REASSESSMENT OF HELMINTH INFECTIONS IN GULU MUNICIPALITY NOTHERN UGANDA AFTER THE TWENTY YEARS OF INSURGENCY: USING THREE DIAGONOSTIC METHODS TO COMPARE THEIR SENSITIVITY.

BACKGROUND: During the period of insurgency there were several internally displace people camps all over the Northern Uganda. People who lived within ten kilometers from Gulu Municipality were forced to evacuate their villages and re-locate and build huts for themselves in areas identified for them by the government. There were several of such camps within the municipality creating influx of people from the villages to the municipality for security. Now with the situation restored to normal, there is need to re-assess and update information on the prevalence of helminth infections in Gulu municipality where many of the internally displaced people (IDP) settled. OBJECTIVE: To find out if S. mansoni and soil transmitted nematode infections are so prevalent and very common in children aged betweenfive to 20 years. In Gulu municipality and that additional preventive and curative measure need to be considered. Further is there a strong need to reconsider more sensitive diagnostic methods at the hospitals or does the standard approach of direct smear examination recognise at least most heavy infected children with any of the parasites. Setting. The study was carried out in Gulu municipality. DESIGN: Purposive and random sampling methods were used. Study Population: Mainly Primary school children aged between five to 20 years randomly selected from four primary schools purposively selected around Gulu municipality were recruited for the study. For control 20 staff of each school randomly selected were also studied. RESULTS: Of the 582 samples tested, 117(20.1%) were found positive for Schistosoma mansoni. Fifteen (2.6%) other samples were found positive for other helminths like Ascaris lumbricoides, Trichuris trichiura H.nana Hookworm. The comparison between the methods showed that the results obtained by the three methods were similar for field research. There is a low intensity of infection with soil transmitted helminths found in the primary schools around Gulu municipality. CONCLUSION: We concluded that the prevalence and intensity of infection with soil transmitted helminths was low among the children aged between 5 to 20 years in the four primary school studied (2.6%) but there was medium infection with S.mansoi (20.1%). The sensitivity in detecting the helminthes eggs in the stool specimen were similar. Though the original Kato/Katz method recorded lowest egg count than the Polderman and Odongo-Aginya methods. This could be due to the fact that the slides were read immediately.

Healthcare-seeking strategies among displaced children in war-ridden northern Uganda: the case of malaria.

A field study was performed to examine suffering and treatment seeking from the perspective of children aged 8-16 years living in war-affected northern Uganda. Various techniques for collecting qualitative and quantitative data were used, including a semi-structured questionnaire about illness experiences and medicine use over a 1-month recall period. The 165 children who were interviewed were attending primary schools for displaced children and/or commuters' night shelters. The children frequently attributed their common febrile ailments to malaria and used a variety of pharmaceuticals and herbal remedies, as self-medication, for their self-diagnosed malarial episodes. Misdiagnosis of febrile illnesses by the children (as well as by the local healthcare providers) and frequent misuse of medicines in the treatment of these illnesses appeared to be very common. Improvement of the health conditions of these children requires a change of focus. Firstly, children above the age of 5 years who are not under adult care and who are often no longer welcome in the local hospital's paediatric ward need to be accepted at the outpatient clinics currently intended for adults. Secondly, the local diagnostic system needs to be improved, not only so that malaria can be reliably diagnosed but also so that alternative diagnoses can be confirmed or rejected, otherwise the current over-consumption of antimalarial drugs may simply be replaced with an over-consumption of antibiotics.

Quality-quantity trade-off of human offspring under adverse environmental conditions.

A central paradigm in life-history theory is the trade-off between offspring number and quality. Several studies have investigated this trade-off in humans, but data are inconclusive, perhaps because prosperous socio-cultural factors mask the trade-off. Therefore, we studied 2461 offspring groups in an area under adverse conditions in northern Ghana with high fertility and mortality rates. In a linear mixed model controlling for differences in age and tribe of the mother and socioeconomic status, each additional child in the offspring group resulted in a 2.3% (95% CI 1.9-2.6%, P < 0.001) lower proportional survival of the offspring. Furthermore, we made use of the polygamous population structure and compared offspring of co-wives in 388 households, thus controlling for variation in resources between compounds. Here, offspring survival decreased 2.8% (95% CI 2.3-4.0%, P < 0.001) for each increase in offspring number. We interpret these data as an apparent quality-quantity trade-off in human offspring.

Mass treatment with albendazole reduces the prevalence and severity of Oesophagostomum-induced nodular pathology in northern Ghana.

Previous surveys conducted in northern Ghana where Oesophagostomum bifurcum is endemic showed that O. bifurcum-induced nodular pathology could be detected in up to 50% of the inhabitants. The impact of albendazole-based mass treatment to control both infection and morbidity is assessed and compared with the situation in a control area where no mass treatment has taken place. A significant reduction in the prevalence of infection based on stool cultures was achieved following two rounds of mass treatment in one year: from 52.6% (361/686) pre treatment to 5.2% (22/421) 1 year later (chi(1)(2)=210.1; P<0.001). At the same time, the morbidity marker of ultrasound-detectable nodules declined from 38.2% to 6.2% (chi(1)(2)=138.1; P<0.001). There was a shift from multinodular pathology, often seen in heavy infections, to uninodular lesions. In the control villages where no treatment took place, O. bifurcum infection increased from 17.8% (43/242) to 32.2% (39/121) (chi(1)(2)=9.6; P<0.001). Nodular pathology decreased slightly from 21.5% to 19.0%, but a higher proportion of these subjects developed multinodular pathology compared with baseline (chi(1)(2)=5.5; P=0.019). It is concluded that repeated albendazole treatment significantly reduces O. bifurcum-induced morbidity.

Distribution of human Oesophagostomum bifurcum, hookworm and Strongyloides stercoralis infections in northern Ghana.

A cross-sectional study was carried out in 216 randomly selected, representative rural villages in the northeastern part of Ghana from March 1995 to May 1998. Inhabitants of randomly selected households, stratified by age and gender, were included. The geographical position of villages was recorded with a global positioning system (GPS). The prevalence of Oesophagostomum, hookworm and Strongyloides stercoralis infections in a study population of 20250 people was determined by microscopic examination of larvae in stool cultures. The overall prevalence was 10.2, 50.6 and 11.6% for the three nematodes, respectively. Hookworm infections were seen in all but one (99.5%) and S. stercoralis in 88.4% of the 216 villages, while Oesophagostomum infections were found to be common in a limited area with prevalences varying from 0 to 75%. An association was found between Oesophagostomum and hookworm infection, both at the individual and at the village level. Spatial analysis of the prevalence data indicated that the endemic area is relatively clearly demarcated to the south of the study area.

Oesophagostomum bifurcum-induced nodular pathology in a highly endemic area of Northern Ghana.

Human infection with Oesophagostomum bifurcum is rare globally, but focally endemic and common in Ghana and Togo. Two clinical presentations are identified: uni-nodular disease, which may be recognized as a 'Dapaong Tumour', and multi-nodular disease. Here, we describe the prevalence of O. bifurcum infection and the association with nodular pathology in northern Ghana. The study was performed in October 2002. Out of a well-defined population of approximately 18000, 928 subjects of all ages were randomly selected for parasitological and ultrasound examination. In stool cultures, 44% had detectable third-stage O. bifurcum larvae present. Females were more often infected than males (P<0.05). In 34% of the samples, nodules were detected along the colon wall, with the ascending and the transverse colon being the most affected regions. Significant correlations existed between the intensity of infection and the presence of nodules, both at the village and the individual level (P<0.001 for both). Patients with multi-nodular pathology had significantly higher larval counts than patients with uni-nodular pathology. The present data suggest that nodular pathology, and probably the severity of the disease, are directly related to intensity of the infection.

A mutation scanning approach for the identification of hookworm species and analysis of population variation.

To overcome limitations in the morphological identification of different developmental stages of hookworms to species, we have established a polymerase chain reaction-linked single strand conformation polymorphism technique (PCR-SSCP) utilizing the internal transcribed spacers (ITS) of ribosomal (r)DNA. These spacers were specifically chosen because they provide reliable species markers for strongylid nematodes. ITS spacers were amplified by PCR from DNA derived from individual parasites of seven species of hookworm, then denatured and subjected to electrophoresis in a mutation detection enhancement (MDE) (non-denaturing) gel matrix. PCR SSCP analysis showed that the single-strand ITS patterns produced allowed the unequivocal identification of all species. The method also allowed the direct display of sequence variation within some species where multiple individual worms were examined. These findings demonstrate the usefulness of the SSCP approach for hookworm identification, the detection of population variation and the direct display of sequence variation in rDNA.

Fatal cerebral toxoplasmosis in a bone marrow transplant recipient with leukemia.

Although opportunistic infections after allogeneic bone marrow transplantation are common, cerebral toxoplasmosis has only been reported once. We report a case of lethal cerebral toxoplasmosis in a patient with acute leukemia who had been submitted to intensive cytotoxic therapy and allogeneic marrow rescue. The clinical course was characterized by an unusually sudden neurological onset. It was remarkable that, in this case, toxoplasma serology remained repeatedly negative. The autopsy revealed that the infection also involved the myocardium. Serological data and pathology findings are presented.

PCR assay for the specific amplification of Oesophagostomum bifurcum DNA from human faeces.

Oesophagostomiasis in humans due to infection with Oesophagostomum bifurcum (nodule worm) is of major human health significance in northern Togo and Ghana where the human hookworm, Necator americanus, also exists at high prevalence. Accurate diagnosis of O. bifurcum infection in humans is central to studying the epidemiology and controlling the parasite. To overcome limitations of current copro-diagnostic methods, we have developed an alternative, molecular approach. Utilising genetic markers in the second internal transcribed spacer (ITS-2) of ribosomal DNA, we have established a two-step, semi-nested PCR method for the specific amplification of minute amounts (fg) of O. bifurcum DNA from human faecal samples. Using a panel of 155 well-defined faecal and DNA samples, the assay achieved a sensitivity of 94.6% and a specificity of 100%. This PCR assay will be useful for the diagnosis of O. bifurcum infection and as a molecular tool for elucidating the epidemiology of human oesophagostomiasis.

Molecular separation of Oesophagostomum stephanostomum and Oesophagostomum bifurcum (Nematoda: Strongyloidea) from non-human primates.

The ITS-2 sequences for adult specimens of Oesophagostomum stephanostomum from the common chimpanzee and Oesophagostomum bifurcum from the Mona monkey were determined. For both species, the length and GC content of the ITS-2 sequences were 216 bp and 43%, respectively. While there was no unequivocal sequence difference among individual worms representing each of the two species, five (2.3%) interspecific nucleotide differences were detected. These differences were associated with the presence of unique restriction sites in the ITS-2 sequence of 0. stephanostomum for multiple endonucleases of diagnostic value for the differentiation of the two taxa by restriction analysis. Pairwise comparisons of the ITS-2 sequences of O. stephanostomum and O. bifurcum with published ITS-2 sequences for five different congeners indicated that these species from the subgenus Conoweberia are closely related, in accordance with previous morphological studies.

Necator americanus (Nematoda: Ancylostomatidae) from Africa and Malaysia have different ITS-2 rDNA sequences.

The nucleotide sequences of the second internal transcribed spacer of rDNA were determined for adult worms of Necator americanus originating from Togo (Africa) and Sarawak (Malaysia). The length of the sequences of specimens from Togo (325 bp) were shorter than those from Sarawak (327 bp). There were six fixed genetic differences in the aligned sequences of N. americanus from Sarawak and Togo, excluding one or two polymorphic sites within the sequence of N. americanus from each geographical region. These findings suggest that there is either population variation in the sequence of N. americanus, or that N. americanus from the two countries may represent genetically distinct but morphologically similar (i.e. cryptic) species, however, comparison of the sequence differences among other hookworm species supports the latter conclusion.

Egg production of Oesophagostomum bifurcum, a locally common parasite of humans in Togo.

In northern Togo and northeastern Ghana, Oesophagostomum bifurcum is a common parasite in humans. Diagnosis is based on coproculture because the eggs of hookworm and Oesophagostomum are indistinguishable. To determine the level of egg production, 12 subjects were treated with 2 x 10 mg/kg of pyrantel pamoate and the worms they evacuated were then counted. Pretreatment and post-treatment species-specific egg counts were calculated on the basis of larval and total egg counts. The median worm burden was 81 (range 12-300) per person. The calculated median egg production was 33.7 egg/gram of feces per female worm. Assuming a total daily stool production of 150 g/day, this amounts to 5,055 eggs/day, which is comparable with the production of other nematodes of the same superfamily.

Oesophagostomiasis, a common infection of man in northern Togo and Ghana.

Infection with Oesophagostomum sp. is normally considered a rare zoonosis and up to this time its diagnosis has been based on the demonstration of larvae and young adult worms in the typical nodules formed in the intestinal wall. Only in Dapaong, in North Togo, and Bawku, North Ghana, have larger series of clinical cases been described. In the rural areas around these towns, a survey was made in which stool samples were collected and cultured. Third-stage larvae of Oesophagostomum sp. could be found after 5-7 days of incubation at room temperature, and the prevalence of infection with this parasite was often high but varied from one village to another. It was over 30% in seven villages out of the 15 villages surveyed. Anthelmintic treatment resulted in the evacuation of adult males and females of O. bifurcum. It is concluded that O. bifurcum is a locally common parasite of humans, not requiring an animal reservoir for completion of its lifecycle.

Geographic distribution and epidemiology of Oesophagostomum bifurcum and hookworm infections in humans in Togo.

In contrast to the rest of the world, infections with Oesophagostomum bifurcum are commonly found in humans in northern Togo and Ghana. In addition, infections with hookworm are endemic in this region. In the present study, a detailed map of the geographic distribution of O. bifurcum and hookworm infections in northern Togo was made. There were a number of foci with high prevalence of infection with O. bifurcum. All the villages examined were infected with hookworm, and the distribution was quite patchy. Women were infected with O. bifurcum more often than men, while infections with hookworm were more prevalent in men than in women. The prevalence and intensity of infection with both parasites were clearly age-dependent. We estimate that more than a 100,000 people in Togo are infected with O. bifurcum and more than 230,000 are infected with hookworm.

Quantitative determination of circulating antigens in human schistosomiasis mansoni using an indirect hemagglutination assay.

In serum and urine specimens collected from a group of Schistosoma mansoni infected individuals from Makundju, Zaire, the schistosome circulating anodic antigen (CAA) and the circulating cathodic antigen (CCA) were quantitatively determined using an indirect hemagglutination reaction with sheep erythrocytes sensitized with mouse IgM monoclonal antibodies directed against these circulating antigens. Levels of CAA in serum (up to 5 ng/ml) and CCA in serum and urine (up to 50 ng/ml) were strongly correlated with egg excretion and with each other. No correlation was found between egg excretion and antibody levels against the circulating antigens. Antigen was detectable only in patients excreting greater than 500 eggs per gram of feces.

SCHISTOSIM: a microsimulation model for the epidemiology and control of schistosomiasis.

A computer simulation model, SCHISTOSIM, has been developed for the epidemiology and control of schistosomiasis, based on the stochastic microsimulation technique. The eventual aim is to evaluate and predict the effects of different control strategies. In the current state of the model, human-, worm-, and infection-related aspects have been included. However, many others, including most transmission and transmission-related mechanisms, have yet to be modeled. By simulating a series of surveys and treatments in Burundi, short-term effects of this program were satisfactorily explained by the model. However, long-term predictions did not match the observed data. Possible extensions of the model to properly describe these effects are identified. The potential of SCHISTOSIM as a tool for the prediction of outcomes of alternative control strategies is illustrated and discussed.

Quantitative determination of circulating soluble egg antigen in urine and serum of Schistosoma mansoni-infected individuals using a combined two-site enzyme-linked immunosorbent assay.

Two enzyme-linked immunosorbent assays (ELISA-5B1 using monoclonal antibody [MAb] 114-5B1-A [IgG1] and ELISA-4D12 using MAb 114-4D12-A [IgG3]) that detect circulating soluble egg antigen (CSEA) of Schistosoma mansoni were combined into one assay. This assay showed better performance than either of the two MAbs alone in detecting egg antigen, which was demonstrated with 80 urine samples from patients infected with Schistosoma mansoni from Zaire. The lower detection limit of the combined ELISA was 90 pg of the trichloroacetic acid-soluble fraction of soluble egg antigen (SEA-TCA) per milliliter. Thirty-two serum samples and 107 urine samples from uninfected Dutch individuals were negative when tested with the combined ELISA. This assay showed the same sensitivity (86.3%) with patients' urine samples as parallel testing with ELISA-5B1 and ELISA-4D12 (85%), while ELISA-5B1 and ELISA-4D12 showed sensitivities of 81.3% and 75%, respectively. The sensitivity of the combined ELISA with 51 serum samples was 84.3%, and three of five serum samples available from the seven patients with negative urine were positive for CSEA. The concentration of CSEA calculated from a four-parameters logistic curve for samples tested showed a correlation with egg output and serum circulating anodic antigen (P < 0.0001). Circulating soluble egg antigen in urine showed a significant decrease with an increase in age of the patients in relation to serum CSEA and egg output.

Intraobserver and interobserver variation of ultrasound diagnosis of Oesophagostomum bifurcum colon lesions.

Infection by the nematode Oesophagostomum bifurcum is focally distributed in Africa and causes a syndrome of abdominal pain, obstruction, or abdominal mass because of its predilection for invasion of colonic mucosa. To determine the reliability of ultrasound for the detection of colon pathology induced by this parasite, three studies to assess the intraobserver and interobserver variation of the technique were performed. In an area of northern Ghana endemic for O. bifurcum, 181 people from a low-prevalence village and 62 people from a high-prevalence village were examined twice by the same observer, and 111 people were independently examined by two observers in a moderately endemic village. The kappa statistics for the prevalence observations in the three studies were 0.82, 0.87, and 0.81, respectively, and kappa values for the intensity observations were 0.66, 0.63, and 0.71, respectively. The upper 95% confidence intervals of the average absolute difference in nodule size measurements in Study 1 and Study 3 were 3.6 and 4.5 mm, respectively. Therefore, ultrasound is useful in the diagnosis and management of O. bifurcum colon infection.

The risk of Strongyloides stercoralis transmission from patients with disseminated strongyloidiasis to the medical staff.

To assess the risk of Strongyloides stercoralis transmission from two patients with disseminated strongyloidiasis to medical staff who had been in close contact with the patients, blood and stool specimens were obtained from medical staff two to three months after close contact with the patients. Antibodies to S. stercoralis were determined in blood. Stool specimens were tested for parasites with three different procedures.Forty-one medical staff were included. Culture and stool examination were negative in all subjects. Serology was negative in all subjects but one who had a borderline titer without signs or symptoms of strongyloidiasis. No evidence of transmission of S. stercoralis from patients with disseminated strongyloidiasis to medical staff was found.

The morbidity of schistosomiasis mansoni in Maniema (Zaire).

The morbidity of schistosomiasis mansoni was assessed in Makundju (population 547; prevalence 96%, mean egg load 791 epg) and Massimelo (pop. 363; prev. 19%, mean egg load 39 epg), 2 similar villages in the forest zone of Maniema, Zaire. The prevalences of other parasites including malaria (holoendemic) were comparable. "Intermittent diarrhoea" (mostly bloody) was a complaint of 55% and 3% of the populations, respectively, "intermittent abdominal pain" of 63% and 25%, and "fatigue" of 33% and 19%. Enlargement of the left liver lobe was present in 45% and 9% of the populations, right lobe hepatomegaly in 32% and 3%, splenomegaly in 29% and 9%. Hepatomegaly and splenomegaly in Makundju were often very impressive, and most frequent in the 6- to 18-year-old group. Anaemia (haematocrit less than or equal to 35%) was present in 30% and 9% of males and 36% and 21% of females. Mean length and weight were lower in Makundju for boys aged 11 to 18 years. Ergometric results (Astrand cyclometer, male adults only) were comparably low in both villages (mean VO2max. 19.3 and 18.9). Analysis of the data according to egg load within the Makundju community revealed a significant relationship only in the following cases: higher frequencies of diarrhoea, abdominal pain and fatigue in those excreting more than 200 epg compared with those excreting fewer; left lobe splenomegaly gradually increased with egg load in children under 18; in people over 40 it occurred at a higher frequency in those excreting more than 2000 epg than in those excreting fewer.(ABSTRACT TRUNCATED AT 250 WORDS)