Parasitic helminth stages among companion animals and in soil from selected public and home environments in Gampaha and Colombo Districts, Sri Lanka.

Introduction

Soil contamination with animal excreta is widespread, posing public health risks. The aim was to describe the prevalence of intestinal helminths among cats and dogs and in soil from selected environments in Colombo and Gampaha Districts, Sri Lanka.

Method

Approximately 200g of subsurface soil was collected into zip-lock bags from randomly selected public sites and home gardens from May 2024 toJanuary 2025. Soil samples were processed for helminths using magnesium sulfate flotation and Baermann techniques.

Wet smears prepared from excreta collected from randomly selected cats and dogs attending veterinary clinics in Colombo were examined microscopically for helminth ova and larvae.

Results

A total of 200 soil samples from Colombo (n=108) and Gampaha (n=92) were analyzed. Study sites included parks (n=32), religious places (n=48), university grounds (n=12), side-roads (n=12), beaches (n=12), school grounds (n=28), hospital grounds (n=8), and home gardens (n=48) .The overall prevalence of helminth ova in soil by flotation was 14% (28/200), with 16.66% (18/108) and 10.86% (10/92) in Colombo and Gampaha, respectively. Helminth species detected were Toxocara spp. 57.14% [16/28], Ascaris lumbricoides 14.2% [4/28] and Ancylostoma spp. 28.57% [8/28]. The prevalence of parasitic helminth larvae in soil detected using the Baermann technique was 22%, for Ancylostoma spp. was 88.63%, and for Strongyloides spp. was 11.36%. Soil contamination was highest at religious sites (22.22%) and in parks (11.11%).

Analysis of faecal samples of 17 animals, including 8 feline and 9 canine samples, detected ova of Toxocara spp. (12.5%) and Ancylostoma spp. (62%) among cats and Ancylostoma spp. (55.5%) and Capilaria spp. (12.5%) among dogs via direct wet smears. Companion animals at religious sites had the highest parasite prevalence, 88.88% (8/9).

Conclusion

The prevalence of animal hookworms was high among cats and dogs in both Gampaha and Colombo Districts. Zoonotic helminth stages were widespread in soil in both districts, with few areas positive for human STH ova. Religious sites and public parks were the most contaminated. Local incidence rates of zoonotic STHs among humans were unknown. We recommend health education, animal deworming, safe disposal of animal excreta and stray animal control.