Rickettsia typhi IN RODENTS AND R. felis IN FLEAS IN YUCATÁN AS A POSSIBLE CAUSAL AGENT OF UNDEFINED FEBRILE CASES / Rickettsia typhi y R. felis en roedores y sus pulgas en Yucatán como posible agente causal de casos febriles indefinidos

Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chain reaction technique and sequencing. The study only identified the presence of Rickettsia typhi in blood samples obtained from Rattus rattus and it reported, for the first time, the presence of R. felis in the flea Polygenis odiosus collected from Ototylomys phyllotis rodent. Additionally, Rickettsia felis was detected in the ectoparasite Ctenocephalides felis fleas parasitizing the wild rodent Peromyscus yucatanicus. This study’s results contributed to a better knowledge of Rickettsia epidemiology in Yucatán.

Rickettsia typhi es el agente causal del tifo murino; una enfermedad zoonótica transmitida por vector mundialmente distribuida, comúnmente asociada con la presencia de roedores domésticos y silvestres. Los casos humanos de tifo murino en el Estado de Yucatán son frecuentes. Sin embargo, no existe evidencia de la presencia de Rickettsia typhi en mamíferos o vectores en Yucatán. En la búsqueda de vectores y reservorios de Rickettsia typhi, evaluamos la presencia de bacterias del género Rickettsia en roedores y sus ectoparásitos de un pequeño municipio del estado de Yucatán por medio de técnicas de PCR convencional y secuenciación de ADN. Se identificó la presencia de Rickettsia typhi en muestras de sangre obtenidas de Rattus rattus y reportamos por primera vez la presencia de Rickettsia felis en la pulga Polygenis odiosus colectado de Ototylomys phyllotis. Complementariamente, Rickettsia felis fue detectado en la pulga Ctenocephalides felis parasitando al roedor Peromyscus yucatanicus. No se identificó especie de Rickettsia en las muestras de sangre de O. phyllotis y P. yucatanicus analizados. Nuestros resultados contribuyen también en el conocimiento de ciclo de vida biológico del género Rickettsia.

Detección de Rickettsia spp. en ectoparásitos de animales domésticos y silvestres de la Reserva Natural Privada Cerro Chucantí y comunidades aledañas, Panamá, 2007-2010 / Detection of Rickettsia in ectoparasites of wild and domestic mammals from the Cerro Chucanti private reserve and from neighboring towns, Panamá, 2007-2010

Introducción. Los ectoparásitos son los principales vectores de rickettsiosis. En Panamá se tienen escasos datos sobre los artrópodos que pudieran considerarse vectores o reservorios. Objetivos. Presentar datos sobre la presencia de Rickettsia spp. en ectoparásitos de fauna silvestre y animales domésticos en la Reserva Natural Privada Cerro Chucantí y poblados vecinos. Materiales y métodos. Se revisaron 9 personas, 95 mamíferos domésticos y 48 silvestres. Los animales domésticos se examinaron con anuencia del propietario, mientras que la fauna silvestre se capturó con trampas Sherman y Tomahawk. Se extrajeron 21 especies de ectoparásitos: pulgas, piojos, garrapatas y otros ácaros, los cuales se preservaron en etanol al 95 %. Se extrajo material genético de garrapatas y pulgas para ser analizado por técnicas moleculares en la detección de Rickettsia spp. Resultados. Se practicaron 425 reacciones de PCR, de las cuales, 270 resultaron negativas y 155 positivas. De las positivas, 86 amplificaron para el gen gltA (55 % de las positivas); de estos también amplificaron 41 (26 %) para ompA. Se encontró material genético de Rickettsia amblyommii, en garrapatas de caballos (Amblyomma cajennense, Dermacentor nitens), de perros (Rhipicephalus sanguineus) y ninfas de Amblyomma recolectadas en el bosque. Además, se detectó ADN de R. felis en pulgas Ctenocephalides felis de perros. Conclusiones. Se pudo detectar la presencia de R. amblyommii y R. felis en garrapatas y pulgas de animales domésticos de los poblados cercanos a Cerro Chucantí, aun cuando no se pudo encontrar material genético de Rickettsia en ectoparásitos de la fauna silvestre.

Introduction. Ectoparasites are the main vectors of rickettsiosis. In Panama, however, limited data are available concerning the arthropod species that serve as vectors or reservoirs. Objectives. Data are presented concerning the presence of Rickettsia in ectoparasites of wildlife and domestic animals in the Cerro Chucantí private nature reserve and in neighboring villages. Materials and methods. Nine humans, 95 domestic mammals and 48 wild mammals were examined. Twenty-one species of ectoparasites were obtained, including fleas, lice, ticks and mites. These were preserved in 95% ethanol. Later, the DNA was extracted from the ticks and fleas and analyzed by molecular techniques to detect presence of Rickettsia. Results. Of a total of 425 PCR reactions, 270 were positive for Rickettsia and 155 negative. Among the positive samples, 86 PCR amplified for the gltA gene (55% of positives) and 41 of these also amplified the ompA gene. DNA of Rickettsiaamblyommii was found in horses ticks (Amblyomma cajennense, Dermacentor nitens), dogs ticks (Rhipicephalus sanguineus) and free living nymphs in the forest. Additionally, DNA of R. felis was found in fleas from dogs Ctenocephalides felis. Conclusions. The presence of R. amblyommii and R. felis was detected in ticks and fleas of domestic animals in villages near Cerro Chucanti; however no Rickettsia DNA was found in ectoparasites of non-domestic wildlife.

Infecção por Yersinia pestis, no Estado da Bahia: controle efetivo ou silêncio epidemiológico? / Yersinia pestis infection in the State of Bahia: effective control or epidemiological silence?

INTRODUÇÃO: A peste, doença infectocontagiosa milenar, continua sendo considerada da maior importância do ponto de vista epidemiológico devido ao alto potencial epidêmico, estando inclusive sujeita ao Regulamento Sanitário Internacional. Apesar da ausência de casos humanos da doença no Brasil, seu agente etiológico, a bactéria Yersinia pestis, permanece firmemente arraigado em seus focos naturais. A ocorrência de sorologia positiva em carnívoros domésticos de regiões pestígenas da Bahia, nos últimos anos, objetivou a realização deste estudo, que se propõe a verificar a existência de circulação do agente no estado, tendo em vista que fatores condicionantes para a doença são mantidos, oferecendo riscos à população. MÉTODOS: Trata-se de um estudo para verificação da presença de infecção por Y. pestis através do inquérito de soroprevalência em humanos, cães e roedores; e pesquisa da bactéria em roedores e pulgas. Utilizou-se de questionário estruturado para avaliação da associação existente entre fatores ambientais, sócioeconômicos e biológicos e a soroprevalência da infecção em humanos. RESULTADOS: Os 630 soros examinados (88 de humanos, 480 de cães, 62 de roedores) apresentaram-se não reagentes para peste e as análises bacteriológicas realizadas em 14 roedores e dois lotes de pulgas não identificaram a bactéria. CONCLUSÕES: Os resultados não configuram erradicação da doença no estado, pois sua natureza cíclica indica que pode passar longos períodos silente e depois ressurgir acometendo um grande número de pessoas. Portanto, a manutenção da vigilância ativa e permanente se faz necessária para a detecção precoce da doença e desenvolvimento oportuno das medidas de controle pertinentes.

INTRODUCTION: From an epidemiological point of view, the plague is still being considered of great importance, because of its high epidemic potential. Despite the absence of cases of human plague in Brazil, its etiologic agent, the bacteria Yersinia pestis, is still deep rooted in its natural environment. The occurrence of positive serology for plague in domestic carnivores in plague areas in Bahia in the past few years implies the need for a more rigorous evaluation in order to verify whether the bacillus of the plague is still active in these areas. METHODS: In this study, the presence of infection caused by Y. pestis was analyzed by seroprevalence tests on humans, dogs and rodents and by the detection of the bacteria in rodents and fleas. A structured questionnaire was used to analyze the association between environmental, socioeconomic and biological factors and seroprevalence in humans. RESULTS: Of the 630 serum samples examined (88 from humans, 480 from dogs and 62 from rodents), all were nonreactive for plague and bacteriological analyses performed on 14 rodents and 2 flea lots showed no signs of the bacteria. CONCLUSIONS: These results cannot confirm the eradication of the disease in the entire State, since the cyclic nature of the plague indicates that it can go silent for long periods and then resurge, affecting large numbers of people. Thus, maintenance of active, permanent surveillance is required for early detection and the development of adequate control measures.

Present susceptibility status of rat flea Xenopsylla cheopis (Siphonaptera: Pulicidae), vector of plague against organochlorine, organophosphate and synthetic pyrethroids 1. The Nilgiris District, Tamil Nadu, India.

The susceptibility status of Xenopsylla cheopis, the efficient vector of human plague in India was assessed in erstwhile plague endemic areas of Nilgiris district, Tamil Nadu following standard WHO techniques. The studies revealed the development of resistance in rat fleas to DDT--4.0%, Malathion--5.0%, Deltamethrin--0.05% and tolerance to Permethrin--0.75% in all the four blocks of Nilgiris hill district. Development of resistance may be due to the extensive use of insecticides in tea plantations and agricultural sectors where the domestic/peri-domestic rodents find their natural habitats and intermingle with each other.

Molecular identification of Rickettsia felis in ticks and fleas from an endemic area for Brazilian Spotted Fever

Rickettsioses are arthropod-borne diseases caused by parasites from the Order Rickettsiales. The most prevalent rickettsial disease in Brazil is Brazilian Spotted Fever (BSF). This work intends the molecular detection of those agents in ectoparasites from an endemic area of BSF in the state of Espírito Santo. A total of 502 ectoparasites, among them Amblyomma cajennense, Amblyomma dubitatum (A. cooperi), Riphicephalus sanguineus, Anocentor nitens and Ctenocephalides felis, was collected from domestic animals and the environment and separated in 152 lots according to the origin. Rickettsia sp. was detected in pools of all collected species by amplification of 17kDa protein-encoding gene fragments. The products of PCR amplification of three samples were sequenced, and Rickettsia felis was identified in R. sanguineus and C. felis. These results confirm the presence of Rickettsia felis in areas previously known as endemic for BSF, disease caused by Rickettsia rickettsii. Moreover, they show the needing of further studies for deeper knowledge of R. felis-spotted fever epidemiology and differentiation of these diseases in Brazil.

Rickettsia infection in five areas of the state of São Paulo, Brazil

This study investigated rickettsial infection in animals, humans, ticks, and fleas collected in five areas of the state of São Paulo. Eight flea species (Adoratopsylla antiquorum antiquorum, Ctenocephalides felis felis, Polygenis atopus, Polygenis rimatus, Polygenis roberti roberti, Polygenis tripus, Rhopalopsyllus lugubris, and Rhopalopsyllus lutzi lutzi), and five tick species (Amblyomma aureolatum, Amblyomma cajennense, Amblyomma dubitatum, Ixodes loricatus, and Rhipicephalus sanguineus) were collected from dogs, cats, and opossums. Rickettsia felis was the only rickettsia found infecting fleas, whereas Rickettsia bellii was the only agent infecting ticks, but no animal or human blood was shown to contain rickettsial DNA. Testing animal and human sera by indirect immunofluorescence assay against four rickettsia antigens (R. rickettsii, R. parkeri, R. felis, and R. bellii), some opossum, dog, horse, and human sera reacted to R. rickettsii with titers at least four-fold higher than to the other three rickettsial antigens. These sera were considered to have a predominant antibody response to R. rickettsii. Using the same criteria, opossum, dog, and horse sera showed predominant antibody response to R. parkeri or a very closely related genotype. Our serological results suggest that both R. rickettsii and R. parkeri infected animals and/or humans in the studied areas.

Desenvolvimento dos fungos Metarhizium anisopliae (Metschnikoff, 1879) Sorokin, 1883 E Beauveria bassiana (Balsamo) Vuillemin, 1912 sobre Ctenocephalides felis felis (Bouché, 1835) / Development of the fungi Metarhizium anisopliae (Metschnikoff, 1879) Sorokin, 1883 and Beauveria bassiana (Balsamo) Vuillemin, 1912 on the Ctenophephalides felis felis (Bouché, 1835)

A pulga Ctenocephalides felis felis é um parasita causador dermatites alérgicas e também pode transmitir diversos agentes etiológicos aos animais domésticos e aos homens. O objetivo deste trabalho foi verificar o desenvolvimento do fungo sobre a cutícula da pulga, através da microscopia eletrônica de varredura. Os isolados fúngicos testados foram o Metarhizium anisopliae 959 e Beauveria bassiana 986, ambos na concentração 10(8) conídios/ml. Após a exposição dos isolados fúngicos no período de duas, 15, 26 e 96 horas , o material foi processado para a microscopia eletrônica de varredura. Com a obtenção das micrografias, pode-se observar que com 2 horas após exposição aos fungos, os conídios estavam aderidos por toda a cutícula, situando-se preferencialmente nas membranas intersegmentais do abdome. Com 15 horas observou-se a formação do tubo de germinação e a cabeça do apressório e após 26 horas foi possível observar as ramificações e o engrossamento das hifas sobre a cutícula das pulgas. Os resultados indicam que os fungos testados foram capazes de se desenvolver sobre a cutícula de C. f. felis.

The flea Ctenocephalides felis felis is a parasite that causes allergic dermatitis and also may transmit etiologic agents to domestic animals and humans. This study investigated by scanning electron microscopy the development of entomopathogenic fungi on flea cuticle. Fleas were exposed to conidia (10(8) ml-1) of Metarhizium anisopliae (isolate 959) or Beauveria bassiana (isolate 986). Following standard protocols for electron microscopy, the specimens were prepared 2, 15, 26 and 96 h after infection. The micrography revealed that 2 h after fungus exposure, conidia attachments encompassed the entire flea cuticle, especially on abdominal intersegmental membranes. The emergence of germ tubes and appressoria formation occurred at 15 h, thickening and branching of hyphae on the flea cuticle was noted at 26 h. Therefore, both of these fungal isolates were able to develop on cuticular surfaces of C. f. felis.

Investigation of Yersinia pestis in Xenopsylla astia.

In this study, at the Department of Parasitology in the Pasteur Institute of Iran, Xenopsylla were allowed to feed on mice infected with Yersinia pestis. After 24-48 hours, they were killed by ether and kept in alcohol (70%) for 20 minutes. They were then examined for pathological signs and bacilli in different tissues and organs, longitudinally and cross-sectionally. The samples were studied using conjugated antibody and fluorescence microscopy. The results of this study revealed that the bacilli are abundant in the proventriculus after 6 hours, but it was found in other organs, rarely.

Pesquisa da infecçäo natural por Yersinia pestis, em pulicídeos provenientes de focos pestosos do nordeste do Brasil / Natural infection by Yersinia pestis, in fleas from plague foci in the northeast of Brasil

Foram avaliados três processos de acondicionamento e transporte de pulgas, objetivando análise bacteriológica para isolamento da Yearsinia pestis. As três abordagens testadas foram: pulgas vivas em tubos de ensaio com tiras dobradas de papel de filtro; pulgas em soluçäo salina; macerados de pulgas em meio de Cary-Blair. Os dois últimos métodos foram quase iguais e superiores ao primeiro. Foram analisadas pelas três técnicas, um total de 29.512 "pools" de pulicídeos provenientes de focos de peste do Nordeste do Brasil no período de 1966 a 1982. Deste total, 236 (0,80%) dos "pools" foram positivos por cultura e/ou inoculaçäo em animais sensíveis

An outbreak of plague in Hlegu, Burma in 1977.

An outbreak of plague occurred in Hlegu Town, Burma in February and March 1977. Altogether 14 bubonic plague cases, with 2 deaths were reported, mostly children under 15 years of age. Twice as many males as females were affected. A retrospective investigation showed that a rat fall took place in the last week of January. Only 9.5% of the rodents which died in the epizootic were found to be infected with Y. pestis; this apparent low infection rate probably resulted from the inclusion in the survey of some dead rats which died of other causes. 14.5% out of 48 trapped rodents were found to be serologically positive. The general flea and cheopis indices were rather high, perhaps because fleas were found to be partially resistant to DDT and also because spraying of insecticide did not effect fleas on the hosts. The cheopis index in Hlegu Town was 1.17, and less than 0.5 in Hlegu suburb (Yankin-Yat) where no epizootic was reported. An active case search revealed 76 suspected plague cases out of which 11 were found to have bubonic plague. A field trial showed that plague vaccination during the outbreak did not result in a rise of detectable antibodies in persons inoculated.