Epidemiology of infections with intestinal parasites and human immunodeficiency virus (HIV) among sugar-estate residents in Ethiopia.

Intestinal parasitic infections could play an important role in the progression of infection with human immunodeficiency virus (HIV), by further disturbing the immune system whilst it is already engaged in the fight against HIV. HIV and intestinal parasitic infections were investigated in 1239, randomly selected individuals, aged 15-54 years, living on a sugar estate in central Ethiopia. Intestinal parasites were identified in faecal samples (one/subject) using direct, concentration, and (for Strongyloides stercoralis larvae) Baermann methods. HIV serological status was determined using ELISA, with ELISA-positive samples confirmed as positive by western blotting. Most (70.1%) of the subjects were infected with at least one intestinal parasite and 3.1% were seropositive (but asymptomatic) for HIV. The intestinal parasites identified in the study population were amoebic parasites (Entamoeba histolytica/Enta. dispar) (24.6%), hookworms (23.8%), Ascaris lumbricoides (22.2%), Trichuris trichiura (19.5%), S. stercoralis (13.0%), Taenia saginata (4.5%), Giardia lamblia (3.0%), and Enterobius vermicularis (1.3%). Overall, the HIV-positives were no more or less likely to carry intestinal parasites than the HIV-negatives (76.2% v. 69.9%; P > 0.05). However, when each parasite was considered separately, amoebic parasites were found to be more common in the HIV-positives than the HIV-negatives (43.7% v. 24.0%; P < 0.05). This difference remained significant in a multivariate analysis, after controlling for the socio-demographic characteristics of the study participants. In conclusion, there was moderate interaction between intestinal parasites and HIV at the asymptomatic stage of HIV infection. The observed association between amoebic and HIV infections requires confirmation in a prospective study, allowing for the analysis of biological mechanisms involved in the association.

Epidemiology of HIV and Schistosoma mansoni infections among sugar-estate residents in Ethiopia.

Few studies have examined the interaction between schistosomiasis and infection with human immunodeficiency virus (HIV). The overlap between the two infections, and the effect of HIV infection on the egg output and worm load of individuals co-infected with Schistosoma mansoni, were therefore investigated in a sugar estate in central Ethiopia. The 1239 subjects were selected by stratified sampling of residents aged 15-54 years. The intensities of infection with S. mansoni were measured as egg output in stools (all subjects) and as the concentration of circulating cathodic antigen (CCA) in urine (a proxy for worm load, measured in 287 subjects). Schistosome infection was detected in 358 subjects [adjusted prevalence (AP) = 31.4%] and HIV infection in 52 (AP = 3.1%). The two infections clustered into different populations of the estate: the schistosome infections were predominantly found in the camps, and primarily affected young people (aged < 20 years) and those working in the field, whereas the HIV epidemic was found in the main village, primarily affecting those aged > 20 years and those who had recently arrived on the estate. Schistosome infection was detected in 348 of the 1187 HIV-negatives (AP = 31.6%) and 10 of the 52 HIV-positives (AP = 25.1%; P > 0.05). Schistosoma mansoni egg output was significantly lower in the HIV-positives than in the HIV-negatives (Mann-Whitney test; P = 0.03; ratio of geometric means = 0.74), and remained so after controlling for potential confounders (gender, age, and residence). However, CCA concentrations (i.e. worm loads) were found to be similar for these two groups, after controlling for potential confounders (age, gender, residence, and duration of residence).

Parasight-F dipstick antigen test in the diagnosis of falciparum malaria in Ethiopia.

OBJECTIVE: To determine the shelf life, rapidity and diagnostic performance of ParaSight-F. DESIGN: Prospective randomised study. SETTINGS: Malaria diagnostic and treatment posts and health centres in central-southern part of the Ethiopian Rift Valley. SUBJECTS: Three hundred and eighty two subjects randomly selected. MAIN OUTCOME MEASURES: Double blind evaluation of the sensitivity, specificity and predictive values of PFT versus CBF. RESULTS: The point prevalence was found to be 29.7% with species dominance of P. falciparum to P. vivax in the ratio of 4:1. The ParaSight-F test showed, considering P. falciparum only, a sensitivity of 92.5% and specificity of 93%. A remarkably high positive predictive value (PPV) of 82% as well as a negative predictive value (NPV) of 99% was obtained. Considering all species of Plasmodium, sensitivity was 78.6% and specificity 93%, with PPV and NPV of 82% and 91% respectively. Moreover, PFT was found to be rapid with a batch of ten-strips--a rack completed in 30 to 50 minutes, which was five to six times faster than CBF reading. In shelf-life studies, after one year of storage at room temperature, results were found similar to the original readings, indicating the stability and long durability of the test strips. CONCLUSION: In their durability and high diagnostic performances, both the microscopic slide readings and PFT were found comparable and interchangeable, and advantage in endemic areas where laboratory facilities are not available. The rapidity of PFT may be of greater value during malaria epidemics. But during non-epidemic seasons, the inability of PFT not to detect all forms of malaria remains a draw back.

Evaluation of the Eiken latex agglutination test for anti-Toxoplasma antibodies and seroprevalence of Toxoplasma infection among factory workers in Addis Ababa, Ethiopia.

Sera from 170 factory workers aged 18-45 years enrolled in a pilot study of human immunodeficiency virus 1 (HIV-1) infection in Addis Ababa, Ethiopia, were screened for anti-Toxoplasma immunoglobulin G antibodies by the Sabin-Feldman test (reference standard) and the Eiken latex agglutination test (under evaluation for use in developing countries). Based on the Sabin-Feldman test, the prevalence of anti-Toxoplasma antibodies was 80.0% (95% confidence interval 73.9-86.1%). The sensitivity and specificity of the Eiken latex agglutination test were 96.3% and 97.1%, respectively, showing its validity for the detection of anti-Toxoplasma antibodies. The prevalence of antibodies did not differ between individuals infected and uninfected with HIV-1 (74.2% versus 83.3%, P > 0.05). However, antibody titres were higher in HIV-infected persons than in those who were uninfected (P < 0.001). Based on these findings, we expect that toxoplasmic encephalitis will be a common opportunistic infection among HIV-infected Ethiopians, and chemoprophylaxis with co-trimoxazole may be beneficial to those with low CD4+ T cell counts. The prognostic significance of high titres of anti-Toxoplasma antibodies remains to be established among Ethiopian HIV-infected individuals.

Cryptosporidium and other parasites in Ethiopian AIDS patients with chronic diarrhoea.

Previous studies in other African countries have shown high prevalences of Isospora belli and Cryptosporidium parvum infections in acquired immunodeficiency syndrome (AIDS) patients with chronic diarrhoea. However, there is lack of information regarding these infectious agents in Ethiopian AIDS patients. Thus, this investigation has been aimed at determining the prevalence of Cryptosporidium and other related gastrointestinal parasites in AIDS patients with diarrhoea in seven Addis Ababa hospitals. Stool specimens from 246 clinically diagnosed AIDS patients were parasitologically screened for parasitic infections constituting HIV-negative with diarrhoea and HIV-positive without diarrhoea control groups. A variety of intestinal protozoa and helminths were found in 50% of AIDS patients and 42% of the controls. Cryptosporidiosis was detected in 38(25.9%), Isosporiasis in two (1.4%), and Blastocystosis in one (0.7%) of the AIDS patients with diarrhoea. The occurrence of cryptosporidiosis among the AIDS patients and possible explanation of the increasingly high study subjects with diarrhoea but without identifiable parasites is discussed.

Newly identified endemic areas of Schistosomiasis mansoni in Tigray, northern Ethiopia.

A survey of Schistosomiasis mansoni and Snail hosts was conducted in 1992-93 in Tigray Region. Forty accessible communities were selected at random and a total of 4786 children from elementary and junior high schools were examined for Schistosomiasis mansoni infection. Schistosomiasis mansoni positive children were found in 32 (80%) communities with prevalences ranging from 1% to 66% and an overall prevalence of 18.4%. Human prevalences of 5% and above were observed in 25 communities of which 19 are newly identified endemic foci. Significantly more males than females were infected with Schistosomiasis mansoni (P < 0.05). The age group of 10-19 years was most affected (P < 0.001). Biomphalaria pfeifferi were collected in 20 (58.8%) habitats of the total of 34 water bodies surveyed covering 18 communities. Infected snails were recovered from 12 (60%) of the 18 communities surveyed and six of these were newly identified transmission foci. The distribution of intestinal schistosomiasis in Tigray and the possible factors contributing to its spread are discussed and possible tactics of control suggested.

The status of Schistosoma mansoni and snail hosts in Tigray and northern Wello regions, northern Ethiopia.

A survey of Schistosoma mansoni infection and snail hosts was carried out in 1992 in six accessible schools and 11 water bodies respectively. Five to ten per cent of the students were randomly selected for stool examination by the Ritichie's method. In Adwa town, however, stools of 100 students out of the 199 selected were re-examined by Kato's method to assess intensity of infection. Results of stools examined by Ritichie's method showed that S. mansoni positive patients were present in four out of six (66.7%) schools, the prevalence for school ranging from 1% in Maychew to 61.8% in Adwa. In all the localities, there was significant male preponderance in the prevalence of infection (p < 0.05). Among those whose stools were examined by the Kato's method in Adwa town, both prevalence and geometric mean egg count per gram of faeces (EPG) were highest in the 10 to 14 years age group reaching 68% and 597 followed by 64% and 591 respectively in the 15 to 19 years of age. Of the S. mansoni positive students in Adwa, 86% excreted 200 or more EPG, 84% of those in the 10 to 14 years of age excreted as high as 1,600 EPG. Sexwise, no significant difference was observed in EPG (p > 0.05). Biomphalaria pfeifferi, the principal snail host of S. mansoni in Ethiopia, were collected from five out of the 11 waterbodies and were found shedding human schistosome cercariae in two of them, their infection rate reaching 0.7%. The ecological characteristics observed were found suitable for snail propagation.(ABSTRACT TRUNCATED AT 250 WORDS)

Hookworm infection among the Melka Sedi banana plantation residents, middle Awash Valley, Ethiopia.

A study of intestinal parasites was done among the people who lived within the banana plantation zone of the Melka Sedi Agricultural Enterprise, Awash Valley, Ethiopia in April 1987. The methods of parasite detection were the Ritchie formal ether and the charcoal culture method for hookworm larvae species identification. From the total 633 population, 311 were examined at random of whom 60.8% were positive for one or more intestinal parasites. Eight parasites were encountered, Ascaris lumbricoides in 1.3%, Trichuris trichiura in 6.4%, Strongyloides stercoralis in 3.9%, hookworm in 53.1%, Taenia sp. in 3.5%, Schistosoma mansoni in 1.9%, Entamoeba histolytica in 0.6% and Hymenolepis sp. in 0.6%. Prevalence of hookworm infection was significantly higher than that of any of the other parasites (p less than 0.001). In the hookworm infected individuals there were more males than females, and the 25 to 34 year age group had significantly higher infection rates (p less than 0.05). The majority of those with hookworm were banana plantation workers. This communication emphasizes the basic guidelines for control and prevention of hookworm and other related faecal/soil-borne infections in this and similar agricultural settings.

Evaluation of the modified Baermann's method in the laboratory diagnosis of Strongyloides stercoralis.

This study compares the modified Baermann's method with the formol-ether concentration and the direct/saline techniques in the diagnosis of Strongyloides stercoralis larvae in stool specimens. This study was conducted at Wonji-Shewa Sugar Estate located at about 110 kms. south east of Addis Abeba. Of the 718 randomly selected and examined stool specimens, 125 were found positive for Strongyloides stercoralis. Of these 98% were recovered by the modified Baermann's method, 23% by the formol-ether, and 22% by the direct saline techniques. The rate of recovery by the modified Baermann's method was significantly different (p less than 0.001) compared with those of the direct and the formol-ether concentration techniques. There was no difference (p greater than 0.1) between the direct saline and the formol-ether methods. The modified Baermann's method accounted for over 60% of the total positive findings. Furthermore, the sensitivity of the method excelled the other two techniques by four fold. Thus, the modified Baermann's method by the Merck and Sharp Dohme Company is effective, cheap and simple to use and hence recommended for routine use and epidemiological surveys.

Susceptibility of Biomphalaria pfeifferi from Amibara irrigation scheme to Schistosoma mansoni parasites from Adua and Gursume, Ethiopia.

A laboratory based susceptibility study was carried out on the snail Biomphalaria pfeifferi from canal habitats of the Amibara Irrigation Scheme (Awash Valley) to Schistosoma mansoni parasites from Adua (northern) and Gursume (eastern) Ethiopia. The objective of the study was to investigate the potential role of the snail in the transmission of S. mansoni in the irrigation network of Amibara. Thirty seven (74%) of the 50 snails and 55 (73.3%) of the 75 snails exposed to Adua and Gursume parasites respectively survived the prepatent period. Among the survivors, 94.6% and 96.4% infection rates were observed in those exposed to Auda and Gursume parasites respectively. Cercariae obtained from the snails were used to infect laboratory mice and the characteristic human Schistosoma mansoni eggs and adult worms were recovered. The implications of this study are discussed and future areas of research indicated.