Seroprevalence of Toxoplasma gondii antibody in Vietnamese villagers.

Toxoplasmosis caused by Toxoplasma gondii is a protozoan infection found worldwide. It usually produces non-specific symptoms, but in pregnant women and immunocompomised individuals, it may cause severe and fatal illness. Many serological studies have been done in various parts of the world, but information is lacking for Vietnam. A seroprevalence study of T gondii antibodies in Vietnamese villagers (n = 650) was performed using the Sabin-Feldman dye test. The average seroprevalence was 4.19% (95% CI = 1.78-4.62), including 6.36% (95% CI = 3.22-11.09), 4.73% (95% CI = 1.92-9.50) and 1.09% (95% CI = 0.23-3.15) from Nghe An, Lao Cai and Tien Giang provinces, respectively. This study confirmed the low prevalence of toxoplasmosis in Vietnam similar to other countries in the region. Further studies are necessary in order to provide a complete picture for the country.

Spa, springs and safety.

Natural mineral water has long been used worldwide for bathing and health purposes. At present, Thailand is famous for health spas and natural hot springs among local people and tourists. Due to possible risks of exposure to harmful agents, we studied hazardous pollutants at 57 natural hot springs from 11 provinces in northern, central, eastern and southern Thailand. Pathogenic, free-living amebae of the genera Naegleria and Acanthamoeba, which can cause central nervous system infection, were found in 26.3% (15/57) and 15.8% (9/ 57), respectively. Dissolved radon, a soil gas with carcinogenic properties, was present in nearly all hot springs sites, with concentration ranging from 0.87-76,527 Becquerels/m3. There were 5 water samples in which radon concentration exceeded the safety limit for drinking. Legionella pneumoniphila (serogroups 1, 3, 5, 6, 7 10 and 13) were found in samples from 71.9% (41/57) of studied sites. Because spas and natural springs are popular tourist attractions, health authorities should be aware of possible hazards and provide tactful measures and guidelines to ensure safety without causing undue alarm to foreign and Thai tourists.

Free-living ameba contamination in natural hot springs in Thailand.

Thermo tolerant free-living ameba, Naegleria spp and Acanthamoeba spp contamination in natural hot springs in Thailand were carried out from 13 provinces. The temperature of hot springs water varied from 28 degrees-65 degrees C and pH from 6-8. We found that 38.2 % (26/68) of water samples were positive, Acanthamoeba was 13.2% (9/68) whilst Naegleria was 35.3% (24/68). Contamination by free-living ameba in natural hot springs may pose a significant health risk to people who use such water for recreation activities.

Toxoplasma gondii antibody in Thai cats and their owners.

Humans are thought to acquire Toxoplasma infection by three major routes: ingesting food and water contaminated with oocysts from cat excreta, consumption of under-cooked infected meat, and transplacental transfer. Congenital clinical toxoplasmosis in the newborn indicating definite transplacental transmission had been reported in Thailand, whilst studies concerning infection due to the other two routes were inconclusive. Since the way domestic cats live and eat and also the eating behavior of Thai people differ from those in the West, we conducted a sero-epidemiological study of T. gondii in cats and their owners in Bangkok metropolitan area. Among 327 humans, the prevalence of Toxoplasma antibody was 6.4% and in 315 cats it was 7.3%. These relatively low prevalence rates may result from the predominantly well-cooked fish and rice diet of stray cats, which congregate in temples where they are fed. Toxoplasma antibody seropositive was associated with living in close proximity to seropositivity cats [OR (95% CI) = 5.43 (1.28-23.04); p=0.01]. Risks were increased in and around temples, particularly if courtyards were of earth or grass, suggesting ground temperature was an important determinant of oocyst survival.