The role of molecular modelling strategies in validating the effects of chrysin on sodium arsenite-induced chromosomal and DNA damage

Chrysin (CHR) is a food-based bioactive ingredient whereas, sodium arsenite (SA) is one of the major contaminant in drinking water. When ingested, SA contributes to tissue damage due to bioactivation by S-adenosyl methionine (SAM)-dependent methyltransferase. Hence, the needs to nullify this effect by investigating the potentials of CHR on SA-induced genotoxicity in rats. The experiment was divided into two successive stages (ameliorative and preventive, curative studies) for 1 week. Rats were divided into four groups: distilled water, 10mg/kg SA, 10mg/kg CHR and co-administration. In stage 2, the experimental groups were given either CHR or SA for 1 week, and treated in reversed order for additional week. Lipid peroxidation, protein carbonyl and DNA fragmentation in liver, blood brain and bone marrow cells micronucleus were assayed for using standard protocols. Molecular docking of SAM-dependent methyltransferase in the presence of CHR was conducted. CHR significantly ( p < 0.05) decreased the level of lipid peroxidation, protein carbonyls and DNA fragmentation in blood, liver and brain tissues as against group treated with SA. It also significantly ( p<0.05) reduced the level of micronuclei generated in bone marrow cells. The effects of CHR were shown to be ameliorative, preventive and curative in nature. Furthermore, CHR was able to dock (with binding energy of −24.81 kcal/mol and predicted inhibition kinetic constant (Ki) of 0.959 µM) into the active site of SAM-dependent methyltransferase with strong hydrogen bond and hydrophobic interactions. The study might have unravelled the potentials of CHR against SA-induced chromosomal and DNA damage, which might be due to inhibition of SAM-dependent methyltransferase.

Mapping, monitoring, and surveillance of neglected tropical diseases: towards a policy framework

As national programmes respond to the new opportunities presented for scaling up preventive chemotherapy programmes for the coadministration of drugs to target lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminthiasis, and trachoma, possible synergies between existing disease-specific policies and protocols need to be examined. In this report we compare present policies for mapping, monitoring, and surveillance for these diseases, drawing attention to both the challenges and opportunities for integration. Although full integration of all elements of mapping, monitoring, and surveillance strategies might not be feasible for the diseases targeted through the preventive chemotherapy approach, there are opportunities for integration, and we present examples of integrated strategies. Finally, if advantage is to be taken of scaled up interventions to address neglected tropical diseases, efforts to develop rapid, inexpensive, and easy-to-use methods, whether disease-specific or integrated, should be increased. We present a framework for development of an integrated monitoring and evaluation system that combines both integrated and disease-specific strategies.

Bulinus forskalii: a new potential intermediate host for Schistosoma haematobium in Niger

Malacological monitoring of two irrigated areas in Niger highlighted the natural susceptibility of Bulinus forskalii to infection with Schistosoma haematobium when the parasitic load is high. This first report of S. haematobium infection in B. forskalii, which is an abundant snail in irrigated areas, has been confirmed experimentally.

[Uro-genital schistosomiasis with S. haematobium and infertility in Niger. Prospective study of 109 cases]

Schistosomiasis represents the second most endemic diseases following malaria. It is now endemic in 76 countries of the world, and it is estimated that more than 200 million persons are infected. The objective of this work is to help in the improvement of knowledge about Female Genital Schistosomiasis (FSG) effects on the women reproductive. A transversal prospective survey during six months, on women consulting for infertility in the health reproductive center of Niamey. The women included (109 persons) have been asked and consulted in gynecology, cervical smears urine pathology, urine ragent strips test, vesico-renal and gynecologic trans-abdominal ultrasound, hysterosalpingography (HSG) and cervical biopsy on infected patients. The infestation prevalence at S.haematobium was 38,5%. The infected persons have presented more gyneco-obstétrical symptomatology than the non infested ones. The proportion of exocervicite was 31,0% by clinical examination. The cervical biopsy done on 26 bilharziosis patients confirmed the frequence of highs chronic exocervicites (50%) and leucoplasia (11,5%). Echography and HSG noticed that the bilharzios patients can let develop other annexiel pathologies such as: ovary cyst, peri-tuboovary adhesions and wide ovaries. The symptomatology felt by infested women showed the parasitose consequence on women in endemic area. The treatment in o large schaddle by the national program allows to reduce morbidity caused by that infection in Niger.

[Prevalence of the HIV infection and five other sexually-transmitted infections among sex workers in Niamey, Niger]

We performed a systematic screening of HIV infection and five other sexually transmitted infections on a consecutive sample of 529 female sex workers from Niamey. HIV seroprevalence rate was 30.1%, with HIV-1 profile in 93.1% of the cases. For curable STI, 4.7% of women had treponematosis, 7% gonorrhoea, 16.8% Gardnerella vaginalis, 36.9% Mycoplasma hominis and 68.2% Chlamydia trachomatis infection. The percentage of women with at least one STI was significantly higher in HIV positive's: 95.6% against 87.9%. Only 7.9% of women were free of any infection.

[Behaviour and HIV seroprevalence investigation in sex workers of Dirkou, Niger, 2002]

In the framework of the Human Immunodeficiency Virus (HIV) surveillance, seroprevalence and behavioural survey was conducted in 2002 in Dirkou, a place of concentration of female sex workers (FSW) in Niger The global HIV seroprevalence found was 50% (CI at 95%: 40.6-59.36%). The behavioural survey revealed that 98% of FSW had heard about HIV whereas 78.7% know at least one HIV transmission way and 76.9% know at least one HIV prevention means. Only 33.3% declared using condom, what show that sensitisation efforts are needed to induce a behaviour change in FSW and their clients.

[The use of dried blood spots for HIV-antibody testing in Sahel]

Undertaking a HIV seroepidemiological survey in Sahel is logistically problematic, since countries like Niger or Mali are very large with scattered populations and harsh climatic conditions. Therefore, the replacement of serum samples by whole blood dried on filter papers has been studied for HIV-antibody testing with commercial kits that are commonly used. In Niger, two tests ELISA (Genscreen HIV1/2 version 2, Vironostika HIV Uni-Form II Ag/Ab) and two rapid tests (Determine HIV1/2 et Immunocomb II HIV1&2 Bispot) were used to compare the dried blood spots and serum samples from 43 control individuals. Both ELISAs gave an excellent correlation (r = 0.99 et r = 0.98) between the dried blood spots and serum absorbance values. Using the rapid tests, the HIV status was found 100% concordant with dried blood spots and serum samples. An algorithm using three out of the four mentioned tests was defined then validated on the dried blood spots of 163 control individuals (100% concordant). In conclusion, dried blood spots may accurately and profitably replace serum samples for the serodiagnosis of HIV infection and for mass serosurveys in Sahel.

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.

[Long-term impact of a mass treatment by praziquantel on morbidity due to Schistosoma haematobium in two hyperendemic villages of 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.

[Heterogeneity of Schistosoma haematobium transmission in irrigated fields]

Heterogeneity of Schistosoma haematobium transmission in irrigated fields. Although irrigated areas exist since a long time in the Niger Valley the distribution of the urinary schistosomiasis does not appear homogeneous, testifying to the existence of limiting or favourable factors. The identification of these factors could lead to a better definition of the distribution of the schistosomiasis risks and to optimise control programmes. The population of five villages about 1,900 inhabitants living in the same irrigated area (Sébéri) was examined at the end of 1999 before treatment and surveyed two and ten months after treatment by praziquantel in order to investigate re-infections. In parallel, the transmission sites were subject to a semi-monthly malacological follow-up from 1998 to 2001 and the water contacts were quantified in the sites of the main village during 2000. Before treatment, schistosomiasis risks appeared related to the proximity between habitat and lateral canals: the infections concerning youngers were all the more intense that the dwellings were close to the canal. The parasitological indices were the highest in the village lacking of other water sources. The morbidity indices followed a similar distribution with maximum values in the children of the 3 villages located to less than 1 km from the canal; however, morbidity was mainly observed in the adult population, in particular male, of the 2 villages which were the most distant from the canal. After treatment, the incidence of the re-infection between 2 and 10 months was comparable in the 3 villages close to the canal (28%) but was significantly weaker in the 2 villages far from the transmission sites (5%). In the villages bordering the canal, the incidence in the children was all the more high since the habitat was close to the canal. Between 1999 and 2000, the collected number of Bulinus truncatus decreased from 1.4 to 0.6 individuals per survey; moreover, no mollusc harbouring parasites was found, representing the decrease of the parasite burden. The abnormal weakness of re-infection, regarding this type of focus, could be explained by the repeated stop of water supply inducing a complete drying out of the canal for 2 months during the year preceding the study. These repeated drying out also resulted in a reduction of the exposure. Whereas the average frequentation of the sites of the canal remained rather comparable between January (cold dry season) and May (dry hot season), it decreased dramatically in September (rainy season but canals were not irrigated this year) from 99 to 11 daily contacts. The use of the lateral canal when filled represented 80% of the contacts. In the event of drying out, 80% of the contacts were transferred in the ponds but not in the river (5% of the contacts whatever the season). These results confirmed (1) that the presence of canals reduced the use of natural sites and (2) that the drying out of the canals induced a total reduction of the contacts.

[Extra uterine pregnancy associated with a tubal schistosomiasis due to Schistosoma haematobium. A case report from Niger]

We are reporting the case of a 21-year-old woman hospitalized for pelvic pains in a context of secondary amenorrhoea, whose examinations revealed a tubal pregnancy After surgical operation, the examination of the operative part showed a schistosomal tubal obstruction. Schistosomal tubal obstructions are the cause of ectopic pregnancies and infertility not to be forgotten in endemic areas. The implementation of a control programme based on chemotherapy by praziquantel will enable the reduction of their frequency.

[Epidemiology of scorpion envenomations in the pediatric service of the Agadez hospital center (Niger) in 1999]

In Agadez, northern Niger, envenomations due to scorpion sting is a major public health problem, ranking first among reasons for emergency admission to hospital and inducing significant mortality. In order to provide best medical care, improved knowledge of scorpion sting envenomation was required. From April to September 1999, we carried out a prospective, descriptive survey on the paediatric ward of the departmental hospital of Algadez. All children admitted to the ward for scorpion stings were included. Data was collected by questionnaire. Requested items were age, sex, type of scorpion, sting location, and clinical development. Over the 6 months of the survey, a total of 44 cases of scorpion sting were recorded on the ward. The majority of the cases (52%) were recorded in July. The main types of scorpion identified according to colour were black (18%), yellow (18%), and brown (5%). In 59% of the cases, the type of scorpion was not identified. 6-15 year-old children represented 50% of the cases. The lower limb was the main site of stings (66%). A majority of cases (52%) were admitted fewer than 30 minutes after the sting, and 30% between 30 minutes and 1 hour after the sting. The overall lethality rate was 23% (10/44). All the deaths occurred within 2 hours following the sting. Of all the deaths, 60% (6/10) occurred with 30 minutes after the sting. Our study has shown that scorpion stings remain a significant health problem in the area. As a consequence of our findings, we have introduced a new therapeutic protocol for the early case management.

[Vaccine coverage survey per cluster sampling after an antimeningococcal mass vaccination campaign at Niamey, Niger in 2000]

The author presents an annotated selection of web sites devoted to documentation and health. This directory may be used as bookmarks especially by the researchers who work in health, HIV/AIDS infection, and development fields.

[Efficacity of praziquantel in school-aged children in a hyperendemic zone for Schistoma haematobium (Niger, 1999)]

Urinary schistosomiasis is endemic in the Niger river valley. The aim of the present study was to assess the efficacy and side effects of a single oral dose of praziquantel at 40 mg/kg in the treatment of schistosomiasis. The investigation took place between April 5, 1999 and May 25, 1999. A total of 318 primary school children, aged from 6 to 16 years, of a Schistosoma haematobium endemic area were included in the survey. They underwent a macroscopic and parasitological examinations of the urine before treatment and two and six weeks after treatment. Treatment with praziquantel was given at 40 mg/kg of body weight in a single dose. Side effects due to praziquantel were assessed within the first 4 hours, and 24 hours after. Side effects were frequent (53.7%), especially occurring in the first four hours. Their expression was not associated with the sex of the child nor the intensity of the infestation. We noted that elder children expressed more complaints. The most frequent symptoms were abdominal pains, headaches and pruritus. All these signs were without gravity and resolved within the first twenty-four hours. Before treatment, the prevalence of infestation was 98%. Six weeks after treatment, 32% of children remained positive despite a marked reduction of egg excretion. In this survey, the side effects of the treatment were very frequent but without gravity. Using praziquantel, 68% of the subjects were cured completely. Urinary schistosomiasis control programs can continue to use it for mass treatment without risk.

[Significance of rapid evaluation indicators during the monitoring of graduated treatment against 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.

[Impact of health education programs on the control of urinary bilharziasis in Niger]

The objective of this study was to assess the effect of health education in the control of bilharziasis, as a part of an investigation on anti-urinary bilharziasis campaign in Niger. We carried out a survey in two groups of endemic villages on the Niger, one group of villages where there are health education campaigns (target villages) and a control village (no education campaign). Five hundred and seventy-seven people were interviewed in the area. The bilharziasis project has been the main source of information on bilharziasis of people in the project zone. The awareness of measures to fight against bilharziasis has been moderate. Indeed, 46.6% of people interrogated in the project area couldn't cite any means for containing bilharziasis. In the area of intervention, 41.5% of people interrogated were unaware of the intervention of an intermediate host in the transmission of the urinary bilharziasis. The notion of reinfestation remains little known. Behaviours that favour the illness were ignored by 1/3 of people interrogated in the project area. However, there was an increase in knowledge about the illness in the program zone in comparison with the control area. Despite the increase in knowledge level, changes in behaviour in relation to the illness remained low. Risky behaviour continued in about 2/3 of people interrogated. Only 33% of persons of the project area declared having adopted at least a single good behaviour. Changes of behaviour are slow to take place. Activities of health education must be sustained throughout a long period of time for sustainable profits of control actions to occur.

[Continued ultrasonic follow-up of children infected with Schistosoma haematobium after treatment with 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.

[Preliminary evaluation of morbidity due to S. haematobium and S. mansoni in the area of the future Adjarala Dam in Benin]

The aim of this study was to provide a preliminary assessment of morbidity due to schistosomiasis in the area of the future Adjarala Dam in Benin. We included 412 schoolchildren from five villages in the study. The mean age of the children was 9.4 +/- 2.3 years and the sex ratio (F/M) was 0.94. These children underwent parasitological examination. The children provided urine samples, which were examined by eye, filtered and tested for blood and protein. Stool samples were examined using Kato's technique and an ultrasound scan of the urinary tract was performed. We carried out a survey of snails at the possible transmission sites of all the villages, with a view to identifying the intermediate hosts. We detected S. mansoni and S. haematobium in the area. Urinary schistosomiasis was mesoendemic (prevalence of 19.7%) whereas schistosomiasis due to S. mansoni was hypoendemic (prevalence of 3. 9%). Ultrasound scans showed that 28% of the children had bladder lesions and that 2.5% were carriers of hydronephrosis. We compared the diagnostic performances of the various indirect indicators of morbidity. We found that a history of hematuria was the most sensitive indicator (88%) but that the sensitivity of this indicator differed significantly according to the sex of the child. Hematuria >= 1+ was the most effective indicator. Snail surveys showed that Biomphalaria pfeifferi and Bulinus globosus were present in the area.

[Preliminary evaluation of usable indicators during a control program for urinary bilharziosis in 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.

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.

[Quality control during ultrasonographic evaluation of morbidity due to Schistosoma haematobium in 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.

[Reduced morbidity of schistosomiasis: report from an expert workshop on the control of schistosomiasis held at CERMES (15-18 February 2000, Niamey, Niger)]

Schistosomiasis remains a problem for public health in sub-Saharan Africa. Despite past efforts, cases have not decreased significantly. Schistosoma haematobium and S. mansoni are endemic in all the West African countries. The distribution of both parasites is focal. During a workshop held at CERMES in Niamey, in February 2000, a group of experts recommended that schistosomiasis control be considered as a public health priority in all the endemic West African countries, and National Control Programmes rapidly implemented. The objective of these control programmes would be to reduce schistosomiasis-related morbidity. Case detection should be based on clinical symptoms such as haematuria or bloody diarrhoea, and be carried out at two levels: health care centres and schools, in order to reach patients and school-age children. Health workers should be trained in case detection and community based control of schistosomiasis. The assembled experts advocated the use of praziquantel dosed at 40 mg.kg-1, which therefore must be made available and accessible in outlying areas. Associated measures consist of sanitation, water supply and health education, especially aimed at improving patients' treatment-seeking behaviour. A West African network for schistosomiasis control was created during the workshop. It runs on the Web site of CERMES as network co-ordinator. (http://www.mpl.ird.fr/cermes/).

[Schistosomiasis in the region of Ziga (Burkina Faso) before the construction of a dam]

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.

[Epidemiology and control of bacterial meningitis in children less than 1 year in 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.

[Intestinal parasitic diseases in an urban environment in Sahel. A study in a district of 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.

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.