Abstract:
Gastroenteritis remains a significant public health issue in peri-urban Pakistan, where waterborne
pathogens like Escherichia coli, Salmonella spp., Campylobacter jejuni and Shigella spp.
contribute to widespread disease, exacerbated by inadequate sanitation and contaminated water
sources. This study investigates pathogen prevalence and microbial diversity along the Shahdara
Stream, comparing contamination across upstream, midstream, and downstream segments, and
includes analysis of both drinking water and stool samples. Using a One Health approach,
culture-based methods, TaqMan-based quantitative PCR, and metagenomic sequencing were
employed to detect bacterial pathogens, quantify loads, and examine microbial community
diversity gradients. Metagenomic findings reveal distinct diversity patterns influenced by
location, with upstream areas showing higher microbial diversity that progressively declines
downstream, likely due to pollution and environmental stressors. Additionally, clinical samples
from symptomatic individuals were analyzed, showing markedly higher pathogen loads,
particularly for Salmonella spp. and Shigella spp., compared to asymptomatic household stool
samples, underscoring asymptomatic carriage and transmission risks within households. These
findings point to an urgent need for targeted interventions, such as water treatment, sanitation
improvements, and hygiene education, to reduce gastroenteritis risks in communities across
Shahdara stream. This research provides critical data to inform public health strategies aimed at
mitigating waterborne diseases in similar settings.
