Browsing by Author "Weldesenbet YD"

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    Prevalence and Load of the Campylobacter Genus in Infants and Associated Household Contacts in Rural Eastern Ethiopia: a Longitudinal Study from the Campylobacter Genomics and Environmental Enteric Dysfunction (CAGED) Project
    (American Society for Microbiology, 2023-07-26) Deblais L; Ojeda A; Brhane M; Mummed B; Hassen KA; Ahmedo BU; Weldesenbet YD; Amin JK; Ahmed IA; Usmane IA; Yusuf EA; Seran AJ; Abrahim FI; Game HT; Mummed BA; Usmail MM; Umer KA; Dawid MM; Gebreyes W; French N; Hassen JY; Roba KT; Mohammed A; Yimer G; Saleem C; Chen D; Singh N; Manary MJ; McKune SL; Havelaar AH; Rajashekara G; Elkins CA
    In our previous cross-sectional study, multiple species of Campylobacter were detected (88%) in stool samples from children (12 to 14 months of age) in rural eastern Ethiopia. This study assessed the temporal fecal carriage of Campylobacter in infants and identified putative reservoirs associated with these infections in infants from the same region. The prevalence and load of Campylobacter were determined using genus-specific real-time PCR. Stool samples from 106 infants (n = 1,073) were collected monthly from birth until 376 days of age (DOA). Human stool samples (mothers and siblings), livestock feces (cattle, chickens, goats, and sheep), and environmental samples (soil and drinking water) from the 106 households were collected twice per household (n = 1,644). Campylobacter was most prevalent in livestock feces (goats, 99%; sheep, 98%; cattle, 99%; chickens, 93%), followed by human stool samples (siblings, 91%; mothers, 83%; infants, 64%) and environmental samples (soil, 58%; drinking water, 43%). The prevalence of Campylobacter in infant stool samples significantly increased with age, from 30% at 27 DOA to 89% at 360 DOA (1% increase/day in the odds of being colonized) (P < 0.001). The Campylobacter load increased linearly (P < 0.001) with age from 2.95 logs at 25 DOA to 4.13 logs at 360 DOA. Within a household, the Campylobacter load in infant stool samples was positively correlated with the load in mother stool samples (r2 = 0.18) and soil collected inside the house (r2 = 0.36), which were in turn both correlated with Campylobacter loads in chicken and cattle feces (0.60 < r2 < 0.63) (P < 0.01). In conclusion, a high proportion of infants are infected with Campylobacter in eastern Ethiopia, and contact with the mother and contaminated soil may be associated with early infections. IMPORTANCE A high Campylobacter prevalence during early childhood has been associated with environmental enteric dysfunction (EED) and stunting, especially in low-resource settings. Our previous study demonstrated that Campylobacter was frequently found (88%) in children from eastern Ethiopia; however, little is known about potential Campylobacter reservoirs and transmission pathways leading to infection of infants by Campylobacter during early growth. In the longitudinal study presented here, Campylobacter was frequently detected in infants within the 106 surveyed households from eastern Ethiopia, and the prevalence was age dependent. Furthermore, preliminary analyses highlighted the potential role of the mother, soil, and livestock in the transmission of Campylobacter to the infant. Further work will explore the species and genetic composition of Campylobacter in infants and putative reservoirs using PCR and whole-genome and metagenomic sequencing. The findings from these studies can lead to the development of interventions to minimize the risk of transmission of Campylobacter to infants and, potentially, EED and stunting.
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    Transmission pathways of Campylobacter jejuni between humans and livestock in rural Ethiopia are highly complex and interdependent
    (BioMed Central Limited, London, United Kingdom, 2025-12-01) Singh N; Thystrup CAN; Hassen BM; Bhandari M; Rajashekara G; Hald TM; Manary MJ; McKune SL; Hassen JY; Smith HL; Marshall JC; French NP; Havelaar AH; Mekuria ZH; Weldesenbet YD; Yang Y; Li X; Gebreyes W; Shaikh N; Bhrane M; Dawid MM; Usmail MM; Deblais L; Mechlowitz K; Umer KA; Roba KT; Hassen KA; Amin JK; Usmane IA; Ahmed IA; Yimer G; Yusuf EA; Chen D; Saleem C; Ahmedo BU; Ojeda AE; Ibrahim AM; Seran AJ
    Background: Campylobacter jejuni and C. coli are the most common causes of bacterial enteritis worldwide whereas symptomatic and asymptomatic infections are associated with stunting in children in low- and middle-income countries. Little is known about their sources and transmission pathways in low- and middle-income countries, and particularly for infants and young children. We assessed the genomic diversity of C. jejuni in Eastern Ethiopia to determine the attribution of infections in infants under 1 year of age to livestock (chickens, cattle, goats and sheep) and other humans (siblings, mothers). Results: Among 287 C. jejuni isolates, 48 seven-gene sequence types (STs), including 11 previously unreported STs were identified. Within an ST, the core genome STs of multiple isolates differed in fewer than five alleles. Many of these isolates do not belong to the most common STs reported in high-resource settings, and of the six most common global STs, only ST50 was found in our study area. Isolates from the same infant sample were closely related, while those from consecutive infant samples often displayed different STs, suggesting rapid clearance and new infection. Four different attribution models using different genomic profiling methods, assumptions and estimation methods predicted that chickens are the primary reservoir for infant infections. Infections from chickens are transmitted with or without other humans (mothers, siblings) as intermediate sources. Model predictions differed in terms of the relative importance of cattle versus small ruminants as additional sources. Conclusions: The transmission pathways of C. jejuni in our study area are highly complex and interdependent. While chickens are the most important reservoir of C. jejuni, ruminant reservoirs also contribute to the infections. The currently nonculturable species Candidatus C. infans is also highly prevalent in infants and is likely anthroponotic. Efforts to reduce the colonization of infants with Campylobacter and ultimately stunting in low-resource settings are best aimed at protecting proximate sources such as caretakers’ hands, food and indoor soil through tight integration of the currently siloed domains of nutrition, food safety and water, sanitation and hygiene.