Epidemiology of intestinal helminthiases in a rural community of Ethiopia: Is it time to expand control programs to include Strongyloides stercoralis and the entire community?

Abstract

Background Soil transmitted helminths are highly prevalent worldwide. Globally, approximately 1.5 billion people are infected with Ascaris lumbricoides, Trichuris trichiura or hookworm. Endemic countries carry out periodic mass treatment of at-risk populations with albendazole or mebendazole as a control measure. Most prevalence studies have focused on school aged children and therefore control programs are implemented at school level, not at community level. In this study, the prevalence of intestinal helminths, including Strongyloides stercoralis, was examined using a comprehensive laboratory approach in a community in northwestern Ethiopia. Methods A cross-sectional survey was conducted on 792 individuals �5 years old in randomly selected houses in a rural district. Stools were examined using three techniques: a formolether concentration, the Baermann technique and a real time polymerase chain reaction test (these last two specific for S. stercoralis). Statistical analyses were performed between two large age groups, children (�14 years old) and adults (�15 years old). Results The prevalence of helminths was 91.3%; (95% CI: 89.3-93.3%). Hookworm was the most prevalent, 78.7% (95% CI 75.6-81.4%), followed by S. stercoralis 55.7% (95% CI 52.2-59.1%). Co-infection with both was detected in 45.4% (95% CI 42.0-49.0%

Performance evaluation of Baermann techniques: The quest for developing a microscopy reference standard for the diagnosis of Strongyloides stercoralis

“…In this study the overall prevalence of S . stercoralis infection was 34.6% which is comparable to results from a previous study using CB in this area of Ethiopia [ 6 ]. Although prevalence of S .…”

“…MBCI demonstrated sensitivity three times higher than CB, which might be due to the application of the gauze used in the filtration step in the case of MBCI that has more permeability to the larvae to migrate towards the warm water than the tissue paper that we used for CB. Previous studies used either tissue papers or gauze for filtration [ 4 , 6 , 24 ] but so far there is no standard tissue paper or gauze recommended for the filtration step either in CB or MB. For this study, locally available tissue roll paper was used for the CB and gauze for MB and MBCI which is adopted in the MB procedure from the Leiden University Medical Center’s (LUMC) in the Netherlands [ 4 ].…”

“…With the assumption of 90% anticipated sensitivity (S N ), prevalence of 33% [ 6 ], precision of 0.05 (L) and 95% confidence interval (Z 2 α/2 ), the minimum sample size required was calculated as 420 using Buderer’s formula [ 20 ].…”

“…After incubation, stool samples were suspended for 1 hour in lukewarm water at room temperature (which is in our case between 25 and 37°C) and filtered using a conventional Baermann apparatus (a strainer on top of a funnel connected to a rubber hose clamped with a hemostatic clamp) supported by a funnel stand, the single layer tissue paper side of the pouch was facing the strainer, ( Fig 2 ). Afterwards, the lower 10 mL from the water contained in the hose was drained off, centrifuged at 2000 rpm for 5 minutes and 1 mL of the sediment was examined microscopically for the presence of larvae [ 6 ]. The detail procedure is given in S1 Text .…”

Strongyloides stercoralis infection in Ethiopia: systematic review and meta-analysis on prevalence and diagnostic methods

“…A relatively high prevalence (55.68 %) of S. stercoralis infection was recorded among participants age greater than five years ( Aramendia et al, 2020 ) followed by (20.71 %) in schoolchildren of rural highlands of Amhara Regional State ( Amor et al, 2016 ), (20.0 %) in SNNPR schoolchildren ( Eriso F, 2014 ), (15.05 %) of schoolchildren in the Amhara Regional State ( Hailu et al, 2020 ), and (12.25 %) in patients of health institution of Addis Ababa City ( Hailegebriel et al, 2017 ) among studies conducted in Ethiopia ( Table 1 ).…”