RESUMO
Data from the Mexican national leprosy control programme 1989-2009 are described and analysed. After initial increases associated with the introduction of MDT and the start of the global elimination initiative in the early 1990 s, both prevalence and incidence declined dramatically throughout most of the country. Reported prevalence fell below 1 per 10000 in 1994 and has remained below that level ever since. There is considerable geographic heterogeneity, with highest case detection rates in western states bordering the Pacific and lowest in the south east. Reasons for these geographic differences are unclear. There is evidence of increases in average age of cases, and in proportions male and MB, as in several other populations with declining leprosy. There is some evidence of increasing leprosy in states bordering on Texas, USA, where M. leprae is known to be harboured in armadillos. The relevance of armadillos for leprosy in Mexico is unclear but a priority question.
Assuntos
Hanseníase/epidemiologia , Distribuição por Idade , Feminino , Humanos , Incidência , Masculino , México/epidemiologia , Prevalência , Distribuição por SexoRESUMO
BACKGROUND: Eight outbreaks of paralytic polio attributable to circulating vaccine-derived poliovirus (cVDPV) have highlighted the risks associated with oral poliovirus vaccine (OPV) use in areas of low vaccination coverage and poor hygiene. As the Polio Eradication Initiative enters its final stages, it is important to consider the extent to which these viruses spread under different conditions, so that appropriate strategies can be devised to prevent or respond to future cVDPV outbreaks. METHODS AND FINDINGS: This paper examines epidemiological (temporal, geographic, age, vaccine history, social group, ascertainment), and virological (type, genetic diversity, virulence) parameters in order to infer the numbers of individuals likely to have been infected in each of these cVDPV outbreaks, and in association with single acute flaccid paralysis (AFP) cases attributable to VDPVs. Although only 114 virologically-confirmed paralytic cases were identified in the eight cVDPV outbreaks, it is likely that a minimum of hundreds of thousands, and more likely several million individuals were infected during these events, and that many thousands more have been infected by VDPV lineages within outbreaks which have escaped detection. CONCLUSIONS: Our estimates of the extent of cVDPV circulation suggest widespread transmission in some countries, as might be expected from endemic wild poliovirus transmission in these same settings. These methods for inferring extent of infection will be useful in the context of identifying future surveillance needs, planning for OPV cessation and preparing outbreak response plans.
Assuntos
Poliomielite/epidemiologia , Poliomielite/etiologia , Vacinas contra Poliovirus/efeitos adversos , Adolescente , Distribuição por Idade , Criança , Pré-Escolar , Surtos de Doenças/estatística & dados numéricos , República Dominicana/epidemiologia , Egito/epidemiologia , Variação Genética/fisiologia , Haiti/epidemiologia , Humanos , Indonésia/epidemiologia , Lactente , Poliomielite/imunologia , Poliomielite/virologia , Poliovirus/genética , Poliovirus/isolamento & purificação , Vacinas contra Poliovirus/genética , Vacinas contra Poliovirus/imunologia , Vigilância da População , Classe SocialRESUMO
Leprosy, a chronic human disease with potentially debilitating neurological consequences, results from infection with Mycobacterium leprae. This unculturable pathogen has undergone extensive reductive evolution, with half of its genome now occupied by pseudogenes. Using comparative genomics, we demonstrated that all extant cases of leprosy are attributable to a single clone whose dissemination worldwide can be retraced from analysis of very rare single-nucleotide polymorphisms. The disease seems to have originated in Eastern Africa or the Near East and spread with successive human migrations. Europeans or North Africans introduced leprosy into West Africa and the Americas within the past 500 years.
Assuntos
Humanos , História Antiga , História Medieval , História do Século XVIII , História do Século XIX , Ásia/epidemiologia , América/epidemiologia , Pseudogenes , Genoma Bacteriano , Análise de Sequência com Séries de Oligonucleotídeos , Polimorfismo de Nucleotídeo Único , África/epidemiologia , Emigração e Imigração , Europa (Continente)/epidemiologia , Genes Bacterianos , Hanseníase/história , Hanseníase/microbiologia , Hanseníase/transmissão , Hanseníase/epidemiologia , Mycobacterium leprae/classificação , Mycobacterium leprae/genéticaRESUMO
We have previously shown that young adults living in a rural area of northern Malawi showed greater gamma interferon (IFN-gamma) responses to purified protein derivatives (PPD) prepared from environmental mycobacteria than to PPD from Mycobacterium tuberculosis. In order to define the mycobacterial species to which individuals living in a rural African population have been exposed and sensitized, we tested T-cell recognition of recombinant and purified antigens from M. tuberculosis (38 kDa, MPT64, and ESAT-6), M. bovis (MPB70), M. bovis BCG (Ag85), and M. leprae (65 kDa, 35 kDa, and 18 kDa) in >600 non-M. bovis BCG-vaccinated young adults in the Karonga District of northern Malawi. IFN-gamma was measured by enzyme-linked immunosorbent assay (ELISA) in day 6 supernatants of diluted whole-blood cultures. The recombinant M. leprae 35-kDa and 18-kDa and purified native M. bovis BCG Ag85 antigens induced the highest percentages of responders, though both leprosy and bovine tuberculosis are now rare in this population. The M. tuberculosis antigens ESAT-6 and MPT64 and the M. bovis antigen MPB70 induced the lowest percentages of responders. One of the subjects subsequently developed extrapulmonary tuberculosis; this individual had a 15-mm-diameter reaction to the Mantoux test and responded to M. tuberculosis PPD, Ag85, MPT64, and ESAT-6 but not to any of the leprosy antigens. We conclude that in this rural African population, exposure to M. tuberculosis or M. bovis is much less frequent than exposure to environmental mycobacteria such as M. avium, which have antigens homologous to the M. leprae 35-kDa and 18-kDa antigens. M. tuberculosis ESAT-6 showed the strongest association with the size of the Mantoux skin test induration, suggesting that among the three M. tuberculosis antigens tested it provided the best indication of exposure to, or infection with, M. tuberculosis.
Assuntos
Feminino , Masculino , Adolescente , Adulto , Criança , Humanos , Antígenos de Bactérias , Especificidade da Espécie , Hanseníase , Interferon gama , Linfócitos T , Malaui , Mycobacterium , Mycobacterium bovis , Mycobacterium leprae , Mycobacterium tuberculosis , Proteínas Recombinantes de Fusão , Teste Tuberculínico , Tuberculose , Vacina BCG , VacinaçãoAssuntos
Adolescente , Antígenos de Bactérias/imunologia , Fatores Epidemiológicos , Fatores Etários , Fatores Sexuais , Hanseníase/diagnóstico , Hanseníase/imunologia , Hanseníase/microbiologia , Hipersensibilidade Tardia/microbiologia , Malaui , Mycobacterium leprae/imunologia , Razão de Chances , Testes CutâneosRESUMO
Data analyzed in this paper were collected within the framework of the Lepra Evaluation Project, an epidemiological study of leprosy in Karonga District, northern Malawi. For 212 patients information on the number of skin lesions, slit-skin smear and skin biopsy results were available. Among 61 patients with a single lesion none were slit-skin-smear positive and two had bacilli detected in skin biopsies. In contrast, among 119 patients with four or more lesions 34 (28.6%) versus 59 (49.6%) had bacilli detectable in slit-skin smears or skin biopsies, respectively. In a further 47 patients skin biopsy results could be compared with split-nerve biopsy results. In 20 of 47 patients the bacterial indexes (BIs) were identical in skin and nerve biopsies, while in 26 of 47 patients the BIs were higher in nerve than in skin biopsies. This difference, which is consistent with several other studies in the literature, provides an insight into the pathogenesis of leprosy.