RESUMEN
Plague, caused by the Yersinia pestis bacterium, has several foci scattered throughout a large area from the Brazilian territory that ranges from the Northeastern State of Ceará to the Southeastern State of Minas Gerais and another separated area at the State of Rio de Janeiro. This review gathers data from plague control and surveillance programs on the occurrence and geographic distribution of rodent hosts and flea vectors in the Brazilian plague areas during the period of from 1952 to 2019. Furthermore, we discuss how the interaction between Y. pestis and some rodent host species may play a role in the disease dynamics. The absence of human cases nowadays in Brazil does not mean that it was eradicated. The dynamics of plague in Brazil and in other countries where it was introduced during the 3rd pandemic are quite alike, alternating epidemics with decades of quiescence. Hence, it remains an important epidemic disease of global concern. The existence of a large animal reservoir and competent vectors demonstrate a need for continuous surveillance to prevent new outbreaks of this disease in humans.
Asunto(s)
Insectos Vectores/microbiología , Peste/transmisión , Roedores/parasitología , Siphonaptera/microbiología , Yersinia pestis/fisiología , Zoonosis/transmisión , Animales , Brasil/epidemiología , Humanos , Peste/epidemiología , Zoonosis/microbiologíaRESUMEN
As a zoonosis, Plague is also an ecological entity, a complex system of ecological interactions between the pathogen, the hosts, and the spatiotemporal variations of its ecosystems. Five reservoir system models have been proposed: (i) assemblages of small mammals with different levels of susceptibility and roles in the maintenance and amplification of the cycle; (ii) species-specific chronic infection models; (ii) flea vectors as the true reservoirs; (iii) Telluric Plague, and (iv) a metapopulation arrangement for species with a discrete spatial organization, following a source-sink dynamic of extinction and recolonization with naïve potential hosts. The diversity of the community that harbors the reservoir system affects the transmission cycle by predation, competition, and dilution effect. Plague has notable environmental constraints, depending on altitude (500+ meters), warm and dry climates, and conditions for high productivity events for expansion of the transmission cycle. Human impacts are altering Plague dynamics by altering landscape and the faunal composition of the foci and adjacent areas, usually increasing the presence and number of human cases and outbreaks. Climatic change is also affecting the range of its occurrence. In the current transitional state of zoonosis as a whole, Plague is at risk of becoming a public health problem in poor countries where ecosystem erosion, anthropic invasion of new areas, and climate change increase the contact of the population with reservoir systems, giving new urgency for ecologic research that further details its maintenance in the wild, the spillover events, and how it links to human cases.
Asunto(s)
Reservorios de Enfermedades/microbiología , Fenómenos Ecológicos y Ambientales , Peste/epidemiología , Peste/transmisión , Yersinia pestis/fisiología , Zoonosis , Animales , Cambio Climático , Brotes de Enfermedades/prevención & control , Humanos , Modelos Biológicos , Peste/microbiología , Salud Pública/estadística & datos numéricos , Salud Pública/tendencias , Estaciones del Año , Siphonaptera/microbiología , Especificidad de la Especie , Yersinia pestis/aislamiento & purificaciónRESUMEN
Invasive transformer species change the character, condition, form, or nature of ecosystems and deserve considerable attention from conservation scientists. We applied the transformer species concept to the plague bacterium Yersinia pestis in western North America, where the pathogen was introduced around 1900. Y. pestis transforms grassland ecosystems by severely depleting the abundance of prairie dogs (Cynomys spp.) and thereby causing declines in native species abundance and diversity, including threatened and endangered species; altering food web connections; altering the import and export of nutrients; causing a loss of ecosystem resilience to encroaching invasive plants; and modifying prairie dog burrows. Y. pestis poses an important challenge to conservation biologists because it causes trophic-level perturbations that affect the stability of ecosystems. Unfortunately, understanding of the effects of Y. pestis on ecosystems is rudimentary, highlighting an acute need for continued research.
La Bacteria de la Peste como una Especie Transformadora en los Perritos de las Praderas y los Pastizales del Oeste de Norteamérica Resumen Las especies invasoras transformadoras cambian el carácter, la condición, la forma o la naturaleza de los ecosistemas y merecen atención considerable por parte de los científicos de la conservación. Aplicamos el concepto de especie transformadora a la bacteria de la peste Yersinia pestis en el oeste de Norteamérica, en donde el patógeno fue introducido alrededor de 1900. Y. pestis transforma los ecosistemas de pastizal al disminuir severamente la abundancia de los perritos de las praderas (Cynomys spp.) y por lo tanto causa declinaciones en la abundancia y diversidad de las especies nativas, incluidas las especies amenazadas y en peligro; altera las conexiones de las redes alimenticias; altera la importación y exportación de nutrientes; causa la pérdida de resiliencia del ecosistema ante las plantas invasoras; y modifica las madrigueras de los perritos. Y. pestis es un reto importante para los biólogos de la conservación ya que causa perturbaciones de nivel trófico que afectan la estabilidad de los ecosistemas. Desafortunadamente, el entendimiento de los efectos de Y. pestis sobre los ecosistemas es rudimentario, lo que resalta una necesidad aguda de investigación continua.
Asunto(s)
Cadena Alimentaria , Pradera , Peste/veterinaria , Enfermedades de los Roedores/microbiología , Sciuridae , Yersinia pestis/fisiología , Animales , Canadá , Conservación de los Recursos Naturales , Especies Introducidas , México , Peste/microbiología , Estados UnidosRESUMEN
If a parasite is not detected during a survey, one of two explanations is possible: the parasite was truly absent or it was present but not detected. We fit occupancy models to account for imperfect detection when combing fleas (Siphonaptera) from black-tailed prairie dogs (Cynomys ludovicianus) during June-August 2012 in the Vermejo Park Ranch, New Mexico, USA. With the use of detection histories from combing events during monthly trapping sessions, we fit occupancy models for two flea species: Oropsylla hirusta (a prairie dog specialist) and Pulex simulans (a generalist). Detection probability was <100% for both species and about 21% lower for P. simulans. Pulex simulans may be especially difficult to detect because it is about half the size of O. hirusta. Monthly occupancy (prevalence) for P. simulans was estimated at 24% (June, 95% confidence intervalâ=â19-30), 39% (July, 32-47), and 56% (August, 49-64) in new prairie dog colonies, and 43% (32-54), 61% (49-71), and 79% (70-87) in old colonies. These results suggest P. simulans can attain high prevalence on prairie dogs, especially in old colonies. If P. simulans is highly prevalent on prairie dogs, it may serve as a "bridge vector" between Cynomys and other mammalian hosts of the plague bacterium Yersinia pestis, and even function as a reservoir of Y. pestis between outbreaks.
Asunto(s)
Infestaciones por Pulgas/veterinaria , Sciuridae , Siphonaptera/clasificación , Animales , Infestaciones por Pulgas/epidemiología , Insectos Vectores/microbiología , Modelos Biológicos , New Mexico/epidemiología , Peste/epidemiología , Peste/transmisión , Peste/veterinaria , Siphonaptera/microbiología , Especificidad de la Especie , Yersinia pestis/fisiologíaRESUMEN
The plague is an infectious disease that has transcended through history and has been responsible for three pandemics with high mortality rates. During the third pandemic that started in Hong Kong (1894), the disease spread through maritime routes to different regions in the world, including South America. In this region, approximately 16 million people are thought to be at risk in relation to this disease due to specific situations like human-rodent coexistence inside houses in rural areas, homes built with inadequate materials that are vulnerable to invasion by these animals, inappropriate storage of crops and an increase in rainfall and deforestation, which allows for the displacement of wild fauna and man invasion of the natural foci of the disease. Between 1994 and 1999, five countries: Bolivia, Brazil, Ecuador, Peru and the United States of America, reported approximately 1,700 cases with 79 related deaths. In Colombia we have historical data about an "infectious pneumonia" with high mortality rates that occurred during the same months, for three consecutive years (1913 to 1915) in the departments of Magdalena, Atlántico and Bolívar, located in the Colombian Atlantic coast, which suggested plague, but could not be confirmed.
Asunto(s)
Brotes de Enfermedades/historia , Peste/historia , África/epidemiología , Microbiología del Aire , Enfermedades de los Animales/diagnóstico , Enfermedades de los Animales/epidemiología , Enfermedades de los Animales/microbiología , Animales , Asia/epidemiología , Análisis por Conglomerados , Colombia/epidemiología , Reservorios de Enfermedades , Vectores de Enfermedades , Historia del Siglo XV , Historia del Siglo XIX , Historia del Siglo XX , Historia del Siglo XXI , Historia Antigua , Historia Medieval , Humanos , Mordeduras y Picaduras de Insectos/microbiología , Mascotas/parasitología , Peste/diagnóstico , Peste/transmisión , Peste/veterinaria , Roedores/parasitología , Estudios Seroepidemiológicos , Pruebas Serológicas , Navíos , América del Sur/epidemiología , Estados Unidos/epidemiología , Infección de Heridas/microbiología , Xenopsylla/microbiología , Yersinia pestis/fisiologíaRESUMEN
Plague occurs episodically in many parts of the world, and some outbreaks appear to be related to increased abundance of rodents and other mammals that serve as hosts for vector fleas. Climate dynamics may influence the abundance of both fleas and mammals, thereby having an indirect effect on human plague incidence. An understanding of the relationship between climate and plague could be useful in predicting periods of increased risk of plague transmission. In this study, we used correlation analyses of 215 human cases of plague in relation to precipitation records from 1948 to 1996 in areas of New Mexico with history of human plague cases (38 cities, towns, and villages). We conducted analyses using 3 spatial scales: global (El Niño-Southern Oscillation Indices [SOI]); regional (pooled state-wide precipitation averages); and local (precipitation data from weather stations near plague case sites). We found that human plague cases in New Mexico occurred more frequently following winter-spring periods (October to May) with above-average precipitation (mean plague years = 113% of normal rain/ snowfall), resulting in 60% more cases of plague in humans following wet versus dry winter-spring periods. However, we obtained significant results at local level only; regional state-wide precipitation averages and SOI values exhibited no significant correlations to incidence of human plague cases. These results are consistent with our hypothesis of a trophic cascade in which increased winter-spring precipitation enhances small mammal food resource productivity (plants and insects), leading to an increase in the abundance of plague hosts. In addition, moister climate conditions may act to promote flea survival and reproduction, also enhancing plague transmission. Finally, the result that the number of human plague cases in New Mexico was positively associated with higher than normal winter-spring precipitation at a local scale can be used by physicians and public health personnel to identify and predict periods of increased risk of plague transmission to humans.
Asunto(s)
Peste/epidemiología , Yersinia pestis/fisiología , Animales , Humanos , Incidencia , Insectos Vectores/crecimiento & desarrollo , New Mexico/epidemiología , Peste/transmisión , Lluvia , Análisis de Regresión , Roedores/crecimiento & desarrollo , Estaciones del Año , Siphonaptera/crecimiento & desarrolloRESUMEN
As PBPs de Yersinia pestis, Y. enterocolitica e Y. pseudotuberculosis crescidas a 28ºC ou a 37ºC foram detectadas após marcaçäo com [3H]-benzilpenicilina e fluorografia dos géis de poliacrilamida. Cada amostra apresentou um perfil único de PBPs composto por 3 a 6 proteínas com peso molecular variando entre 120.000 e 43.000. Incubaçäo a 37ºC resultou em mudanças significativas nos perfis de PBPs das 3 espécies estudadas. As possíveis implicaçöes destes resultados na açäo dos antibióticos ß-lactâmicos e na fisiologia destas bactérias
Asunto(s)
Penicilinas/farmacología , Yersinia pestis/fisiología , Lactamas/farmacología , Proteínas Portadoras/análisisRESUMEN
Plague caused by Yersinia pestis, has persisted in Brazil in several natural foci spread throughout rural areas in the States of Ceara, Paraiba, Pernambuco, Piaui, Rio Grande do Norte, Alagoas, Bahia, Minas Gerais and Rio de Janeiro. Nationwide surveillance of plague in Brazil based on serological testing started in 1983. We now present an update report of the examinations carried out in our laboratory from 1983 to 1992. The passive hemagglutination test for antibodies against fraction 1A antigen of Y. pestis and the passive hemagglutination inhibition control were employed for testing a total of 220,769 sera. Samples analyzed included 2,856 sera from clinically diagnosed plague cases or suspects, 49,848 sera from rodents of 24 species and 2 species of small wild carnivores (marsupials), 122,890 sera from dogs, and 45,175 sera from cats. Specific antibodies were found in 92 (3.22%) human sera; 143 (0.29%) sera from rodents of 8 species and from the two species of marsupials, 1,105 (0.90%) sera from dogs and 290 (0.64%) sera from cats. The presence of significant levels of specific anti-F1A antibodies among rodents and wild or domestic carnivores (dogs and cats) indicates that all the Brazilian plague foci remain active in spite of the absence of human cases in some of them.
Asunto(s)
Peste/epidemiología , Animales , Antígenos Bacterianos/sangre , Brasil/epidemiología , Gatos , Cricetinae , Brotes de Enfermedades , Perros , Cobayas , Pruebas de Hemaglutinación , Humanos , Marsupiales , Ratones , Peste/diagnóstico , Peste/prevención & control , Ratas , Salud Rural , Vigilancia de Guardia , Yersinia pestis/inmunología , Yersinia pestis/fisiologíaRESUMEN
La PESTE o PLAGA ha sido una de las enfermedades más devastadoras en la historia del hombre y a pesar de los avances científicos actuales, no ha podido ser erradicada. Causada por la Yersinia pestis, produce cuadros clínicos de diversa severidad y alta mortalidad tales como las formas bubónica, septicémica, neumónica, cutánea y meníngea. Aunque se ha presentado en todos los continentes, no ha llegado a todos los países incluido el nuestro; sin embargo, ha afectado a países vecinos como Brasil, Perú y Ecuador. De los países desarrollados ha sido vitualmente eliminada, sin poder asegurar la erradicación del patógeno en sus reservorios naturales. La Yersinia es una enterobacteria que ha servido como modelo para estudiar las características de los gérmenes invasivos y como Yersinia pestis, ha desarrollado múltiples estrategias de virulencia que le han ayudado a mantenerse en un nivel constante en el ambiente, sin matar al huésped, mediante una PATOGENICIDAD BALANCEADA. Nuestro objetivo es el de revisar un mnicroorganismo enigmático e interesante en su contexto filogenético y de patogénesis en el hombre, sin entrar a describir las manifestaciones clínicas ni a discutir discutir diagnóstico y manejo
Asunto(s)
Humanos , Preescolar , Niño , Peste , Yersinia pestis/inmunología , Yersinia pestis/patogenicidad , Yersinia pestis/fisiología , Yersinia pestis/ultraestructuraRESUMEN
Plague is a deadly disease of obvious concern to individuals, communities, and public health officials. The rapid recognition of plague victims is of paramount importance in saving the lives of the victims and in the protection of contacts. Three autopsied plague cases have been presented and the pathological features have been discussed.