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.

Pressor effects elicited by stimulation within the medullary raphe nuclei of the guinea pig (Cavia porcellus)

The medullary raphe nuclei are involved in central autonomic regulation. In all species investigated, electrical stimulation of the raphe nuclei causes cardiovascular responses, although, these changes vary between species. The present study was designed to investigate the participation of these nuclei in cardiovascular regulation in the guinea pig. We studied the effect on arterial blood pressure (BP) and heart rate (HR) of electrical stimulation (isolated cathodal square wave pulses for 10 s at 100 Hz, 40-100 muA and 1-ms pulse duration) within the medullary raphe nuclei in urethane-anesthetized (1.2g/kg, i.p.) guinea pigs (400-600g. either sex). Electrical stimulation of the same sites was performed on a group of paralyzed (Flaxedil®, 1 mg/kg, i.v.) and artificially ventilated animals. Stimulation sites were histologically defined and maps of the stimuli were obtained for the effect of electrical stimulation on arterial blood pressure. In another series of experiments, L-glutamate (0.2 M) was microinjected (75 to 150 nl) into the nucleus raphe obscurus. Electrical stimulation of the raphe nuclei produced predominantly pressor responses (delta= +15 to +100 mmHg: 43 percent of the stimulated sites). Hypotension (delta= -10 to -25 mmHg, 24 percent of the stimulated sites), biphasic responses (2 percent) or no change in BP (31 percent) were evoked from fewer stimulation sites. Pressor responses were also predominant in paralyzed animals (delta= +15 to +95 mmHg; 47 percent of the stimulates sites), and after microinjection of L-glutamate into the raphe obscurus (A= +20 to +45 mmHg). The present results demonstrate that in the guinea pig the stimulation of these nuclei evokes mainly pressor responses. These responses are similar to those obtained in the rat and hamster but opposite to those observed in the cat and rabbit.

Vigilancia epidemiológica de las infecciones intrahospitalarias: estudios sistematizados de prevalencia (1993-1994) / Epidemiological surveillance in intrahospital infections: systemic studies of prevalence (1993-1994)

A partir de la sistematización de los estudios de prevalencia en 1993, continuamos con la presentación de los datos obtenidos en 1994, en conjunto con los del peíodo anterior. Esto permite tener una visualización gráfica de los resultados obtenidos pudiéndose analizar así sus tendencias. Si bien la metodología básica de los estudios no se ha modificado, a partir de diciembre de 1993 se incorporó al análisis, un sistema subjetivo que permite estratificar el nivel de gravedad de los pacientes y relacionarlo con el riesgo de infección intrahospitalaria. Este modelo fue validado a partir de los estudios de diciembre de 1993, abril y agosto de 1994, evaluándose además su reproducibilidad. El análisis comparativo de los estudios de prevalencia, muestra la persistencia de una proporción elevada de pacientes con acceso vascular (>50 por ciento) y catéter urinario (>20 por ciento), lo que determina un riesgo incrementado de desarrollar infecciones asociadas a estos factores. La tasa de prevalencia de infecciones intrahospitalarias se mantuvo por encima del 10 por ciento...