Epidemiological and Genetic Data Supporting the Transmission of Ancylostoma ceylanicum among Human and Domestic Animals

Parasitic zoonoses pose a continuing public health problem, especially in endemic developing countries where the majority of populations live in poor, overcrowded conditions, lack education, and practice poor standards of hygiene and improper sanitary disposal of feces. Close contact with domestic animals such as dogs and cats coupled with a lack of proper veterinary care and sanitation expose these communities to high risk of acquiring zoonotic infections. Our study combined the application of conventional and molecular epidemiological tools to determine the probable role of domestic animals, in particular dogs and cats, in the transmission of hookworms in parasite-endemic communities in Malaysia. Epidemiological observation such as univariate and multivariate analyses were used to identify factors associated with hookworm infection in humans, while molecular tools provided the ability to discriminate the different hookworm species, which cannot be achieved by conventional microscopic examination of feces alone. The application of these tools in this present study allowed the accurate determination of parasite species prevalence, hence confirming that Ancylostoma ceylanicum infection is common among human population in Malaysia and the close contact of human and domestic animals (i.e., dogs and cats) contributed to the propagation of this hookworm species

Epidemiological and Genetic Data Supporting the Transmission of Ancylostoma ceylanicum among Human and Domestic Animals

Background: Currently, information on species-specific hookworm infection is unavailable in Malaysia and is restricted worldwide due to limited application of molecular diagnostic tools. Given the importance of accurate identification of hookworms, this study was conducted as part of an ongoing molecular epidemiological investigation aimed at providing the first documented data on species-specific hookworm infection, associated risk factors and the role of domestic animals as reservoirs for hookworm infections in endemic communities of Malaysia. Methods/Findings: A total of 634 human and 105 domestic canine and feline fecal samples were randomly collected. The overall prevalence of hookworm in humans and animals determined via microscopy was 9.1% (95% CI = 7.0–11.7%) and 61.9% (95% CI = 51.2–71.2%), respectively. Multivariate analysis indicated that participants without the provision of proper latrine systems (OR = 3.5; 95% CI = 1.53–8.00; p = 0.003), walking barefooted (OR = 5.6; 95% CI = 2.91–10.73; p,0.001) and in close contact with pets or livestock (OR = 2.9; 95% CI = 1.19–7.15; p = 0.009) were more likely to be infected with hookworms. Molecular analysis revealed that while most hookworm-positive individuals were infected with Necator americanus, Ancylostoma ceylanicum constituted 12.8% of single infections and 10.6% mixed infections with N. americanus. As for cats and dogs, 52.0% were positive for A. ceylanicum, 46.0% for Ancylostoma caninum and 2.0% for Ancylostoma braziliense and all were single infections. Conclusion: This present study provided evidence based on the combination of epidemiological, conventional diagnostic and molecular tools that A. ceylanicum infection is common and that its transmission dynamic in endemic areas in Malaysia is heightened by the close contact of human and domestic animal (i.e., dogs and cats) populations

Hookworm species detected from human and animal samples as determined by PCR assays.

<p>*<i>A. caninum</i> were found in dogs;</p><p>**<i>A. ceylanicum</i> were found in both cats and dogs;</p><p>***<i>A. braziliense</i> was found in cats.</p

Potential associated factors associated with hookworm infection by microscopy in human (Univariate analysis, N = 634).

<p>Reference group marked as OR = 1; 95% CI: 95% Confidence interval; Significant association.</p><p>(<i>p</i><0.05).</p><p>*Variables were confirmed by multivariate analysis as significant predictors of hookworm infection.</p

Overall prevalence of hookworm infection in the studied populations as determined by microscopically.

<p>N: Total number examined; n: Hookworm positive by microscopy; %: Percentage; 95% CI: 95% Confidence interval.</p