Douglas Castillo

Contaminación ambiental por huevos de Toxocara sp. en algunas plazas y parques públicos de Santiago de Chile, 1999

Most of cases of visceral larva migrans syndrome are caused by Toxocara canis larvae. Man acquires the infection by accidental ingestion of ripe eggs of the helminth. In order to find out the frequency of the presence of Toxocara sp. eggs in dog fecal specimens from public places of Santiago city in 1999 july-september a study was carried out in 84 squares and 12 parks from 32 counties. Three fecal samples were collected in each of these places, making a total of 288. Each sample was processed according to a modified Telemann method and three smears of each were microcopically examined. Toxocara sp. eggs were found in 39 (13.5%) fecal specimens. In 28/84 (33.3%) squares and in 8/12 (66.7%) parks these eggs were detected. These results make necessary the control of dogs and cats populations with the aim of reduce the presence of animals without responsible owners. It should be advisable to prevent dogs and cats defecation in public areas grounds, trying to exclude these animals from recreation areas.

Exposure to larva migrans syndromes in squares and public parks of cities in Chile

Between November 2001 and December 2002, 600 dog fecal samples were collected in main squares and public parks of 13 cities in Chile, from the extreme north to the extreme south of the country. The samples were processed in the laboratory by centrifugal sedimentation and the Harada-Mori methods. T. canis eggs were found in 12 cities. Detection rates ranged from 1.9 to 12.5% with an average of 5.2%. Seven percent of the samples had eggs and 9.5% had rhabditoid and/or filariform larvae of Ancylostomatidae. Strongyloides stercoralis were not found. Squares and public parks in Chile pose a potential risk of exposure to visceral, ocular, and/or cutaneous larva migrans syndromes.

Molecular identification of the Diphyllobothrium species causing diphyllobothriasis in Chilean patients

Diphyllobothriasis caused by the infection of adult Diphyllobothrium tapeworms sporadically occurs in Chile. The occurrence of the disease is closely linked to the consumption of raw or undercooked freshwater and marine fishes. Diagnosis of diphyllobothriasis has been based on laboratory examinations of the morphological characteristics of proglottids and eggs passed in the feces. Although determination of the parasite to the species level is possible through histologic examination of proglottid specimens, the parasites of patients who only discharge eggs cannot be diagnosed to the species level. Determining the species responsible for the infection of humans and other animals in affected areas is an important component of understanding the epidemiologic and enzootic characteristics of any infectious disease. We therefore compared the classification results obtained using a molecular approach with those obtained from morphological and histopathological examination of proglottids or eggs from five Chilean individuals with diphyllobothriasis. DNA analysis confirmed that the causative Diphyllobothrium species in Chile were first identified as Diphyllobothrium latum and Diphyllobothrium pacificum at least. Furthermore, mitochondrial cytochrome c oxidase subunit 1 gene analysis also supported the hypothesis that D. latum from Chile originated from Europe.

Fascioliasis hepática humana: resistencia al tratamiento con triclabendazol

Human fascioliasis is a parasitic zoonosis that affects the liver of human and herbivorous animals. In chronic cases, its diagnosis is confirmed by direct visualization of parasitic eggs in stool examination, by positive testing for Fasciola hepatica antigens in stools, or by direct observation of parasites by endoscopic retrograde cholangiography or surgery. In acute cases, serological reactions as immunoblothing or detection of parasite antigens in the blood are useful. The treatment of choice is triclabendazole. However, parasite resistance in animals, as well as in man, has been reported to this drug. We report four patients in whom the parasitic infection persisted despite a course of treatment with triclabendazole.

Infecciones por protozoos y helmintos intestinales en pre-escolares y escolares de la Comuna de Colina, Santiago, Chile. 2003

* Unidad de Parasitologia Basico-Clinica, Instituto de Ciencias Biomedicas (ICBM), Facultad deMedicina, Universidad de Chile.** Laboratorio de Referencia de Parasitologia, Instituto de Salud Publica de Chile.*** Servicio de Gastroenterologia, Hospital Clinico Jose Joaquin Aguirre, Universidad de Chile.****Departamento de Parasitologia, Instituto de Biologia, UNICAMP, Campinas, Sao Paulo, Brasil.Email: rmercado@machi.med.uchile.cl

Estudio comparativo de la sensibilidad y mortalidad de las ninfas III y IV de Triatoma infestans usadas en el xenodiagnóstico de pacientes crónicos.

: Triatoma infestans nymphs have shown a good sensitivity for detecting Trypanosoma cruzi in the blood stream of infected hosts when are used in the xenodiagnosis (XD). This method, with its natural limitations, using seven nymphs III of T. infestans, has been routinely utilized with a satisfactory yield. With the aim of an eventual improving of the yield of XD (with 7 nymphs), two series of 54 XD boxes each, containing a total of 378 nymphs III and 378 nymphs IV respectively, were applied--one of each during three consecutive days--to nine chronic chagasic patients. Each of the nymphs was weighted before and after the application of the boxes, and the intestinal content of them was examined 30, 60 and 90 days later. The main comparative results obtained with nymphs III and IV of T. infestans were: blood ingestion 40 versus 107 mg (2.7 higher), positivity of insects 35.8% versus 50.6% (15.8% higher), positivity of XD boxes (7 nymphs each) 46.3% versus 55.6% (9.3% higher), and mortality rates 28.6% versus 12.2% (16.4% lower). All these results demonstrate that nymphs IV of T. infestans, because their higher capacity of ingesting blood and higher tolerance to examination manipulations, are more suitable for been used in XD.

Enfermedad de Chagas crónica en Chile. Experiencia de intervención educativa

* Carrera de Medicina. Facultad de Medicina. Universidad de Chile.** Laboratorio de Parasitologia Basico-Clinico. Programa de Biologia Celular y Molecular. ICBM. Facultad deMedicina. Universidad de Chile.*** Hospital Clinico. Universidad de Chile.**** Departamento de Educacion en Ciencias de la Salud. Facultad de Medicina. Universidad de Chile.***** Escuela de Tecnologia Medica. Facultad de Medicina. Universidad de Chile.****** Carrera de Psicologia. Universidad de Ciencias de la Informatica.******* Hospital de Combarbala. Servicio de Salud Coquimbo. IV Region. Chile.

Parasitosis ilusoria intestinal y dermatológica: casos clínicos

Illusory parasitosis, better known as delusional parasitosis, is a neuropsychiatric syndrome in which patients have the belief of suffering a parasitic disease, that can not be demonstrated after an exhaustive medical study. These patients are characterized by being polyconsultants in different medical specialties and, many of them, have antecedents of psychiatric disorders, some of them undiagnosed. Knowing the existence of the clinical picture, diagnosing early and empathizing with the patient, could give to clinician some clues for a timely and assertive psychiatric referral, and improve patient adherence to the proposed treatment.