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Boletín chileno de parasitología

versión impresa ISSN 0365-9402

Bol. chil. parasitol. v.56 n.3-4 Santiago jul. 2001 

Intestinal parasitic infections in human immunodeficiency virus (HIV) positive 
individuals in Southeastern Venezuela

Alejandro Caraballo1, Indhira Orozco2 and Liliana Muñoz2.

1) Departamento de Parasitología y Microbiología, Escuela de Medicina, Universidad de Oriente, Núcleo Bolívar, Apartado Postal 15, Ciudad Bolívar, Venezuela.
2) Departamento de Medicina, Hospital Universitario "Ruiz y Páez", Ciudad Bolívar, Venezuela.


Infecciones parasitarias intestinales en individuos positivos con el virus de la inmunodeficiencia humana
(VIH) en el Sureste de Venezuela

Un estudio fue realizado en relación a establecer la presencia de parásitos intestinales en 35 pacientes infectados con el virus de la inmunodeficiencia humana (VIH), desde julio 1997 a octubre 1998, admitidos en el Hospital Universitario "Ruiz y Páez" de Ciudad Bolívar, Venezuela.
Parásitos fueron detectados en heces usando diversos métodos para la investigación de protozoos y hemintos, concentración éter-formalina, tinción de Kinyoung y tricromico. Edad, sexo, estado clínico de la infección de VIH fueron registrados para cada participante del estudio. Todos los pacientes presentaron diarrea crónica. En 20 pacientes infectados con VIH (57%), uno o más parásitos intestinales fueron encontrados. Los protozoos más frecuentemente encontrados fueron: Blastocystis hominis (28,6%), Cryptosporidium sp. (22,8%) e Isospora belli (2,9%). Microsporidia no fueron detectados. Estos datos enfatizan la importancia de los portozoos oportunistas en pacientes infectados con VIH.

Palabras clave (Key words): Parásitos intestinales (intestinal parasites), pacientes infectados con VIH (HIV infected patients); Cryptosporidium sp.; Isospora belli; Venezuela


Chronic diarrhea is the most frequent symptom of HIV-infected patients. The prevalence of diarrhea in this group varies from 33 to 45% (Pape et al., 1994; Sorvillo et al., 1995). Much attention is currently being focused on the detection of specific pathogens as cause of fiarrhea in HIV-patients, since its correct treatment could improve the patient's general well-being. For example, the intrecellular intestinal protozoa: Cryptosporidium parvum, Cyclospora cayetanensis, Isospora belli and microsporidia are apportunistic in patients with acquired immunodeficiency syndrome (AIDS) and are often the major cause of uncontrollable, debilitanting diarrhea (Malebranche et al., 1983; Laughon et al., 1988; Wuhib et al., 1994).

Intestinal parasites in HIV-infected South American patients have been reported in Argentina (Mendez et al., 1994), Brazil (Dias et al., 1988a, 1988b; Moura et al., 1989; Magalhaes et al., 1993; Sauda et al., 1993; Wuhib et al., 1994; Costa-Cruz et al., 1996; Amato et al., 1999; Baraldi et al., 1999; Brasil et al., 1999; Cimerman et al., 1999a, 1999b; Lainson and Silva, 1999;) and Venezuela (Chacin-Bonilla et al., 1992; Chacin-Bonilla and Sánchez, 1993; Paez et al., 1999; Uzcategui et al., 1999a, 1999b). The aim of our study was to document prevalence of intestinal parasite infections in HIV-infected patients seen in the "Ruiz y Paez", University Hospital, Ciudad Bolivar, Venezuela.


Patients. The study was conducted between july 1997 and october 1998 at the "Ruiz y Paez" University

Hospital in Ciudad Bolivar, Venezuela. HIV-positive patients with diarrhea were asked to participate in the study. diarrhea (minimum of three loose stools per day with a duration of at least one week) (Weber and Bryan, 1994) was self-reported by the patient. The presence of HIV in the study group was detected by a microagglutination assay (Abbott Diagnostics, Chicago, IL). The positive samples by microagglutination were confrmed by Western Blot (Labtech, Singapore) following the manufacturer's instructions; all of 35 patients met the criteria for AIDS set by the Centers for Disease Control and Prevention (1992). All the patients gave their consent to participate in this investigation. At the time of enrollment into the study the medical record of each participant was reviewed.

Methods. For each patient, one fresh stool specimen was obtained every three days during ten days, and processed throught the methods of Hoffman et al., 1934; Faust et al., 1938; and Rugai et al., 1954. A single fecal sample was collected from each patient for parasitologic diagnosis and divided into two vials, one containing polyvinyl alcoho (PVA) and one containing 10% formalin fixatives (Para-Pak ®; Meridian Diagnostics; Cincinnatti, OH). Samples collected in formalin were examined for intestinal coccidia using the Kinyoun method (Ma and Soave, 1988) and the helminth eggs and larvae following formalin-ether concentration. Formalin preserved samples were also examined using modified trichrome stain for detection of Microsporidia (Weber and Bryan, 1994). Permanent thichrome-stained preparations were made from the samples collected in PVA and examined for intestinal protozoa. To ensure quality control, positive and negative controls for microsporidia (Meridian Diagnostics) and commercially available permanent slides and samples with protozoan cysts and trophozoites were included with each batch of samples that was stained and analized.


The study group was comprised of 26 (74.2%) males and 9 (25.8%) females, with a mean age 29.2 years (S.D.± 8.1; range 14-34 years); all were from Bolivar state.

The distribution of intestinal parasites detected in HIV-positive patients stools is shown in Table I. One or more parasites were identified in 57% of the study group. The most frequently diagnosed intestinal parasitic infections were Ascaris lumbricoides (14.2%), Trichuris trichiura (8.6%) and hookworm (8.6%). The protozoa most frequently found were Blastocystis hominis (28.6%), Cryptosporidium sp. (22.8%) and I. belli (2.9%) Microsporidia were not found.

Crytosporidium sp., and Isospora belli are among the sporulate protozoa identified frequently in infected patients with the HIV (Pape, 1988). Fecal samples are required for their diagnosis using several methods, i.e.: concentration, mounted preparations and stains; however, oocysts may not be observed by low levels of infectivity or by significant variability in the determinations with the fast-acid stain. For that reason, the employ of differents techniques of stains, of biometry and the morphologic characteristics in each case are necessary to establish the differential diagnosis. Therefore, parasitlogists should be trained for the visualization of these parasites in smears of fecal samples stained with the diverse techniques and physicians should be familiarized with the clinical findings and treatment of these parasitic infections, either in inmunocompetent and inmunocompromised host (Di Gliullo et al., 2000).

Among coccidian infected patients, diarrhea was the most frequent symptom. However, aymptomatic carriage was seen in two cases: one with I. belli and the other with C. cayetanensis.

In the group of protozoa, Blastocistis hominis was observed in a high percentage. However, this organism is common in this region, and rates as high as 30 to 40% have been observend in different populations (Devera et al., 1998a, 1998b).

In the HIV-positive patients, Cryptosporidium sp. was associated with diarrhea. Although we did not search for other enteropathogens such as bacteria and viruses it appears tha this protozoan could be responsible for the illness encountered in these patients. Our observations suggest that the occurrence of Cryptosporidium sp. infection is common. Our findings are similar to those reported in a study carried out in Zulia State, Venezuela (Chacín-Bonilla 1992). Isospora belli has become more prevalent in recent years because of its role as an apportunistic infective agent in persons with AIDS (Moura et al., 1989; Escobedo and Núñez , 1999). This enteric coccidian appears to be uncommon in Venezuela (Chacín-Bonilla and Sanchez, 1993). The low prevalence or isosporiasis (2.9%) is comparable to that reported in Brazil (Costa-Cruz et al., 1996; Baraldi et al., 1999; Cimmerman et al., 1999a), Cuba (Escobedo and Núñez, 1999) and United States (Ma and Soave, 1988; Sorvillo et al., 1995) and could be explained by the fact that patients received prophylactic medication against Pneumocystis carinii (Balanshard et al., 1992; Chacín-Bonilla and Sanchez, 1993; Pape et al., 1994).

Correspondence to: Dr. Alejandro Caraballo. Departamento de Parasitología y Microbiología, Escuela de Medicina, Universidad de Oriente, Núcleo Bolivar, Apartado Postal 15, Ciudad Bolívar, benezuela.


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