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Hookworm infection

INTRODUCTION

Hookworm infections are common in the tropics and subtropics [1,2]. The prevalence of hookworm infection is highest in sub-Saharan Africa, followed by Asia, Latin America, and the Caribbean. Infection is rare in regions with less than 40 inches of rainfall annually.

There are two major species of hookworm that cause human infection: Ancylostoma duodenale (in Mediterranean countries, Iran, India, Pakistan, and the Far East) and Necator americanus (in North and South America, Central Africa, Indonesia, islands of the South Pacific, and parts of India). There are also case reports from Asia of zoonotic hookworm infections with Ancylostoma ceylanicum [3].

EPIDEMIOLOGY AND LIFE CYCLE

It is estimated that over 800 million people are infected with hookworms worldwide [2,4]. The prevalence of hookworm infection in rural areas of the southeastern United States in the early 20th century was high; extensive control efforts have diminished the prevalence. (See 'Prevention and control' below.)

Three conditions are important for transmission of hookworm infection: human fecal contamination of soil, favorable soil conditions for larval survival (moisture, warmth, shade) and contact of human skin with contaminated soil. Individuals who walk barefoot or with open footwear in fecally contaminated soil are at risk for infection; risk groups include native residents of endemic areas, tourists, and infantry troops [2,5].

The hookworm life cycle begins with passage of eggs from an adult host into the stool (figure 1). Hookworm eggs hatch in the soil to release rhabditiform larvae that mature into infective filariform larvae. Infection is transmitted by larval penetration into human skin; as few as three larvae are sufficient to produce infection [6]. From the skin, larvae migrate into the blood vessels and are carried to the lungs. Approximately 8 to 21 days following infection, larvae penetrate into the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed. In addition to percutaneous larval penetration (the principal mode of transmission), A. duodenale infection may also be transmitted by the oral route.

            

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Literature review current through: Nov 2014. | This topic last updated: Dec 10, 2014.
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References
Top
  1. de Silva NR, Brooker S, Hotez PJ, et al. Soil-transmitted helminth infections: updating the global picture. Trends Parasitol 2003; 19:547.
  2. Hotez PJ, Brooker S, Bethony JM, et al. Hookworm infection. N Engl J Med 2004; 351:799.
  3. Phosuk I, Intapan PM, Thanchomnang T, et al. Molecular detection of Ancylostoma duodenale, Ancylostoma ceylanicum, and Necator americanus in humans in northeastern and southern Thailand. Korean J Parasitol 2013; 51:747.
  4. Pullan RL, Smith JL, Jasrasaria R, Brooker SJ. Global numbers of infection and disease burden of soil transmitted helminth infections in 2010. Parasit Vectors 2014; 7:37.
  5. Kelley PW, Takafuji ET, Wiener H, et al. An outbreak of hookworm infection associated with military operations in Grenada. Mil Med 1989; 154:55.
  6. Beaver PC. Observations on Necator infection resulting from exposure to three larvae. Rev Iberica Parasitol 1955; 1:1.
  7. Nawalinski TA, Schad GA. Arrested development in Ancylostoma duodenale: course of a self-induced infection in man. Am J Trop Med Hyg 1974; 23:895.
  8. Beaver PC. Light, long-lasting Necator infection in a volunteer. Am J Trop Med Hyg 1988; 39:369.
  9. Hotez PJ, Pritchard DI. Hookworm infection. Sci Am 1995; 272:68.
  10. Ogilvie BM, Bartlett A, Godfrey RC, et al. Antibody responses in self-infections with Necator americanus. Trans R Soc Trop Med Hyg 1978; 72:66.
  11. Wright V, Bickle Q. Immune responses following experimental human hookworm infection. Clin Exp Immunol 2005; 142:398.
  12. Anyaeze CM. Reducing burden of hookworm disease in the management of upper abdominal pain in the tropics. Trop Doct 2003; 33:174.
  13. Stassens P, Bergum PW, Gansemans Y, et al. Anticoagulant repertoire of the hookworm Ancylostoma caninum. Proc Natl Acad Sci U S A 1996; 93:2149.
  14. Del Valle A, Jones BF, Harrison LM, et al. Isolation and molecular cloning of a secreted hookworm platelet inhibitor from adult Ancylostoma caninum. Mol Biochem Parasitol 2003; 129:167.
  15. Crompton DWT, Stephenson LS. Hookworm infection, nutritional status and productivity. In: Hookworm disease: Current status and new directions, Schad GA, Warren KS (Eds), Taylor & Francis, London 1990. p.231.
  16. Chu D, Bungiro RD, Ibanez M, et al. Molecular characterization of Ancylostoma ceylanicum Kunitz-type serine protease inhibitor: evidence for a role in hookworm-associated growth delay. Infect Immun 2004; 72:2214.
  17. Goka AK, Rolston DD, Mathan VI, Farthing MJ. Diagnosis of Strongyloides and hookworm infections: comparison of faecal and duodenal fluid microscopy. Trans R Soc Trop Med Hyg 1990; 84:829.
  18. Phuphisut O, Yoonuan T, Sanguankiat S, et al. Triplex polymerase chain reaction assay for detection of major soil-transmitted helminths, Ascaris lumbricoides, Trichuris trichiura, Necator americanus, in fecal samples. Southeast Asian J Trop Med Public Health 2014; 45:267.
  19. van Mens SP, Aryeetey Y, Yazdanbakhsh M, et al. Comparison of real-time PCR and Kato smear microscopy for the detection of hookworm infections in three consecutive faecal samples from schoolchildren in Ghana. Trans R Soc Trop Med Hyg 2013; 107:269.
  20. Kato T, Kamoi R, Iida M, Kihara T. Endoscopic diagnosis of hookworm disease of the duodenum. J Clin Gastroenterol 1997; 24:100.
  21. Genta RM, Woods KL. Endoscopic diagnosis of hookworm infection. Gastrointest Endosc 1991; 37:476.
  22. Nutman TB, Ottesen EA, Ieng S, et al. Eosinophilia in Southeast Asian refugees: evaluation at a referral center. J Infect Dis 1987; 155:309.
  23. White CJ, Maxwell CJ, Gallin JI. Changes in the structural and functional properties of human eosinophils during experimental hookworm infection. J Infect Dis 1986; 154:778.
  24. Keiser J, Utzinger J. Efficacy of current drugs against soil-transmitted helminth infections: systematic review and meta-analysis. JAMA 2008; 299:1937.
  25. Drugs for Parasitic Infections, 3rd Ed, The Medical Letter, New Rochelle, NY 2013.
  26. Steinmann P, Utzinger J, Du ZW, et al. Efficacy of single-dose and triple-dose albendazole and mebendazole against soil-transmitted helminths and Taenia spp.: a randomized controlled trial. PLoS One 2011; 6:e25003.
  27. Albonico M, Bickle Q, Ramsan M, et al. Efficacy of mebendazole and levamisole alone or in combination against intestinal nematode infections after repeated targeted mebendazole treatment in Zanzibar. Bull World Health Organ 2003; 81:343.
  28. Sacko M, De Clercq D, Behnke JM, et al. Comparison of the efficacy of mebendazole, albendazole and pyrantel in treatment of human hookworm infections in the southern region of Mali, West Africa. Trans R Soc Trop Med Hyg 1999; 93:195.
  29. Drugs for parasitic infections. Treatment guidelines from The Medical Letter, 2010. Vol 8 (Suppl).
  30. Bethony J, Brooker S, Albonico M, et al. Soil-transmitted helminth infections: ascariasis, trichuriasis, and hookworm. Lancet 2006; 367:1521.
  31. Friis H, Mwaniki D, Omondi B, et al. Effects on haemoglobin of multi-micronutrient supplementation and multi-helminth chemotherapy: a randomized, controlled trial in Kenyan school children. Eur J Clin Nutr 2003; 57:573.
  32. Albonico M, Montresor A, Crompton DW, Savioli L. Intervention for the control of soil-transmitted helminthiasis in the community. Adv Parasitol 2006; 61:311.
  33. de Silva NR. Impact of mass chemotherapy on the morbidity due to soil-transmitted nematodes. Acta Trop 2003; 86:197.
  34. Stephenson LS. Optimising the benefits of anthelmintic treatment in children. Paediatr Drugs 2001; 3:495.
  35. Taylor-Robinson DC, Maayan N, Soares-Weiser K, et al. Deworming drugs for soil-transmitted intestinal worms in children: effects on nutritional indicators, haemoglobin and school performance. Cochrane Database Syst Rev 2012; 7:CD000371.
  36. Bieri FA, Gray DJ, Williams GM, et al. Health-education package to prevent worm infections in Chinese schoolchildren. N Engl J Med 2013; 368:1603.
  37. McSorley HJ, Loukas A. The immunology of human hookworm infections. Parasite Immunol 2010; 32:549.
  38. Bethony JM, Simon G, Diemert DJ, et al. Randomized, placebo-controlled, double-blind trial of the Na-ASP-2 hookworm vaccine in unexposed adults. Vaccine 2008; 26:2408.
  39. Diemert DJ, Bethony JM, Hotez PJ. Hookworm vaccines. Clin Infect Dis 2008; 46:282.