Revista Panamericana de Infectología

ARTÍCULO ORIGINAL / ARTIGO ORIGINAL

Correlation of intestinal parasitic pathogens in
HIV-seropositive adult with and without diarrhea in Northeast region
of São Paulo State, Brazil

Correlación de patógenos parasitarios intestinales en adultos VIH positivos, con y sin diarrea, en la Región Noreste del Estado de Sao Paulo, Brasil

Luciana Ventura Cardoso¹
Fabiana Rangel Marques¹
Carlos Eugênio Cavasini¹
Magali Carmem de Almeida²
Nair Aparecida Bassi²
Delzi Vinha de Nunes Gongóra³
Irineu Luiz Maia³
Andréa Regina Baptista Rossit¹
Ricardo Luiz Dantas Machado¹

¹ Center for Microrganisms Investigation, Dermatological, Infeccious and Parasitical Diseases Department,
Faculty of Medicine, São José do Rio Preto, SP, Brazil.
² Central Laboratory, Hospital de Base, São José do Rio Preto, SP, Brazil.
³ AIDS Ambulatory, Hospital de Base, São José do Rio Preto, SP, Brazil.

Rev Panam Infectol 2004;6(2):8-11.

Financial support: Body Shop Foundation

Recibido en 18/3/2004.
Aceptado para publicación en 20/5/2004.

Abstract

We describe the prevalence of intestinal parasitic infections in human immunodeficiency virus (HIV)-seropositive subjects. Fecal samples were collected from 99 HIV-seropositive patients. All specimens were processed according to standard methods for detecting ova, larva and cysts. A commercially available ELISA to detect C. parvum specific coproantigen was used. Twenty-six patients (26,26%) were found to harbor an intestinal parasite. C. parvum was the most common (9.09%), followed by Strongyloides stercoralis (6.06%). Giardia lamblia and Isospora belli each were detected in 4.04% of the patients, while Entamoeba coli was detected in 3.03% of the patients. Of the 26 patients who tested positive for intestinal parasites, 57.69% had diarrhea. The HIV-seropositive patients did have diarrhea, irrespective of the CD4+ T-cell counts. The results show no significant association between the presence of parasites and diarrhea. The parasites were not responsible for diarrheal disease in this population. The etiology of diarrhea in HIV-seropositive adults in the Northeast region of São Paulo State, Brazil, can be associated with antiretroviral therapy and/or others enteropathogens.
Key words: Diarrhea, Parasites, Acquired immunodeficiency syndrome, Brazil.

Resumen

En este estudio describimos la prevalencia de infecciones parasitarias intestinales en pacientes infectados por el virus de la inmunodeficiencia humana (VIH). Se colectaron muestras de heces en 99 pacientes VIH positivos. Todos los especimenes fueron procesados de acuerdo a métodos estandarizados para detectar huevos, larvas y quistes. Se utilizó también un ELISA disponible comercialmente para detectar el coproantígeno específico de Cryptosporidium parvum. Veinte y seis pacientes (26,26%) presentaron parásitos intestinales. El más común fue C. parvum (9.09%), seguido de Strongyloides stercoralis (6.06%). Se detectó también Giardia lamblia e Isospora belli en 4.04% de los pacientes. Por otro lado, Entamoeba coli fue encontrado en 3.03% de los casos. Considerando los 26 pacientes con parásitos intestinales, 57.69% tuvieron diarrea. Los pacientes VIH positivos tuvieron diarrea, independientemente del recuento de células T- CD4+. Los resultados no demostraron asociación significante entre la presencia de parásitos y diarrea. Los parásitos no fueron responsables por la enfermedad diarreica en esta población. La etiología de la diarrea en adultos VIH positivos de la Región Noreste del Estado de São Paulo, Brazil, puede estar asociada a la terapia antiretroviral y/o a la presencia de otros enteropatógenos.
Palabras clave: Diarrea, Parásitos, Síndrome de la inmunodeficiencia adquirida, Brasil.

Introduction

Human immunodeficiency virus (HIV) infection, a worldwide phenomena, is a serious problem in the present day⁽¹⁾. Diarrhea is a common clinical manifestation of HIV infection regardless of whether or not patients have Aids⁽²⁾. Reports indicate that diarrhea occurs in 30-60% of Aids patients in developed countries, whereas it reaches up to 90% of Aids patients in developing countries⁽³⁾.

Intestinal opportunistic parasitic infections are one of the important causes of this disease⁽⁴⁾ which is a serious health problem in tropical regions. Protozoan parasites, namely Entamoeba histolytica, Giardia lamblia and Cryptosporidium parvum are the major agents of parasite-induced diarrheal disease⁽⁵⁾. These protozoans has been recognized as the pathogens causing diarrhea in Aids patients⁽⁶⁾, and it has been postulated that HIV-infected individuals may have immune activation from such parasites, thus affecting the progression of HIV disease⁽⁷⁾. Furthermore, particularly chronic diarrhea and, in a few cases, acute diarrhea, can be strongly associated with lower CD4+ T-cell counts⁽⁸⁾.
The Hospital de Base de São José do Rio Preto (HB) is a tertiary care hospital catering to a large population from the Northeast region of São Paulo State, Brazil. The present study reports the prevalence of intestinal parasites in HIV-seropositive patients in São Paulo State and investigates the correlation of these infections with diarrhea.

Subjects and methods

Sample collection: From September 2002 to April 2003, 99 HIV-positive patients attending the HB Aids ambulatory were chosen randomly and included in the present study. The samples were obtained after informed consent from all individuals. The CD4+ T-cell counts, measured by flow cytometry, were obtained by reviewing patient’s charts. The inclusion criteria to participate in this study were: age over 15 years old; belonging to any HIV risk category and the presence of anti-HIV antibodies, measured by enzyme-linked immunosorbent assay. Forty persons, employees of the FAMERP or their relatives, all apparently healthy, were included as controls. Information on the epidemiological details was obtained according to a protocol approved by the Research Board of the Faculdade de Medicina de São José do Rio Preto.

Laboratory methods: Each participant was provided with one standard fecal collection vial containing 5% formalin and a spatula. All specimens were processed according to methods for detecting ova, larva and cysts devised by Hoffman et al, by Faust et al, and by Baerman-Moraes, as described elsewhere, by two experienced microscopist. A commercially available immunoenzimatic assay (Alexon, Inc., BIOBRAS) to detect C. parvum specific coproantigen was used⁽⁹⁾.

Analyses were performed using EPIINFO version 6.0 statistical software. To obtain the independence among the proportions, the chi-square test was applied or the Fisher’s exact test. The relationship between the CD4+ T-cell count of the patient who provided the stool sample and diarrheal symptoms was assessed using the Wilcoxon rank-sum test. The adopted significance level for statistical inference was 5%.

Results

The age of the patients ranged from 15 to 67 years, with median of 36 years. Among these, the majority were adults, with male preponderance (68.7%). Intestinal parasites were found in the stool samples of 26 patients (26.26%) all of them infected with only one parasitic pathogen. Cryptosporidium was the commonest (9.09%), followed by Strongyloides stercoralis (6.06%). G. lamblia and Isospora belli were both detected in 4.04% of the patients, while Entamoeba coli was detected in 3.03% of the patients (table 1). Of the 40 control samples tested, G. lamblia was detected in 3 subjects (7.5%), and E. coli were found in 2 persons (5%). Cryptosporidium and S. stercoralis were not detected in the control sample.

CD4+ T-cell counts were only available for 15 out of 26 patients in whom parasites were detected due to the absence of these information on the patient’s charts. A majority of the HIV-seropositive patients did have diarrhea, irrespective of the TCD4+ cell counts (P > 0.05). Of the studied HIV-seropositive samples, 51(51.51%) were identified as diarrhea stool, while 48 (48.48%) were not. Among the 26 patients who tested positive for intestinal parasites, 15 (57.69%) had diarrhea. Among the 73 negative stool exams, 36 (49,31%) were nondiarrheic and 37 (50.68%) presented this gastrointestinal symptom (table 2). The results show no significant association between the presence of the studied parasites and clinical signs of diarrhea (P > 0.05).

Discussion

The wide diversity of social, economic, climatic and geographic features in Brazil may reflect the presence of different areas endemic to distinct parasites⁽¹⁰⁾. Intestinal parasite infection is an important problem in HIV-infected patient. With the impaired immunity in these patients infestation with such pathogens, resulting in diarrheal symptom, is commonly seen⁽¹⁾.

The Cryptosporidium is not a new specie, but strong evidence suggests its emergence as an important community disseminated protozoan since this parasite has been frequently detected in untreated surface water, as well as in swimming and wade pools, day-care centers, and hospitals⁽¹¹⁾. Furthermore, this coccidian represents the leading cause of persistent diarrhea in HIV-infected individuals in developing countries, which additionally contributes for community dissemination. Interestingly, our results could not incriminate this opportunistic pathogen as responsible for diarrheal symptoms. One possible explanation for such negative association could be the fact that diarrhea, caused by Cryptosporidium in HIV-patient, could be alleviated by effective antiretroviral therapy⁽¹²⁾ to which our study patients are submitted. In Brazil, the global occurrence of cryptosporidiosis in the HIV-infected population is 0,7%⁽¹³⁾. However, our data, in agreement with previously reported results for the city of São Paulo (capital - 450 Km apart)⁽¹⁰⁾, showed higher rates (7%) of Cryptosporidium in patients with acquired immunodeficiency syndrome. Probably, the relatively low detection of this protozoan in our country may be due to deficient detection of these organisms in fecal specimens by conventional staining direct smear microscopy⁽¹⁰⁾.

S. stercoralis was the second most common parasite detected. Earlier studies in two different HIV-infected Brazilian populations reported rates of infection with this nematode between 7-16%^(7,14). Our results agree with some published reports where no relation was seen between this parasite detection and diarrhea in HIV-positive patients⁽¹⁵⁾. In fact, complications involving S. stercoralis have been associated primarily with the use of immunosuppressive therapy, particularly corticosteroids⁽¹⁶⁾.

Yet, the prevalence of G. lamblia and I. belli in our investigation shows that giardiasis and isosporiasis does not occur in expressive frequency in HIV-seropositive adults. For G. lamblia this is surprising, since in some regions of São Paulo state, up to 40% of the population carries this protozoan, although often without apparent symptoms⁽¹⁰⁾. In accordance to previous work^(1,17), I. belli in this group of patients showed a low prevalence. This can be due to immature oocysts being shed intermittently, which might not correspond to periods of clinical symptoms and not be shed during initial phase of infection, and the clinical symptoms become apparent⁽¹⁷⁾. Indeed, the difficulty of I. belli diagnosis is linked to systemic use of trimethoprim and sulfamethoxazole, which is given with low CD4+ T-cell counts as a prophylactic treatment of pneumocystosis⁽¹⁸⁾.

We conclude that cryptosporidiosis, strongyloidiasis, giardiasis and isosporiasis are the most frequent parasitic infections in HIV-infected adults living in the Northeast region of São Paulo, Brazil. However, we were not able to associate those classic enteropathogens with clinic diarrhea. If this association (HIV and diarrhea) is due to immune dysregulation, it must occur as a result of immune dysfunction not represented by CD4+ T-cell count, as previously reported in another Brazilian HIV-positive population⁽⁷⁾. Thus, the etiology of diarrhea in HIV-seropositive adults, in this area, could be associated with antiretroviral therapy and/or other non detected enteropathogens like bacteria, fungi, virus or other emerging coccidians. Current investigations are being ruled in our laboratory in order to clarify the role of diverse enteropathogenic agents in this group of patients.

Acknowledgments: To all patients enrolled in this study. Financial support was provided by Body Shop Foundation. The protocol for this study was reviewed and approved by the Research Board of the Faculty of Medicine of São José do Rio Preto.

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Correspondencia:

Dr. Ricardo Luiz Dantas Machado
Av. Brigadeiro Faria Lima, 5416, 15090-000,
São José do Rio Preto, SP, Brasil.
Fax: 55-17-2105700 R. 5587
e-mail: ricardomachado@famerp.br