Molecular identification of Ancylostoma ceylanicum in the Philippines

Abstract

Hookworms are some of the most widespread of the soil-transmitted helminths (STH) with an estimated 438.9 million people infected. Until relatively recently Ancylostoma ceylanicum was regarded as a rare cause of hookworm infection in humans, with little public health relevance. However, recent advances in molecular diagnostics have revealed a much higher prevalence of this zoonotic hookworm than previously thought, particularly in Asia. This study examined the prevalence of STH and A. ceylanicum in the municipalities of Palapag and Laoang in the Philippines utilizing real-time polymerase chain reaction (PCR) on stool samples previously collected as part of a cross-sectional survey of schistosomiasis japonica. Prevalence of hookworm in humans was high with 52.8% (n = 228/432) individuals positive for any hookworm, 34.5% (n = 149/432) infected with Necator americanus, and 29.6% (n = 128/432) with Ancylostoma spp; of these, 34 were PCR-positive for A. ceylanicum. Considering dogs, 12 (n = 33) were PCR-positive for A. ceylanicum. This is the first study to utilize molecular diagnostics to identify A. ceylanicum in the Philippines with both humans and dogs infected. Control and elimination of this zoonotic hookworm will require a multifaceted approach including chemotherapy of humans, identification of animal reservoirs, improvements in health infrastructure, and health education to help prevent infection.

Risk profiling and efficacy of albendazole against the hookworms Necator americanus and Ancylostoma ceylanicum in Cambodia to support control programs in Southeast Asia and the Western Pacific

“… [14] , [15] , [16] Unlike the hookworms Necator americanus and Ancylostoma duodenale, A. ceylanicum is zoonotic and is the second most common hookworm infecting humans in many regions in Southeast Asia and the Western Pacific, including the Solomon Islands 17 , Lao People's Democratic Republic (Lao PDR) 18 , Malaysia 19 , Cambodia 20 , Myanmar 21 , 22 and also The Philippines. 23 …”

Geographic Distribution of Human Infections with Zoonotic Ancylostoma ceylanicum and Anthropophilic Hookworms in Ecuador: A Retrospective Analysis of Archived Stool Samples

“…The application of highly specific molecular detection methods has permitted better understanding of the geographic distributions and epidemiology of different hookworm species in human populations. 16 , 19 , 23 – 25 All three species of hookworms infecting humans are globally distributed, including A. ceylanicum , which has been described in Asia, Oceania, Africa, 2 , 26 , 27 and more recently the Americas. 4 , 5 …”

In vitro immunoregulatory role of recombinant Ancylostoma ceylanicum calreticulin

“…The buccal capsule of these blood-feeding parasites contains hook-shaped teeth for attachment to and laceration of the host’s intestinal mucosa [ 1 ], leading to malnutrition and iron-deficiency anemia. Necator americanus and Ancylostoma duodenale only infect humans, whereas A. ceylanicum and A. caninum are zoonotic that infect dogs, cats, and humans [ 2 ]. A. ceylanicum is the second most common hookworm infection in people in Southeast Asia [ 3 ], causing abdominal pain, diarrhea, malnutrition, and iron-deficiency anemia.…”