Seroprevalence of antibodies against Chlamydia trachomatis and enteropathogens and distance to the nearest water source among young children in the Amhara Region of Ethiopia

Abstract

The transmission of trachoma, caused by repeat infections with Chlamydia trachomatis, and many enteropathogens are linked to water quantity. We hypothesized that children living further from a water source would have higher exposure to C. trachomatis and enteric pathogens as determined by antibody responses. We used a multiplex bead assay to measure IgG antibody responses to C. trachomatis, Giardia intestinalis, Cryptosporidium parvum, Entamoeba histolytica, Salmonella enterica, Campylobacter jejuni, enterotoxigenic Escherichia coli (ETEC) and Vibrio cholerae in eluted dried blood spots collected from 2267 children ages 0-9 years in 40 communities in rural Ethiopia in 2016. Linear distance from the child's house to the nearest water source was calculated. We derived seroprevalence cutoffs using external negative control populations, if available, or by fitting finite mixture models. We used targeted maximum likelihood estimation to estimate differences in seroprevalence according to distance to the nearest water source. Seroprevalence among 1-9year-olds was 43% for C. trachomatis, 28% for S. enterica, 70% for E. histolytica, 54% for G. intestinalis, 96% for C. jejuni, 76% for ETEC and 94% for C. parvum. Seroprevalence increased with age for all pathogens. Median distance to the nearest water source was 473 meters (IQR 268, 719). Children living furthest from a water source had a 12% (95% CI: 2.6, 21.6) higher seroprevalence of S. enterica and a 12.7% (95% CI: 2.9, 22.6) higher seroprevalence of G. intestinalis compared to children living nearest. Seroprevalence for C. trachomatis and enteropathogens was high, with marked increases for most enteropathogens in the first two years of life. Children living further from a water source had higher seroprevalence of S. enterica and G. intestinalis indicating that improving access to water in the Ethiopia's Amhara region may reduce exposure to these enteropathogens in young children.

Estimating typhoid incidence from community-based serosurveys: a multicohort study

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Estimating typhoid incidence from community-based serosurveys: A multicohort study in Bangladesh, Nepal, Pakistan and Ghana

“…Additionally, it may overcome sources of uncertainty or bias in facility-based surveillance caused by healthcare seeking and prior antibiotic use. Cross-sectional sero-surveillance has been useful for rapidly generating data on the transmission of COVID-19, pertussis, dengue, and other diseases (3–7) . However, sero-surveillance for typhoidal Salmonella has been limited by the lack of sensitive and specific serologic markers.…”

“…Population-based serologic surveillance (serosurveillance) can be used to estimate infection transmission in settings lacking facility-based surveillance. Cross-sectional serosurveillance has been useful for rapidly characterizing transmission of COVID-19, pertussis, dengue, and other diseases (3)(4)(5)(6)(7). However, serosurveillance for typhoidal Salmonella has been limited by the lack of sensitive and specific serologic markers.…”

Effect of Biannual Mass Azithromycin Distributions to Preschool-Aged Children on Trachoma Prevalence in Niger

“…32 Serological tests for chlamydia were performed from dried blood spots for this study, which showed a lower chlamydia seroprevalence and flatter age-seroprevalence curves than other areas with more prevalent trachoma, consistent with low levels of chlamydia transmission. [33][34][35][36][37] Indeed, no child in the study was seropositive for both pgp3 and CT694 antibodies, and titers from children who were seropositive were generally low, so even the few seropositive results may have been falsepositive. Serological thresholds do not currently exist to differentiate areas with ongoing trachoma transmission vs those that have eliminated trachoma.…”