[First cases of imported cutaneous leishmaniasis in Bangui Central African Republic: efficacy of metronidazole]. / Premier cas de leishmaniose cutaneé d'importation à Bangui en République Centrafricaine: efficacité du métronidazole.

Cutaneous leishmaniasis is an uncommon disease in the Central African Republic (CAR). The purpose of this report is to present a case that was imported into Bangui, CAR from the neighboring Republic of Chad. The polymorphous aspects of lesions and the spectrum of laboratory findings associated with the disease in this patient are described. Oral treatment with metronidazole led to rapid resolution with minimal scarring.

[Results of active surveillance of acute flaccid paralysis in the Central African Republic and Chad from 1995 to 2000]. / Bilan de la surveillance active des paralysies flasques aigues en Republique Centrafricaine et au Tchad de 1995 a 2000.

The threefold purpose of this report is to describe the epidemiology of acute flaccid paralysis (AFP), to determine the impact of the National Immunization Days (NID), and evaluate the quality of active surveillance in the Central African Republic (CAR) and Chad. The data in this study was obtained from the Enterovirus Division of the Pastear Institute in Bangui (National WHO Inter-country Reference Laboratory for the CAR and Chad and Regional Poliovirus Reference Laboratory in Africa). An increase in the number of AFP cases was observed in the CAR between 1995 and 2000 and in Chad between 1997 and 2000, mainly as a result of enhancement of the surveillance system. The goals set by the WHO in terms of the proportion of AFP cases with 2 specimens collected within 14 days of onset of paralysis and the number of cases with 60-day follow-up have not been reached in either country. The presence of 2 strains of wild poliovirus (types 1 and 3) and several genotypes (West African 13 and West African 7 for type 1 and Central African and Nigeria-P3 for type 3) not only show that Central Africa is still a significant reservoir for poliovirus transmission but also raise serious doubts about the quality of the NID organized over the last 3 years. The priority of the next NID round must be to reach unimmunized children who have been missed by routine immunization coverage.

[Forest ecosystems and Ebola virus]. / Ecosystèmes forestiers et virus Ebola.

Despite data collected since the emergence of the Ebola virus in 1976, its natural transmission cycle and especially the nature of its reservoirs and means of transmission are still an enigma. This means that effective epidemiological surveillance and prevention are difficult to implement. The location of outbreak areas has suggested that the reservoir and the transmission cycle of the Ebola virus are closely linked to the rainforest ecosystem. The fact that outbreaks seldom occur suggests the presence of a rare animal reservoir having few contacts with man. Paradoxically, various serological investigations have shown a high prevalence in human beings, especially in forest areas of the Central African Republic (CAR), with no pathology associated. This would appear to suggest a circulation of both pathogenic and non-pathogenic strains as well as frequent contacts with man. The ecological changes resulting from human activity (agriculture and logging) account for the modification of the fauna (movement of rainforest fauna, introduction of savannah species) and could explain a multiplication of contacts. Likewise, it is interesting to note that the centre of outbreaks has always been in areas bordering on forests (ecotone foreset-savannah in the Democratic Republic of Congo, savannah in Sudan). All these considerations have led us to establish a permanent "watch" in areas bordering on forests in the CAR, involving a multidisciplinary approach to the virological study (strain isolation, molecular biology) of the biodiversity of small terrestrial mammals. The results of a study conducted on 947 small mammals has shown for the first time the presence of the Ebola virus genome in two species of rodents and one species of shrew living in forest border areas. These animals must be considered as intermediary hosts and research should now focus on reservoirs in the ecosystem of forest border areas where contacts with man are likely to be more frequent.

[Circulation of the poliovirus in endemic zones with children vaccinated by the oral polio vaccine]. / Circulation des poliovirus dans les zones d'endémie chez les enfants vaccinés par le vaccin polio oral.

Strategies aiming to eradicate the poliovirus and poliomyelitis seek primarily to eliminate wild strains associated with the disease, by means of world wide vaccination campaigns using the oral attenuated vaccine (OPV). OPV contains attenuated viral strains which retain their replicating capacity in the digestive tract and thus induce the development of an antiviral local intestinal immunity and limit the circulation of the virus. In such a context, poliomyelitis surveillance laboratories should study above all cases of acute flaccid paralysis (AFP), highlighting the circulation of wild strains, identifying regional reservoirs and guiding vaccination strategies. Alongside circulation, there appear to be important genetic and phenotypic shifts in vaccinating strains, since the OPV is capable of preserving a reservoir of pathogenic stains and thereby impairing vaccination efficacy and the eradication of the virus. Furthermore, non-polio enteroviruses should be considered as a source of emerging pathogenic strains. These questions are being studied by the Pasteur Institute with the objective of determining the effects of OPV campaigns on the circulation of the poliovirus. We have studied the poliovirus vaccine and the circulation of wild strains in urban and peripheral urban areas in African countries known to be endemic for poliomyelitis (Central African Republic, Madagascar, Côte d'Ivoire). The study population consisted of children who had already been vaccinated and new-borns in the course of vaccination. We also evaluated the diffusion of the vaccine strains in their immediate environment. Genetic interchanges were taken into account. For children who received the 3-4 OPV doses, asymptomatic virus excretion was insignificant (0.4-2.4%). The rate of virus excretion in the surrounding environment of children in the course of being vaccinated was relatively low (1.76-5.3%). Our study also detected variant and recombinant strains.

Ebola and Marburg virus antibody prevalence in selected populations of the Central African Republic.

With the natural history of the filovirus family seemingly unknown, filovirus ecology in its natural environment remains a rudimentary field of research. In order to investigate the maintenance cycle of filovirus in Central Africa, a study was conducted within the rain forest of the Central African Republic. The epidemiological study determines the frequency and distribution of filovirus seroprevalence in a selected human population. Using an ELISA, serum samples from Pygmy and non-Pygmy populations were tested for Ebola-Zaire virus and Marburg (MBG) virus antibody. Filovirus antibody reacting sera were found in all zones investigated, and in all populations studied (Ebola virus IgG 5.3%; Marburg virus IgG 2.4%). Pygmies appeared to have a significantly higher seroprevalence (P < 0.03) against Ebola-Zaire virus (7.02%) than non-Pygmies (4.2%). MBG virus or related unknown filovirus strains also seem to be present in the western part of Central Africa. MBG virus antibodies were present in different Pygmy groups (ranging from 0.7 to 5.6%, mean 2.05%) and in several non-Pygmy populations (ranging from 0.0 to 3.9%, mean 3.4%) without an overall significant difference between the two groups (P = 0.14). The potentialities of nonpathogenic filovirus strains circulating in the Central African Republic are discussed.

Identification of Ebola virus sequences present as RNA or DNA in organs of terrestrial small mammals of the Central African Republic.

The life cycle of the Ebola (EBO) virus remains enigmatic. We tested for EBO virus in the organs of 242 small mammals captured during ecological studies in the Central African Republic. EBO virus glycoprotein or polymerase gene sequences were detected by reverse transcription PCR in RNA extracts of the organs of seven animals and by PCR in DNA extract of one animal. Neither live virus nor virus antigen was detected in any organ sample. Direct sequencing of amplicons identified the virus as being of the Zaire/Gabon subtype. Virus-like nucleocapsids were observed by electron microscopy in the cytoplasm of the spleen cells of one animal. The animals belonged to two genera of rodents (Muridae; Mus setulosus, Praomys sp1 and P. sp2) and one species of shrew (Soricidae; Sylvisorex ollula). These preliminary results provide evidence that common terrestrial small mammals living in peripheral forest areas have been in contact with the EBO virus and demonstrate the persistence of EBO virus RNA and DNA in the organs of the animals. Our findings should lead to better targeting of research into the life cycle of the EBO virus.

[Toxoplasmosis at the Pasteur Institute of Bangui, Central African Republic (1996-1998): serological data]. / La toxoplasmose à l'Institut Pasteur de Bangui, République centrafricaine (1996-1998): données sérologiques.

A serological study of toxoplasmosis was conducted between 1996 and 1998 on 1953 patients of the Medical Analysis Laboratory of the Institut Pasteur de Bangui. The mean age of patients was 28 years. Among sera tested by ELISA, seropositivity to IgG antibodies was observed in 50.6%, and 2.6% sera were found positive for IgM antitoxoplasma antibodies (immuno-capture). The seroprevalence did not vary significantly according to sex or age. The results showed 40.8% sera had IgG antibodies titered 400 Ul/ml and more. The proportion of high level (> 400 Ul) IgG was more important in males than in females. High level IgG antibodies were statistically significant more frequently in the sera of females aged 10-29 years. Of the procreative women, 49.1% were at risk of contacting toxoplasmosis. The diagnosis of recently acquired infection, based on the coexistence of IgM antibodies and high level IgG antibodies, was noted in 1.6% among sera of procreative women. In the Central African Republic, serologic survey during pregnancy is not systematic and HIV seroprevalence is high (15%). Risks of acute infections during pregnancy and of opportunistic infections in HIV-infection patients are high. A control of toxoplasmosis is justifiable (screening during pregnancy, sanitary education) in CAR.

The molecular epidemiology of type 1 poliovirus in Central African Republic.

An increase in the incidence of acute flaccid paralysis cases associated with wild-type 1 poliovirus occurred in children in the city of Bangui, Central African Republic (CAR), in 1993 and 1994. Genetic relationships of 33 isolates were analysed by restriction fragment length polymorphism and by sequencing the VP1/2A junction region (150 nucleotides) of the viral genome. Two distinct genotypes, A and B, were co-circulating in 1993, while in 1994 only a third genotype, C, was observed. Comparison of the sequences found, with those of the sequences from isolates from neighbouring and other endemic countries revealed that genotype A isolates were related to strains from Egypt (90.7% identity), genotype B isolates to strains from Kenya (96.7% identity), Sudan and Egypt, and genotype C isolates to strains from various countries in western and southern Africa (89.0% identity). Genotypic diversity and genetic linkage with strains from neighbouring countries indicate intense poliovirus circulation and transmission that does not respect national borders. Therefore, eradication of poliomyelitis from CAR can only be achieved by a coordinated multinational strategy that stops poliovirus circulation in the whole of Africa.

[Dengue 1 epidemic in the Grand Comoro Island (Federal Islamic Republic of the Comores). March-May 1993]. / Epidémie de dengue 1 sur l'île de la Grande Comore (République Fédérale Islamique des Comores). Mars-mai 1993.

An epidemic of dengue fever occurred in Grande Comore island from March to May 1993. Dengue 1 virus has been isolated. The epidemic did not affect the other islands of the archipelago. No compound clinical picture, in particular hemorrhagic, was reported. A random sampling survey conducted towards the end of April showed that 26% of the population aged 5 years old or more had IgM dengue antibodies. The epidemic concerned essentially individuals under 45 years of age. The number of inhabitants of Grande Comore affected by the outbreak can be estimated between 56,000 and 75,000. The results of the sero-epidemiological survey allowed to find the serological scar of two previous epidemics of dengue: the first one around 1948, which may correspond with dengue 1, the other one in 1984, probably with dengue 2.

[Serological markers for hepatitis A, B and C in Madagascar. First investigation in a rural area]. / Les marqueurs sérologiques des hépatites A, B et C à Madagascar. Première enquête en zone rurale.

The first serological survey of hepatitis A, B and C virus infection was carried out in Madagascar during 1993 in two rural villages (653 sera) of the middle-west. This study shows a high frequency of positivity of hepatitis A virus markers (94.9%). Hepatitis A is acquired in early childhood. The data show the high frequency of positivity of hepatitis B (HBV) markers: in the two villages 72.5% and 89.8% have one marker, and seroprevalence of HBs antigene is 18.9% and 30.5%. Hepatitis B also is acquired in early childhood. The data show that not only hepatitis A and B but also hepatitis C is highly prevalent (2.2% and 5.8%). There was an increase in HCV antibody prevalence with age.

[HIV infection in tuberculosis patients in Madagascar. Situation in 1-93]. / L'infection à VIH chez les tuberculeux à Madagascar. Situation en 1993.

In Madagascar, the estimated incidence of tuberculosis is high (320 per 100,000) when human immunodeficiency virus (VIH) infection progress slowly. The authors have studied HIV seroprevalence in a group of tubercular patients and in two reference groups (general population and outpatients of the Clinical Biology Centre of Institut Pasteur). Circulation of HIV1 virus was observed with a low prevalence rate in all the 3 groups. There was no significant difference between tubercular patients and healthy population. Tubercular people ought to be a watch group for the epidemiological surveillance of HIV infection evolution in Madagascar.

[Situation of endemic rabies in Madagascar]. / Situation de l'endémie rabique à Madagascar.

The course of endemic rabies in Madagascar between 1982 and 1991 is related. Rabies has been raging over the whole island and dog is essentially affected, constituting the single vector of human rabies cases. The authors recall the main measures of struggle against rabies.

[Influenza surveillance in Tananarive during the year 1992]. / La surveillance de la grippe à Tananarive au cours de l'année 1992.

The authors relate the 1992 results of influenza surveillance in Antananarivo. 24 influenza virus A (H3N2) strains were isolated from 467 pharyngeal swabs. The virus had been continually spreading from January to September, with a peak in July, along with some monthly sporadic isolations. The highest respiratory morbidity was observed in June and July. The collection processes of influenzal and respiratory morbidity statistics are also discussed in order to standardize data and to define the real impact of influenza and other acute affections of respiratory tracts on the population.

[Poliomyelitis situation in Madagascar in 1993. Several considerations about the role of the laboratory in the eradication strategy]. / La situation de la poliomyélite à Madagascar en 1993. Quelques considérations sur la place du laboratoire dans la stratégie d'éradication.

After he has explained the worldwide strategy of poliovirus eradication, the author describes the Madagascar situation by reporting the rate of vaccinal coverage and the current surveillance system. He underlines the importance of laboratory in the poliomyelitis diagnosis, the isolated strain serotyping, the determination of strain characteristics: wild or Sabin-like, and their variability. From 1985 to the first five months of 1993, 65 poliovirus strains had been isolated, the most frequent of them is serotype 1. The realization of a map of neutralization epitope on a few type 1 poliovirus strains showed a major part of wild strains; the same case is valid for two other serotypes. The RFLP analysis of 6 type 1 poliovirus strains allowed to record their identity.