Spatial distribution of soil-transmitted helminths, including Strongyloides stercoralis, among children in Zanzibar

Abstract

Abstract.A programme periodically distributing anthelminthic drugs to school-aged children for the control of soiltransmitted helminthiasis was launched in Zanzibar in the early 1990s. We investigated the spatial distribution of soiltransmitted helminth infections, including Strongyloides stercoralis, in 336 children from six districts in Unguja, Zanzibar, in 2007. One stool sample per child was examined with the Kato-Katz, Koga agar plate and Baermann methods. The point prevalence of the different helminth infections was compared to the geological characteristics of the study sites. The observed prevalences for Trichuris trichiura, Ascaris lumbricoides, hookworm and S. stercoralis were 35.5%, 12.2%, 11.9% and 2.2%, respectively, with considerable spatial heterogeneity. Whilst T. trichiura and hookworm infections were found in all six districts, no A. lumbricoides infections were recorded in the urban setting and only a low prevalence (2.2%) was observed in the South district. S. stercoralis infections were found in four districts with the highest prevalence (4.0%) in the West district. The prevalence of infection with any soil-transmitted helminth was highest in the North A district (69.6%) and lowest in the urban setting (22.4%). A. lumbricoides, hookworm and, with the exception of the North B district, S. stercoralis infections were observed to be more prevalent in the settings north of Zanzibar Town, which are characterized by alluvial clayey soils, moist forest regions and a higher precipitation. After a decade of large-scale administration of anthelminthic drugs, the prevalence of soil-transmitted helminth infections across Unguja is still considerable. Hence, additional measures, such as improving access to adequate sanitation and clean water and continued health education, are warranted to successfully control soil-transmitted helminthiasis in Zanzibar.

Intestinal parasites and genotypes of Giardia intestinalis in school children from Berisso, Argentina

“…Considering that 40% of the families in the district are immigrants from the north of the country or the bordering countries Bolivia and Paraguay, where geohelminths are very frequent [34], it is possible that the ecologic conditions of this district are not favorable for the transference of these parasites [35].…”

Prevalence of Strongyloides stercoralis and other intestinal parasitic infections among mentally retarded residents in central institution of southern Iran

“…Soil-transmitted helminthes (STH) as a major health problem caused by Ascaris lumbricoides, Trichuris trichiura and the hookworms are the most prevalent worldwide [7] and, Strongyloides stercoralis (S. stercoralis) is the most neglected one among them [9,11,12] . It is estimated that over 1 billion people are infected with STH and 30-100 millions with S. stercoralis worldwide [7,[11][12][13][14] .…”

“…It is estimated that over 1 billion people are infected with STH and 30-100 millions with S. stercoralis worldwide [7,[11][12][13][14] . S. stercoralis's unique life cycle makes it possible to survive in human host and causes autoinfection to lead chronic disease which could have remained for several years [13][14][15] .…”

Malaria and soil-transmitted intestinal helminth co-infection and its effect on anemia: a meta-analysis

“…43 Published studies have documented that obtaining only a single fecal sample for A. lumbricoides and T. trichiuria can lead to underestimation of infection rates by up to 50%. 54,74 Sensitivity for low infection rates increased from 20 to 54% when three fecal samples were examined on separate days. 74,75 Although confounding factors were addressed in many of the primary studies identified for the current analysis, it is likely that there still may be unmeasured confounding factors which might have induced bias to this meta-analysis.…”

“…Of these, a total of 44 full-text articles were reviewed, of which only 30 were included in the metaanalysis. [8][9][10] Studies were excluded if data on the noncoinfected group were not available, [52][53][54][55][56][57] data on the co-infected group were not available, 58 the majority were HIV-infected participants or tested positive for HIV, 59,60 samples were duplicated, 61,62 data were insufficient to compute effect estimate as only abstracts were available 63,64 and the study was on treatment efficacy. Table 1 gives the characteristics of the included studies.…”