Pattern of water contact activities in relation to S. mansoni infection in rural area in Giza Governorate, Egypt.

Schistosomiasis is associated with human behavior in relation to water. Study of different patterns of water contact activities would help in planning strategies for control. This study aims to describe patterns of water contact activities in relation to S. mansoni infection in El-Shobak El-Sharki village in Giza governorate, in Egypt. A sample of 695 households was taken from about 127 houses. They provided stools samples and a water contact questionnaire for different activities, regions, sites, time of the day, duration of activities, patterns in different age and sex groups. Univariate and multivariate analysis of data was done. It was found that, adult males had the highest prevalence rate, then adult females while children had the least (33.5%, 27.5% and 17.4% respectively, p-value < 0.0001). Infection rate is higher in those having water contact activities, with Odds Ratio (OR) 2.01 and 95% Confidence Intervals (CI) (.94-4.24). Other significant factors are, the site of activities, time of the day and duration of contact, with p-value < 0.05. The highest score for the different patterns of activities in adult males are mainly occupational as agriculture and irrigation, their OR (95% CI) are 2.82 (.91-5.94) and 2.58 (.89-5.41), respectively. As regards females, the highest score is for domestic daily activities as washing infant clothes and utensils, their OR (95% CI) is 2.19 (.91-4.73) and 1.83 (.80-4.16) respectively. Children have the least score, their activities is mainly recreational as swimming, OR (95% CI) is 1.77 (.79-4.02). Multiple logistic regression analysis revealed that, male's activities and their longer duration are highly significant factors with prevalence as the dependant variable, OR (95% CI) is 3.07 (.73-8.19) for activities, and is 3.67 (.31-9.38) for duration. It is concluded that, human exposure pattern, in general, favors the transmission of S. mansoni. Prevalence of infection coincides with water contact activities in different age, sex and farming occupation. So, the control of S. mansoni in Egypt is not a pure medical affair. It needs multidisciplinary upgrading actions to be taken in different sectors of agriculture and irrigation reform in Egypt.

Upgrading of Kato-Katz technique for diagnosis of S. mansoni infection in rural Egypt.

Processing of the same stool samples was done using standard Kato-Katz (KK) technique with 41.7 mg of stools and one of the three modifications. These included KK technique using a higher concentration of glycerin (one and quarter, usual one) for preparation, or another stain (negrosin-eosin), with a specified formula, instead of the standard malachite green, or processing a smaller volume of stools (20mg). The results showed that, using cumulative infection rate from the two comparable tests as the reference, KK with higher concentration of glycerin was more sensitive than standard KK (sensitivities 77.6% and 61.2%. respectively). Using negrosin-eosin stain showed higher sensitivity (75.0%) in relation to standard KK technique (70.8%). Kato-Katz with higher concentration of glycerin showed the same sensitivity as KK with negrosin-eosin stain (85.7%) in relation to others. All comparisons showed statistically insignificant differences ((P>0.5). Using 20 mg of stools showed very low sensitivity in relation to standard KK technique (57.9% & 100.0% respectively). The statistical difference was highly significant. All specificities were 100%. Other screening indices showed the same trend of sensitivities. Degree of microscope clarity was optimal with higher concentration of glycerin. Negrosin-eosin showed better visualization of ova than the standard KK. All modifications took only an hour after processing to be examined. KK technique used with any of these modifications, is simple, inexpensive. use of either a higher concentration of glycerin or negrosin-eosin stain and recommended for both field studies and primary health care settings.