating an aggregative type of distribution. There was no evidence that the attractiveness of areas was correlated with the availability of preferred host plants. Egg dispersal within areas was then studied using randomly chosen plots of 1 X 1 m or 15 X 15 cm as sampling units. This again revealed aggregative egg distributions which could be fitted to a negative binomial expectation. The amount of visible water surface, rather than the availability of host plants, appeared to determine the attractiveness of the plots. The dispersal within 1 m2 experimental plots containing the host plants Pistia, Eichhornia and Salvinia was then investigated and this showed clearly that specific levels of attractiveness of plant species influenced egg dispersal. These levels were modified by (i) the presence of grasses in the immediate surroundings, (ii) features of grass growth and (iii) the type of host plant arrangement. It was concluded that the factors responsible for egg aggregations vary with the size of the samples compared, and that the host plant species plays a significant role only for the distribution within quite small units of the breeding place.

Observations on the feeding habits of four species of Mansonia (Mansonioides) mosquitoes in Southern Thailand.

Studies on feeding habits of Mansonia annulata, M. annulifera, M. indiana and M. uniformis were carried out in southern Thailand. This study showed that M. annulata and M. uniformis were both strongly exophagic mosquitoes which avoided approaching and entering human dwellings. The biting frequency on the verandah was considerably higher than indoors. M. indiana was not repelled by houses but avoided biting indoors. M. annulifera was endophagic, it was attracted by houses and bit on the verandah as frequently as indoors. Some species showed differential preference for age- and sex-groups of human hosts: M. annulata was more attracted by adolescents and adults than by children and M. annulifera preferred female hosts. The other species did not distinguish between host groups.

Some aspects on biting cycles of Culex quinquefasciatus in Bangkok.

The indoor and outdoor biting cycles of Culex quinquefasciatus were studied in Bangkok. The biting cycle was nocturnally periodic and preferably endophilic in character. There were two minor peaks on top of the nocturnally periodic peak. The first peak was between 2200 and 2300 hours, the latter peak was after midnight being at 0100 and 0400 hours. Parous mosquitoes formed 0%-20.0% of hourly total population. More parous mosquitoes were collected indoor and also during in the latter half of the night. Comparisons made between Bangkok, the none endemic area for Wuchereria bancrofti and Sri Lanka the endemic area, revealed that Bangkok has a lower survival rate of Culex quinquefasciatus, based on parous rates and that the older mosquitoes, which are potentially infective vectors were collected late in the night. This evidence could explain why Bangkok is not endemic area for periodic Wuchereria bancrofti.

Alcohol consumption, liver function tests and nutritional status in Thai males.

31 healthy Thai males, 22 Thai male regular drinkers not suffering from any clinical signs or symptoms of alcoholism, and 52 patients from a neurological hospital in Bangkok suffering from the effects of chronic alcohol consumption were investigated. Alcohol consumption in asymptomatic drinkers ranged from 7 to 134 (median 44) g/d ethanol, and for the patients 22 to 517 (median 197) g/d ethanol, as assessed by questionnaires. The symptomatic alcohol drinkers had consumed alcohol for 2 to 35 years and the hospitalized patients for 5 to 40 years. Only the median levels of serum triglycerides and serum glutamyl transferase (gamma-G) were significantly increased and vitamin B1 deficiency was found with higher frequency in the group of alcohol drinkers without clinical signs compared with the healthy non-alcohol drinkers. Statistically significant correlations were demonstrated in the group of asymptomatic alcohol drinkers only, between alcohol consumption and the Quetelet's index, gamma-G, and alkaline phosphatase levels. Alkaline phosphatase also correlated significantly with gamma-G. In the group of hospitalized patients, compared with healthy males statistically significantly higher median values of systolic and diastolic blood pressure, serum triglyceride, gamma-G, aspartate aminotransferase (GOT), alanine aminotransferase (GPT), alkaline phosphatase, haemoglobin, hematocrit, folate and total protein were found. The median levels of cholesterol, bilirubin, vitamin B2, B6 and B12 in the hospitalized group were lower than, but not significantly different from the other two groups.

The vectors of Brugia malayi in Southern Thailand.

Mansonia uniformis, with an infective rate of 0.02, was incriminated as the vector of periodic Brugia malayi in Pattani province. Mansonia bonneae and Ma. dives, with infective rates of 0.18 and 0.20 respectively, were the vectors of B. malayi in Narathiwat, where the microfilarial periodicity was the subperiodic form.

Studies on the life history of Megaselia scalaris (Loew) in Thailand.

The morphological, life-cycle, and experimental studies of Megaselia scalaris were reported. This fly is commonly found both in urban and rural areas in Thailand. It is easily identified and the humped thorax was the most distinct characteristic of the adult. The egg to the adult stage and the life span required 15 to 20 days for the male and 16 to 22 days for the female. Experimental attempts to induce myiasis infection in laboratory animals were unsuccessful.

A survey of houseflies in bangkok and neighboring provinces.

A survey of flies in Bangkok and neighboring province revelaed that among 8,675 flies collected there were 10 genera and 18 species of flies, eg. Musca domestica, M. bezzii, M. conducens, M. nebulo, Chrysomyia megacephala, C. rufifacies, Phaenicia sericata, P. cuprina, Sarcophaga ruficornis, S. peregrina, S. orchidae, S. albiceps, Megaselia scalaris, Lispe orientalis, Anaclysta flexa, Morellia hortensia, Hemipyrellia ligurriens and Orthellia coeruleifrons. Musca mostly bred in low-protein content media, eg., garbage piles of vegetable and rice, and was predominant in the morning while Chrysomyia and Phaenicia mostly bred in high-protein content media, eg., animal carcasses, and were predominant in the afternoon. Female flies were bigger than male and they were more predominant than males in or around breeding places. The density of flies was correlated with the relative humidity but not with rainfall or temperature. The density of flies was correlated with the occurrence of gastrointestinal diseases. Some cases of myiasis have been reported from Thailand.