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Genetic factors have clearly been shown to play a role in controlling malarial infection in animal models. There is now also increasing evidence for the genetic control of malaria in man. We carried out a segregation analysis based on blood parasite load phenotype for a population of the town of Bobo-Dioulasso (Burkina-Faso). This analysis demonstrated a strong genetic effect. Our results were not consistent with the segregation of a major gene and thus suggest that parasite load is under the control of minor genes. The genetic effect was stronger in children than in adults. We carried out a regression analysis in children and found that there was an association between the phenotype for blood parasite load and the q31-33 region of chromosome 5. We identified a gene in this region, Pfil1 (Plasmodium falciparum infection levels 1), which accounted for almost 50% of the variance in blood parasite load and which played a fundamental role in the control of infection. The 5q31-33 region contains several genes encoding cytokines that regulate T lymphocytes. The identification of genes controlling malarial infection opens up new possibilities for preventive and treatment strategies. It should be possible in the near future to identify individuals at risk of malaria, who would derive the greatest benefit from preventive and therapeutic measures. Finally, a deeper understanding of these genes controlling protective immune responses could be of value for the development of vaccines.

The in vitro sensitivity of P. falciparum drug-resistant isolates was evaluated in the region of Bobo-Dioulasso during the 1995 and 1996 rainy seasons. Two routinely used antimalarials (chloroquine and quinine) and two new antimalarials (mefloquine and halofantrine) were assessed using 24-hour in vitro cultures with tritiated hypoxanthine and a parasite density > or = 4,000/microl of blood. The proportion of chloroquine-resistant isolates was 20% in 1995 and 19% in 1996, whilst in 1996, the proportion of isolates resistant to halofantrine was greater than in 1995 (9.6% versus 1%). No significant differences were seen in the mean IC50 values in relation to the susceptibility of chloroquine-resistant or chloroquine-sensitive isolates to mefloquine and halofantrine. In the case of quinine, the mean IC50 values were significantly higher in chloroquine-resistant isolates than in chloroquine-sensitive ones. A significant positive correlation was found between the following IC50 values: chloroquine versus quinine, quinine versus mefloquine and mefloquine versus halofantrine.

A case-control study was carried out to identify risk factors for neonatal tetanus in rural Burkina Faso. Each of the 31 cases identified prospectively were matched with two controls. Risk factors such as the instrument used to cut the umbilical cord and the qualification of the midwives were only identified in the univariate analysis. The multifactorial analysis identified factors commonly believed to be associated with neonatal tetanus: lack of mother's immunization and place of birth other than maternity clinics. However, applying karite nut butter on the umbilical cord was found to be a strong independent factor associated with neonatal tetanus. Immunization of mothers against tetanus should be enforced. Health education must take into consideration sociocultural realities of these populations.

Stool disposal practices have been shown to be associated with childhood diarrhoea. However, efforts to promote improved hygiene behaviour are hampered by a lack of understanding of what determines those behaviours. Data from 2793 household interviews with mothers of children from the town of Bobo-Dioulasso in Burkina Faso were analyzed to examine what differentiated mothers who reported using safer stool disposal practices from those who did not. Three 'outcomes' were considered: where the child was reported to defaecate; where the mother reported disposing of the child stools; and whether excreta were observed in the compound. Regression models were developed to identify those factors with the strongest independent associations with the outcomes. There was a consistent association between the source of water and the outcomes. Mothers with access to a tap in the yard reported using safe hygiene practices three times more often than mothers using wells outside the compound and twice as often as mothers who used public standpipes or wells within the yard. The source of water showed a similar pattern of association with observations of faecal matter in the environment. Improved sources of water may contribute to safer stool hygiene by reducing the time spent on water collection or by encouraging mothers to conform to higher standards of hygiene. Other factors which played a role in predicting the hygiene behaviour of mothers were the husbands' occupation, the number of health education sessions that she had attended, her zone of residence and family ownership of certain valuable objects. These factors are likely to be related and to be, to some extent, proxies for the real determinants of her behaviour. A model of the cultural, psycho-social and infrastructural proximate determinants of hygiene behaviour is proposed. Data from focus group discussions suggested that the main purpose of hygienic behaviour is to conform to existing norms of social etiquette. Trials of interventions based on changing such norms are needed to test whether this is an effective means of promoting of safer hygiene practices.

Objective: To investigate the association between where young children defecate, where stools are disposed of, and the presence of human stools on the ground in the compound and the rate of hospital admission with diarrhoea., Design: This was a case-control study with two control groups., Setting: The study took place in Bobo-Dioulasso, the second city of Burkina Faso in West Africa., Participants: Three groups of children aged 36 months and under, and living in Bobo-Dioulasso were studied. Cases were 757 children admitted to hospital with symptoms of diarrhoea or dysentery. The first control group comprised 757 neighbourhood control children approximately matched on age and date of recruitment, and the second, 631 children admitted to the same hospital without symptoms of diarrhoea or dysentery., Main Results: There was no evidence of any association between where the child was reported to defecate and hospital admission with diarrhoea or dysentery (odds ratio = 1.10; 95% confidence interval (CI) 0.78, 1.57, cases v neighbourhood controls; odds ratio = 0.84; 95% CI 0.60, 1.18, cases v hospital controls). There was evidence of an association between where the mother reported disposing of the child's stools and hospital admission with diarrhoea or dysentery (odds ratio = 1.50; 95% CI 1.09, 2.06, cases v neighbourhood controls; odds ratio = 1.31; 95% CI 0.96, 1.79, cases v hospital controls). Human stools were more frequently observed in the yards of cases than controls (odds ratio = 1.38; 95% CI 0.98, 1.95, cases compared with neighbourhood controls; odds ratio = 1.33; 95% CI 0.96, 1.84, cases compared with hospital controls)., Conclusions: The findings suggest that it is not where the child defecates that matters but how the mother then deals with the child's stools.

Background: Natural immunity to Haemophilus infection type b that is acquired by the mothers and passively transmitted to their newborns is not well-known in developing countries, where the frequency of Haemophilus meningitis in infancy is high., Population and Methods: Blood samples (5 ml) were taken from 89 women at the time of delivery and from the cord of their babies. Blood samples were also taken from 290 infants and children, distributed into nine subgroups as a function of their age. Children with protein-calorie malnutrition and immune deficiency were excluded from the study. Antibodies against Haemophilus influenzae were measured by Elisa and radioimmunologic methods. Blood concentrations of 0.15 pg/ml or more were considered to be protective., Results: All the blood samples of mothers and cords contained protective levels of antibodies, as did the samples from 30% of those infants aged 0-60 days (all the infants were less than 1 month). No infant in the subgroup 12-23 months had protective levels of antibodies. The incidence of Haemophilus meningitis was correlated with the absence of antibodies., Conclusion: Maternal immunity is gradually lost by babies during their first 2 months of life, earlier than in developed countries. Early vaccination, at 3 months of age, is mandatory.

The obstetrical referral patients admitted to the Sanon Souro hospital in Bobo-Dioulasso (Burkina Faso) during 1991 were retrospectively reviewed. During the study period 741 women were admitted. The median distance between the referring centre and Bobo-Dioulasso was 33 km. Median age was 22 years and median parity was 3. Indications for referral were dominated by obstructed labour, haemorrhages and infections. The proportion of maternal mortality in the study was 5.4% and was not related to maternal age or parity. However, there was a linear trend of increasing mortality according to the distance between the referring centre and Bobo-Dioulasso (X2 for trend: 7.56; p = 0.006). The perinatal mortality rate of 420 p. thousand was not related to maternal age, but a parity exceeding 4 was a risk factor for the occurrence of perinatal death (relative risk: 1.4; 95% C.I.: 1.2-1.7). As for maternal mortality, there was a linear increase of perinatal mortality with the distance from the referring centre (X2: 20.8; p = 0.00001). There was no marked seasonal variation in the number of referrals nor in the mortality rates per month.

The environmental and socioeconomic risk factors for preterm delivery were assessed in a West African urban population (Bobo-Dioulasso, Burkina Faso). The study population were 102 cases of preterm delivery matched with 102 controls obtained from 4124 sequential deliveries which occurred between May and October 1989 in the three maternity centres in the city. The univariate analysis identified the risk factors as age (< 20 years), primiparity, marital status (single), low frequency of antenatal visits, death of a previous child and level of education of the mother. The following risk factors identified by multivariate analysis (logistic regression) are consistent with those identified in previous studies: youth of the mother, primiparity (P = 0.01) and death of a previous child (P < 0.05). On the other hand, in this study, the level of education of the parent was identified as an independent risk factor (P < 0.001). This finding could be used to determine a target population for prevention programmes.

Objective: To define a clinical profile indicative of HIV infection in a population of severely malnourished children in Burkina Faso. A total of 433 children (average age, 19 months) were recruited at the Sanou Souro National Hospital, Bobo Dioulasso, Burkina Faso., Results: Sixty-three per cent presented with marasmus, 13% with kwashiorkor and 24% with both forms of malnutrition. The prevalence of HIV infection in children aged over 12 months was 13.8%, with a marked predominance of HIV-1 (95.8%). Mother-to-child transmission was proven in 77% of the cases; in 10% of the observed paediatric AIDS cases, transmission may have occurred through multi-injections with contaminated equipment. Marasmus was the form of malnutrition most frequently associated with HIV (P < 0.001); its severity was exacerbated by HIV infection. Adenopathy (P < 0.0001), oral candidiasis (P < 0.0006), skin disorders (P < 0.01) and hepatomegaly (P = 0.01) appeared to be significantly related to HIV infection. Discriminant analysis revealed that the presence of adenopathies was the strongest indicator symptom of HIV infection. Multivariate analysis revealed that a clinical profile of marasmus, adenopathies and oral candidiasis (specificity, 82%) was indicative of HIV infection in this population. The short-term clinical prognosis was poor and usually led to the death of the child when seropositive (P < 0.001)., Conclusions: Among children exhibiting severe malnutrition, HIV-positive children are distinguished by a high horizontal transmission rate, a high specific clinical profile and a very poor prognosis.

Reported are our findings from a case-control study of the association between prolonged breast-feeding and clinical malnutrition in an urban setting in West Africa. The cases were children aged 12-36 months who had been hospitalized with a diagnosis of clinical malnutrition. Children of a similar age who lived in neighbouring courtyards were recruited as controls. For 152 case-control pairs in which both children were receiving solid foods, non-breast-feeding was associated with an increased risk of clinical malnutrition (crude odds ratio = 2.37; 95% confidence interval = 1.24, 4.55). This association remained statistically significant after controlling for various potentially confounding variables (P = 0.03). Our findings suggest that either prolonged breast-feeding may offer substantial protection against clinical malnutrition in the study population or malnutrition leads mothers to stop breast-feeding. These results are inconsistent with those of a number of workers who have reported that prolonged breast-feeding is associated with an increased risk of malnutrition. This inconsistency might have arisen because of differences in the definition of malnutrition used or because of variations in the quantity and quality of weaning foods available in different settings. We found no evidence to support the hypothesis that prolonged breast-feeding may be detrimental to children.

A case control study was done in Bobo-Dioulasso (Burkina Faso) during a one year period (1989), to identify practices during the pregnancy and childbirth, environmental and sociocultural factors associated with the occurrence of neonatal tetanus.

From January 1986 through June 1987, 714 children with measles were admitted to the Pediatric Department of the Sanou Souro Hospital in Bobo-Dioulasso, Burkina-Faso. Eighty-four per cent of cases occurred during the first semester of 1987. Sixty per cent of patients were 9 to 35 months of age. The case-fatality rate was 29.1% (31.5% during the first semester of 1987, 12% in 1986). Fifty-five per cent of deaths occurred within 24 hours of admission. The most common clinical features upon admission included dehydration (91% of patients), diarrhea (64%), conjunctivitis (56%), fever in excess of 39.5 degrees C (50%), respiratory infection (46%), and cardiovascular collapse (34.5%). Factors associated with a fatal outcome included dehydration and cardiovascular collapse, poor nutritional status, and occurrence of the disease during the dry season (March, April, May). In most cases, immunization status of affected children was unknown. The high mortality rate can be ascribed to the significant delay with which medical care was provided, due in part to the inadequacy of primary health care facilities. This outbreak denotes the inadequacy of immunization against this disease that is included in the Extended Immunization Program.