Molecular Detection of Ancylostoma duodenale, Ancylostoma ceylanicum, and Necator americanus in Humans in Northeastern and Southern Thailand

Abstract

The 2 principal species of hookworms infecting humans are Necator americanus and Ancylostoma duodenale. Case studies on zoonotic hookworm infections with Ancylostoma ceylanicum and/or Ancylostoma caninum are known mainly from Asian countries. Of these 2 zoonotic species, only A. ceylanicum can develop to adulthood in humans. In the present study, we report a molecular-based survey of human hookworm infections present in southern and northeastern Thailand. Thirty larval hookworm samples were obtained from fecal agar plate cultures of 10 patients in northeastren Thailand and 20 in southern Thailand. Partial ITS1, 5.8S, and ITS2 regions of the ribosomal DNA genes were amplified using PCR. The amplicons were sequenced, aligned, and compared with other hookworm sequences in GenBank database. The results showed that, in Thailand, N. americanus is more prevalent than Ancylostoma spp. and is found in both study areas. Sporadic cases of A. ceylanicum and A. duodenale infection were seen in northeastern Thailand.

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

“…However, A. duodenale, A. ceylanicum, and A. caninum were also detected in different parts of the country. 8,13 The predominance of N. americanus in Lower Myanmar is similar to a report from Peninsular Malaysia where N. americanus was more common than A. ceylanicum, but A. duodenale infection was not discovered. 10 In contrast, a report from Lao PDR people found that infections due to A. duodenale and the animal hookworms, A. caninum and A. ceylanicum, were slightly more prevalent than those due to N. americanus.…”

“…Each genus and species of hookworm infecting humans has its own distinct biology, life cycle, pathophysiology, and epidemiology, knowledge of which therefore impacts on designing control measures. 6 A molecular approach to identification is therefore imperative and copro-molecular methods for species identification of hookworms have been reported in neighboring countries (Thailand, 8,13 Lao People's Democratic Republic [PDR], 14 and Cambodia 6,15 ). Molecular methods were used to identify as A. ceylanicum a case of hookworm infection in a French individual who had visited Myanmar.…”

“…8 The PCR reaction and conditions were as reported previously. 13 PCR products were run on a 1% agarose gel to demonstrate amplicons of approximately 485 base pairs (bp) (typical for N. americanus) or 380 bp (typical for Ancylostoma spp.). Eleven samples yielded positive PCR results.…”

Prevalence of gastrointestinal helminth parasites of zoonotic significance in dogs and cats in lower Northern Thailand

“…In Thailand, infections of hookworms and O. viverrini are the major public health problems [15, 16, 25, 30, 33]. Infections of zoonotic hookworms, A. ceylanicum and A. caninum , have been reported in many areas [25, 33].…”

“…Infections of zoonotic hookworms, A. ceylanicum and A. caninum , have been reported in many areas [25, 33]. Molecular analysis showed A. ceylanicum is prevalent in humans and dogs in the Central and the Northeastern areas of Thailand [25, 33]. Prevalence and species of zoonotic hookworms in dogs and cats in the lower Northern area of Thailand are still unknown.…”