Major enteropathogens in humans, domestic animals, and environmental soil samples from the same locality: prevalence and transmission considerations in coastal Odisha, India

Abstract

Objectives: Regions with limited sanitation facilities have higher rates of infections with various enteric pathogens. It is therefore important to identify different hosts and their relative contribution to pathogen shedding into the environment, and to assess the subsequent health risks to humans.

Methods: In this study, human faecal (n=310), animal faecal (n=150), and environmental (soil) samples (n=40) were collected from the same locality and screened for selected enteric pathogens by immunochromatography and/or polymerase chain reaction.

Results: At least 1 microbial agent was detected in 49.0%, 44.7%, and 40.0% of the samples from human, animals, and soil, respectively. Among humans, rotavirus was predominantly detected (17.4%) followed by enteropathogenic Escherichia coli (EPEC) (15.4%), Shigella (13.8), and Shiga toxin-producing E. coli (STEC) (9.7%). Among animals, STEC was detected most frequently (28.0%), and EPEC was the major enteric pathogen detected in soil (30.0%). The detection rate of rotavirus was higher among younger children (≤2 years) than among older children. Single infections were more commonly detected than multiple infections in humans (p<0.01), unlike the observations in animal and soil samples. For diarrhoeagenic E. coli and Shigella, most of the human and animal isolates showed close relatedness, suggesting possible cross-infection between humans and domesticated animals in the area studied.

Conclusions: The present study provides an improved understanding of the distribution of major enteric pathogens coexisting in humans and animals in the region, thereby suggesting a high potential for possible transmission among livestock and communities residing in the studied locality.

Keywords: Coinfection; Diarrhoea; India; Molecular epidemiology; Zoonoses.

Figure 1.

Sample collection site. The geographic location of Odisha is marked in red on the map of India. Samples were collected from four different zones blue colored regions in Bhubaneswar map showed sample collection site.

Figure 2.

Principal component analysis. A total of 500 samples were analyzed to see the pattern of diarrheal infectious agents in study region, samples were calculated at 95% similarity. Two samples position in score plot close to each other are more alike and samples positions are far away are dislike from each other. (A) Score plot represents the presence of diarrheal agents in humans, animals and soil samples. Overlapping area in plot represents the similar pattern of infectious agents. (B) Zone wise pattern of infectious agent presented in the study area. Most of the samples share common overlapping zones, which showed all detected pathogens are present almost equally in each study zone.

Figure 3.

Possible routes of major diarrheal pathogens in the study area. STEC, Shiga toxin-producing Escherichia coli; EPEC, enteropathogenic E. coli.