Hookworm and Cutaneous Larval Migrans PDF

HOOKWORM Dr. Gloria Omosa-Manyonyi Department of Medical Microbiology University of Nairobi  1.0 Introduction Intestinal nematode, found in small intestines Caused by Ancylostoma duodenalis & Necator americanus Worldwide distribution, more in tropics In Afri...

HOOKWORM Dr. Gloria Omosa-Manyonyi Department of Medical Microbiology University of Nairobi  1.0 Introduction Intestinal nematode, found in small intestines Caused by Ancylostoma duodenalis & Necator americanus Worldwide distribution, more in tropics In Africa, Necator americanus predominates Common in areas with poor sanitation Disease called ancylostomiasis or necatoriasis 2nd most common intestinal parasite, Ascaris lumbricoides (1st)  2.0 Morphology 3 forms – Adults, Larvae, Eggs Adults 1-1.5 cm in length; females > males; Mouth parts of A. duodenale - 2 pairs of teeth N. americanus has cutting plates; Eggs – have a visible segmented ovum Larvae Rhabditiform larvae – short and stout Filariform larvae – infective form, long and slender Mouth parts, N. americanus Mouth parts, A. duodenale Hookworm egg  3.0 Life cycle Adults in small intestine, mate, female lays eggs, eggs passed in stool Develop to release rhabditiform larvae (7 days), then to filariform stage (7 days) Penetrate skin of man (usually feet), get into blood circulation, go to heart, lungs, out of blood, bronchi, coughed out, ascend trachea to epiglottis, swallowed Stomach > small intestine attach to mucosa, develop to adult.  From skin penetration to adult: 6-8 weeks  A. duodenale > N. americanus,  A. duodenale also infect via mucous membrane in mouth  4.0 Clinical presentation Early infection – dermatitis (ground itch), dry cough, dyspnoea, abdominal pain & discomfort Light infection often asymptomatic Heavy infection – anaemia: pallor, leg swelling, dyspnoea, palpitation, PBF- hypochromic microcytic; anaemia = sucking of blood (A.duodenale > N.americanus), bleeding sites, anticoagulants from worms Black stool (melena). digested blood from upper GIT bleed  5.0 Laboratory Diagnosis  Stool microscopy – characteristic eggs  Stool (non-fresh) – rhabditiform larvae  Kato-Katz technique - Parasite quantification  6.0 Treatment Albendazole, Mebendazole, Levamisole, Bephenium hydroxynaphthoate, Pyrantel pamoate Supportive treatment – iron supplements, transfusion of blood if anaemia is severe  7.0 Prevention & Control Proper faecal disposal – pit latrines etc Don’t use untreated human waste as manure Wearing of protective shoes Health education on how infection is transmitted and how it can be prevented Treatment of infected persons Treatment of soil CUTANEOUS LARVAL MIGRANS  1.0 Introduction Zoonotic infection with hookworm species that do not use humans as a definitive host Most commonly A. braziliense & A. caninum Normal definitive hosts for these species are dogs & cats, respectively. 2.0 Life cycle Cutaneous larval migrans  Treatment and Prevention Systemic Albendazole Ivermectin Topical Thiabendazole Prevention Avoiding exposure of skin to contaminated soil or sand - wearing shoes in areas where these parasites are known to be endemic offers protection from infection. Ban dogs from loitering e.g beaches in an attempt to control human infection.[