Incidence and Risk Factors of Hookworm Infection in a Rural Community of Central Thailand

Abstract

A cohort study to identify incidence and risk factors of hookworm infection was conducted in a rural community, central Thailand from November 2005 to February 2007. Stool specimens were examined for hookworm eggs using wet preparation, Kato thick smear, and water-ethyl acetate sedimentation technique. The incidence rate of hookworm infection was 7.5/100 person-years. The independent risk factors for acquiring hookworm infection were barefoot walking (incidence rate ratio [IRR] = 4.2, 95% confidence interval [CI] = 1.2–14.5) and raising buffaloes around the house (IRR = 4.8, 95% CI = 1.9–11.8). Sequencing of internal transcribed spacer 1 (ITS1)-5.8S-ITS2 region of the ribosomal RNA gene were performed for identifying species of hookworm. Necator americanus was the most common hookworm identified in this population. Ancylostoma duodenale and A. ceylanicum were also detected. Our data suggest transmission of both human and animal hookworms in this community. Thus, prevention and control strategies of hookworm infection should cover both human and animal infection.

Patterns and Risk Factors of Soil-Transmitted Helminthiasis Among Orang Asli Subgroups in Peninsular Malaysia

“…33,34 Moreover, more studies are reporting on the zoonotic ancylostomiasis caused by A. ceylanicum in humans in endemic areas in Southeast Asia. 23,[34][35][36] A recent genetic study to provide further evidence on zoonotic transmission of A. ceylanicum between humans and animals in Malaysia showed that some of the A. ceylanicum strains from both the human and animal host in the same geographical location are clustered together within the same group. 37 This provides evidence that dogs and humans share genetically similar genotypes of A. ceylanicum within the same geographical location.…”

Molecular Identification of Human Hookworm Infections in Economically Disadvantaged Communities in Peninsular Malaysia

“…4,5 Besides the two human species, intestinal zoonotic infections with canine and/or feline hookworm such as A. ceylanicum, A. caninum, and Ancylostoma braziliense have also been reported in many parts of the world. [6][7][8] More recently, zoonotic ancylostomiasis caused by A. ceylanicum was detected by using copro-molecular diagnostic tools in rural communities in Thailand 9,10 and Laos. 11 Accurate diagnosis by precise identification and differentiation of species involved is essential in monitoring the efficacy of mass treatment and effective control of hookworm infection.…”

First Molecular Identifications of Necator americanus and Ancylostoma ceylanicum Infecting Rural Communities in Lower Myanmar

“…4,5 Ancylostoma ceylanicum is now the second most common hookworm species infecting humans in Asia and possible cause of cutaneous larvae migrans or abdominal symptoms in infected patients, with reported high egg-positivity rates in Thailand, Laos, Cambodia, and Malaysia. [6][7][8][9][10] National surveys on the prevalence of soil-transmitted helminths (STHs) in Myanmar reported a reduction in hookworm prevalence in schoolchildren from 6.5% to 0.3% 7 years after a national deworming program. 11,12 A diagnosis of hookworm infection was usually made by microscopic examination of eggs or larvae in the fecal samples.…”

“…Several molecular epidemiologic surveys have also reported that N. americanus and A. ceylanicum are the two most common hookworm species infecting humans and dogs in Asia. [6][7][8][9][10] Prevalences of hookworms in Cambodia are reportedly very high, 18 and are predominantly due to N. americanus and A. ceylanicum (51.6% equal prevalence): only 3.2% of people were found infected with A. duodenale. 6 In Thailand, the principal hookworm species infecting humans was confirmed as N. americanus.…”