TRANSACTIOKSOF THE ROYAL SOCIETYOF TROPICALMEDICINE ANDHYGIENE (1992)86, 543-545
Intestinal
parasites
in Zambian
patients
543
with AIDS
G. Hunterl, A. F. Bagshawe2, K. S. Baboo3, R. Luke4 and P. Prociv 1 ‘Department of Parasitology, The University of Queensland, Queensland4072, Australia; ‘Department of Medicine, and 3Department of Community Medicine, University Teaching Hospital, P.O. Box 50110, Lusaka, Zambia; 4Aboriginal Health Program, Queensland Department of Health, Brisbane, Queensland 4000, Australia Abstract
Previous studies have found a high prevalence of Isospora belli and Cyptosporidium parvum infections in African acquired immune deficiency syndrome (AIDS) patients with chronic diarrhoea. We aimed to determine the prevalence of gastrointestinal parasite in AIDS patients in hospital, not only those with diarrhoea, and to compare them with the general community. Clinically diagnosedAIDS patients in a Zambian teaching hospital were interviewed and examined, and stool specimenswere studied for parasite infection. A control group was recruited from adults in a township near Lusaka. Of 90 AIDS patients (58% male), 50 (56%) had chronic diarrhoea and 9 (10%) had diarrhoea of shorter duration. In the control group (105 adults; 85% female), only one complained of diarrhoea. A variety of intestinal protozoa and helminths was found m 57% of AIDS patients and 88% of the community members. Isosporiasis was detected in 7, and cryptosporidiosis in 2, AIDS patients, all with diarrhoea, but not in any control. Strongyloides was found in 2 AIDS patients with diarrhoea and one community resident. Hospital patients with AIDS had fewer Entamoeba coli and E. histolytica infections, probably becauseof previous chemotherapy. We conclude that AIDS predisposes to isosporiasis and cryptosporidiosis, but not to infection with extracellular intestinal parasites, such as Entamoeba species, Blastocystis, Chilomastix, Endolimax, Ascaris and Necator. Introduction
The acquired immunodeficiency syndrome (AIDS) caused by human immunodeficiency virus 1 (HIV-l) infection predisposes to several parasitic diseases,such as Pneumocystis carinii pneumonia and Toxoplasma encephalitis. Among intestinal parasites, only the intracellular coccidia, Zsospora belli and Ctyptosporidium parvum, are clearly opportunistic (FLEMING, 1990). The microsporidian Enterocytozoon bieneusi may be another significant enteric pathogen (CANNING & HOLLISTER, 1990). Intestinal nematodes, amoebae and other protozoa have not been shown to be opportunistic in AIDS patients. Why AIDS does not predispose to disseminated strongyloidiasis, which may complicate other immunosuppressive states,remains to be explained. Investigations for intestinal parasitic infection in AIDS patients in Africa have focused on patients with chronic diarrhoea. Isospora and Gyyptosporidium have been found consistently in-such patie$ ai prevalence rates varying from 8 to 32% and 12 to 19%, respectivelv, in studies of 42-46 patients with chronic diarrhoea and-other clinical manifestations and/or serological evidence of HIV-l infection (HENRY et al., 1986; COLEBUNDERS et al., 1988; CONLON et al., 1990). A smaller study, of 23 HIV posltive patients with diarrhoea, weight loss and oral candidiasis, found isosporiasis in 3 (13%) and cryptosporidiosis in 11 (48%) (SEWENKAMBO et al., 1987). In nearly all studies, these opportunistic infections were more common than the more ‘conventional’ parasitic protozoa and helminths, and were probably more prevalent than in the general community. The aim of our study was to compare the prevalence of intestinal parasites in clinically diagnosed hospital patients with AIDS with that in the general community. Subjects and Methods Outline of study
Personal, demographic and clinical information from 2 study populations, patients and controls, were obtained by interview and physical examination. Parasite infections were diagnosed by the examination of a single stool specimen, using severalmethods. Patient selection
Hospital patients satisfying a clinical casedefinition for (WHO, 1986) were invited to participate, and were interviewed and examined bv a single observer (G.H.). Addressfor correspondence:Dr Paul Prociv, Departmentof Parasitology,The University of Queensland,QLD 4072,Australia. AIDS
HIV serology was not done specifically, but was recorded when available. AIDS patients were identified clinically by the presence of 2 or more major signs and one or more minor signs, or the presence of disseminated Kaposi’s sarcoma or cryptococcal meningitis, in the absence of other known causes of immunosuDDression (Table 1). These last 2 AIDS-defining illnesses were diagnbsed clinically and by cerebrospinal fluid microscopy, respectively. Fever was judged subjectively in most subjects who were recently admitted. Precise weight loss, rarely known, was judged by the patient’s history and the degree of wasting. Chronic diarrhoea was defined as 2 or more unusually loose stools daily for at least a month, or intermittently for at least 2 months. Generalized lymphadenopathy was defined as nodes larger than 1 cm in at least 2 non-contiguous extra-inguinal sites. Recurrent or necrotizing multi-dermatomal herpes zoster and chronic aggressiveor ulcerated herpes simplex infection were recognized by their typical clinical features (HIRA et al., 1988). Chronic cough was excluded as a minor criterion, to improve the specificity of this clinical definition for AIDS in Africa, where tuberculosis is widely prevalent (WIDY-WIRSKYet al., 1988; COLEBUNDERS et al., 1989). Community survey
Adult residents of George township, on the outskirts of Lusaka, Zambia, were enrolled in a house-to-house survey by- a group-of 10 medical students, who conducted interviews and brief clinical examinations. A single stool specimen was collected from each participant. Stool examination
Only fresh hospital specimenswere examined as saline wet mounts, fixed in 10% formalin in normal saline. Formol-ether concentration involved shaking approximately 2 g of each specimen in 8.5 ml of fixative with 1.5 ml ether before centrifuging at 2000 rpm for 5 min. Filter paper slant cultures (LITTLE, 1966) were examined for nematode larvae by stereomicroscopy at least twice, after 2-3 and l&12 d incubation. Air-dried thin smearswere stained by a modified Kinyoun method for Cyptosporidium and Isospora oocysts (fixed in methanol for 3 min, stained with Kinyoun carbol-fuschin 10 min, decolourised in 1% HCl in methanol 1 min, washed in running tapwater, counterstained with 0.1% malachite green 1 min, washed in running water and dried). One observer (G.H.) did all the microscopy. Statistics
Two-way contingency tables were used for analysis.
544 AIDS patients with chronic diarrhoea, and in 21 of 40
Results AIDS Patients
Of the 90 hospital patients with clinically defined AIDS, 52 were males (58%) and 38 were females (42%), with median age groups 30-34 years and 20-24 years respectively. Of the 52 patients who had been tested, HIV1 serology was positive in 51. Clinical features are shown in Table 1. Chronic diarrhoea was reported by 50 (56%),
Table 1. Diagnostic clinical features of 90 patients with investigated for gastrointestinal parasite infections AIDV
Major signs Severe weight loss g j;gj Chronic diarrhoea Prolonged fever 45 (502) Minor signs Generalized lymphadenopathy 2: [gq Oropharyngeal candidiasis Generalized pruritic dermatitis ;fj [;gq Herpes zoster: recurrent or 00 multidermatomal necrotic Herpes simplex: chronic or aggressive 1 (l-l)% ulcerated Diagnostic Disseminated Kaposi’s sarcoma 18 (20%) 1(1-l%) Cryptococcal meningitis aBasedon the WHO (1986) case definition. and 9 others (10%) had diarrhoea of shorter duration. Specific antiparasitic treatment had been given to 17 patients (18%), including mebendazoleto 3 during the previous 12 months, metronidazole to 12 in the previous 3 months, and both drugs to 2. Another 28 patients had received unspecified drug treatment for diarrhoea. At least one intestinal parasite specieswas found in 5 1 patients. Of the recognised pathogens, detected in 24 patients, the commonest were Isospora belli, Ascaris lumbricoidesand hookworms, each found in 7 patients (Table 2). In all casesof hookworm infection, the specieswas Table 2. Parasite species identified in single-stool examinations from 90 hospital patients with AIDS and 105 representatives of a periurban community in Lusaka, Zambia AIDS patients
All parasites Pathogens
Community
51 (57%) 24 (27%)
Isospora belli Cryptosporidium Ascaris lumbricoides Necator americanus Strongyloides Schistosoma mansoni Entamoeba histolytica
‘Non-pathogens’ Entamoeba coli Entamoeba hartmanni Endolimax nana Iodamoeba buetschlii Chilomastix mesnili Trichomonas hominis Blastocystis hominis
5 (4.8%)
confirmed to be Necator americanus by larval culture. The ‘non-pathogens’ (Table 2) often occurred in multiple infections. Chronic diarrhoea affected 30 of 51 (59%) AIDS patients who had faecal parasites, and 20 of 39 (51%) without parasites. Parasiteswere identified in 30 of 50 (60%)
(53%) who did not suffer diarrhoea. Chronic diarrhoea occurred in all 7 patients with isosporiasis, which was the only infection clearly associatedwith this symptom. Associations were not identified between parasite prevalence and personal or demographic characteristics of the patients, such as age, sex, type of dwelling, size of household, type of latrine used, or water source. Previous antiparasitic drug treatment did not appear to influence the prevalence of Ascaris, hookworm or intestinal protozoan infections. Community group
While the study population comprised 105 of 109 adults interviewed, it was not a representative sample. The total adult population of the houses visited was 361, but most were not at home; the survey was undertaken during working hours. Selection bias is reflected by the predominance of females (85%), most of whom (43%) were young (aged 15-24 years) and formally unemployed. Females had a higher prevalence of E. coli infection (P
Intestinal
parasites
in Zambian
patients
543
with AIDS
G. Hunterl, A. F. Bagshawe2, K. S. Baboo3, R. Luke4 and P. Prociv 1 ‘Department of Parasitology, The University of Queensland, Queensland4072, Australia; ‘Department of Medicine, and 3Department of Community Medicine, University Teaching Hospital, P.O. Box 50110, Lusaka, Zambia; 4Aboriginal Health Program, Queensland Department of Health, Brisbane, Queensland 4000, Australia Abstract
Previous studies have found a high prevalence of Isospora belli and Cyptosporidium parvum infections in African acquired immune deficiency syndrome (AIDS) patients with chronic diarrhoea. We aimed to determine the prevalence of gastrointestinal parasite in AIDS patients in hospital, not only those with diarrhoea, and to compare them with the general community. Clinically diagnosedAIDS patients in a Zambian teaching hospital were interviewed and examined, and stool specimenswere studied for parasite infection. A control group was recruited from adults in a township near Lusaka. Of 90 AIDS patients (58% male), 50 (56%) had chronic diarrhoea and 9 (10%) had diarrhoea of shorter duration. In the control group (105 adults; 85% female), only one complained of diarrhoea. A variety of intestinal protozoa and helminths was found m 57% of AIDS patients and 88% of the community members. Isosporiasis was detected in 7, and cryptosporidiosis in 2, AIDS patients, all with diarrhoea, but not in any control. Strongyloides was found in 2 AIDS patients with diarrhoea and one community resident. Hospital patients with AIDS had fewer Entamoeba coli and E. histolytica infections, probably becauseof previous chemotherapy. We conclude that AIDS predisposes to isosporiasis and cryptosporidiosis, but not to infection with extracellular intestinal parasites, such as Entamoeba species, Blastocystis, Chilomastix, Endolimax, Ascaris and Necator. Introduction
The acquired immunodeficiency syndrome (AIDS) caused by human immunodeficiency virus 1 (HIV-l) infection predisposes to several parasitic diseases,such as Pneumocystis carinii pneumonia and Toxoplasma encephalitis. Among intestinal parasites, only the intracellular coccidia, Zsospora belli and Ctyptosporidium parvum, are clearly opportunistic (FLEMING, 1990). The microsporidian Enterocytozoon bieneusi may be another significant enteric pathogen (CANNING & HOLLISTER, 1990). Intestinal nematodes, amoebae and other protozoa have not been shown to be opportunistic in AIDS patients. Why AIDS does not predispose to disseminated strongyloidiasis, which may complicate other immunosuppressive states,remains to be explained. Investigations for intestinal parasitic infection in AIDS patients in Africa have focused on patients with chronic diarrhoea. Isospora and Gyyptosporidium have been found consistently in-such patie$ ai prevalence rates varying from 8 to 32% and 12 to 19%, respectivelv, in studies of 42-46 patients with chronic diarrhoea and-other clinical manifestations and/or serological evidence of HIV-l infection (HENRY et al., 1986; COLEBUNDERS et al., 1988; CONLON et al., 1990). A smaller study, of 23 HIV posltive patients with diarrhoea, weight loss and oral candidiasis, found isosporiasis in 3 (13%) and cryptosporidiosis in 11 (48%) (SEWENKAMBO et al., 1987). In nearly all studies, these opportunistic infections were more common than the more ‘conventional’ parasitic protozoa and helminths, and were probably more prevalent than in the general community. The aim of our study was to compare the prevalence of intestinal parasites in clinically diagnosed hospital patients with AIDS with that in the general community. Subjects and Methods Outline of study
Personal, demographic and clinical information from 2 study populations, patients and controls, were obtained by interview and physical examination. Parasite infections were diagnosed by the examination of a single stool specimen, using severalmethods. Patient selection
Hospital patients satisfying a clinical casedefinition for (WHO, 1986) were invited to participate, and were interviewed and examined bv a single observer (G.H.). Addressfor correspondence:Dr Paul Prociv, Departmentof Parasitology,The University of Queensland,QLD 4072,Australia. AIDS
HIV serology was not done specifically, but was recorded when available. AIDS patients were identified clinically by the presence of 2 or more major signs and one or more minor signs, or the presence of disseminated Kaposi’s sarcoma or cryptococcal meningitis, in the absence of other known causes of immunosuDDression (Table 1). These last 2 AIDS-defining illnesses were diagnbsed clinically and by cerebrospinal fluid microscopy, respectively. Fever was judged subjectively in most subjects who were recently admitted. Precise weight loss, rarely known, was judged by the patient’s history and the degree of wasting. Chronic diarrhoea was defined as 2 or more unusually loose stools daily for at least a month, or intermittently for at least 2 months. Generalized lymphadenopathy was defined as nodes larger than 1 cm in at least 2 non-contiguous extra-inguinal sites. Recurrent or necrotizing multi-dermatomal herpes zoster and chronic aggressiveor ulcerated herpes simplex infection were recognized by their typical clinical features (HIRA et al., 1988). Chronic cough was excluded as a minor criterion, to improve the specificity of this clinical definition for AIDS in Africa, where tuberculosis is widely prevalent (WIDY-WIRSKYet al., 1988; COLEBUNDERS et al., 1989). Community survey
Adult residents of George township, on the outskirts of Lusaka, Zambia, were enrolled in a house-to-house survey by- a group-of 10 medical students, who conducted interviews and brief clinical examinations. A single stool specimen was collected from each participant. Stool examination
Only fresh hospital specimenswere examined as saline wet mounts, fixed in 10% formalin in normal saline. Formol-ether concentration involved shaking approximately 2 g of each specimen in 8.5 ml of fixative with 1.5 ml ether before centrifuging at 2000 rpm for 5 min. Filter paper slant cultures (LITTLE, 1966) were examined for nematode larvae by stereomicroscopy at least twice, after 2-3 and l&12 d incubation. Air-dried thin smearswere stained by a modified Kinyoun method for Cyptosporidium and Isospora oocysts (fixed in methanol for 3 min, stained with Kinyoun carbol-fuschin 10 min, decolourised in 1% HCl in methanol 1 min, washed in running tapwater, counterstained with 0.1% malachite green 1 min, washed in running water and dried). One observer (G.H.) did all the microscopy. Statistics
Two-way contingency tables were used for analysis.
544 AIDS patients with chronic diarrhoea, and in 21 of 40
Results AIDS Patients
Of the 90 hospital patients with clinically defined AIDS, 52 were males (58%) and 38 were females (42%), with median age groups 30-34 years and 20-24 years respectively. Of the 52 patients who had been tested, HIV1 serology was positive in 51. Clinical features are shown in Table 1. Chronic diarrhoea was reported by 50 (56%),
Table 1. Diagnostic clinical features of 90 patients with investigated for gastrointestinal parasite infections AIDV
Major signs Severe weight loss g j;gj Chronic diarrhoea Prolonged fever 45 (502) Minor signs Generalized lymphadenopathy 2: [gq Oropharyngeal candidiasis Generalized pruritic dermatitis ;fj [;gq Herpes zoster: recurrent or 00 multidermatomal necrotic Herpes simplex: chronic or aggressive 1 (l-l)% ulcerated Diagnostic Disseminated Kaposi’s sarcoma 18 (20%) 1(1-l%) Cryptococcal meningitis aBasedon the WHO (1986) case definition. and 9 others (10%) had diarrhoea of shorter duration. Specific antiparasitic treatment had been given to 17 patients (18%), including mebendazoleto 3 during the previous 12 months, metronidazole to 12 in the previous 3 months, and both drugs to 2. Another 28 patients had received unspecified drug treatment for diarrhoea. At least one intestinal parasite specieswas found in 5 1 patients. Of the recognised pathogens, detected in 24 patients, the commonest were Isospora belli, Ascaris lumbricoidesand hookworms, each found in 7 patients (Table 2). In all casesof hookworm infection, the specieswas Table 2. Parasite species identified in single-stool examinations from 90 hospital patients with AIDS and 105 representatives of a periurban community in Lusaka, Zambia AIDS patients
All parasites Pathogens
Community
51 (57%) 24 (27%)
Isospora belli Cryptosporidium Ascaris lumbricoides Necator americanus Strongyloides Schistosoma mansoni Entamoeba histolytica
‘Non-pathogens’ Entamoeba coli Entamoeba hartmanni Endolimax nana Iodamoeba buetschlii Chilomastix mesnili Trichomonas hominis Blastocystis hominis
5 (4.8%)
confirmed to be Necator americanus by larval culture. The ‘non-pathogens’ (Table 2) often occurred in multiple infections. Chronic diarrhoea affected 30 of 51 (59%) AIDS patients who had faecal parasites, and 20 of 39 (51%) without parasites. Parasiteswere identified in 30 of 50 (60%)
(53%) who did not suffer diarrhoea. Chronic diarrhoea occurred in all 7 patients with isosporiasis, which was the only infection clearly associatedwith this symptom. Associations were not identified between parasite prevalence and personal or demographic characteristics of the patients, such as age, sex, type of dwelling, size of household, type of latrine used, or water source. Previous antiparasitic drug treatment did not appear to influence the prevalence of Ascaris, hookworm or intestinal protozoan infections. Community group
While the study population comprised 105 of 109 adults interviewed, it was not a representative sample. The total adult population of the houses visited was 361, but most were not at home; the survey was undertaken during working hours. Selection bias is reflected by the predominance of females (85%), most of whom (43%) were young (aged 15-24 years) and formally unemployed. Females had a higher prevalence of E. coli infection (P
