Safety and immunogenicity of three doses of a Neisseria meningitidis A + C diphtheria conjugate vaccine in infants from Niger.

BACKGROUND: High rates of endemic disease and recurrent epidemics of serogroup A and C meningococcal meningitis continue to occur in sub-Saharan Africa. A meningococcal A + C polysaccharide diphtheria-toxoid-conjugated vaccine may address this issue. METHODS: In Niger three doses of a bivalent meningococcal A + C diphtheria-toxoid-conjugated vaccine (MenD), containing 1, 4 or 16 microg of each polysaccharide per dose, administered at 6, 10 and 14 weeks of age, were compared with Haemophilus influenzae type b-tetanus toxoid-conjugated (PRP-T) vaccine given with the same schedule or with a meningococcal A + C polysaccharide vaccine (MenPS) given at 10 and 14 weeks of age. One blood sample was taken at the time of enrollment (6 weeks of age) and another was taken 4 weeks after the primary series. RESULTS: All doses of MenD were well-tolerated. After the primary series a higher proportion of infants had detectable serum bactericidal activity against serogroup A for each dose of MenD (from 94% to 100%) than for MenPS (31%) or H. influenzae type b-tetanus toxoid-conjugated vaccine (18.9%); P < or = 0.05. Significant differences were also observed for serogroup C MenD 4 microg or MenD 16 microg (100%) vs. MenPS (69.7%) or Haemophilus influenzae type b-tetanus toxoid-conjugated vaccine (24.3%); P < or = 0.05. When MenPS vaccine was given to 11-month-old children, the immune response measured by both enzyme-linked immunosorbent assay and serum bactericidal assay was greater in those previously immunized with MenD than in those immunized with MenPS vaccine. CONCLUSION: MenD was safe among infants in Niger, and immunization led to significantly greater functional antibody activity than with MenPS. The 4-microg dose of MenD for both the A and C serogroups has been selected for further studies.

Response to conjugate Haemophilus influenzae B vaccine among infants in Niamey, Niger.

Despite near elimination of Haemophilus influenzae b (Hib) meningitis from several industrialized countries following introduction of conjugate Hib vaccines into infant immunization schedules, Hib remains a major cause of meningitis and pneumonia in resource-poor countries. In Niger, Hib causes nearly 200 cases of meningitis per 100,000 children < one year of age, and > 40% of cases are fatal. We evaluated the immunogenicity of Hib polysaccharide-tetanus toxoid conjugate vaccine (PRP-T) administered in the same syringe as diphtheria-tetanus-pertussis (DTP) vaccine among infants in Niger. Infants were randomized into group 1 (PRP-T at six, 10, and 14 weeks), group 2 (PRP-T at 10 and 14 weeks), or a control group (meningococcal A/C polysaccharide vaccine). By 14 weeks of age, all subjects in groups land 2 had > or = 0.15 microg/ml of anti-PRP antibody, and 82% versus 76% had > or = 1.0 microg/ml of antibody (P=not significant). By nine months of age the proportion of infants with > or = 0.15 and > or = 1.0 microg/ml was group I=97% and 76%; group 2=93% and 67%; controls=10% and 2.6%. Four weeks after the first, second, and third doses of PRP-T, infants in group 1 showed geometric mean titers (GMTs) of 0.19, 3.97, and 6.09 microg/ml while infants in group 2 had GMTs of 2.40 and 4.41 microg/ml four weeks after the delayed first and second doses. Both PRP-T groups had significantly higher GMTs at 18 weeks and nine months of age than infants in the control group. The Hib PRP-T vaccine was immunogenic in infants in Niger. The strong response after PRP-T was initiated one month after the first DTP vaccination may reflect carrier priming. Two dose schedules of PRP-T should be given serious consideration, particularly if their reduced cost permits vaccine introduction that would be otherwise unaffordable.

Successful treatment of a high-grade intraepithelial neoplasia with imiquimod, with vulvar pemphigus as a side effect.

Imiquimod modulates the immune response, and is a new approach for treatment of papillomavirus-associated lesions, although it has not been approved for the treatment of intraepithelial neoplasia. We present a case of a patient treated with imiquimod on account of high-grade intraepithelial neoplasia in the vulva and other locations. The posterior biopsies confirm the absence of lesions but show drug-induced pemphigus as a side effect.

Benign intracardiac teratoma detected prenatally. Case report and review of the literature.

Primary cardiac tumors are rare and, until recently, were mostly incidental postmortem findings. Nowadays, due to the widespread use of prenatal ultrasound scans, we are able to diagnose them in utero. We present a case of an intracardiac teratoma diagnosed at 38 weeks, menstrual age. Previous scans had been normal. Labor was induced, and a female infant with an Apgar score of 9 and 4, at 1 and 5 min, was delivered. Her condition worsened rapidly. She died 16 h after birth. Necropsy was performed, and a cystic, mature teratoma of 4 cm was found in the interventricular septum, growing into the right ventricle. No other anomalies were found. This probably represents the first case of an intracardiac, benign teratoma diagnosed prenatally.

[Epidemiology and control of bacterial meningitis in children less than 1 year in Niamey (Niger)]. / Epidémiologie et contrôle des méningites bactériennes chez les enfants de moins d'un an à Niamey (Niger).

A bacteriological and epidemiological study of bacterial meningitis occurring in infants under one year of age was performed from September 1981 to June 1997 in Niamey, a city of 575,000 residents, located within the African meningitis belt. Cases of meningitis were defined either by culture of the cerebrospinal fluid (CSF), specific antigen agglutination, staining or cell counts of the CSF. Over the 16 years involving both epidemic and non epidemic periods, 1,481 infant's CSF were analysed, representing 20% out of the total CSF samples. The average of annual incidence rates was 511.4 cases per 100,000 infants under one year. Haemophilus influenzae b represented 35.1% of the cases, Streptococcus pneumoniae 26.3% and Neisseria meningitidis 17.6%. The other bacteria represented 5.5% and, for 15.5% out of the analysed CSF, the causative agent was not identified. The average annual mortality rate was 146.9 deaths for 100,000 infants under one year. The specific case fatality rates were 43% for H. influenzae b, 58.9% for S. pneumoniae and 17.8% for N. meningitidis. This study showed that in Niamey, as in the rest of the meningitis belt, S. pneumoniae and H. influenzae b were the main causes of bacterial meningitis occurring in infants under one year. However, the specific incidence of N1 meningitidis was identical for every age group between 0 and 20 years, and varied from 45 per 100,000 during non epidemic year to 550 per 100,000 during epidemic year. Immunisation with conjugate vaccines, particularly anti-Haemophilus vaccine appears to be the best preventive measure. The systematic use of ceftriaxone in infants, during meningococcal meningitis either epidemics or not, is highly recommended.

[Significance of rapid evaluation indicators during the monitoring of graduated treatment against Schistosoma haematobium]. / Intérêt des indicateurs d'évaluation rapide au cours de la surveillance d'un traitement à large échelle contre Schistosoma haematobium.

In the course of a large-scale treatment programme for the control of schistosomiasis in Niger, the authors evaluated the capacity of rapid assessment indicators to determine the impact of praziquantel on morbidity, as well as the moment when the renewal of treatment is required. In 10 villages belonging to 5 different irrigated project areas, the macroscopic aspect of urine from all children was followed during a control programme (before mass treatment and three years after intervention) and compared to the results of examinations performed simultaneously in pupils of the same age (7-15 years) from schools of the same villages. In these sentinel schools, parasitological (oviuria), clinical (macroscopic aspect of urine and microhaematuria) and ultrasonographic indicators were able to measure the level of endemia before treatment, the impact of the treatment and the evolution of both the prevalence and the morbidity during the three years following the treatment. Rapid assessment indicators, and in particular macroscopic aspect of urine: cloudy urine as versus bloody urine, clearly reflected the evolution of parasitological and ultrasonographic indicators after treatment with praziquantel. Cloudy urine indicated the prevalence of infection, while bloody urine indicated the morbidity due to S. haematobium. The agreement of results obtained in sentinel schools and village children made it possible to organise a surveillance system using these rapid assessment indicators in an area endemic for S. haematobium. Likewise, the control programme and the moment for treatment renewal can now be monitored.

[Long-term impact of a mass treatment by praziquantel on morbidity due to Schistosoma haematobium in two hyperendemic villages of Niger]. / Evaluation à long-terme d'un traitement de masse par praziquantel sur la morbidité due à Schistosoma haema- tobium dans deux villages hyper-endémiques du Niger.

Although it is established that the treatment by praziquantel reduces the urinary lesions due to Schistosoma haematobium, the frequency of mass treatment necessary to maintain a low morbidity level remains poorly known. The objective of this work was to study the impact over three years of a single praziquantel mass treatment on schistosomiasis morbidity in two different systems of disease transmission in Niger. The study was performed in 2 villages hyperendemic for schistosomiasis in the South-West of Niger presenting respectively 2 different systems of schistosomiasis transmission: Koutoukalé-Zéno (K Zéno), located close to an irrigated area of the Niger River Valley where the transmission is permanent, and Téguey located along a temporary pond where the transmission is seasonal. After the initial evaluation (1994), we carried out a survey 3 years later (1997) except in K. Zéno where an intermediate evaluation was performed 10 months after the initial survey (1995). Approximately 300 randomised people have been examined as follows: macroscopic examination of urine and reagent sticks for macro- and micro-haematuria, filtration and microscopic examination of urine for Schistosoma eggs, and ultrasound scan of the urinary tract for morbidity. The therapeutic coverage has reached 69.9% in K. Zéno and 78.2% in Téguey. The prevalence of infestation decreased from 74.1% to 56.4 % in K. Zéno (p < 0.001) and from 65.3% to 30.4% in Téguey (p < 0.001) at the end of the 3 years. The prevalence of heavy infestation (eggs > or = 50) went in the same time from 9.9% to 12.8% (p = 0.3) in K. Zéno and from 9.1% to 3.3% in Téguey (p = 0.01). Using ultrasound scan, the prevalence of the bladder lesions reached its previous level in both villages. However the prevalence of hydronephrosis decreased from 21.1% to 3.9% in K. éno (p < 0.001) and from 12.6% to 4.2% in Téguey (p < 0.001). Three years after the single mass treatment, the morbidity did not reach the initial level. The effectiveness of the treatment is better in the pond system where the transmission is seasonal. The lesions of the upper tract decreased more slowly than the bladder lesions, but a long time after the treatment. The re-infestation induced the re-appearance of the bladder lesions sooner than the lesions of the upper tract. The periodicity of the treatment should be variable according to the transmission system. It should occur every 2 years in irrigated areas and could be delayed (3 years) in temporary ponds. The control was beneficial in the pond system and induced a significant reduction of the severe lesions.

[Schistosomiasis in the region of Ziga (Burkina Faso) before the construction of a dam]. / Les schistosomoses dans la région de Ziga (Burkina Faso) avant la construction du barrage.

The authors report the results of a survey on schistosomiasis in the zone of Ziga (Burkina Faso) where a dam is going to be built. They examined 438 children aged from 7 to 15 years in 5 villages. The appraisal of macroscopic or microscopic hematuria, urine filtration, stool analysis and ultrasonographic examination made possible the assessment of the prevalence and severity of both schistosomiasis. The area was hyperendemic for urinary schistosomiasis. The general prevalence of S. haematobium was higher than 46% and 55% of the children presented at least one lesion of the bladder and 2% of hydronephrosis at ultrasonography. Intestinal schistosomiasis was not observed although few cases have been described in the regional hospital and intermediate host snails have been collected in the area. A surveillance of schistosomiasis, based on school surveys, was strongly recommended in the dam area.

[Intestinal parasitic diseases in an urban environment in Sahel. A study in a district of Niamey, Niger]. / Les parasitoses intestinales dans l'environnement urbain au Sahel. Etude dans un quartier de Niamey, Niger.

Health and environment in Niamey, a capital in Sahel, are particularly linked owing to population growth, promiscuity and large pollution induced by human and animal excreta. One district, located in the centre of the town, was surveyed for drinking water quality (ammoniac and bacterial count) and use, as well as for the prevalence of parasites through both a random sample (fixed tools with methiolate-iodine-formaldehyde) and a systematic one (scotch-test). Water consumption was 16.5 litres/day/man from fresh water supplies (87%) and private wells (13%). Ammoniac measures were low in the wells but high in running water (pool and river). It was the same for faecal coliform bacteria. These results give evidence of biotope faecal pollution. The random sample (322 persons, male/female sex ratio 0,85, average age 20,6 years) showed a 42.1% parasitic prevalence. Amoeba was the most frequent parasite (53.6%); and Giardia (14.9%) was the most frequent pathogenic parasite. In the second sample (161 children under 10 years), 24.2% were carriers of oxyuris. This large intestinal parasitism, without any change in connection with previous data in Niger, points to an important fecal contamination of the people more by the way of "dirty hands" than consumption of drinking water. The parasites observed have a short biological cycle, not necessitating long-term maturation in the environment. Those whose ova or larvae must complete their cycle outside have no possibility of surviving in Sahel, thanks to the beneficial effect of sunlight (heat and ultraviolet light). The inhabitants of this district seem to have adapted to intestinal parasitism. But the occurrence of malnutrition linked to a new drought could lead rapidly to a very serious adverse result.

[Pharyngeal carriage of Neisseria meningitidis in a school of Niamey, Niger]. / Portage rhino-pharyngé de méningocoque X dans une école primaire de Niamey (Niger).

This study of pharyngeal carriage of Neisseria meningitidis in a school in Niamey, Nigeria was carried out to confirm the feasibility of evaluating the impact of conjugate vaccine on the meningococcal carriage. All 90 pupils attending the school were examined during the dry season in February 1998. All children had been vaccinated using polysaccharide A/C in 1996. Samples were collected from the soft palate and immediately seeded on selective medium. After incubation at 37 degrees C for 24 hours, suspicious colonies were re-seeded on Miller-Hinton medium. Identification of N. meningitidis was based on standard biochemical criteria, agglutination grouping and DNA fingerprinting. Seven carriers of N. meningitidis X:NT:P1.5 were found. One of these carriers also presented a strain of N. meningitis A:4:P1.9. The high prevalence of serogroup X strains coincided with an outbreak of meningitis involving the same sub-type and sequence-type in Niamey.

[Quality control during ultrasonographic evaluation of morbidity due to Schistosoma haematobium in Niger]. / Contrôle de qualité lors de l'évaluation échographique de la morbidité due à Schistosoma haematobium au Niger.

Within the framework of a campaign to control urinary schistosomiasis in Niger, a quality control audit was performed on ultrasonographic assessment of morbidity due to Schistosoma haematobium. The purpose of this audit was to determine variance and reproductibility of epidemiological data provided by two trained independent observers. Three parameters were studied, i.e.,: interobserver variability on matched data, interobserver variance at the community level on the same or different subjects, including some after treatment with praziquantel, and intra-observer variance. A total of 1750 ultrasound examinations were carried out on 1416 inhabitants from 10 hyperendemic villages (70 p. 100 schoolchildren) according to a slightly modified version of the WHO Cairo protocol. Inter-observer variance at the individual level was high for some elementary abnormalities of the bladder. Variance was around 20 p. 100 for the 2 main indicators, i.e. presence of at least one bladder lesion and dilatation of the upper urinary tract. At the community level, inter-observer variance was moderate and the two observers' global assessment of morbidity due to Schistosoma haematobium was the same. Variations of morbidity related to level of endemicity were given perceived in parallel. Similar findings were noted for the intra-observer variability at the individual or community level. Ultrasound examination is supposed to furnish reliable morbidity data for selecting communities at risk and scheduling treatments during schistosomiasis control programs. The results of this study show that the level of inter- and intra-observer variance in ultrasonographic assessment in Niger is compatible with this critical role.

[Preliminary evaluation of usable indicators during a control program for urinary bilharziosis in Niger]. / Evaluation préliminaire des indicateurs utilisables au cours d'un programme de lutte contre la bilharziose urinaire au Niger.

The performance of several indirect screening tests was evaluated during the start-up phase of a urinary schistosomiasis control program in Niger. Urine tests were carried out on a total of 354 children attending 3 primary schools on five consecutive days. Tests included filtration of 10 ml of urine, search for microscopic hematuria using reagent strips, and gross examination of urine. In addition a questionnaire was administered on the first day to identify signs of dysuria and hematuria. Repeat testing had a strong effect on the epidemiological profile of urinary schistosomiasis in the 3 schools. Although day-to-day counts varied greatly, egg excretion could be considered as high in all infected subjects. The screening sensitivity of urine filtration was low when the level of endemicity was moderate (up to 55 p. 100). Microscopic hematuria was common. However the sensitivity of this method was overestimated in comparison with urine filtration alone and use of reagent strips can be inconvenient. Using carefully defined diagnostic criteria, gross examination of urine was as effective as urine filtration and easier to perform. The value of the questionnaire for evaluation of morbidity was low despite relatively good performance of the diagnostic techniques. The children's responses concerning hematuria were not objective and questions concerning dysuria were poorly understood and time-consuming. In the next phase of study, these findings will be validated by ultrasound imaging.

[Optimizing the response to epidemics of meningococcal meningitis: report of a workshop of experts at CERMES (Niamey, Niger, 12th to 14th January 1998)]. / Optimiser la riposte aux épidémies de méningite à méningocoque: rapport d'un atelier d'experts réunis au CERMES (12 au 14 janvier 1998, Niamey, Niger). Atelier de Niamey.

Recent meningitis epidemics in West Africa have drawn attention to shortcomings in the response of the health services. The health ministries of the countries involved have identified particular requirements. Following WHO recommendations, OCCGE organized a meeting of experts at CERMES, Niamey, in January 1998. The aim of this workshop was to consider the problems common to these countries, identify their needs and to produce concrete recommendations defining the roles of OCCGE and CERMES. Difficulties in mobilization, as no procedure had been established, and a lack of resources limited the efficiency of the response to epidemics. There was also insufficient training of personnel and laboratory facilities were often inadequate. OCCGE could draft a procedure manual specifying tasks and responsibilities for the control of an epidemic. It was suggested that a sub-regional stock of drugs, vaccines and injection equipment should be set up at CERMES. This should improve the speed of the response and complement national and international distribution systems. The group stressed the importance of improving the surveillance of meningitis epidemics. This approach depends on a structured network based around a reference laboratory. CERMES plans to support government initiatives by training and by maintaining the network. Efforts will be made to report and make best use of epidemiological information at all levels of the "health pyramid". Some OCCGE institutes (e.g. IPR and CERMES) have computer tools such as the Geographical Information System, which can be made available to governments. Analysis of sub-regional epidemics demonstrated the limitations of an alert threshold of 15 cases per 100,000 people. The sensitivity and specificity of this threshold differs between climatic zones OCCGE recommends that each country carry out its own research to determine the most appropriate alert threshold for each zone. Epidemics are currently managed by treatment with short courses of chloramphenicol in oil (injected into muscle). This approach may change as ceftriaxone becomes more affordable. The systematic use of ceftriaxone in infants under the age of 1 year presenting with meningitis is justified by the frequency of non-meningococcal bacterial causes. A consensus was reached on the most appropriate vaccination strategies: Emergency vaccination implemented rapidly in response to an epidemic. The entire population of a district between the age of 6 months and 30 years are vaccinated. Prophylactic vaccination in high-risk zones. This is carried out in the zone itself or in neighboring regions where there was an epidemic the preceding year. There is evidence that those not infected during an epidemic are at high risk the following year. These vaccinations should be carried out as soon as possible, at least before the start of the next epidemic season. Systematic vaccination is currently limited to special groups (e.g. school children, military personnel and pilgrims). It is hoped that the conjugated vaccine will become available for integration into the infant vaccination program.

Epidemiology of bacterial meningitis in Niamey, Niger, 1981-96.

In the African meningitis belt the importance of endemic meningitis is not as well recognized as that of epidemics of meningococcal meningitis that occur from time to time. Using retrospective surveillance, we identified a total of 7078 cases of laboratory-diagnosed bacterial meningitis in Niamey, Niger, from 1981 to 1996. The majority (57.7%) were caused by Neisseria meningitidis, followed by Streptococcus pneumoniae (13.2%) and Haemophilus influenzae b (Hib) (9.5%). The mean annual incidence of bacterial meningitis was 101 per 100,000 population (70 per 100,000 during 11 non-epidemic years) and the average annual mortality rate was 17 deaths per 100,000. Over a 7-year period (including one major epidemic year) for which data were available, S. pneumoniae and Hib together caused more meningitis deaths than N. meningitidis. Meningitis cases were more common among males and occurred mostly during the dry season. Serogroup A caused 85.6% of meningococcal meningitis cases during the period investigated; three-quarters of these occurred among children aged < 15 years, and over 40% among under-5-year-olds. Both incidence and mortality rates were highest among infants aged < 1 year. In this age group, Hib was the leading cause of bacterial meningitis, followed by S. pneumoniae. The predominant cause of meningitis in persons aged 1-40 years was N. meningitidis. Use of the available vaccines against meningitis due to N. meningitidis, S. pneumoniae, and Hib could prevent substantial endemic illness and deaths in sub-Saharan Africa, and potentially prevent recurrent meningococcal epidemics.

PIP: The study presented information on the epidemiology of bacterial meningitis in Niamey, Niger from 1981 to 1996 using retrospective surveillance. During the 15-year period, 7078 cases of laboratory-diagnosed bacterial meningitis were identified. 3 years (1984-85, 1985-86, and 1994-95) were considered to be epidemic years, and in these years incidence of bacterial meningitis exceeded 140 cases/100,000 population. The major pathogens were Neisseria meningitidis (57.7%), Streptococcus pneumoniae (13.2%), and Haemophilus influenzae (Hib) (9.5%). Mean annual incidence of bacterial meningitis was 101/100,000 population with an average annual mortality rate of 17 deaths/100,000. Both S. pneumoniae and Hib had caused more meningitis deaths than N. meningitidis, as observed over the 7-year period for which data were available. Meanwhile, N. meningitidis was the major cause of meningitis in persons aged 1-40 years. Meningitis was more common among males than females and was more prevalent during dry seasons. Incidence of meningococcal meningitis was higher (74.3%) in children under 15 years of age, and over 40% of these cases occurred in children below 5 years old. Infants aged less than 1 year had the highest incidence and mortality rates; neonatal (1 month of age) meningitis was identified in 101 cases. The high rate of endemic illness and deaths due to meningitis in sub-Saharan Africa could be prevented through the use of available vaccines such as meningococcal polysaccharide vaccines and Hib conjugate vaccines.

Preventive immunisation could reduce the risk of meningococcal epidemics in the African meningitis belt.

Control of meningitis epidemics is based on early case detection followed by mass campaigns of immunisation. However, this strategy showed severe inadequacies during recent outbreaks in Africa. In Niamey, Niger, meningococcal vaccinations began in 1978 and detailed bacteriological and epidemiological surveillance of meningitis started in 1981. When vaccine coverage rates were higher than 50%, the prevalences of Neisseria meningitidis A meningitis were low in Niamey, although there was a concurrent epidemic in rural Niger. A massive outbreak of meningitis in Niamey in 1994-1995 followed a 6-year period during which the mean rate of vaccine coverage remained < 25%. The data indicate that, in the meningitis belt, preventive immunization should avoid a great number of deaths and be less expensive than mass immunisation campaigns performed after epidemics have begun.

[Continued ultrasonic follow-up of children infected with Schistosoma haematobium after treatment with praziquantel]. / Suivi échographique prolongé d'enfants infestés par Schistosoma haematobium après traitement par praziquantel.

During a Schistosoma haematobium morbidity control program in Niger, we conducted a survey to describe rhe resolution of lesions after treatment with praziquantel. to determine reinfection rates and to define retreatment schedules. 114 schoolchildren (7-15 years old) living in an hyperendemic village underwent 10 successive examinations over 34 months following an initial evaluation and the administration of 40 mg/kg of praziquantel. All children, whether apparently infected with S. haematobium or not, were treated. Egg output, microhaematuria, visual aspect of urine and abnormalities of the urinary tract by ultrasound were assessed. The initial prevalence tif infection was 74.5%. Reinfection began 5 months after treatment and the final prevalence was 47.1%. Bladder abnormalities decreased rapidly, but incompletely, probably due to reinfestation: initial prevalence: 89.5%). Their prevalence increased 8 months after treatment to 72.4% at month 34. Dilatations of the upper urinary tract regressed more slowly but constantly until the end of the study (initial prevalence: 43%; 4.6% at month 34), Three years after treatment, despite reinfection, the general morbidity level (prevalence and severity of lesions) was lower than at baseline in our cohort, which would suggest the advantage of a long interval between mass treatments in the epidemiological context of our survey.

The WHO Collaborating Centre for Research and Control of Schistosomiasis at Niamey, Niger.

The Centre de Recherche sur les Méningites et les Schistosomes (CERMES) is a research institute depending on the Organisation de Coordination et de Coopération pour la lutte contre les Grandes Endémies--a West African Organization for Public Health--devoted to the studies on schistosomiasis and meningitis. The staff includes 32 persons with 11 scientists and one financial officer. The activities of the CERMES involving schistosomiasis concern three research units: (a) ecology of human and animal schistosomiasis transmission; the CERMES defined the different patterns of schistosomiasis transmission in Niger (involving African dry savana); in this field, we have shown, (i) the existence of important variability in conditions of transmission of S. haematobium and, (ii) natural hybridization between parasitic species of the ruminants (S. bovis and S. curassoni) and genetic interaction between human and animal parasites; (b) definition of morbidity indicators usable for rapid assessment methods, for appraisal of the severity of the disease and for the evaluation of the efficiency of control methods; we have established the correlation between ultrasonographic data and some cheap and simple field indicators; (c) immune response and protective immunity induced by recombinant glutathion S-transferase (Sm28, Sb28 and Sh28) in homologous and heterologous animal models including goats, sheep and non human primates (Erythrocebus patas). In Niger, we participate in all control programs against schistosomiasis to define control strategies, to supervise operations and to participate in their evaluation with external experts. International collaborations constitute a frame including four laboratories in Africa and six laboratories in developed countries (Europe and USA).

PIP: The Centre de Recherche sur les Meningites et les Schistosomoses (CERMES), a research center in Niamey, Niger, affiliated with a West African public health organization, conducts studies in the areas of parasitology, epidemiology, and immunology. Significant variability in factors related to transmission of Schistosoma haematobium have been noted. Experimental research on the Schistosoma-bulinid compatibility and field surveys of the geographic distribution and role of snails in transmission have been essential to the design of parasite control interventions in West Africa. A CERMES-sponsored project, supported by the European Community, is examining urinary schistosomiasis control in the Niger river valley and the impact of treatment on ultrasonically visualized urologic lesions. The Experimental Vaccine Unit seeks to improve the route of administration and choice of adjuvant and to propose a vaccine protocol for field testing. Recombinant proteins have been found to alter the development of the parasite either by inducing a reduction in the parasite burden or an inhibition of the fecundity of the parasite.

Immunogenicity, safety, and memory of different schedules of Neisseria meningitidis A/C-diphtheria toxoid conjugate vaccine in infants in Niger.

We studied one to four doses of meningococcal polysaccharides A and C conjugated to diphtheria toxoid (Men D) versus A/C polysaccharide (Men PS) vaccine in 618 infants in Niger. Men PS at 24 months permitted evaluating memory. Two Men D doses (at 3 and 9 months) induced higher serum bactericidal activity (SBA) than other regimens. SBA titers after Men PS at 24 months were higher in those given Men D in infancy versus Men PS. While responses were lower for serogroup C, hyporesponsiveness was not evident. Men D was well-tolerated. A single Men D dose in infancy appeared to induce memory.