RESUMEN
SETTING: A national survey of Mycobacterium tuberculosis resistance was conducted for the first time in Madagascar between October 2005 and July 2007. OBJECTIVE: To determine resistance rates among new and previously treated cases of pulmonary tuberculosis. METHODS: In a cluster sampling representative of the general population of the country, 1275 smear-positive tuberculosis patients recruited at 34 sites, 926 new patients and 87 previously treated patients underwent drug susceptibility testing against rifampicin (RMP), isoniazid (INH), streptomycin and ethambutol on Löwenstein-Jensen medium using the indirect proportion method. RESULTS: Resistance among new cases was 6.5% (95%CI 4.9-8) and among previously treated cases it was 11.5% (95%CI 4.8-18.2). Monoresistance among new cases was 5.8% (95%CI 4.2-7.3), mainly to INH (3.7%). Multiresistance to INH and RMP was 0.2% (95%CI 0-0.5) among new cases and 3.4% (95%CI 0-7.2) among previously treated cases. No significant difference was noted with regard to sex or age. CONCLUSION: The rates of resistance among new and previously treated cases remain relatively low in Madagascar.
Asunto(s)
Antituberculosos/uso terapéutico , Farmacorresistencia Bacteriana Múltiple , Mycobacterium tuberculosis/aislamiento & purificación , Vigilancia de la Población/métodos , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Adolescente , Adulto , Anciano , Niño , Preescolar , Femenino , Humanos , Incidencia , Lactante , Recién Nacido , Madagascar/epidemiología , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis/efectos de los fármacos , Estudios Retrospectivos , Tuberculosis Resistente a Múltiples Medicamentos/diagnóstico , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Adulto JovenRESUMEN
As a follow-up to the first AfroREB (Africa Rabies Expert Bureau) meeting, held in Grand-Bassam (Côte-d'Ivoire) in March 2008, African rabies experts of the Afro-REB network met a second time to complete the evaluation of the rabies situation in Africa and define specific action plans. About forty French speaking rabies specialists from Northern, Western and Central Africa and Madagascar met in Dakar (Senegal), from March 16th to 19th, 2009. With the participation of delegates from Tunisia, who joined the AfroREB network this year, 15 French speaking African countries were represented. Experts from the Institut Pasteur in Paris, the Alliance for Rabies Control, and the Southern and Eastern African Rabies Group (SEARG, a network of rabies experts from 19 English speaking Southern and Eastern African countries) were in attendance, to participate in the discussion and share their experiences. AfroREB members documented 146 known human rabies cases in all represented countries combined for 2008, for a total population of 209.3 million, or an incidence of 0.07 cases per 100,000 people. Even admitting that the experts do not have access to all reported cases, this is far from the WHO estimation of 2 rabies deaths per 100,000 people in urban areas and 3.6 per 100,000 in rural Africa. It was unanimously agreed that the priority is to break the vicious cycle of indifference and lack of information which is the main barrier to human rabies prevention.
Asunto(s)
Rabia/prevención & control , Animales , Congresos como Asunto , Notificación de Enfermedades , Enfermedades de los Perros/prevención & control , Enfermedades de los Perros/virología , Perros , Educación en Salud , Humanos , Vigilancia de la Población , Rabia/epidemiología , Rabia/veterinaria , Vacunas Antirrábicas , Vacunación/estadística & datos numéricos , Vacunación/veterinariaRESUMEN
Rabies experts from 14 francophone African countries met in Grand Bassam (Côte d'Ivoire), 10-13 March 2008. They presented the situation in their respective countries, acknowledging the lack of rabies awareness among the population, health care workers and health authorities. They recognized that infrastructure for the management of rabies exposure is scarce, modern vaccines are in limited quantity and immunoglobulins are lacking in most of their countries. They defined as a priority the need to have reliable figures on the disease burden, which is necessary for informed decision making and priority setting, and for applying for aid in controlling the disease. This meeting sealed the establishment of the Africa Rabies Expert Bureau (AfroREB).
Asunto(s)
Planificación en Salud , Rabia/epidemiología , Rabia/prevención & control , África , Animales , Niño , Preescolar , Conducta Cooperativa , Educación en Salud , HumanosRESUMEN
SETTING: The search continues for a simple, rapid culture system for the isolation of Mycobacterium tuberculosis in low-income countries. Bio FM (BIO-RAD) medium is an enriched 7H9 medium optimised for the growth of mycobacteria and contains a chromogenic indicator. OBJECTIVE: To evaluate the detection rate and time to detection of mycobacteria using the Bio FM system in comparison with the Löwenstein-Jensen (LJ) medium method routinely used in our laboratory. MATERIALS AND METHODS: A total of 270 pulmonary and 178 extra-pulmonary samples were cultured in parallel on Bio FM and LJ media. The mycobacterial detection rate and time were compared. RESULTS: The mycobacteria detection rate on Bio FM and LJ were not significantly different (respectively 97.9% and 93.15%, P > 0.05). The growth of M. tuberculosis was faster on Bio FM (mean 12.42 days [3-41] vs. 20.7 [10-48] days for LJ, P < 10(-6)). CONCLUSION: In our study, the culture method on liquid Bio FM medium was faster, but the detection rate was not better than with solid LJ medium.
Asunto(s)
Mycobacterium tuberculosis , Mycobacterium , Técnicas Bacteriológicas , Medios de Cultivo , Técnicas de Cultivo , Humanos , Laboratorios , Mycobacterium/aislamiento & purificación , Mycobacterium tuberculosis/aislamiento & purificación , Pobreza , Factores de TiempoRESUMEN
UNLABELLED: An epidemiological investigation (Ministry of Health/Institut Pasteur de Madagascar (IPM)) was conducted in July 2002, in two districts of a same province (Fianarantsoa: Fianarantsoa II and Ikongo) considering the high frequency of deaths linked with acute respiratory infection (ARI). Morbidity and mortality data was collected in the Centre de Santé de Base (CSB) which gave the alert (village of Sahafata, district Fianarantsoa II). Analysis of monthly activity reports (MAR) allowed calculation of incidence rates of ARI/pneumonia in Fianarantsoa province. Virological data was based on the analysis of nasopharyngeal samples collected during the investigations. Clinical symptoms and homogeneity of laboratory results are consistent with an origin of these epidemics being related to the circulation of an influenza virus A subtype H3N2. Attack rates were very high. CFR was significantly higher in individuals of less than 1 year and more than 65 years. This data was confirmed by posterior investigations of teams from MoH/WHO. Surprisingly, this large epidemic was due to a known influenza virus that previously circulated in countries of northern hemisphere (the year before) and even in Antananarivo weeks before. Different hypothesis could be proposed to explain such phenomenon: great restriction of exchanges between different geographical zones, nutritional status.... CONCLUSION: The epidemic episodes of acute respiratory infections in Madagascar in July 2002 were due to an influenza virus A subtype H3N2 without any genotypic or phenotypic features. Various factors, could explain the importance of the epidemic and particular high lethality found in some age groups. This epidemic illustrates the relative incapacity for a developing country, to face and manage a flu epidemic caused by a classical influenza virus.
Asunto(s)
Brotes de Enfermedades/estadística & datos numéricos , Virus de la Influenza A , Infecciones del Sistema Respiratorio/epidemiología , Enfermedad Aguda , Adolescente , Adulto , Distribución por Edad , Anciano , Causas de Muerte , Niño , Preescolar , Notificación de Enfermedades , Métodos Epidemiológicos , Humanos , Incidencia , Lactante , Madagascar/epidemiología , Persona de Mediana Edad , Morbilidad , Nasofaringe/virología , Vigilancia de la Población , Características de la Residencia/estadística & datos numéricos , Infecciones del Sistema Respiratorio/diagnóstico , Infecciones del Sistema Respiratorio/virología , Factores de Riesgo , Estaciones del AñoRESUMEN
The wide geographic distribution of the West Nile virus and the increase in virulence observed since 1994 in the Mediterranean basin, central Europe and North America, with several outbreaks of lethal encephalitis, demonstrate the importance of regular surveillance of the epidemiological data regarding this virus in the world. The Institut Pasteur de Madagascar has shown between 1975 and 1990 that this arbovirus was most abundant in Madagascar, where it had an endemic circulation. There has been no further study since that time. In order to evaluate the level of circulation, the seroprevalence of anti-West Nile antibodies in children that are 15 or less was measured on two different collections of sera. These collections came from population studies realised respectively in the region of Ambositra in the Highlands in 1996 and in the city of Mahajanga on the north west coast in 1999. The seroprevalence were 2.1% and 10.6% respectively, these results indicate that the circulation of this climatic dependent virus is still significant.
Asunto(s)
Enfermedades Endémicas/estadística & datos numéricos , Fiebre del Nilo Occidental/epidemiología , Academias e Institutos , Adolescente , Distribución por Edad , Animales , Anticuerpos Antivirales/sangre , Niño , Preescolar , Clima , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunoglobulina G/sangre , Lactante , Insectos Vectores/virología , Madagascar/epidemiología , Masculino , Vigilancia de la Población , Características de la Residencia/estadística & datos numéricos , Salud Rural/estadística & datos numéricos , Estudios Seroepidemiológicos , Distribución por Sexo , Salud Urbana/estadística & datos numéricos , Fiebre del Nilo Occidental/sangre , Fiebre del Nilo Occidental/inmunología , Fiebre del Nilo Occidental/transmisión , Fiebre del Nilo Occidental/virología , Virus del Nilo Occidental/inmunología , Virus del Nilo Occidental/patogenicidadRESUMEN
Being associated to fecal-oral transmission, cysticercosis is contracted either by auto-infection or by ingestion of food contaminated with eggs from the pork tape worm (Taenia solium). In the stomach, the larvae named cysticercus (Cysticercus cellulosae) hatches from the eggs and invades the host through the mucosa membrane. Human cysticercosis occurs in highly prevalent proportions in many developing countries including Madagascar where hygiene conditions are deplicable. Serology tests applicable to epidemiological surveillance of cysticercosis and associated pathology in the Malagasy population have been developed: an enzyme-linked immunosorbent assay (ELISA) for screening purpose, and an enzyme-linked immunoelectrotransfer blot assay (EITB) for confirmative testing. Two specific bands (13 and 14 kDa) have been identified as significant markers of the cysticercus in an active (vesicle) stage of the infection when cestocidal treatment is strongly indicated. The same bands may on the other hand be absent at early (cyste) as well as late (calcified) stages of the infection. Series of studies, including 4,375 serum samples, have been undertaken from 1994 until 1999 aiming at determinating the cysticercosis sero-prevalence in different provinces of Madagascar. It was confirmed that cysticercosis is highly frequent on the island, and that there exists a marked variation in the prevalence from 7 to 21% between the different provinces: less than 10% in coastal regions (Mahajanga and Toamasina) increasing to 20% in central regions (Ihosy, Ambositra and Mahasolo). It has also been observed that cysticercosis may occur in individuals at any age, and that it is equally distributed in urban as in rural areas. However, it is more frequently detected in women than in men. Madagascar is an endemic country for cysticercosis, which causes major and severe disease with implications in the public health sector. A national control program is, therefore, urgently warranted.
Asunto(s)
Cisticercosis/epidemiología , Enfermedades Endémicas/estadística & datos numéricos , Adolescente , Adulto , Distribución por Edad , Anciano , Niño , Estudios Transversales , Cisticercosis/complicaciones , Cisticercosis/diagnóstico , Cisticercosis/prevención & control , Cisticercosis/transmisión , Huevos/parasitología , Enfermedades Endémicas/prevención & control , Ensayo de Inmunoadsorción Enzimática , Epilepsia/parasitología , Heces/parasitología , Femenino , Desinfección de las Manos , Humanos , Técnicas para Inmunoenzimas , Madagascar/epidemiología , Masculino , Tamizaje Masivo/métodos , Tamizaje Masivo/normas , Persona de Mediana Edad , Evaluación de Necesidades , Vigilancia de la Población/métodos , Características de la Residencia/estadística & datos numéricos , Estudios Seroepidemiológicos , Distribución por Sexo , Cuartos de Baño/estadística & datos numéricosRESUMEN
Epidemics of acute respiratory infections in Madagascar in 2002 : from alert to confirmation : An epidemiological investigation (Ministry of Health/Institut Pasteur de dagascar (IPM)) was conducted in July 2002; in two districts of a same province (Fianarantsoa : Fianarantsoa II and Ikongo) considering the high frequency of deaths linked with acute respiratory infection (ARI). Morbidity and mortality data was collected in the Centre de Sante de Base (CSB) which gave the alert (village of Sahafata; district Fianarantsoa II). Analysis of monthly activity reports (MAR) allowed calculation of incidence rates of ARI/pneumonia in Fianarantsoa province. Virological data was based on the analysis of nasopharyngal samples collected during the investigations. Clinical symptoms and homogeneity of laboratory results are consistent with an origin of these epidemics being related to the circulation of an influenza virus A subtype H3N2. Attack rates were very high. CFR was significantly higher in individuals of less than 1 year and more than 65 years. This data was confirmed by posterior investigations of teams from MoH/WHO. Surprisingly; this large epidemic was due to a known influenza virus that previously circulated in countries of northern hemisphere (the year before) and even in Antananarivo weeks before. Different hypothesis could be proposed to explain such phenomenon : great restriction of exchanges between different geographical zones; nutritional status
Asunto(s)
Brotes de Enfermedades , Humanos/prevención & control , Gripe Humana , Síndrome Respiratorio Agudo GraveRESUMEN
Persistence of an endemic circulation of the virus West Nile in Madagascar:The wide geographic distribution of the West Nile virus and the increase in virulence observedsince 1994 in the Mediterranean basin; central Europe and north America; with several outbreaks of lethal encephalitis; demonstrate the importance of regular surveillance of the epidemiological data regarding this virus in the world. The Institut Pasteur de Madagascar has shown between 1975 and 1990 that this arbovirus was most abundant in Madagascar; where it had an endemic circulation. There has been no further study since that time. In order to evaluate the level of circulation; the seroprevalence of nti-West Nile antibodies in children that are 15 or less was measured on two different collections of sera. These collections came from population studies realised respectively in the region of Ambositra in the Highlands in 1996 and in the city of Mahajanga on the north west coast in 1999. The seroprevalence were 2.1
Asunto(s)
Anticuerpos , ArbovirusRESUMEN
The first case of plague was introduced in Madagascar in 1898 in the east coast by way of boat from India. In 1921, plague reach the highlands and a large epidemic over the next twenty years. Until the beginning of the 80's, only of few case were identified, notified mostly in rural setting. However gradually it has re-emerged as a public health problem. Urban plague is located in the city of Antananarivo (resurgence in 1978 after 28 years of apparent silence) and in Mahajanga port (resurgence in 1991 after 63 years of silence). The reactivation of the Plague National Control Program from 1994 will allow better surveillance. The aim of this analysis is to update the epidemiological data on human plague in Madagascar based on reported cases obtained from the Central Lab of the Pasteur Institute of Madagascar from 1980 to 2001 (16,928 suspected cases of which 3,500 are likely positives or confirmed positives). The Plague season runs from October to March on the central highlands and July to November on the north-western coast. Sex-ratio male/female is 1.3/1, and the age-group of 5 to 25 years is more affected. The case fatality rate was 40% in the beginning of the 1980's, and decreased to 20% by the end of the 1990's. The percentage of case with pulmonary plague decrease from 15% to less than 5%. However, geographical extension is demonstrated: 4 districts in 1980, 30 districts in 1999 and 21 districts in 2001. In 2002, the diffusion of a new rapid test (reagent strip) in the primary health centres (CSB) in 42 endemic districts may help to decrease the morbidity and the letality due to plague and improve its control at the national level.
Asunto(s)
Brotes de Enfermedades/estadística & datos numéricos , Peste/epidemiología , Adolescente , Adulto , Distribución por Edad , Niño , Preescolar , Notificación de Enfermedades , Femenino , Humanos , Incidencia , Madagascar/epidemiología , Masculino , Persona de Mediana Edad , Morbilidad , Peste/diagnóstico , Peste/prevención & control , Vigilancia de la Población , Tiras Reactivas , Salud Rural/estadística & datos numéricos , Estaciones del Año , Distribución por Sexo , Salud Urbana/estadística & datos numéricosRESUMEN
La peste est entrée à Madagascar en 1898, à partir du port de Toamasina, suite à l'escale d'un bâteau venant d'Inde. En 1921, elle arrive à Antananarivo et s'étend sur les Hautes Terres Centrales en y provoquant des épidémies sans précédent pendant près de 20 ans. Jusqu'au début des années 1980, elle a persisté à bas bruit surtout en milieu rural, avant de connaître une reviviscence au point de constituer un problème de santé publique de nos jours. La peste urbaine existe surtout dans la ville d'Antananarivo (réémergence en 1978 après 28 ans de silence apparent) et dans le port de Mahajanga (réémergence en 1991 après 63 ans de silence apparent). La re-dynamisation du programme national de lutte contre la peste, à partir de 1994, a permis une meilleure surveillance de la maladie. Cette analyse a pour objectif une actualisation des données épidémiologiques de la peste humaine à Madagascar, à partir des cas déclarés (16 928 cas suspects dont 3 500 confirmés ou probables) obtenus au Laboratoire Central à l'Institut Pasteur de Madagascar de 1980 à 2001. La saison pesteuse sur les hautes terres se situe d'octobre à mars et celle de la ville de Mahajanga de juillet à novembre. Le sex-ratio homme/femme est de 1,3/1, la tranche d'âge la plus touchée est celle des sujets âgés de 5 à 25 ans. Le taux de létalité de 40% au début des années 1980 a diminué à 20% vers la fin des années 1990, le pourcentage de formes pulmonaires est passé de 15% à moins de 5%, indiquant une amélioration de la prise en charge des cas. Par contre, on a assisté à une extension géographique de l'endémie pesteuse dans le pays : 4 districts confirmés en 1980, un pic de 30 districts en 1999 et 21 districts en 2001. En 2002, la diffusion d'un nouveau test de diagnostic rapide de la peste (bandelettes), dans les centres de santé de base des 42 districts endémiques, devrait contribuer à diminuer la morbidité et la létalité due à la peste, et améliorer sa surveillance au niveau national
Asunto(s)
Madagascar , Peste/diagnóstico , Peste/epidemiología , Peste/prevención & controlRESUMEN
To assess the impact of mass vaccination campaigns using oral poliovirus vaccine (OPV) in Madagascar, serum neutralizing antibodies and geometrical mean titres (GMTs) to poliovirus were measured among 472 children aged up to 59 months, before and after the mass campaign, regardless of their previous history of routine vaccination. In this study, overall coverage with three routine and two mass campaign OPV doses was 69.9 and 93.4%, respectively. Seroprevalences to all poliovirus types were significantly higher after the mass campaign among the children who were not vaccinated through routine programme: 67.5% vs. 90.2% (P < 0.001) for type 1; 66.7% vs. 95.1% (P < 0.001) for type 2; and 55.3% vs. 82.9% (P < 0.001) for type 3. Geometrical mean titres to all poliovirus types also significantly increased after the mass campaign among the same study group: 34.5 vs. 238.9 (P < 0.001) for type 1; 35.1 vs. 402.6 (P < 0.001) for type 2; and 13.3 vs. 92.6 (P < 0.001) for type 3. Post-mass campaign seroprevalences and GMTs for poliovirus, especially types 1 and 3, among children who received up to two routine and two mass campaign OPV doses were significantly higher than pre-mass campaign seroprevalences among children who received three routine OPV doses. Reasons for lack of adherence to the vaccination programme and the mass campaign are discussed. The findings strongly support the WHO strategy of conducting mass campaign in all endemic countries. However, as the mass campaign strategy now has been discontinued, it is crucial to increase the routine coverage and to improve acute flaccid paralysis surveillance in order to fulfil the goal of poliomyelitis eradication.
Asunto(s)
Programas de Inmunización , Poliomielitis/inmunología , Poliomielitis/prevención & control , Vacuna Antipolio Oral/administración & dosificación , Poliovirus/inmunología , Anticuerpos Antivirales/sangre , Niño , Preescolar , Femenino , Humanos , Esquemas de Inmunización , Lactante , Recién Nacido , Madagascar , Masculino , Pruebas de Neutralización , Vacuna Antipolio Oral/inmunología , VacunaciónRESUMEN
Between the 20th October and the 18th November 1998, an outbreak of bubonic plague was declared in a hamlet in the Ikongo district of Madagascar. We conducted an epidemiological survey because of the re-emergence of the disease in this area (the last cases had been notified in 1965) and because of the low altitude compared to the classical Malagasy foci. The outbreak had been preceded by an important rat epizootics during September. A total of 21 cases were registered with an attack rate of 16.7% (21/126) and a lethality rate of 33% (7/21). The disease was more prevalent in males (66% of cases) and children aged < 15 years, as observed in general throughout the country. The anti-F1 seroprevalence among the contact population was 13.5% (13/96), probably attributable to subclinical infection by Yersinia pestis. No rodent was trapped during the survey, but an endemic hedgehog (Tenrec ecaudatus) was highly seropositive, suggesting a recent transmission of the plague bacillus among this species. The small mammals and vectors possibly involved in these new foci were investigated in May 1999.
Asunto(s)
Brotes de Enfermedades , Peste/epidemiología , Adolescente , Animales , Anticuerpos Antibacterianos/sangre , Niño , Preescolar , Femenino , Erizos/microbiología , Humanos , Madagascar/epidemiología , Masculino , Peste/transmisión , Yersinia pestis/inmunologíaRESUMEN
Our survey of mammals and fleas arose as a result of an outbreak of bubonic plague at an usually low altitude in the Ikongo district (Madagascar), while a previous study had found anti-F1 antibodies in an endemic hedgehog. Animals were sampled with live traps in two hamlets (Antanambao-Vohidrotra, 540 m alt. and Ambalagoavy, 265 m alt.) and with pitfall traps in a neighbouring forest (750 m alt.). Rat fleas were collected by brushing the fur and free-living fleas by use of light traps. The introduced shrew Suncus murinus was found only in the village of Ambalagoavy while the black rat (Rattus rattus) was found in all three sites and the only seropositive rat was caught at Antanambao-Vohidrotra. In contrast, among the Tenrecidae (endemic shrews and hedgehogs) found in the forest near the first village, four animals were found seropositive for anti-F1 antibodies. One of them was carrying the endemic flea Paractenopsyllus pauliani, not yet reported as a vector of plague. The endemic vector of plague, Synopsyllus fonquerniei, was found only in the first village of Antanambao-Vohidrotra, and the cosmopolite flea Xenopsylla cheopis only in Ambalagoavy. Although no Yersinia pestis could be isolated and no F1-antigen could be detected in these animals, we found evidence of the recent transmission of plague in Antanambao-Vohidrotra and the nearby forest, but not in Ambalagoavy. These data corroborate with the sylvatic plague cycle hypothesis in Madagascar and its involvement in the outcome of the bubonic plague outbreak in this district.
Asunto(s)
Brotes de Enfermedades , Reservorios de Enfermedades , Vectores de Enfermedades , Peste/epidemiología , Animales , Anticuerpos Antibacterianos/sangre , Erizos/microbiología , Humanos , Madagascar/epidemiología , Muridae/microbiología , Peste/transmisión , Ratas , Musarañas/microbiología , Siphonaptera/microbiología , Yersinia pestis/inmunologíaRESUMEN
Plague was introduced to Madagascar in 1898, and it has been characterized by a predominant distribution to the central highlands in the following decades. An increase of plague cases has been observed in the past 20 years, in particular in the capital, Antananarivo, and in the coastal town, Mahajanga, after long periods of silence in 28 and 63 years, respectively. A total of 2,982 confirmed or presumptive cases were reviewed in order to describe the changes in the epidemiological pattern of the disease from 1980 through 1999. The mean annual number of plague cases has increased from 33 during the 1980-1984 period to 298 during the 1995-1999 period. A similar trend of distribution has been observed from the first period to the second by an increase of endemic districts above 800 m altitude from 17 to 37. However, the lethality rate has in the same 20 years observation period decreased from 41.6% to 20.7%, probably due to re-enforcing measures as part of the national control program.
Asunto(s)
Enfermedades Transmisibles Emergentes/epidemiología , Brotes de Enfermedades/estadística & datos numéricos , Enfermedades Endémicas/estadística & datos numéricos , Peste/epidemiología , Altitud , Causas de Muerte/tendencias , Enfermedades Transmisibles Emergentes/microbiología , Humanos , Incidencia , Madagascar/epidemiología , Peste/microbiología , Vigilancia de la PoblaciónRESUMEN
The transmission of Yersinia pestis is intense among rats in the wholesale market Tsenabe Isotry in the capital Antananarivo (anti-F1 sero-prevalence 80%, flea index 8.4 for a cut-off risk index of > 1). However, the number of plague-suspected (not laboratory confirmed) human cases has only been 3 in this district during a four years period from 1995 to 1999. A seroepidemiological survey among the market vendors was undertaken in June 1999 to test the hypothesis that the low incidence of human plague is due to acquired immunity. In addition, surveillance of the rat and the flea populations in the market was carried out. Only 3 (3.2%) of 95 screened vendors were anti-F1 IgG positive, whereas the markers of plague transmission among rodents and fleas were still high. This result suggests that the low incidence of human plague was not due to acquired immunity but to other factors such as the limited contact between humans and the rat fleas because of the abundance of rats, the absence of epizootic due to the resistance of rats in the capital and a particular behaviour of the predominant rat Rattus norvegicus.
Asunto(s)
Comercio/estadística & datos numéricos , Brotes de Enfermedades/estadística & datos numéricos , Peste/epidemiología , Salud Urbana/estadística & datos numéricos , Adolescente , Adulto , Anciano , Animales , Anticuerpos Antibacterianos/sangre , Proteínas Bacterianas/inmunología , Vectores de Enfermedades , Femenino , Humanos , Inmunidad Activa/inmunología , Incidencia , Madagascar/epidemiología , Masculino , Persona de Mediana Edad , Peste/sangre , Peste/inmunología , Peste/transmisión , Densidad de Población , Vigilancia de la Población , Ratas/microbiología , Ratas/fisiología , Factores de Riesgo , Estudios Seroepidemiológicos , Siphonaptera/microbiología , Siphonaptera/fisiología , Encuestas y CuestionariosRESUMEN
Après avoir touché Madagascar en 1898, la peste a atteint Antananarivo en 1921 et s'est étendue sur les Hautes Terres Centrales où elle persiste jusqu'à nos jours. Une recrudescence des cas a été constatée depuis une vingtaine d'années pendant lesquelles, la peste a réemergé dans la capitale Antananarivo et, dans le port de Mahajanga après respectivement 28 et 63 ans de silence apparent. Le programme national de lutte et de surveillance a, de ce fait, été renforcé. L'évolution de l'endémie dans le temps et dans l'espace au cours de cette période a été analysée à partir de 2 982 cas bactériologiquement confirmés ou probables(sex-ratio H/F : 1,3/1). L'incidence annuelle moyenne des cas de peste confirmés ou probables est passée de 33 pendant la période 1980-1984 à 298 pendant la période 1995-1999. Cette augmentation s'est accompagnée d'une large extension géographique de la zone d'endémie, passant de 17 à 37 districts pour la plupart situés à plus de 800 m d'altitude, sauf le port de Mahajanga. Par contre, le taux de létalité a baissé pendant la même période, passant de 41,6% à 20,7%. Un des objectifs des recherches actuelles est une meilleure compréhension des différents cycles épidémiologiques de la peste à Madagascar, afin d'améliorer les stratégies de lutte
Asunto(s)
Madagascar , Peste/epidemiología , RecurrenciaRESUMEN
La surveillance de la peste murine en 1995 dans le marché de gros Tsenabe Isotry à Antananrivo a montré une circulation intense du bacille pesteux (80% de rats séropositifs) et un index cheopis (8,4) supérieur au seuil classique de risque épidémique (>1). Pourtant, le nombre de malades suspects déclarés dans ce quartier est très faible (3 cas suspects sans confirmation de 1995 à 1999). Dans le but de vérifier si la faible incidence de la peste humaine pouvait être due à l'acquisition d'une immunité, une enquête séroépidémiologique a été menée auprès des marchands en juin 1999 associée à l'analyse des données de la surveillance des rongeurs entre 1998 1999. La séroprévalence des porteurs d'anticorps anti-F1 est de 3,2% (3/95 marchands), alors que les marqueurs de la transmission de la peste chez les rongeurs et les puces continuent d'être très élevés. Ces résultats suggèrent que l'incidence de la peste parmi les marchands n'est pas liée à une immunité acquise, mais probablement à d'autres facteurs : le faible contact entre l'homme et les puces de rat en raison de l'abondance des rats, l'absence d'épizootie murine due à la résistance des rats de la capitale et le comportement du rongeur prédominant Rattus norvegicus moins commensal que R. rattus
Asunto(s)
Bacteriología , Madagascar , Peste/epidemiologíaRESUMEN
Plague is still prevalent in more than 20 countries. Two F1 antigen diagnostic assays (an immunocapture ELISA and an immunogold chromatography dipstick) were evaluated using bubo aspirates, serum and urine specimens from patients suspected with plague. The specificity of the two F1 assays was found 100%. Using bacteriology as a gold reference diagnostic assay, 52 patients were Yersinia pestis culture positive and 141 negative. The sensitivity of the F1 ELISA test was 100% in bubo, 52% in serum and 58% in urine specimens. In culture negative patients, the F1 antigen could be found in 10% bubo aspirates, 5% serum and 7% urine specimens of culture negative patients for whom a seroconversion for anti-F1 antibodies was also observed. The sensitivity of the dipstick assay was 98% on bubo aspirates specimens. Compared to the ELISA test, the agreement rate was 97.5% and the correlation coefficient tau = 0.90 (p < 10(-3)). In conclusion, the diagnosis of bubonic plague has to be performed on bubo fluid rather than on serum or urine specimens. Both the F1 ELISA and the dipstick assays are valuable tools for an early diagnosis and for the surveillance of plague.
Asunto(s)
Antígenos Bacterianos/análisis , Proteínas Bacterianas/análisis , Peste/diagnóstico , Yersinia pestis , Anticuerpos Monoclonales , Antígenos Bacterianos/sangre , Antígenos Bacterianos/orina , Proteínas Bacterianas/sangre , Proteínas Bacterianas/orina , Brotes de Enfermedades , Ensayo de Inmunoadsorción Enzimática , Humanos , Inmunohistoquímica , Madagascar , Peste/inmunología , Sensibilidad y EspecificidadRESUMEN
We conducted a seroepidemiological survey of human plague in the general population using random sampling in the area of Ambositra, the main focus of plague in the central highlands of Madagascar (520 confirmed and presumptive cases notified during the past 10 years). Sera were tested using an ELISA IgG F1 assay. Considering the internal validity of the assay and the sampling method, the overall corrected prevalence of F1 antibodies was 0.6% (95% CI: 0.2%-1.8%). Being nearly 0 up to the age of 40, the corrected prevalence increased markedly after 45 years to 6.2%. Six of 20 individuals who declared to have been treated for clinical suspicion of bubonic plague in the past had F1 antibodies. The seroprevalence did not differ according to gender except in individuals > 60, where antibodies were significantly more frequent in males. This study suggests that the number of clinically suspected cases of plague provided by the surveillance network was plausible, despite some true cases being missed and a significant number of false positives. We also confirm that Yersinia pestis infections may occur without marked clinical manifestations and patients may recover without treatment, in accordance with old observations of pestis minor.