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A case of intestinal parasitosis due to animal hookworm/ Un caso de parasitosis intestinal ocasionado por anquilostomideo de animales/ Um caso de parasitose intestinais ocasionado por ancylostomideo de animais.

Case Report

A 20 years old male from Caracas, Venezuela, consulted with a one-month history of watery diarrhea, epigastric stomachache and a significant weight loss (13kg). Initial laboratory: white blood cell count (WBC) of 16000/[mm.sup.3] with toxic granulation, 4% eosinophils and Giardia duodenalis in stool examinations. As his WBC count increased to 20000/[mm.sup.3] he was hospitalized, suspecting appendicitis. Endoscopy and upper abdominal ecosonogram were unremarkable, and stool re-examination demonstrated Entamoeba histolytica cysts. WBC increased to 26000/[mm.sup.3] with fluctuating eosinophilia (858%). Clinical improvement with antibiotics and antiamebics did not abolish all symp toms, being referred to the Amebiasis Laboratory, Department of Parasitology, Escuela de Bioanalisis, Facultad de Medicina, Universidad Central de Venezuela. The patient reported remaining mild discomfort, stomach ache and watery diarrhea, and was found pale and moderately ill. Laboratory data showed: hemoglobin 14.2g/dl, hematocrit 41.3%, MCV 90.3, MCH 31.1, MCHC 34.5, WBC 28600/[mm.sup.3], platelets 395000/[mm.sup.3], neutrophils 20.5%, lymphocytes 21%, eosinophils 50.5%, basophils 0.5%, monocytes 2.5%. Anysocitosis. Stool examination included direct method, Willis, Baermann, Rugai, Harada-Mori culture and Ziehl-Nielsen for prot ozoa's. After three days, one mature male specimen of Ancylostoma with one pair of teeth in the buccal capsule (Figures 1a-c) was detected by Baermann's method, followed on next day by Charcot-Leyden crystals and typical hookworms eggs. By the third day of thiabendazole therapy (25mgs/kg/ day) clinical improvement was induced, and on the eighth day WBC decreased to 8800/[mm.sup.3] and eosinophils to 11%.


Several species of the Ancylostoma genus (A. caninum, A. braziliense and A. ceylanicum) are frequent intestinal invaders of canines and felines. Percutaneous larval entry in humans triggers cutaneous larva migrans (CLM), a tortuous trajectory of pruritic erythematous papules, mostly on upper and lower extremities, erratic migration, and a progression of about 2 to 5 cm/day. It behaves as a self-limited process that generally disappears with topical therapy (Rey, 2001).

Multinational clinical and epidemiological investigations (New Guinea, Thailand, Malaysia, etc.) revealed invasion and adaptation of A. ceylanicum to the human intestine, preceded sometimes by cutaneous lesions (Anten and Zuidema, 1964). Maplestone (1933) inoculated A. braziliense to volunteers, inducing intestinal infections preceded by itching papules. Haydon and Bearup (1963) reproduced a similar clinical picture by infecting three people with A. ceylanicum larvae derived from a Solomon Islands habitant. As larval inoculation was expanded (Wijers and Smit, 1965), so did information about the clinical spectrum. In the early stages (6h) linear streaks of pruritic papules are common followed during the next 15-20 days by epigastric and abdominal discomfort, headache, fatigue and weakness. Around the fifth week, eggs of A. braziliense var. ceylanicum become detectable, together with leukocytosis and eosinophilia. Excluding diarrhea, the latter authors emphasize similarities with Brumpt's observations in therapeutic trials using A. duodenale in polycythemia and hypertension patients. Not all inoculated volunteers develop dermic lesions but digestive symptoms tend to coincide with marked egg excretion and eosinophilia (Carrol and Grove, 1984a). In agreement with Bearup (1967) they also highlighted the dissociation between onset and intensity of symptoms and the coexisting parasitic load.

The human pathogenesis has had additional corroboration when in multilocated communities 4% of 788 individuals harbored A. ceylanicum (Velasquez and Cabrera, 1968; Yoshida et al, 1968; Chowdhury and Schad, 1972; Bungiro et al., 2003; Jiraanankul et al., 2011; Conlan et al., 2012). In addition, mixed epidemiological animal/human testing supports the contaminating role of animal reservoirs. A single step PCR study (Traub et al, 2008) revealed A. ceylanicum and A. caninum in dogs, and N. americanus and A. ceylanicum in humans, strongly suggesting canine-derived human contamination. Contact related zoonosis has been further supported (Mahdy et al., 2012; Ngui et al., 2012a, b) by analysis of animal prevalence in which A. ceylanicum predominated in urban dogs and domestic cats, and A. caninum in dogs of rural areas (Scholz et al., 2003; Ngui et al, 2012b).

The patient under study exhibited manifestations of a severe acute intestinal parasitic infection, similar to those induced experimentally, without anemia (Wijers and Smit, 1966; Carrol and Grove, 1984a). Epidemiologically noteworthy, he referred that four months preceding his current illness, after bathing in a river located in a rural area, he developed a poorly described cutaneous reaction, which resolved with steroids. The approximate elapsed time until symptoms ensued differs from the conventional incubation period for hookworms, of 4-5 weeks. However, a dormant state in muscle tissue (hypobiosis) of A. caninum (and other animal parasites) lasting up to 8 months remains possible (Nawalinsky and Schad, 1974; Little et al., 1983; Botero and Restrepo, 2012). Although no previous human invasion by this Ancylostoma species has been documented in Venezuela, contamination from frequent domestic canine contacts is the most likely explanation. Retrospectively, the ineffectiveness of antibiotics and antiamebic drugs suggested an unusual infection. Although diarrhea, abdominal symptoms, malaise, weight loss, leukocytosis and eosinophilia are common nonspecific manifestations of high parasitic loads, the patient lacked evidence of predisposing immunological deficiencies or malnutrition.

The teeth visualized in the buccal capsule identified the Ancylostoma genus. Both A. braziliense and A. ceylanicum possess only one pair, but exhibit different morphological characteristics in the buccal capsule and the copulatory bursa (Velasquez and Cabrera, 1968). A sample slide was sent for verification to the Universidade Federal de Minas Gerais, Brazil, but the single available specimen lacked the necessary features to determine the culprit specie.

Accurate quantification of the parasitic load was unattainable. The day following the finding of the parasite, hookworm eggs confirmed the existence of more specimens, but suggested a low load. The patient was treated successfully, but did not provide additional adequate samples. In experiments with dogs, the number of fecal eggs is proportional to the amount of inoculated larvae (Carroll and Grove, 1984b). Possible differences in the clinical features of spontaneous infections and induced larval administration both in humans or animals must be considered. Thus, the present case exemplifies the recognized divergence between clinical severity and extent of parasitic load (Bearup, 1967).

A systematic search for previous reports of this specific specie in human infestations in Venezuela was unsuccessful. In 1904, Rangel described 'Ankilostomiasis in Venezuela' in anemic cases (Rangel, 2006). Much later, compilations carried out in 1957 from the Vargas Hospi tal, Caracas, revealed infections by N. americanus y A. duodenale. Since neither report refers morphological descriptions of the adult parasite's buccal capsule, the species involved remain unknown (Perez Gimenez et al., 1957).

This fortuitous finding should stimulate gastroenterologists, parasitologists and medical technicians to perform detailed evaluations of fecal samples in cases with digestive complaints, leukocytosis and eosinophilia. There is ample proof that cohabitation or contact with untreated pets or domestic animals may induce some human zoonosis. We found in human feces a parasite species common in animals.

Received: 03/09/2014. Modified: 06/13/2014. Accepted: 06/16/2014.


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Luz Nunez. M.D. and M.Sc. in Hematology, Universidad Central de Venezuela (UCV), Venezuela. Professor, UCV, Venezuela. Address: Catedra de Parasitologia, Escuela de Medicina Vargas, 2 piso, Esquina de Pirineos, San Jose, Caracas, 1010. e-mail:

Carmen Guzman de Rendon. Bioanalist and M.Sc. in Parasitology, UCV, Venezuela. Professor, UCV, Venezuela.

Eva Perez de Suarez. Bioanalist and Parasitologist, UCV, Venezuela. Professor, UCV, Venezuela.

Amadita Lopez. Bioanalist, UCV, Venezuela. Professor, UCV, Venezuela.

Marcos Pezzi Guimaraes. Veterinarian. Mestre and Doctor in Parasitology, Universidade Federal de Minas Gerais (UFMG), Brazil. Professor, UFMG, Brazil.

Carlos Goldstein. M.D., UCV, Venezuela. Centro Medico de Caracas, Venezuela.
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Title Annotation:texto en ingles
Author:Nunez, Luz; Guzman de Rondon, Carmen; Perez de Suarez, Eva; Lopez, Amadita; Pezzi Guimaraes, Marcos;
Article Type:Estudio de caso
Date:Jun 1, 2014
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