Strongyloides stercoralis infection and chronological changes of other soil-transmitted helminthiases in an endemic area of southern Thailand.

A field survey was conducted in 4 primary schools in Nakhon Si Thammarat Province, southern Thailand. By Sasa modified Harada-Mori cultivation method, 1.8% of the schoolchildren were found to be infected with Strongyloides stercoralis, and 25.1% had hookworm infection. By Kato's thick smear method, the overall prevalence of soil-transmitted helminths was 46.8%, being Trichuris trichiura 28.5%, hookworm 18.0%, and Ascaris lumbricoides 5.7%. Fecal examination, performed by Kato's thick smear and culture method, indicated that the prevalence of hookworm infection was 26.9%. The prevalence in the present study was very much lower than many previous reports in the past decade. This may indicate the partial success of the parasite control project in Thailand by mass treatment, improving the sanitation and personal hygiene of the people in the endemic area. In light infection with Trichuris, albendazole administered at a dosage of 200 mg daily for 3 days showed a 48.7% cure rate. When mebendazole was given at 100 mg twice daily for 3 days, its effectiveness was 88.5%. A lower cure rate was obtained (70.0%) in moderate to heavy infection.

Efficacy of multiple dose mebendazole against trichuriasis in Thai and Karen patients.

Treatment of trichuriasis with mebendazole 500 mg for three days, and 100 mg twice daily for three days, yielded cure rates of 93.9 and 88.9% in Thai patients, while the cure rates in Karen patients were 96.2 and 95.5% respectively. The total number of Thai and Karen trichuriasis patients were 60 and 48, when tested by modified cellophane thick smear Kato-Katz technique. There were no significant differences among the two groups of patients and doses of treatment (p > 0.05).

Minimum effective doses of mebendazole in treatment of soil-transmitted helminths.

Three hundred and fifteen primary school children infected with soil-transmitted helminths were divided into 5 groups. Three groups were treated with 25, 50 and 75 mg mebendazole (MBZ) single dose. One group was given MBZ conventional dose of 100 mg twice daily for 3 days and another group was given albendazole (ABZ) standard dose of 400 mg single dose. Every trial lower MBZ dose 75 mg, 50 mg and 25 mg regimen were highly effective against Ascaris lumbricoides but only moderately effective against Trichuris trichiura and Necator americanus.

The impact of primary health care intervention on reinfection of soil-transmitted helminths in the community.

A study to evaluate the impact of primary healthy (PCH)care practices on the prevention of reinfection of soil-transmitted helminths (STH) was carried out in Nakhon Si Thammarat Province, southern Thailand. Fecal samples from the inhabitants of Ban Paruhas, the implementing village, and Ban Pungsing, the control village, were examined following mass treatment with a three-day regimen of albendazole (400 mg). Training of health volunteers, implementation of a health education program through village broadcasting system and improvements in sanitation including increasing the number of latrines were carried out at Ban Paruhas village. After one year of implementation, prevalence and intensity of STH in both villages were determined using Kato-Katz's method. Pre- and post intervention stool examination results were compared. The overall prevalence of STH at post-intervention decreased significantly in both villages, with a greater degree of reduction appearing in ascariosis and hookworm infections in the village where PHC was implemented.

Vitamin B1, B2 and B6 deficiency in primary school children infected with hookworm.

One thousand and seven hundred thirty-six school children from two districts in Nakhon Si Thammarat Province were screened for hookworm infection using the Kato-Katz stool examination technic. Two hundred students who have at least 2,000 eggs per g of stool were recruited into the program. The students were divided into six groups: groups 1, 2 and 3 were from Tha Sala district while groups 4, 5 and 6 were from Ronpibul district. Three milliliter blood samples were obtained from the cubital vein of each subject and were evaluated for erythrocyte transketolase activity (ETK) for vitamin B1, erythrocyte glutathione oxidoreductase activity (EGR) for vitamin B2, and erythrocyte aspartate aminotransferase activity (EAST) for vitamin B6. The school children were divided into three groups: those infected only with hookworm, those with both hookworm and Trichuris trichiura, and those whose stools show no parasite eggs. The results show that 10-20% of the school children are vitamin B1 deficient, about 40% to 80% are vitamin B2 deficient, and about 14% to 23% are vitamin B6 deficient. No correlation could be made between vitamin deficiencies and parasitic infection.

Efficacy of single-dose mebendazole, polymorphic forms A and C, in the treatment of hookworm and Trichuris infections.

A therapeutic trial of single mebendazole, 300 mg polymorph A, 300 mg polymorph C and 500 mg polymorph C, in the treatment of hookworm and Trichuris infections was carried out at primary schools in Southern Thailand. The total of 958 children were randomly allocated in seven treatment groups including the placebo control and the standard dose control (100 mg polymorph C bid for 3 days). The egg reduction rates and the cure rates of 300 mg and 500 mg polymorph C were similar, but inferior to those of the standard dose in both hookworm and Trichuris infections. The efficacy of single dose 300 mg polymorph A was not different from that of the placebo control (alpha = 0.05) in both infections.

Prevalence and zoonotic potential of Ancylostoma ceylanicum in cats in Thailand.

Ancylostoma ceylanicum and Ancylostoma caninum were found in cats from Prachin Buri, Thailand, with infection rates of 92% and 23%, respectively. In this survey, 75% of cats were infected with A. ceylanicum alone, the rest had mixed infections of A. ceylanicum and A. caninum. The worm burden range in 26 cats for A. ceylanicum and A. caninum were 1 to 83 and 1 to 10, respectively. For A. ceylanicum, both males and females were found in the gut from the first part of duodenum to rectum. In the case of A. caninum the distribution was not constant. The sex ratio between male and female A. ceylanicum was 1:1.4. The egg count for A. ceylanicum was in the range 31-150 per gram of faeces (mean 70). The zoonotic potential of these parasites was discussed.