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The mechanism through which the brain senses the metabolic state, enabling an animal to regulate food consumption, and discriminate between nutritional and non-nutritional foods is a fundamental question. Flies choose the sweeter non-nutritive sugar, L-glucose, over the nutritive D-glucose if they are not starved. However, under starvation conditions, they switch their preference to D-glucose, and this occurs independent of peripheral taste neurons. Here, we found that eliminating the TRPγ channel impairs the ability of starved flies to choose D-glucose. This food selection depends on trpγ expression in neurosecretory cells in the brain that express diuretic hormone 44 (DH44). Loss of trpγ increases feeding, alters the physiology of the crop, which is the fly stomach equivalent, and decreases intracellular sugars and glycogen levels. Moreover, survival of starved trpγ flies is reduced. Expression of trpγ in DH44 neurons reverses these deficits. These results highlight roles for TRPγ in coordinating feeding with the metabolic state through expression in DH44 neuroendocrine cells.

Primary visual cortex (V1) in the mouse projects to numerous brain areas, including several secondary visual areas, frontal cortex, and basal ganglia. While it has been demonstrated that optogenetic silencing of V1 strongly impairs visually guided behavior, it is not known which downstream areas are required for visual behaviors. Here we trained mice to perform a contrast-increment change detection task, for which substantial stimulus information is present in V1. Optogenetic silencing of visual responses in secondary visual areas revealed that their activity is required for even this simple visual task. In vivo electrophysiology showed that, although inhibiting secondary visual areas could produce some feedback effects in V1, the principal effect was profound suppression at the location of the optogenetic light. The results show that pathways through secondary visual areas are necessary for even simple visual behaviors.

Many cortical network models use recurrent coupling strong enough to require inhibition for stabilization. Yet it has been experimentally unclear whether inhibition-stabilized network (ISN) models describe cortical function well across areas and states. Here, we test several ISN predictions, including the counterintuitive (paradoxical) suppression of inhibitory firing in response to optogenetic inhibitory stimulation. We find clear evidence for ISN operation in mouse visual, somatosensory, and motor cortex. Simple two-population ISN models describe the data well and let us quantify coupling strength. Although some models predict a non-ISN to ISN transition with increasingly strong sensory stimuli, we find ISN effects without sensory stimulation and even during light anesthesia. Additionally, average paradoxical effects result only with transgenic, not viral, opsin expression in parvalbumin (PV)-positive neurons; theory and expression data show this is consistent with ISN operation. Taken together, these results show strong coupling and inhibition stabilization are common features of the cortex.

Objective: To examine whether maternal depressed mood at birth moderated the protective effect of a home-visiting intervention on the quality of caregiving for children growing up in a low- and middle-income country., Method: Almost all pregnant mothers in 24 Cape Town neighborhoods were recruited into a cluster randomized controlled trial matched by neighborhoods to the Philani home-visiting condition (HVC) or the standard care condition (SC). At 3 years after birth, the quality of mother-child interactions between HVC and SC mothers with and without antenatal depressed mood was assessed in a representative subset by rating videotaped observations of mother-child interactions on 10 dimensions of caregiving., Results: As predicted, maternal depressed mood at birth moderated the effect of the HVC on the quality of mother-child interactions. Among nondepressed mothers, mothers and their children in the HVC scored significantly higher on 5 of the 10 dimensions of the maternal-child interaction scale than mothers in the SC: mothers exhibited more maternal sensitivity, talked more, had more harmonious interactions, and had children who paid more attention and exhibited more positive affect. However, being in the HVC did not significantly affect the mother-child interaction scores among mothers with depressed mood. Among HVC children, those with mothers with depressed mood showed significantly less positive affect and talked less with their mothers than children with nondepressed mothers. SC children with mothers with depressed mood were more responsive and paid attention to their mothers than children with nondepressed mothers., Conclusion: Home visiting resulted in a better quality of caregiving for mothers without depressive symptoms. Future interventions need to specifically target maternal depression and positive mother-child interactions., Clinical Trial Registration Information: Mentor Mothers: A Sustainable Family Intervention in South African Townships; https://clinicaltrials.gov; NCT00972699; Philani Home-based Nutrition Intervention Program; https://clinicaltrials.gov; NCT00995592., (Copyright © 2019 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.)

Serologic markers of hepatitis B virus (HBV) infection were measured in children from Manduar and Keneba, two adjacent villages in The Gambia, in 1980 and in 1984. The rate of HBV infection over the 4 years differed markedly: in Manduar 71% of children who were less than 5 years of age in 1980 became infected, whereas in Keneba only 37% became infected. Male children were more frequent carriers of either HBs or e antigen than were female children. Marked clustering of hepatitis B surface antigen (HBsAg) antigenemia within sibling relationships was shown in both villages. The chance of the youngest child in a household being a carrier of HBsAg was strongly related to the number of antigen-positive siblings. Four years later, 53% of children who were initially positive for HBsAg and 33% who were positive for hepatitis B e antigen still carried these antigens. Jaundice was not observed.

Mortality and morbidity in children under 5 years of age were measured in 41 villages and hamlets in a rural area of The Gambia for a 1-year period before and for a 3-year period after the introduction of a primary health care (PHC) programme into 15 of the larger villages in the area. Both infant mortality and child mortality rates fell during the post-intervention period but declines were similar in PHC and in non-PHC villages suggesting that factors such as an up-grading of the Farafenni dispensary, improvements in transport and the survey itself may have played an important part in bringing about these changes. Measurements of morbidity showed a lower prevalence of diarrhoea, vomiting or severe cough in PHC villages after the introduction of the PHC programme. Introduction of the PHC programme had no significant effect on nutritional status or on vaccine coverage. Significant improvements in the health of children in the Farafenni study area have taken place during the past 5 years but the PHC programme is probably only one of the factors that have brought about these changes.

In 1983 a primary health care (PHC) programme was introduced into the Farafenni area of The Gambia; an important component of this programme was the identification and training of a traditional birth attendant (TBA) in each village with a population of 400 or greater. The outcome of pregnancy has been documented among women resident in 15 villages which joined the PHC programme and in 26 which were too small to do so, for 1 year before and for 3 years after the start of the programme. In PHC villages 65% of women were assisted at delivery by a trained TBA during the post-implementation period and the proportion of women who delivered in a hospital or health centre increased. Both maternal and neonatal death rates fell in PHC villages during the post-intervention period, declining to about half the levels recorded during pre-intervention surveys during the last year of the study. In non-PHC villages there was also a fall in the maternal death rate but little change in the neonatal death rate. Trained traditional birth attendants probably played some part in improving the outcome of pregnancy in the Farafenni area but other factors, such as improvements in transport, may also have contributed.

The nutrition of a group of Nigerian children who received weekly chemoprophylaxis with chloroquine during their first one or two years of life was compared with the nutrition of a group of children exposed frequently to malaria. Fewer episodes of severe malnutrition and fewer deaths from malnutrition occurred among protected than among control children. Protected children tended to be taller and heavier than control children and to have a larger mid-upper arm circumference. Mean serum albumin and pre-albumin levels were higher in protected than in control children. However differences between the two groups were small and only in a few instances were they statistically significant.

The antibody response to group C meningococcal polysaccharide vaccine was studied in a Nigerian village. Household clustering of poor responders to immunization was detected. Age had a marked effect on antibody response, maximal titres being obtained only in those over the age of 10 years. Children with malaria parasitaemia had a lower antibody response than those without parasitaemia and subjects with the genotype AA had a lower antibody response than those with the genotype AS. The antibody response to the vaccine was not influenced by mild degrees of malnutrition but children with clinical marasmus or kwashiorkor were excluded from the study.

Mortality from meningococcal disease was determined during an epidemic in a rural area of The Gambia with few medical resources, but where a system of registration of births and deaths had been established before the introduction of a primary health care programme. 33 deaths were recorded among 127 patients, a case mortality rate of 26%. 84% of deaths occurred within the first 24 h of illness and many patients died before they could reach any source of treatment. Previous studies, based on regional statistics or on hospital series, may have underestimated mortality from epidemic meningitis in Africa. Mortality from this infection will be reduced only if treatment can be made readily accessible to patients early in the course of their illness.

A survey of deaths in children under the age of 7 years was made over a 1-year period in a rural area of The Gambia with few facilities for curative medicine but with a good record of infant immunizations. One hundred and eighty-four deaths were investigated. Only 12% of deaths occurred in a hospital or health centre but an attempt was made to establish a cause of death by interviewing the family of each dead child and by examining any health records that were available. The infant mortality rate was 142 per 1000 live births and the child mortality rate (death in children aged 1-4 years) 43 per 1000 per year. Acute respiratory infections, malaria and chronic diarrhoea with marasmus were the most frequent causes of death after the 1st month of life. Few children died of diseases that could have been prevented by routine immunizations. An effective immunization programme has probably had some effect on deaths in infancy and early childhood but it will be necessary to find ways of preventing deaths from malaria, acute respiratory infections and chronic diarrhoea/marasmus at the primary health care level if infant and childhood mortality are to be reduced further in rural areas of The Gambia.

The immune response of 198 young Nigerian children protected against malaria by chemoprophylaxis with chloroquine to immunization with triple, poliomyelitis, measles, typhoid, meningococcal and BCG vaccines was compared with the immune response to vaccination of 185 control children. Good responses to triple, measles and BCG vaccines were shown by children in both groups; poorer responses were obtained to poliomyelitis, typhoid and meningococcal vaccines. The response to immunization of protected children was similar to that observed among control children for all the vaccines tested except for meningococcal polysaccharide vaccine. Protected children showed a significantly greater antibody response to both group A and group C meningococcal polysaccharides than control children. This finding supports the results of previous studies which have shown that the immune response to meningococcal polysaccharide vaccines is adversely affected both by acute malaria and by asymptomatic malaria parasitaemia.

Audiological and other long-term neurological sequelae were determined in 157 cases and their controls matched for age, sex and village 6 to 12 months after an epidemic of group A meningococcal meningitis in rural West Africa. 19 cases (12.1%) and 3 controls (1.9%) had moderate or severe neurological sequelae of any type (P less than 0.001); 6 cases (3.9%) and no controls had severe or profound sensorineural hearing loss (P = 0.03). There was no difference in conductive hearing loss between cases and controls. Other cranial nerve sequelae (except visual defects) and generalized neurological and motor and co-ordination sequelae were also significantly increased in cases. Sensorineural hearing loss and other cranial nerve sequelae occurred significantly more frequently in males than in females, and co-ordination sequelae more frequently in cases aged 10 years or more than in younger cases. Sensorineural hearing loss and loss of visual acuity were found significantly more frequently in cases whose treatment was delayed for 4 d or more, compared with those who received treatment sooner.

Two drug strategies for the control of malaria in children aged 3-59 months have been compared in a rural area of The Gambia--treatment of presumptive episodes of clinical malaria with chloroquine by village health workers, and treatment combined with fortnightly chemoprophylaxis with 'Maloprim' (pyrimethamine/dapsone) which was also given by village health workers. Treatment alone did not have any significant effect on mortality or morbidity from malaria. In contrast, treatment and chemoprophylaxis reduced overall mortality in children aged 1-4 years, mortality from probable malaria, and episodes of fever associated with malaria parasitaemia. A high level of compliance with chemoprophylaxis was obtained and no harmful consequences of chemoprophylaxis were observed.

Fishing, bathing, swimming and playing in water were the most important activities at the Ruwan Sanyi dam site, northern Nigeria, in terms of schistosomiasis transmission. Various washing activities were important in exposure to the infection. Males were responsible for 98% of activity involving contamination and exposure. This accounted for the marked male predominance of Schitosoma haematobium infection in the Muslim communities of this area, where boys under the age of 21 years were responsible for more than 77% of environmental egg contamination. Peak water-contact activity occurred in the afternoon and this coincided with the peak cercarial shedding period and the peak urinary egg output. As a result of the construction of many such dams in this part of northern Nigeria, the recent upward trend in schistosomiasis tramission is likely to be maintained. Fishing is a new and a potentially important activity in transmission. Any future programme to control urinary schistosomiasis in this area should pay particular attention to this activity as well as group swimming activity by young males, who should be the prime target.

In 1977 Zaria, in Northern Nigeria, was affected by a severe epidemic of group A meningococcal infection, 1,257 patients being admitted to hospital with the disease during a three-month period. The epidemic started towards the end of the dry season when it was hot, dry and dusty and finished shortly after the onset of the rains. The over-all attack rate was 3.6 per 1,000 but this varied considerably from area to area within the town. Few cases occurred amongst those belonging to the upper social classes. The disease was seen most frequently amongst those from five to 14 years old and there was a strong male preponderance. The over-all mortality was 8.3% but mortality was much higher (40.6%) amongst 67 patients with acute meningococcaemia.

A comparison has been made of Lapudrine (chlorproguanil) and Maloprim (pyrimethamine +dapsone) as malaria chemoprophylactics when given every two weeks for 3 years to Gambian children under the age of 5 years. Both drugs produced falls in spleen and malaria parasite rates and an increase in packed cell volume. Maloprim, but not chlorproguanil, significantly reduced the incidence of episodes of fever accompanied by malaria parasitaemia. Children who received Maloprim, but not those who received chlorproguanil, grew better than children in the placebo group. This finding suggests that brief clinical episodes of malaria are more important in impairing growth than more prolonged periods of asymptomatic parasitaemia. No serious side-effect attributable to either drug was observed. After chemoprophylaxis had been given for 3 malaria transmission seasons the level of resistance of Plasmodium falciparum to pyrimethamine and to chlorproguanil was about 10%.

Haematological measurements were made in 198 Nigerian children aged three months to two years who received weekly malaria chemoprophylaxis with chloroquine from shortly after birth until the age of one or two years and in 185 age-matched control children. Children protected against malaria had a higher mean haemoglobin level and a higher packed cell volume than control children, and they showed fewer abnormalities of their red cells. Total and differential white blood cell counts, mean plasma folate and mean serum ferritin concentrations were similar in both groups of children. However, the geometric mean red cell folate level of children exposed to malaria was significantly higher than the mean level of control children; and it may be that malaria raises the red cell folate through intracellular synthesis by malaria parasites. Children with malaria parasitaemia had a significantly lower haemoglobin and packed cell volume and a significantly higher geometric mean red cell folate and ferritin level than children without parasitaemia. Serum ferritin is probably an unreliable index of iron status in children with malaria.

One hundred and ninety-eight Nigerian children who received weekly chemoprophylaxis with chloroquine from shortly after birth until the age of one year or two years and 185 age-matched controls were studied. Chemoprophylaxis with chloroquine was partially, but not completely, effective in controlling malaria. Clinical malaria was documented significantly less frequently in protected children than in control children, and only 9% of random blood films obtained from protected children were positive for Plasmodium falciparum while 41% of random blood films from control children were positive for this parasite. Mean malaria antibody levels were lower in protected than in control children; for ELISA and precipitin antibodies the difference between the two groups was less marked at two years than at one year. Mortality was similar among protected and among control children. No rebound mortality or morbidity was observed after chemoprophylaxis was stopped.

The epidemiology of infection due to Neisseria meningitidis and Neisseria lactamica was studied in a northern Nigerian community. A low meningococcal carriage rate was observed throughout the two-year survey. Initially, most meningococci isolated from nasopharyngeal carriers belonged to serogroup C or to serogroup Y. Following an outbreak of group A meningococcal disease, more group A meningococcal carriers were detected. Antibody studies indicated that infection with group A meningococci had been more widespread in the community than was suggested by regular carrier surveys. Carriage of meningococci was detected most frequently in children one to nine years of age. Children were identified as the first carriers in households more frequently than adults. The half-life of carriage was three months. The meningococcal carriage rate did not increase during the hot dry season when epidemics of meningococcal disease occur most frequently in Nigeria. Neisseria lactamica was isolated from the nasopharynx of children more frequently than were meningococci.

For 228 of 425 deaths (54%) occurring among 26 100 people of known age in the Malumfashi area of northern Nigeria, data were collected on symptoms present prior to death. Information was obtained on monthly registration visits, as part of demographic investigations, and data for the period November 1977-October 1978 have been analysed. Enumerators used a carefully prepared list of 25 symptoms to elicit information from relatives of the deceased. Pyrexia, diarrhoea and measles accounted for 77% of all deaths. Epidemiological determinants were responsible for all cases of meningococcal infections in the dry season and most cases of diarrhoea in the wet season. Most deaths attributed to measles occurred in the late dry season and early wet season. Epidemics of measles seemed to be localized at any one time in certain villages and the micro-epidemiology of this feature is considered. Malaria does not appear to be responsible for all deaths from pyrexia in the nought to four age group.

This paper considers some of the procedures used and problems encountered in the collection of demographic data for a large-scale medical project: the Endemic Diseases Research Project at Malumfashi in northern Nigeria, 1974-1979. 43,216 people were enumerated and a subset of 26,100 were visited monthly for one year for the purpose of registration of vital events. The majority of problems encountered are relevant to similar studies in developing countries. Some difficulties cannot be avoided, but it is considered helpful to identify them. Other situations, however, deserve particular attention, such as the development of adequate on-site data-checking mechanisms, as these are areas in which future programmes could benefit from the experience of the demographic studies in Malumfashi. More effort still needs to be put into the improvement of data collection methods themselves.

A combined group A and group C meningococcal polysaccharide vaccine was given to 438 Nigerian schoolboys shortly before an outbreak of group A meningococcal disease occurred in their school. Four months after vaccination the carriage rate of group A meningococci among vaccinated subjects (11%) was no different from that found among the controls (12%), although a good antibody response to both components of the vaccine was observed. One case of group A meningococcal disease was recorded amongst 438 vaccinated subjects while five cases occurred among 874 controls.

1. Children aged 6-35 months in an urban community in The Gambia, West Africa, were weighed and their lengths measured at four surveys over an 18-month period, twice towards the end of the rains, and twice during the dry season. 2. Relative to international standards, height-for-age deteriorated steadily with age, while weight-for-age fell sharply in the second-half of infancy but showed no further deterioration from 12 to 35 months of age. 3. Height-for-age showed little seasonal variation, but weight-for-age and weight-for-height were lower at the end of the rains than during the dry season. Weight and height velocities were much lower during the rains than in the dry season, with more than 20% of the children losing weight during the rains. Possible reasons for these seasonal variations are discussed. Compensatory weight gain in the dry season exceeded the velocity expected from the standards in children aged 12 months or more, but height velocity fell below the standards all year. 4. The results are compared with previous findings from Keneba, a rural Gambian village. Weight velocity during the dry season was similar in the two communities, but the village children experienced a sharper decline in weight gain during the rains. 5. These results suggest that seasonal ecological factors may seriously influence the nutritional status of children living in an urban environment with adequate availability of food.

Significant variations in the prevalence of splenomegaly were found among members of the three main ethnic groups resident in North Bank Division, The Gambia. Among young children splenomegaly and malaria were less prevalent in Mandinkas than in Wollofs or Fulas, suggesting that some genetic or environmental factors protect Mandinka children from this infection. Among older children and adults splenomegaly was found most frequently in Fulas. Six of 22 adults with very large spleens had a high serum IgM level and probably had the hyperreactive malarial splenomegaly (tropical splenomegaly) syndrome. Four of these six subjects were Fulas. This finding, together with the results of a previous study in Nigeria, suggest that Fulas have a predisposition to this condition.

The prevalence of hepatitis B virus infection was markedly different in two neighbouring Gambian villages. 62% of children in Manduar aged 2-4 years were infected whereas in Keneba, the other village, only 27% of this age-group were infected. However, in both villages few infants were infected--none under 6 months of age and only 2 of 58 between the ages of 6 and 12 months. Carriage of hepatitis B surface antigen (HBsAg) was high, reaching a peak of 36% in the 5-9 age-group in Manduar and 17.6% in the 2-4 age-group in Keneba. 86% of all the children under the age of five who were HBsAg-positive also carried hepatitis B e antigen (HBeAg). This proportion fell to 17.6% for children aged 10-14 years and to 12.9% for mothers. Infection clustered in families, transmission from sib to sib being of major importance. The chances of a child being an HBsAg carrier were approximately 42% if an elder sib carried the antigen, 27% if either mother or father was a carrier, and 15% if neither mother or father was a carrier. There were 4 HBeAg-positive mothers who were highly infectious, since 10 of 11 of their children became HBsAg carriers. Carriage of surface antigen lasted many years; 63% of those carrying the antigen in 1972 were still positive in late 1980. 4 cases of primary hepatocellular carcinoma out of 672 adults have been diagnosed in the past five years. All 4 were in HBsAg carriers.

A study was made of factors that influenced susceptibility to group A meningococcal disease during an epidemic that affected The Gambia, West Africa during the dry season of 1982-83. No explanations were found for the distribution of cases between villages or within affected villages. Socio-economic status, crowding, nutrition and previous exposure to meningococcal disease all appeared to be unimportant. Examination of serum samples obtained before the outbreak from a few children who subsequently became patients and from an equal number of age-matched controls from the same village showed a higher mean serum IgA value in children who became patients than in controls. There were not, however, any significant differences found in the concentrations of IgG, IgM, complement or meningococcal antibody between the two groups. Four children who developed culture-proven group A meningococcal disease had raised titres of bactericidal antibody to the epidemic strain 2-3 months before their illnesses. Our findings suggest that some important risk factors for group A meningococcal disease remain to be identified.

A study was undertaken in the Farafenni area of The Gambia to determine the relation between morbidity from malaria in children and the use of bed-nets (mosquito-nets). From comparisons of parasite and spleen rates in bed-net users and in non-users it seemed that bed-nets had a strong protective effect. However, the prevalence of malaria in the study population was also influenced by ethnic group and place of residence, and the association of bed-net use with these two confounding factors accounted for some of the differences observed between bed-net users and non-users. Nevertheless, a significant inverse correlation between splenomegaly and the use of bed-nets remained. This suggests that bed-nets give Gambian children some protection against malaria and that the use of bed-nets, either untreated or treated with an insecticide such as permethrin, should be investigated further as a means of malaria control in Africa.

A five-year malaria chemoprophylaxis study has begun with Maloprim in children aged three months to five years and pregnant women in a population of 13,000 in the area of Farafenni, The Gambia. Sensitivity of Plasmodium falciparum to pyrimethamine, Maloprim and chloroquine was assessed in vivo and in vitro in rural Gambian villages before drug intervention. 569 children aged one to seven years inclusive were sampled at the end of the wet season of 1982; 46% had positive blood films. All afebrile children were treated with a single dose of one of the antimalarials under study. Febrile children were treated with chloroquine. 109 infected children were retested 7 to 10 days after treatment and none showed asexual parasitaemia. 83 micro in vitro tests were successfully performed from fingerprick blood samples and the results confirmed the in vivo study. Pyrimethamine in combination with dapsone, in the proportion present in Maloprim, i.e., 1:8, showed a synergistic effect, the mean effective dose of pyrimethamine being reduced 13 times at the 50% inhibitory level.

The faecal microflora of breast-fed infants, weaned children and adults has been examined in rural Nigeria and urban U.K. Breast-fed infants had a similar anaerobic flora dominated by bifidobacteria but bacteroides were isolated in less than a quarter of either community. Weaned children in both communities had greater numbers of bacteroides and clostridia than breast-fed infants. Even higher numbers of bacteroides and clostridia were present in U.K. adults but not in Nigerian adults. Numbers of bacteroides and clostridia were greater in a group of Nigerian infants drinking cow's milk than those receiving breast milk alone and lower in a group of weaned children with diarrhoea compared with uninfected subjects.

Eight lowland villages in which onchocerciasis is hyperendemic are compared with two upland (low prevalence) control villages in the middle Hawal valley, Nigeria. Detailed demographic data from the hyperendemic villages and from the control villages are analysed. The population was found to be more mobile in the lowland zone, which is also the zone of village desertion. Variables influencing the probability of village abandonment are discussed. It is suggested that onchocerciasis is only a part of a complex of desertion, though probably the most important single element. Particularly in association with remoteness, itself related to onchocerciasis and its troublesome vector, onchocerciasis has been instrumental in depopulating riverain areas and continues to perpetuate their unattractiveness.

Haematological indices and red cell folate levels (RCF) were measured during two annual surveys in a group of Gambian children aged 3 months-5 years who were participating in a trial of malaria chemoprophylaxis with Maloprim or chlorproguanil given with or without folate supplements. Chlorproguanil was given in an adult dose of 20 mg, Maloprim as one quarter or one half of the adult dose of 25 mg pyrimethamine and 100 mg dapsone. Antimalarials and folate supplements were given fortnightly. About 20% of children had low RCF levels (less than 100 ng/ml). Among children who did not receive supplementation with folate there were no significant differences in mean RCF levels between children who received Maloprim, chlorproguanil or placebo. Among children who received folate supplements, the mean RCF was significantly lower among those receiving chlorproguanil than among the controls. Mean RCF values were similar in children who received Maloprim or placebo. If chlorproguanil is used for malaria chemoprophylaxis in young children an age-related dose should be used.

The incidence of meningococcal disease varies seasonally in both tropical and temperate countries. This association is most apparent in sub- Saharan Africa, where almost all epidemics start in the dry season and abate during the rains . Meningococcal carriage rates do not vary with season either in Africa or in temperate countries, suggesting that seasonal factors have little influence on the frequency of meningococcal transmission. It is suggested that changes in the ratio of clinical to subclinical cases of infection are more important than changes in the frequency of transmission in producing seasonal variations in the incidence of meningococcal disease. Some evidence to support this hypothesis was obtained during an epidemic of group A meningococcal disease in northern Nigeria in 1977-79.

A high incidence of protein energy malnutrition (PEM) was found in a community survey of preschool children in rural northern Nigeria among whom gastro-enteritis is common. Wasting (less than 80% Weight/Height) was more common (37.9%) among those with scanty, unprotected water supplies than in those with copious protected water (10.2%) whereas the incidence of stunting (less than 90% Height/Age)) was similar. Severe coliform contaminatin of all water sources was demonstrable. Even higher numbers of coliforms in foods sampled suggests that other factors related to water supply may be more important than water purity in the genesis of the PEM/gastro-enteritis complex.

Plasmodium falciparum and P. malariae were found less frequently in blood obtained from Nigerian children under the age of two years who had the haemoglobin genotype AS than in blood films obtained from those who had the genotype AA. However, differences between the two groups were statistically significant only for P. falciparum asexual forms. The prevalence of malaria antibodies, as measured by an ELISA, did not differ significantly between the two groups.

The immune response of young Nigerian children to a full course of infant immunizations was studied in relation to their nutritional state at the time of vaccination. No significant correlations were found between anthropometric measurements made at the time of vaccination and the antibody response to triple, polio, measles, meningococcal and typhoid vaccines. Significant correlations were found between serum pre-albumin levels and the response to group A meningococcal polysaccharide vaccine and between serum albumin levels and the response to group C meningococcal polysaccharide vaccine. These correlations may reflect the depressive effect of malaria both on serum albumin and pre-albumin levels and on immune responsiveness to meningococcal polysaccharides. No significant correlations were found between nutritional state at the time of BCG vaccination and the development of a positive tuberculin reaction five weeks later. We conclude that under-nutrition has little or no effect on the immune response to vaccines used in routine infant immunization programmes.