Evaluation of a real-time multiplex PCR for the simultaneous detection of Campylobacter jejuni, Salmonella spp., Shigella spp./EIEC, and Yersinia enterocolitica in fecal samples.

Conventional diagnosis of infectious diarrhea caused by bacteria is time-consuming, labor-intensive, and has a suboptimal sensitivity. We have therefore developed a multiplex real-time polymerase chain reaction (PCR) for the simultaneous detection of Campylobacter jejuni, Salmonella spp., Shigella spp./enteroinvasive Escherichia coli (EIEC), and Yersinia enterocolitica in fecal samples. No cross reactivity between the different pathogens was observed, and the multiplex setup of the assay did not have an impact on the sensitivity of the PCR. The analytical sensitivity was 87 CFU/mL for C. jejuni, 61 CFU/mL for Shigella spp./EIEC, 5,528 CFU/mL for Salmonella spp., and 1,306 CFU/mL for Y. enterocolitica. An extensive validation of the assay was performed by testing 1,687 patient samples by both PCR and with conventional techniques. The use of PCR increased the overall clinical sensitivity from 78 to 100 % (p < 0.0001), the specificity was 99.4 % for the PCR, compared with 99.9 % for conventional culture. The novel PCR assay allows for rapid, sensitive, inexpensive, and high-throughput testing of the most common bacterial causes of gastroenteritis.

In silico Mechanics of Stem Cells Intramyocardially Transplanted with a Biomaterial Injectate for Treatment of Myocardial Infarction.

PURPOSE: Biomaterial and stem cell delivery are promising approaches to treating myocardial infarction. However, the mechanical and biochemical mechanisms underlying the therapeutic benefits require further clarification. This study aimed to assess the deformation of stem cells injected with the biomaterial into the infarcted heart. METHODS: A microstructural finite element model of a mid-wall infarcted myocardial region was developed from ex vivo microcomputed tomography data of a rat heart with left ventricular infarct and intramyocardial biomaterial injectate. Nine cells were numerically seeded in the injectate of the microstructural model. The microstructural and a previously developed biventricular finite element model of the same rat heart were used to quantify the deformation of the cells during a cardiac cycle for a biomaterial elastic modulus (Einj) ranging between 4.1 and 405,900 kPa. RESULTS: The transplanted cells' deformation was largest for Einj = 7.4 kPa, matching that of the cells, and decreased for an increase and decrease in Einj. The cell deformation was more sensitive to Einj changes for softer (Einj ≤ 738 kPa) than stiffer biomaterials. CONCLUSIONS: Combining the microstructural and biventricular finite element models enables quantifying micromechanics of transplanted cells in the heart. The approach offers a broader scope for in silico investigations of biomaterial and cell therapies for myocardial infarction and other cardiac pathologies.

Effect of biomaterial stiffness on cardiac mechanics in a biventricular infarcted rat heart model with microstructural representation of in situ intramyocardial injectate.

Intramyocardial delivery of biomaterials is a promising concept for treating myocardial infarction. The delivered biomaterial provides mechanical support and attenuates wall thinning and elevated wall stress in the infarct region. This study aimed at developing a biventricular finite element model of an infarcted rat heart with a microstructural representation of an in situ biomaterial injectate, and a parametric investigation of the effect of the injectate stiffness on the cardiac mechanics. A three-dimensional subject-specific biventricular finite element model of a rat heart with left ventricular infarct and microstructurally dispersed biomaterial delivered 1 week after infarct induction was developed from ex vivo microcomputed tomography data. The volumetric mesh density varied between 303 mm-3 in the myocardium and 3852 mm-3 in the injectate region due to the microstructural intramyocardial dispersion. Parametric simulations were conducted with the injectate's elastic modulus varying from 4.1 to 405,900 kPa, and myocardial and injectate strains were recorded. With increasing injectate stiffness, the end-diastolic median myocardial fibre and cross-fibre strain decreased in magnitude from 3.6% to 1.1% and from -6.0% to -2.9%, respectively. At end-systole, the myocardial fibre and cross-fibre strain decreased in magnitude from -20.4% to -11.8% and from 6.5% to 4.6%, respectively. In the injectate, the maximum and minimum principal strains decreased in magnitude from 5.4% to 0.001% and from -5.4% to -0.001%, respectively, at end-diastole and from 38.5% to 0.06% and from -39.0% to -0.06%, respectively, at end-systole. With the microstructural injectate geometry, the developed subject-specific cardiac finite element model offers potential for extension to cellular injectates and in silico studies of mechanotransduction and therapeutic signalling in the infarcted heart with an infarct animal model extensively used in preclinical research.

Microbiology and risk factors for catheter exit-site and -hub colonization in neonatal intensive care unit patients.

OBJECTIVE: To identify risk factors and describe the microbiology of catheter exit-site and hub colonization in neonates. DESIGN: During a period of 2 years, we prospectively investigated 14 risk factors for catheter exit-site and hub colonization in 862 central venous catheters in a cohort of 441 neonates. Cultures of the catheter exit-site and hub were obtained using semiquantitative techniques at time of catheter removal. SETTING: A neonatal intensive care unit at a university hospital. RESULTS: Catheter exit-site colonization was found in 7.2% and hub colonization in 5.3%. Coagulase-negative staphylococci were predominant at both sites. Pathogenic flora were found more frequently at the catheter hub (36% vs 14%; P<.05). Through logistic regression, factors associated with exit-site colonization were identified as umbilical insertion (odds ratio [OR], 8.1; 95% confidence interval [CI95], 2.35-27.6; P<.001), subclavian insertion (OR, 54.6; CI95, 12.2-244, P<.001), and colonization of the catheter hub (OR, 8.9; CI, 3.5-22.8; P<.001). Catheter-hub colonization was associated with total parenteral nutrition ([TPN] OR for each day of TPN, 1.056; CI95, 1.029-1.083; P<.001) and catheter exit-site colonization (OR, 6.11; CI95, 2.603-14.34; P<.001). No association was found between colonization at these sites and duration of catheterization and venue of insertion, physician's experience, postnatal age and patient's weight, ventilation, steroids or antibiotics, and catheter repositioning. CONCLUSION: These data support that colonization of the catheter exit-site is associated with the site of insertion and colonization of the catheter hub with the use of TPN. There is a very strong association between colonization at both catheter sites.

Operational validation of the direct agglutination test for diagnosis of visceral leishmaniasis.

The validity of the direct agglutination test (DAT) for visceral leishmaniasis (VL) was studied with a standardized field kit on 148 clinically suspected persons and 176 healthy controls recruited between 1993 and 1994 from an endemic area in Gedaref State, Sudan. A sensitivity of 95.9% and a specificity of 99.4% were found at a 1: 8,000 cut-off titer when parasitologically confirmed cases were compared with healthy controls. While corroborating previously reported sensitivity and specificity estimates of this serodiagnostic test, this study examined the bias generated by commonly used test validation procedures. The fundamental methodologic problem in VL test validation is the absence of a reliable gold standard. Moreover, any operational guideline on DAT use has to consider the critical dependency of the predictive values of the test on VL prevalence rates. The DAT diagnostic cut-off titer depends upon many external factors, among which the prevalence of disease in the area and the case mix seem the most important.

A randomised trial of the impact of counselling on treatment adherence of tuberculosis patients in Sialkot, Pakistan.

SETTING: Tuberculosis Department, Bethania Hospital, Sialkot, Pakistan. OBJECTIVE: To determine whether intensive counselling can improve treatment adherence. DESIGN: In a randomised controlled intervention trial of 1,019 adult tuberculosis patients, 49% were assigned to the intervention group and 51% to the control group. Baseline data were obtained through semi-structured interviews. Patients were followed until the end of treatment (cure, default, referral or death). The intervention included counselling at the start of treatment and at each subsequent visit for ambulatory patients, or weekly for hospitalised patients. Counselling combined health education with strategies to strengthen patients' self-efficacy. Control group patients received the usual care. The outcome measure was treatment default. RESULTS: The default rate was 54% in the control group and 47% in the intervention group: the default risk ratio was 0.87, implying a reduction in defaulting of 13%. The impact was stronger in women, ambulatory patients, re-treatment patients, women who worked in the home, and patients who were not the main provider, those with a poor knowledge of the disease or those with a short treatment delay. CONCLUSIONS: Intensive counselling has a significant, although limited, impact on treatment adherence.

Risk factors for central vascular catheter-associated bloodstream infections among patients in a neonatal intensive care unit.

The aim of this study was to identify risk factors for catheter-associated bloodstream infection (CABSI) in neonates. We undertook a prospective investigation of the potential risk factors for CABSI (patient-related, treatment-related and catheter-related) in a neonatal intensive care unit (NICU) using univariate and multivariate techniques. We also investigated the relationship between catheter hub and catheter exit site colonization with CABSI.Thirty-five episodes of CABSI occurred in 862 central catheters over a period of 8028 catheter-days, with a cumulative incidence of 4.1/100 catheters and an incidence density of 4.4/1000 catheter days. Factors independently associated with CABSI were: catheter hub colonization (odds ratio [OR] = 44.1, 95% confidence interval [CI] = 14.5 to 134.4), exit site colonization (OR = 14.4, CI = 4.8 to 42.6), extremely low weight (< 1000 g) at time of catheter insertion (OR = 5.13, CI = 2.1 to 12.5), duration of parenteral nutrition (OR=1.04, CI=1.0 to 1.08) and catheter insertion after first week of life (OR = 2.7, CI = 1.1 to 6.7). In 15 (43%) out of the 35 CABSI episodes the catheter hub was colonized, in nine (26%) cases the catheter exit site was colonized and in three (9%) cases colonization was found at both sites. This prospective cohort study on CABSI in a NICU identified five risk factors of which two can be used for risk-stratified incidence density description (birthweight and time of catheter insertion). It also emphasized the importance of catheter exit site, hub colonization and exposure to parenteral nutrition in the pathogenesis of CABSI.

Catheter manipulations and the risk of catheter-associated bloodstream infection in neonatal intensive care unit patients.

A prospective cohort study was performed to evaluate the influence of catheter manipulations on catheter associated bloodstream infection (CABSI) in neonates. Neonates admitted between 1 November 1993 and 31 October 1994 at the neonatal intensive care unit of a university hospital were included in the study. Seventeen episodes of CABSI occurred in 357 central catheters over a period of 3470 catheter-days, with a cumulative incidence of 4.7/100 catheters and an incidence density of 4.9/1000 catheter-days. Patient and catheter-related risk factors independently associated with CABSI were: catheter hub colonization (odds ratio [OR] = 32.6, 95% confidence interval [95% CI] = 4.3-249), extremely low weight (

Uptake of preventive health care among Mediterranean migrants in Belgium.

STUDY OBJECTIVE: The aim was to investigate the influence of ethnicity on the demand for preventive care by Mediterranean migrants in Belgium. DESIGN: This was a survey of patient contacts with general practitioners. SETTING AND PATIENTS: 33 general practitioners working in Belgian localities with the highest migrant density collaborated in the study. During two months they recorded information on consultations with an estimated 72,600 clients. Participation was obtained from all subjects attending for preventive care or for a new episode of illness (n = 6256). MAIN RESULTS: An average of 30% of the patients sought preventive care, but multivariate analysis showed ethnicity to be a strong independent predictor of this type of demand. The higher primary preventive uptake by female Moroccans and Turks and the higher secondary preventive uptake by males from the same ethnic groups, as compared with the Belgian reference population, contrasted with a lower demand for tertiary prevention in migrants of either gender. The relative demand for preventive care by the more acculturated migrants was, however, quite similar to the demand of the Belgian population. CONCLUSIONS: The differential uptake of primary preventive care could be partly explained by the higher fertility rates of immigrant women, and the differential secondary uptake by a lower incidence of tuberculosis in the indigenous population. The meagre demand for tertiary prevention by Moroccan and Turkish migrants could be due to weaker compliance with treatments for chronic disorders, which is related to the perceptions of illness in these ethnic groups. The establishment of cross cultural mechanisms of dialogue should enhance compliance and improve the access of immigrants to the benefits of tertiary preventive care.

Human immunodeficiency virus infection and human African trypanosomiasis: a case-control study in Côte d'Ivoire.

To assess the association between human immunodeficiency virus (HIV) infection and human African trypanosomiasis (HAT) in Côte d'Ivoire, West Africa, a cross-sectional case-control study was conducted on 301 HAT patients recruited in the main foci of the country. For each HAT patient, 3 controls, matched for sex, age and residence, were selected. Data relating to socio-demographic factors and potential risk factors for Trypanosoma brucei gambiense and HIV infections were obtained, and serum samples were collected for HIV-1 and HIV-2 tests. A positive test consisted of enzyme immunoassay reactive to HIV-1, HIV-2 or both and confirmed by a synthetic peptide test or Western blot. Data were analyzed using conditional logistic regression with EGRET software. No statistically significant difference was found between the prevalence of HIV infection in HAT patients and controls (4.3% and 3.5% respectively; crude odds ratio (OR) 1.28, 95% confidence interval (CI) 0.65-2.50). In multivariate analysis, allowance for 5 covariates did not change the association between the 2 infections (adjusted OR 1.27, 95% CI 0.64-2.52). Although this study had limited statistical power, no significant association was found between HIV infection and T.b. gambiense infection in rural Côte d'Ivoire. Studies are needed to determine whether HIV infection influences the clinical course of HAT, a question not addressed in the present study.

Migration, acculturation and utilization of primary health care.

This study explored the roles of acculturation, urban-rural provenance and length of residence as determinants of the utilization pattern of first line health services by Moroccan, Turkish and Italian migrants in Belgium. Concurrently, utilization characteristics were recorded in Belgian reference patients. With increasing acculturation the demand for preventive care decreased, vague complaints became more prevalent, the delay before consulting for a curative problem shortened and the prognosis improved. There was no correlation between the occurrence of psychological problems and acculturation but, except for 15-44 year old female migrants, the rate of social problems was negatively associated with this study factor. Migrants with an urban background consulted earlier and presented more frequently vague complaints than migrants from rural provenance. We observed no significant influence of length of residence on utilization characteristics and only a marginal influence on morbidity pattern. Although acculturation seems to be a strong determinant of the migrant's utilization pattern of primary health care services, it does not consistently lead to a decrease of utilization differentials with the Belgian reference population. This may imply that there is a need for public health interventions targeted at ethnic minorities.

Perception and social consequences of tuberculosis: a focus group study of tuberculosis patients in Sialkot, Pakistan.

Treatment defaulting is one of the major causes of the failure of TB control programs. In Bethania Hospital, Sialkot, defaulting rates are high: 72% for the standard 12 months course and 56% for the 8 months course. Attrition is especially important in the first weeks of treatment: < 70% of the patients start the 10th week of treatment. A focus group discussion study has been carried out to gain a better understanding of the impact of social stigmatization, treatment cost and pregnancy on defaulting. The study population consisted of 3 male and 3 female groups each with 8 hospitalized TB patients. The study shows that TB is perceived as a very dangerous, infectious and incurable disease. This perception has many social consequences: stigmatization and social isolation of TB patients and their families: diminished marriage prospects for young TB patients, and even for their family members: TB in one of the partners may lead to divorce. Due to fear patients often deny the diagnosis and reject the treatment. While both male and female TB patients face many social and economical problems, female patients are more affected. Divorce and broken engagements seem to occur more often in female patients. Females are usually economically dependent on their husbands and family in law, and need their cooperation to avail of treatment. The belief that pregnancy enhances the risk for relapse decreases their marriage prospects. Pregnancy is also a reason for stopping TB treatment as both are considered as incompatible. The findings of this study reveal the urgent need for a health education campaign to convince the general population that tuberculosis is curable. All health care providers should act as destigmatizers.

[Epidemiologic study of inguinal hernia in Kauta, Kasonogo zone, Zaire]. / Etude épidémiologique des hernies inguinales à Kauta, zone de Kasongo, Zaïre.

In the male population of Kauta, suburb of Kasongo city, Zaïre, a survey has been carried out to detect the magnitude of the inguinal hernia problem, the risk factors of the herniae and of their main complication: the strangulation of the hernia. Among the 364 people examined, 86 (= 24%) resulted positive to inguinal hernia and/or postoperative scars. The age of onset was determined from prevalence data. Age is a risk factor of the incidence of the herniae. The right inguinal canal has a higher risk for developing a hernia and for strangulation of that hernia than the left one. Tribe and labour characteristics were not associated with hernial occurrence. 80% of the patients declared that in the previous 12 months they had suffered from one or more episodes of hernial strangulation and that those episodes were successfully treated by indigenous techniques. This absolutely surprising figure needs to be verified and merits further study.

[Chronic Chagas cardiomyopathy: methods for identifying groups at risk and/or risk behaviors]. / La cardiopathie chagasique chronique: propositions méthodologiques pour l'identification des groupes et/ou des comportements a risque.

Chagas' disease is still in 1992 a true problem of Public Health in several countries of South America. Almost 1/3 of the infested patients will develop a heart complications particularly lethal: the Chagas' chronic cardiopathy. The existing drugs do not cope with this Public Health problem. Such a lack of therapy enlarged because of the success of vectors control, has based the main strategies for the years to come, i.e. eradication of the insects of Triatoma. infestans group. So, there is a great risk to look upon the patients already infested and threatened with acute heart complication. Many factors have an influence on the occurrence of such a complication. Therefore, identification of groups or behaviours at risk should lead to an adapted strategy to take care of the patients already infested by Trypanosoma Cruzi. The authors propose a methodology which taking into consideration all "may be risk factors", eases a graded conceptual model. This model will be certainly useful in identifying some pertinent parameters, in elaborating or accepting some data collection technology, in data analysis, as well as in setting up some operational research projects.

[Schistosoma intercalatum bilharziasis: clinical and epidemiological considerations]. / La bilharziose à Schistosoma intercalatum: considèrations cliniques et èpidèmiologiques.

Schistosoma intercalatum bilharziasis continues to raise numerous questions regarding pathogenicity and gravity. The parasite was identified recently and the last fully described outbreak occurred 10 years ago in the city of Bata, Equatorial Guinea. Geographically Schistosoma intercalatum biharziasis is limited to one part of the African continent but has shown a tendency to spread. Hybridization of Schistosoma intercalatum and Schistosoma haematobium has been observed. The main clinical manifestation of Schistosoma intercalatum is rectal bleeding. The endoscopic appearance of lesions is variable and non-specific ranging from granulomas or polyps to ulcerations. Complications include severe rectitis or genital involvement such as salpingitis with secondary sterility. Spontaneous abortion has also been reported. Association with salmonella and klebsiella infection has been confirmed and can lead to life-threatening situations. Few studies have been performed to assess the value of diagnostic tests. The sensitivity of stool smears and urinary sedimentation testing is 81.7% and 56.3% respectively using the two examinations as references for one another. The sensitivity of immunological tests is generally good but varies depending on the reference technique used. Specificity can be affected by cross-reaction with other schistosomas or trematodes and even with nematodes and hematozoons. Treatment with a single dose of Biltricide has proven to be effective. Prevention requires education of the population at risk and use of molluscacides. The control strategy must be adapted in function of the epidemiology of the disease, diagnostic data, cost and effectiveness of screening and treatment.

[Evaluation of the Ivory Coast sentinel surveillance system for antimalarial drug sensitivity]. / Evaluation du systéme ivoirien de survelliance sentinelle de la chimosensibilité des antipaludiques.

This study was performed to assess the sentinel surveillance system on malaria resistance in Cote d'Ivoire using a new method. Evaluation was based on documentation describing routine products and on activity reports obtained from the surveillance system. A qualitative approach was used to assess system design and quantitative approach to assess its operation. Degree of satisfaction with evaluation criteria was scored on a scale of 1 to 5. Score reproducibility in this study was good. Overall the system was considered as satisfactory. The strong points of the system are relevance, functions, sustainability, and data quality. The weak points are poor planning, overcentralization, and underuse of information. Correction of these weakness will require concentration by all parties at the national level involved in the surveillance system. The evaluation method used was simple, cheap and reproducible and thus could serve as an alternative approach for evaluation of sentinel surveillance systems in areas with scarce resources.

[Study of the factors determining an unexpected occurrecne of Chagas cardiomyopathy in Sucre, Bolivia]. / Etude des facteurs determinant la survenue d'une myocardiopathie chagasique a Sucre, Bolivie.

The purpose of this case-control study carried out between February 1, 1994 and December 22, 1994 at the "Instituto de Gastroenterologia Boliviano-Japonés" in Sucre, Bolivia was to determine risk factors for chronic Chagas cardiomyopathy in adult patients with positive serological tests for Trypanosoma cruzi. A total of 196 subjects were included. Inclusion criteria were positive serological tests for Trypanosoma cruzi, residence in the city of Sucre, Bolivia for at least 3 months, and age over 14 years. There were 62 cases presenting electrocardiographic findings consistent with Chagas cardiomyopathy and 134 controls presenting normal electrocardiographic findings. Both cases and controls underwent a standardized protocol including physical examination and laboratory tests. Interviews were set up to evaluate personal and familial history of Chagas disease, socioeconomic status, and presence of Triatoma infestans in the home. Bivariate analysis of data indicated that Chagas cardiomyopathy was associated with the following risk factors: heart rate (p < 0.05), fecaloma (p < 0.05), occupation requiring strenuous physical exertion (p < 0.001), proximity with domestic animals (p < 0.005), especially pigs (p < 0.005), dwelling features including outbuildings, more than 2 bedrooms, and inside ceilings (p < 0.001). Multivariate analysis revealed the following risk factors: occupation requiring strenuous physical exertion (p < 0.005), a yard around the house (p < 0.05), and inside ceilings (p < 0.05). The results of this study show that prevention of chronic Chagas cardiomyopathy in Sucre, Bolivia will depend on improvement of living conditions.

[Risk factors for human African trypanosomiasis in the endemic foci of Ivory Coast]. / Les facteurs de risque de la trypanosomiase humaine africaine dans les foyers endemiques de Cote d'Ivoire.

A case-control study on risk factors of Trypanosoma brucei gambiense human african trypanosomiasis was carried out in 111 patients diagnosed in the three main foci of Ivory coast. Each case was age and sex matched with one seronegative control living in the same locality. Based upon previous epidemiological surveys conducted in similar areas, the potential risk factors were identified and assessed using a standard questionnaire. The study demonstrates that in the forest area of Ivory coast human trypanosomiasis in a behavioral disease affecting mainly coffee and cocoa farmers. The allogenous populations coming from sudano-sahelian savannah are more exposed to the disease than other ethnic groups. People sleeping at the farm (encampments) are more likely to become infected than those living at the village (ODDS-Ratio = 4.5). People fetching water in natural holes and pools have an increased risk (ODDS-Ratio = 3.6). Cases reported more often than controls that they are foodstuffs dealers from the farms to the villages (ODDS-Ratio = 13.0). These results are consistent with data from previous studies. We identified preventable risk factors, upon which interventions should be carried out to reduce the incidence of the disease. The possibility of using these findings to improve sleeping sickness control programme in the forest areas of Ivory Coast is discussed.

[Childhood malaria in Kinshasa (Zaire). Influence of seasons, age, environment, and family social conditions]. / Le paludisme de l'enfant à Kinshasa (Zaïre). Influence des saisons, de l'âge, de l'environnement et du standing familial.

Frequency of malaria in children was evaluated from march 1986 to February 1987 in six districts of Kinshasa by paludometric survey with multiple visits. The six districts were selected according to their geographical situation and their degree of urbanisation. Each month, two stocks of children from 0 to 10 years old dwelling in a street were selected district and visited twice randomization in each selected district and visited twice at 2 weeks of interval. 5,541 children were examined at the occasion of the second visit. Influence of seasons, age, district, socio-economic level of the family and level of education of the parents was determined by analysing the following parameters: plasmodial index, parasitic density, incidence of fever attacks, conversion rate of thick smear, antimalaria drug consumption. Parasitic prevalence is 50 p.c. annual incidence of fever attacks is 50 p.c. and annual frequency of antimalaria drugs is 3,64 per child. Dry seasons (June-September and January-February) ease the pathophoresis and pathogenicity of plasmodia. The age group of less than one year is relatively less parasitized but from 2 years, contact with parasites is very high and without any significant evolution up to 10 years. The district where a child is living plays a predominant role on paludometric indices. Transmission is deeply influenced by geographical situation in the center of the town or in outlying districts and by the socio-economic environment (basic equipment, streets conditions, quality of accommodation). The socio-economic level of the child's family is also important in regard to malaria prevention. The level of education of the parents and mainly the mother has the greatest influence.

[Historical aspects of the risk factors of Schistosoma intercalatum schistosomiasis]. / Historique des facteurs de risque de la bilharziose à Schistosoma intercalatum.

Bilharziosis is a considerable public health problem. It is caused by many species of schistosoma, four of which have wide geographical distribution: Schistosoma mansoni, S. haematobium, S. japonicum and S. intercalatum. The recently discovered S. intercalatum is limited to central and west Africa. Its spread is progressive and its pathogenicity is not completely known. S. intercalatum bilharziosis is usually manifested in the form of dysentery. The physiopathologic explanation of this clinical manifestation is less clear. Immunopathologically, the formation of an inflammatory granuloma constitutes the origin of its symptoms. This is due to many biological factors including delayed hypersensitivity reactions. All cellular immunity changes will facilitate the appearance of symptoms. Our aim has been to show the importance of malnutrition as a pathogenic factor of S. intercalatum bilharziosis. The initial research hypothesis was as follows: malnutrition plays a role in the evolution of a patient from an asymptomatic state of infection to a symptomatic state of illness. We carried out the study in the suburbs of Bata, in Equatorial Guinea. The inhabitants of Ncolombong, essentially rural immigrants, comprised our study population. Following their consent, we recruited individuals less than 45 years of age who had not taken praziquantel during the last 12 months. We included a total of 297 patients. Our study was a case-control, matching on sex and age. A case was defined as an infected patient with acute or chronic diarrhea occurring within the last month' preceding the stool sample analysis. All cases were retained after exhaustive screening of the study population. Each case (group 1) was matched with one or several asymptomatic infected patients (group 2) and two or several asymptomatic noninfected patients chosen at random (group 3). The definition of malnutrition was as follows: weight/height < or = 90% for children less than 15 years of age or weight/height < or = 90% with a corporal mass index < or = 20 for children more than 15 years of age. Two logistical regression models were performed in order to distinguish pathogenic from infection factors. Among the confusion bias identified, none of the helminthiasis in Bata are risk factors. The risk factors of the infection have been searched with an interrogatory. The bias caused by the interviewer is minimized because all the team staff were trained for a week before the beginning of the study. Apart from malnutrition, the other causes of cellular immunodeficiency do not seem to have any relationship with the development of symptoms. The logistical model of infection identified the classical risk factors of infection: river leisures (OR = 3.97, CI 95%: 1.86-8.47), poor or average quality of walls of the house (OR = 2.53, CI 95%: 1.15-5.58), lack of water well (OR = 2.08, CI 95%: 1.08-4). Our study could not show any relationship between malnutrition and bilharziosis. The nutritional state does not play a significative role in the infection or development of the disease. Nevertheless, the nutritional state of the host probably influences other host or parasite factors. As a result, we still don't know its influence on ADCC (Antibody Dependent Cellular Mediated Cytotoxicity) mechanisms, on adult parasite adaptation and the efficiency of laying of eggs which affects the parasitological charge. We haven't found any relationship between parasitological load and appearance of symptoms. The parasitological load indirectly reflects the efficiency of the laying and nothing proves that it is correlated with the intensity of delayed type hypersensibility reactions. In the logistical model of the disease, a stay of more than 2 months in an endemic area (OR = 0.14, CI 95%: 0.03-0.76) and a poor or average quality of walls of the house decreased the risk (OR = 0.31, CI 95%: 0.11-0.85). This result permits us to suppose that there is a tolerance to schistosomian antigens by cellular immunity