RESUMO
Some field trials have already demonstrated the high antischistosomal potential of combination therapies using Artesunate (ART) and current antimalarial drugs (Boulanger <I>et al.,</I> 2007; Mohamed <I>et al.,</I> 2009; Sissoko <I>et al.,</I> 2009). The antischistosomal effects of these drugs are noteworthy, especially when they are used for the treatment of malaria in schistosomiasis endemic areas. However, the antischistosomal effects of Amodiaquine (AQ), Primaquine (PQ), Chloroquine (CQ) and Pyrimethamine (Py) have never been assessed by <I>in vitro</I> incubation. The objective of the present study is to assess the <I>in vitro</I> effects of current antimalarial drugs on the egg productivity of adult worm pairs of <I>S. mansoni</I> and their survival times. The effect of the current antimalarial drugs Mefloquine (MQ), quinine (QN), AQ, PQ, CQ, Sulfadiazine (Sf) and Py on the egg output of adult worm pairs of <I>Schistosoma mansoni</I> and their survival times during <I>in vitro</I> culture were assessed at a concentration of 10 Μg⁄ml. AQ, PQ, CQ and Py significantly inhibited the daily egg output of paired female worms at a concentration of 10 Μg⁄ml during the 1 or 2-day <I>in vitro</I> cultivation. However, QN and Sf did not significantly affect the daily egg output during the 8-day incubation. One-day exposure to MQ killed all paired male and female adult worms. AQ and PQ significantly decreased the survival of both paired male and female worms during the 14-day incubation, but QN, CQ, Py and Sf did not exert any similar effect. The present result is consistent with an assessment of the antischistosomal effects of artemisinin-based combination therapy in malaria and schistosomiasis co-endemic areas.
RESUMO
Contamination of water and air by soil-transmitted helminth eggs was investigated in a small village located in the suburbs of Hanoi, Vietnam. Water samples were collected from 29 households, two schools, two kindergartens, one restaurant, three ponds and 23 ditch sites during the rainy season. Water samples were also collected at the same places, except for one household and one restaurant, during the dry season. The water samples collected from households, schools, kindergartens and restaurant were comprised of well-water and rain-water. These samples included both water filtrated with sand and gravel and non-filtrated water. Two-liter water samples were examined for helminth eggs by either a centrifugation or flotation method. The contamination of air by helminth eggs was assessed by the method of Kroeger <I>et al</I>. (1992). Eggs in air were trapped on adhesive tapes hanging in rooms and in the area around 29 houses, two schools, two kindergartens, one restaurant and 18 utility poles.<br>Out of 63 water samples collected from households in the rainy season, helminth eggs were found in four water samples; one from non-filtrated well-water and three from filtrated well-water samples. The one non-filtrated water sample contained six eggs of <I>Toxocara</I> sp., while the three filtrated water samples contained one egg each of <I>Trichuris</I> sp., <I>Trichiuris</I> sp. and <I>Taenia</I> sp. No eggs were found in the water samples collected from schools, kindergartens or the restaurant in the rainy season. All water samples collected from ponds and ditches in the rainy season contained many helminth eggs. The eggs found were <I>Ascaris</I> sp., <I>Trichuris</I> sp., <I>Toxocara</I> sp., <I>Ascaridia galli</I>, hookworm, <I>Taenia</I> sp. and <I>Fasciola</I> sp. Examination of the adhesive tapes hanging in the air showed that four sites were contaminated by helminth eggs, i. e. one site near the house, two sites near the school and one site at a utility pole. The species of eggs found were <I>Trichuris</I> sp., <I>Ascaridia galli</I> and <I>Taenia</I> sp. The number of eggs found on tapes was only one or two. In the dry season, a few samples of well-water and rain-water collected from the residential area were contaminated with helminth eggs, and all samples collected from ponds and ditches contained many eggs of various species similar to those collected in the rainy season. The present study clearly indicates that, in our study area, the villagers were subject to infection from soil-transmitted helminthes directly and indirectly through water.
RESUMO
An attempt was made to examine the long-term impact of the introduction of communal piped water supply on pattern of water use and transmission of schistosomiasis haematobia in an endemic area of Kenya. In the study area, Mtsangatamu, a control program based on repeated selective mass-chemotherapy had been carried out for 6 years from 1987 to 1993. The pre-treatment overall prevalence and intensity of infection in 1987 were 59.2% and 10.9 eggs⁄10 ml of urine (Muhoho <I>et al</I>., 1997). During the control program, the prevalence was kept at a low range of 20 to 40% (Muhoho <I>et al</I>., 1994). At the end of the program, in 1994, gravity-fed water supply was provided to the village. Although the water facilities were damaged by flooding in 1998, new and further expanded gravity-fed water supply facilities consisting of 7 standpipes were introduced in 2000. The follow-up survey done in 1999 revealed reduced prevalence and intensity of infection, I.e. 23.0% and 1.2 eggs⁄ 10 ml of urine (unpublished data). The present study was carried out in 2006, 6 years after the last mass-chemotherapy. Urine examination showed that the prevalence and intensity of infection had return to 52.2% and 7.4 eggs⁄10 ml, nearly the same level as the pre-treatment level. The results of our study demonstrated that, over the long-term, the gravity-fed water supply facilities had little impact on the overall prevalence and intensity of infection in this village. However, analysis of the spatial pattern of infection, observation of human water contact at the river and a questionnaire on water use shed light on the possible impact of water supply on human water contact. The younger people (5-19 years old) with easy access to the standpipes showed a lower prevalence and intensity of infection, while the relationship was not clear in other age groups.<br>The result of the questionnaire indicated that the long distance from household to standpipe was the major factor limiting the use of the communal tap water. Most of the villagers who used piped water as the main source of water lived within 800 m of the nearest standpipe, and villagers who used river water exclusively lived beyond that distance. Observation of water-related activities at the communal water facilities also indicated that the residents who lived near standpipes used the piped water more frequently.<br>The frequency of total visits to river water sites did not differ between residents who lived near and far from the standpipe. However, water contact in the form of playing, the highest risk behavior, was observed exclusively among children who lived far (>250m) from standpipes, although the number of observations was small.<br>The present study demonstrated that the water facilities had little effect on the dispersed population but might have a beneficial effect on some villagers given easy access to standpipes.