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Hookworm infection is endemic in many countries throughout the world; however, the information about the prevalence of each species, Necatoramericanus and Ancylostomaduodenale, is inaccurate in many South American countries. We aimed to determine the prevalence of human hookworm species by combining the results of both microscopy and PCR among endemic populations in Argentina, represented by natives and immigrants. A total of 140 serial fecal specimens were obtained from natives in the province of Misiones and an immigrant community living in the province of Buenos Aires. Samples were examined using the formalin-ethyl acetate concentration technique (FECT) and one flotation technique (screening tests) and specific PCRs for N. americanus and A. duodenale. We characterized samples containing N. americanus by sequencing a fragment of the cytochrome b gene. The observed hookworm prevalence as assessed by the screening tests and PCR were 24.3% and 32.8%, respectively. PCR positive samples were identified as N. americanus. PCR had 100% sensitivity compared with 73.9% of screening tests. A total of 12 samples from individuals with hookworm-infected household members were positive only by PCR. N. americanus sequences showed 90.5% identity, being more similar to each other than to any of the sequences obtained from GenBank. This is the first study that provides molecular data and characterization of N. americanus in Argentina. The complementary use of FECT and one flotation technique to screen hookworm infections, followed by PCR to differentiate the species contribute to produce better prevalence estimates.

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Resumen Durante 11 años un varón de 38 años de edad, residente en una región subtropical de Ecuador, había sido diagnosticado de anemia crónica y tratado con transfusiones de sangre en un hospital de la provincia de Cotopaxi, Ecuador. Fue transferido a Quito por una anemia grave, con hemoglobina de 4 g/dL. Se realizó una duodenoscopia en que se observaron nemátodos adultos, identificados posteriormente como Ancylostoma duodenale. El paciente fue tratado exitosamente con albendazol durante cinco días consecutivos y transfusiones de sangre. En el seguimiento a los ocho meses, no se encontró anemia ni huevos de anquilostomas en el examen de heces.

For 11 years, a 38-year-old male residing in a subtropical region of Ecuador, was repeatedly diagnosed with chronic anemia, and treated with blood transfusions in a hospital of province of Cotopaxi, Ecuador. He was transferred to Quito for severe anemia, having hemoglobin of 4 g/dL. Duodenoscopy was performed and adult nematodes, identified later as Ancylostoma duodenale, were observed. The patient was successfully treated with albendazole for five consecutive days and given blood transfusions. In the control visit at eight months, without anemia and no hookworm ova in the stool examined were found.

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Las enteroparasitosis, en general, constituyen un gran problema de salud pública en el mundo. De éstas, las nematodosis figuran entre las más destacadas en Colombia. Debido a que estos parásitos pueden ingresar al organismo por vía oral o por la piel, los hábitos higiénico-sanitarios deficientes, entre ellos el fecalismo, facilitan su transmisión y conservación.Entre las nematodosis más prevalentes en nuestro país tenemos aquéllas causadas por Ascaris lumbricoides, Trichuris trichiura (tricocéfalo), uncinarias (Necator americanus y Ancylostoma duodenale) y Strongyloides stercoralis. Cuando la carga de dichos parásitos es considerablemente alta o se acompaña de alteraciones en las defensas del hospedero, se pueden producir complicaciones que comprometen seriamente la salud del paciente.En la actualidad se sabe que el control farmacológico de estas nematodosis es efectivo y seguro. No obstante, sin autocuidado y mantenimiento sostenible de buenas condiciones higiénico-sanitarias, no es posible su erradicación.Por lo anterior, esta revisión dirigida al personal de la salud, especialmente a los médicos generales, discutirá los aspectos más relevantes de estas nematodosis y de sus complicaciones, haciendo énfasis en su biología, fisiopatología, manifestaciones clínicas, diagnóstico, tratamiento y algunos datos epidemiológicos.

Abstract Intestinal parasites, in general, constitute a great worldwide, public health problem. Of them, nematodes are among the most outstanding in Colombia. Because these parasites can enter into the organism either by ingestion or through the skin, faulty hygienic-sanitary habits facilitate their transmission and conservation. Among nematodosis the more frequent in Colombia are those caused by Ascaris lumbricoides (roundworm), Trichuris trichiura (whipworm), hookworms (Necator americanus and Ancylostoma duodenale) and Strongyloides stercoralis. When the burden of these parasites is considerably high and/or is accompanied by alterations in host defenses, complications can take place that seriously affect health. Presently it is known that pharmacological control of these nematodosis is effective and safe. Nevertheless, without selfcare, and maintenance of good hygienic-sanitary conditions, their eradication will not be feasible. This review of outstanding aspects of nematodosis, with emphasis on their biology, physiopathology, clinical manifestations, diagnosis, treatment, and some epidemiologic data, intends to update physicians as a basis for adequate management of this problem.

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