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Background In Cameroon, considerable research has been conducted on human ascariasis, but no studies have been undertaken to determine whether pigs contribute to the persistence of the infection in children or to unravel the evolutionary relationship between human-derived and pig-derived Ascaris. Methods DNA was extracted from adult Ascaris worms collected from humans and pigs. Segments of the cytochrome c oxidase subunit 1 (cox 1) and NADH dehydrogenase subunit 1 (nad 1) genes were sequenced and analysed for 83 worms to dissect the local transmission dynamics of Ascaris in Cameroon. Results The data showed high genetic diversity and revealed demographically expanding populations in the human and pig Ascaris samples. A restricted gene flow between Ascaris lumbricoides and Ascaris suum populations correlating with the preference for humans and pigs, respectively, as hosts was evident. Phylogenetic analyses and haplotype networks split the haplotypes into two major clusters, A and B. However, support for cross-transmission between hosts and hybridization were revealed through shared haplotypes among worms from both hosts. Conclusions This study provides useful baseline information for future studies of the genetics of Ascaris in Cameroon and suggests that effective and sustainable control of human ascariasis should target both human and pig hosts. [ABSTRACT FROM AUTHOR]

BACKGROUND: Soil-transmitted helminths (STH) infections remain an important public health problem in the tropics. This study aimed to evaluate the soil contamination rate and prevalence of infestations of geohelminth among residents in Bazou. METHODS: Four hundred (400) soil samples and 182 stool specimens were collected respectively from four sites and from inhabitants aged 1 to 40 years and above in 12 households. A questionnaire was administered to evaluate risk factors of STHinfections. Soil samples were screened using sucrose centrifugal flotation method while stool specimens were analyzed using two techniques. RESULTS: Out of the 400 soil and 182 stool samples examined, 13(3.3%) and 9(4.95%) were positive respectively after analyses. Soil contamination rates were 2%, 1% and 0.3% for Ascaris, Trichuris and hookworm eggs respectively while 4.95% of stool samples were positive to one species nematode (Ascaris lumbricoides). The soil contamination rate observed (5%) in the rainy season was significantly different (p>0.05) from the one observed (1.5%) in the dry season. Irrespectively of the season, the most frequent parasite identified was Ascaris spp. Soils around houses were more contaminated 6(12%) as compared to those collected from markets 5(10%) and roads 2(4%) while those around classrooms were not contaminated. Participants in the age group of 1-10 were more infected. Factors such as no hand washing habit and untrimmed finger nails were found to be important risk factors for STH. CONCLUSION: These results suggest the necessity to promote measures that could help to reduce STH infections. [ABSTRACT FROM AUTHOR]