eMedicine Specialties > Pediatrics: General Medicine > Parasitology

Ancylostoma Infection: Differential Diagnoses & Workup

Author: Vinod K Dhawan, MD, FACP, FRCP(C), Professor, Department of Clinical Medicine, University of California at Los Angeles; Professor of Medicine, Charles R Drew University of Medicine and Science; Chief, Division of Infectious Diseases, MLK-Harbor Hospital
Coauthor(s): Swati Garekar, MBBS, Staff Physician, Department of Pediatrics, Children's Hospital of Michigan; Basim Asmar, MD, Director, Department of Pediatrics, Division of Infectious Diseases, Children's Hospital of Michigan; Professor, Department of Pediatrics, Wayne State University School of Medicine
Contributor Information and Disclosures

Updated: May 1, 2008

Differential Diagnoses

Anemia, Acute
Anemia, Chronic
Pneumonia
Scabies

Other Problems to Be Considered

Once iron deficiency anemia from blood loss is diagnosed, keep in mind that rare causes of intestinal blood loss (eg, polyps, Meckel diverticulum) are far less common in developing countries.

Respiratory symptoms with peripheral eosinophilia suggest a parasitic etiology.

Differentiation between scabies and cutaneous larva migrans is not always easy, especially if the latter occurs with atypical rash. Important distinguishing criteria for scabies are history of exposure, crusty lesions on the hands or feet, and generalized pruritus.

Workup

Laboratory Studies

  • Stool examination
    • Stool concentration techniques are unnecessary because most individuals with clinically significant infection excrete a large number of eggs. Eggs are easily detectable in unconcentrated stool specimen at rates of about 1200 eggs/mL or more.
    • Each ovoid, thin-shelled egg measures approximately 60 X 40 µm (see Media file 2). Various methods (eg, Kato-Katz technique) can be used for quantitative assessments.
    • Eggs of A duodenale and N americanus cannot be differentiated using light microscopy. Larvae and adult worms can be distinguished by rearing filariform larvae in a fecal smear on a moist filter paper strip for 5-7 days (ie, Harada-Mori filter paper strip culture).
    • Distinguishing between the 2 species is not critically important for choosing the type of anthelminthic drug, except that arrested larvae of A duodenale can enter breast milk and cause vertical transmission; these arrested larvae can also reactivate after initial treatment and again cause intestinal disease without reinfection.
    • No eggs are found in cases of eosinophilic enteritis because adult A caninum worms do not produce eggs in human hosts.
    • Stool examination is not indicated in cases of cutaneous larva migrans because the diagnosis can be made clinically, and the larvae in almost all cases remain confined to the skin.
    • Progress is being made in polymerase chain reaction (PCR)-based methods for the specific diagnosis of hookworm infection.3
  • CBC count
    • Peripheral blood eosinophilia is often initially noticed during an asymptomatic infection with human hookworms, possibly as early as during the larval migration through the lungs.
    • Eosinophilia (and raised serum immunoglobulin E [IgE] levels) is uncommon in cases of cutaneous larva migrans but is almost universally present in cases of eosinophilic enteritis.4
    • Cases of classic hookworm disease exhibit characteristic blood indices of iron deficiency anemia (eg, hypochromic microcytic).

Other Tests

  • Serologic tests (eg, tests for A caninum) are usually available only in research laboratories.

Procedures

  • In cases of eosinophilic enteritis, colonoscopy may reveal ileal and colonic ulceration and, occasionally, adult hookworms.

More on Ancylostoma Infection

Overview: Ancylostoma Infection
Differential Diagnoses & Workup: Ancylostoma Infection
Treatment & Medication: Ancylostoma Infection
Follow-up: Ancylostoma Infection
Multimedia: Ancylostoma Infection
References
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References

  1. Prociv P, Croese J. Human eosinophilic enteritis caused by dog hookworm Ancylostoma caninum. Lancet. Jun 2 1990;335(8701):1299-302. [Medline].

  2. Albonico M, Stoltzfus RJ, Savioli L, et al. Epidemiological evidence for a differential effect of hookworm species, Ancylostoma duodenale or Necator americanus, on iron status of children. Int J Epidemiol. Jun 1998;27(3):530-7. [Medline].

  3. Gasser RB, Cantacessi C, Loukas A. DNA technological progress toward advanced diagnostic tools to support human hookworm control. Biotechnol Adv. Jan-Feb 2008;26(1):35-45. [Medline].

  4. Jelinek T, Maiwald H, Nothdurft HD, Loscher T. Cutaneous larva migrans in travelers: synopsis of histories, symptoms, and treatment of 98 patients. Clin Infect Dis. Dec 1994;19(6):1062-6. [Medline].

  5. Caumes E, Datry A, Paris L. Efficacy of ivermectin in the therapy of cutaneous larva migrans. Arch Dermatol. Jul 1992;128(7):994-5. [Medline].

  6. de Silva N, Guyatt H, Bundy D. Anthelmintics. A comparative review of their clinical pharmacology. Drugs. May 1997;53(5):769-88. [Medline].

  7. Horton J. Albendazole: a review of anthelmintic efficacy and safety in humans. Parasitology. 2000;121 Suppl:S113-32. [Medline].

  8. Kabatereine NB, Brooker S, Koukounari A, Kazibwe F, Tukahebwa EM, Fleming FM. Impact of a national helminth control programme on infection and morbidity in Ugandan schoolchildren. Bull World Health Organ. Feb 2007;85(2):91-9. [Medline].

  9. Larocque R, Casapia M, Gotuzzo E, MacLean JD, Soto JC, Rahme E. A double-blind randomized controlled trial of antenatal mebendazole to reduce low birthweight in a hookworm-endemic area of Peru. Trop Med Int Health. Oct 2006;11(10):1485-95. [Medline].

  10. Diemert DJ, Bethony JM, Hotez PJ. Hookworm vaccines. Clin Infect Dis. Jan 15 2008;46(2):282-8. [Medline].

  11. Hughes RG, Sharp DS, Hughes MC. Environmental influences on helminthiasis and nutritional status among Pacific schoolchildren. Int J Environ Health Res. 2004;14(3):163-77.

  12. Bennett A, Guyatt H. Reducing intestinal nematode infection: efficacy of albendazole and mebendazole. Parasitol Today. Feb 2000;16(2):71-4. [Medline].

  13. Flohr C, Tuyen LN, Lewis S, Minh TT, Campbell J, Britton J. Low efficacy of mebendazole against hookworm in Vietnam: two randomized controlled trials. Am J Trop Med Hyg. Apr 2007;76(4):732-6. [Medline].

  14. American Academy of Pediatrics. Hookworm infection. In: 2000 Red Book: Report of the Committee on Infectious Diseases. 2000:321-2.

  15. Hochedez P, Caumes E. Hookworm-related cutaneous larva migrans. J Travel Med. Sep-Oct 2007;14(5):326-33. [Medline].

  16. Hotez PJ. Hookworm disease in children. Pediatr Infect Dis J. Aug 1989;8(8):516-20. [Medline].

  17. Hotez PJ, Brooker S, Bethony JM, et al. Hookworm infection. N Engl J Med. Aug 19 2004;351(8):799-807. [Medline].

  18. Hotez PJ, Pritchard DI. Hookworm infection. Sci Am. Jun 1995;272(6):68-74. [Medline].

  19. Kucik CJ, Martin GL, Sortor BV. Common intestinal parasites. Am Fam Physician. Mar 1 2004;69(5):1161-8. [Medline].

  20. Long SS, Pickering LK, Prober CG. Hookworm. In: Principles and Practice of Pediatric Infectious Diseases. 1997:1462-4.

  21. Mandell GL, Bennett JE, Dolin R. Principles and Practice of Infectious Diseases. 2000:2941-2.

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Further Reading

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Keywords

hookworm infection, hookworm, hookworm disease, Ancylostomatidae, Ancylostoma duodenale, Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, Ancylostoma braziliense, cutaneous larva migrans, eosinophilic enteritis, iron deficiency anemia, protein malnutrition, iron deficiency anemia, protein malnutrition, helminthic infections, hookworm anemia, malabsorption, hypoproteinemia, malnutrition, GI hemorrhage, ancylostoma infection, ground itch, dew itch, Wakana disease, melena, leukocytosis, erythema

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Contributor Information and Disclosures

Author

Vinod K Dhawan, MD, FACP, FRCP(C), Professor, Department of Clinical Medicine, University of California at Los Angeles; Professor of Medicine, Charles R Drew University of Medicine and Science; Chief, Division of Infectious Diseases, MLK-Harbor Hospital
Vinod K Dhawan, MD, FACP, FRCP(C) is a member of the following medical societies: American College of Physicians, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, and Royal College of Physicians and Surgeons of Canada
Disclosure: Pfizer Inc None None

Coauthor(s)

Swati Garekar, MBBS, Staff Physician, Department of Pediatrics, Children's Hospital of Michigan
Swati Garekar, MBBS is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.

Basim Asmar, MD, Director, Department of Pediatrics, Division of Infectious Diseases, Children's Hospital of Michigan; Professor, Department of Pediatrics, Wayne State University School of Medicine
Basim Asmar, MD is a member of the following medical societies: American Academy of Pediatrics, American Society for Microbiology, Infectious Diseases Society of America, and Pediatric Infectious Diseases Society
Disclosure: Nothing to disclose.

Medical Editor

Michael D Nissen, MBBS, BMedSc, FRACP, FRCPA, Associate Professor in Biomolecular, Biomedical Science & Health, Griffith University; Director of Infectious Diseases and Unit Head of Queensland Paediatric Infectious Laboratory, Sir Albert Sakzewski Viral Research Centre, Royal Children's Hospital
Michael D Nissen, MBBS, BMedSc, FRACP, FRCPA is a member of the following medical societies: American Academy of Pediatrics, American Society for Microbiology, Pediatric Infectious Diseases Society, Royal Australasian College of Physicians, and Royal College of Pathologists of Australasia
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc
Disclosure: Pfizer Inc Stock Investment from broker recommendation; Avanir Pharma Stock Investment from broker recommendation

Managing Editor

Martin Weisse, MD, Program Director, Associate Professor, Department of Pediatrics, West Virginia University
Martin Weisse, MD is a member of the following medical societies: Ambulatory Pediatric Association, American Academy of Pediatrics, and Pediatric Infectious Diseases Society
Disclosure: Nothing to disclose.

CME Editor

Robert W Tolan Jr, MD, Chief, Division of Allergy, Immunology and Infectious Diseases, The Children's Hospital at Saint Peter's University Hospital; Clinical Associate Professor of Pediatrics, Drexel University College of Medicine
Robert W Tolan Jr, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa, and Physicians for Social Responsibility
Disclosure: GlaxoSmithKline Honoraria Speaking and teaching; MedImmune Honoraria Consulting; MedImmune Honoraria Speaking and teaching; Merck Honoraria Speaking and teaching; Novartis Honoraria Speaking and teaching; sanofi pasteur Grant/research funds Unrestricted research grant; sanofi pasteur  Consulting; sanofi pasteur Honoraria Speaking and teaching; Tap Honoraria Speaking and teaching

Chief Editor

Russell W Steele, MD, Head, Division of Pediatric Infectious Diseases, Ochsner Children's Health Center; Clinical Professor, Department of Pediatrics, Tulane University School of Medicine
Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, and Southern Medical Association
Disclosure: None None None

 
 
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