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Randomized Controlled Trial
. 2016 Aug 3;10(8):e0004891.
doi: 10.1371/journal.pntd.0004891. eCollection 2016 Aug.

Molecular Identification of Hookworm Isolates in Humans, Dogs and Soil in a Tribal Area in Tamil Nadu, India

Santosh George  1   2 , Bruno Levecke  2 , Deepthi Kattula  1 , Vasanthakumar Velusamy  1 , Sheela Roy  1 , Peter Geldhof  2 , Rajiv Sarkar  1 , Gagandeep Kang  1
Affiliations
Randomized Controlled Trial

Molecular Identification of Hookworm Isolates in Humans, Dogs and Soil in a Tribal Area in Tamil Nadu, India

Santosh George et al. PLoS Negl Trop Dis. .

Abstract

Background: Hookworms (Necator americanus and Ancylostoma duodenale) remain a major public health problem worldwide. Infections with hookworms (e.g., A. caninum, A. ceylanicum and A. braziliense) are also prevalent in dogs, but the role of dogs as a reservoir for zoonotic hookworm infections in humans needs to be further explored.

Methodology/principal findings: As part of an open-label community based cluster-randomized trial in a tribal area in Tamil Nadu (India; 2013-2015), a total of 143 isolates of hookworm eggs from human stool were speciated based on a previously described PCR-RFLP methodology. The presence of hookworm DNA was confirmed in 119 of 143 human samples. N. americanus (100%) was the most prevalent species, followed by A. caninum (16.8%) and A. duodenale (8.4%). Because of the high prevalence of A. caninum in humans, dog samples were also collected to assess the prevalence of A. caninum in dogs. In 68 out of 77 canine stool samples the presence of hookworms was confirmed using PCR-RFLP. In dogs, both A. caninum (76.4%) and A. ceylanicum (27.9%) were identified. Additionally, to determine the contamination of soil with zoonotic hookworm larvae, topsoil was collected from defecating areas. Hookworm DNA was detected in 72 out of 78 soil samples that revealed presence of hookworm-like nematode larvae. In soil, different hookworm species were identified, with animal hookworms being more prevalent (A. ceylanicum: 60.2%, A. caninum: 29.4%, A. duodenale: 16.6%, N. americanus: 1.4%, A. braziliense: 1.4%).

Conclusions/significance: In our study we regularly detected the presence of A. caninum DNA in the stool of humans. Whether this is the result of infection is currently unknown but it does warrant a closer look at dogs as a potential reservoir.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Phylogenetic tree constructed using Pairwise Alignment to draw inferences on relationship between different hookworm species.
Sequences were aligned by pairwise alignment using the ClustalW method with MegAlign DNASTAR software. The pairwise alignment was done to draw inference on the relationship between hookworms from humans, dogs and soil. A bootstrap consensus tree inferred from 100 replicates was used to generate the tree.
See this image and copyright information in PMC

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