The epidemiology survey of Pfcrt and Pfmdr 1 mutant genes in malaria infection in Edo State was carried out between June 2005 and May 2006. Five hundred and sixty one (561) subjects with a history of fever, joint pains, and bitterness of the mouth were enlisted for this study. With regard to place of residence, 229 subjects were from Edo South, 177 from Edo Central and 155 from Edo North. Genotyping of resistance markers “Plasmodium falciparum Chloroquine Resistance Transporter” (Pfcrt K76T) and Plasmodium falciparum Multi-Drug resistance (Pfmdr1) was carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). There was no statistical difference (P>0.05) in the prevalence of malaria infection among the three senatorial districts (90.8%, 94.2% and 96.1% respectively). The general prevalence of mutant Pfcrt K76T and Pfmdr 1 mutant genes in the state were 21.9% and 15.1% respectively. No statistical difference existed when the prevalence of these genes was compared within the senatorial districts (P>0.05). The treatment of malaria has reached a crisis point in the sub-Sahara regions. The present findings also revealed a relatively high prevalence of these resistance genes in Edo State, underlining the need for urgent policy intervention before the situation escalates beyond control.
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 et al., 1997). During the control program, the prevalence was kept at a low range of 20 to 40% (Muhoho et al., 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survey done in 1999 revealed reduced prevalence and intensity of infection, I.e. 23.0% and 1.2 eggs⁄ 10 ml of urine (unpublished data).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. 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. 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. 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.
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 et al. (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. 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 Toxocara sp., while the three filtrated water samples contained one egg each of Trichuris sp., Trichiuris sp. and Taenia 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 Ascaris sp., Trichuris sp., Toxocara sp., Ascaridia galli, hookworm, Taenia sp. and Fasciola 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 Trichuris sp., Ascaridia galli and Taenia 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.
As part of the Pacific Program to Eliminate Lymphatic Filariasis (PacELF), baseline surveys were conducted in 1999 and 2004 in Nauru to determine the prevalence of filariasis by rapid immunochromatotraphic test (ICT). In 1999, the survey demonstrated a filariasis prevalence of 0.26%, and Nauru was classified as a non-endemic country at the time. In 2004, the prevalence resulting from the survey was 1.66%. Since it exceeded 1.0%, this high prevalence warranted the implementation of Mass Drug Administration (MDA) according to WHO guidelines and gave rise to an urgent need to re-establish the filariasis policy in Nauru, as the target year for filariasis elimination in the Pacific is 2010. The present study was conducted to determine the current prevalence of filariasis, to decide whether implementation of the MDA program is necessary, and to compare the demographic characteristics of participants according to the ICT test results. Blood sampling and interviews, based on a simple questionnaire asking about filariasis-related symptoms, were conducted by trained health staff members. A total of 1,513 people were enrolled for the survey in January 2007. Filariasis positivitiy was detected in three subjects (0.2%) by ICT test. Nauru was reconfirmed as a non-endemic country and therefore did not require the MDA implementation. The prevalence did not vary significantly according to the demographic characteristics. The three seropositive cases did not have any filariasis-related symptoms. However, two of the three positive cases of filariasis lived in the same district and the other lived in a neighboring district. To assess the interruption of filariasis transmission, further surveys are recommended.