Estudo molecular da febre maculosa brasileira no diagnóstico diferencial com dengue no estado do Rio de Janeiro durante o período de 2010 a 2011 / Molecular study of brazilian spotted fever in the differential diagnosis with dengue in the state of Rio de Janeiro during the period from 2010 to 2011

Doenças febris agudas são comuns e frequentemente associadas com agentes infecciosos em países tropicais como o Brasil. Com manifestações clínicas inespecíficas de difícil diferenciação com uma série de doenças endêmicas como dengue, leptospirose e outras doenças fatais, a febre maculosa brasileira (FMB) raramente tem sido considerada no diagnóstico, fato que, com o consequente retardo no tratamento antimicrobiano específico, tem determinado a elevada letalidade frequentemente observada em nosso país. A dengue é uma das doenças infecciosas mais importantes e frequentes no Brasil, onde epidemias são relatadas periodicamente no estado do Rio de Janeiro...

Acute febrile diseases are common and often associated with infectious agents in tropical countries such as Brazil. With nonspecific clinical manifestations and hard to differentiate with a number of endemic diseases such as dengue, leptospirosis, and other fatal diseases, Brazilian Spotted Fever (BSF) has rarely been considered in the diagnosis, fact that with the consequent delay in the specific antimicrobial treatment, has determined high lethality often observed in our country. Dengue is one of the most important and frequent infectious diseases in Brazil, where epidemics are reported periodically in the State of Rio de Janeiro.

Imaging of rickettsial, spirochetal, and parasitic infections.

This article is an update and literature review of the clinical and neuroimaging findings of the commonly known rickettsial, spirochetal, and eukaryotic parasitic infections. Being familiar with clinical presentation and imaging findings of these infections is crucial for early diagnosis and treatment especially in patients who live in or have a travel history to endemic regions or are immunocompromised.

Infection of the endothelium by members of the order Rickettsiales.

The vascular endothelium is the main target of a limited number of infectious agents, Rickettsia, Ehrlichia ruminantium, and Orientia tsutsugamushi are among them. These arthropod-transmitted obligately-intracellular bacteria cause serious systemic diseases that are not infrequently lethal. In this review, we discuss the bacterial biology, vector biology, and clinical aspects of these conditions with particular emphasis on the interactions of these bacteria with the vascular endothelium and how it responds to intracellular infection. The study of these bacteria in relevant in vivo models is likely to offer new insights into the physiology of the endothelium that have not been revealed by other models.

Fiebre maculosa de las Montañas Rocosas

Las rickettsiosis son un grupo de enfermedades producidas por bacterias pleomorfas que se comportan como parásitos intracelulares. Aunque estas enfermedades son raras en nuestro medio, la proliferación de viajes internacionales a zonas endémicas suponen un riesgo de aparición en nuestro país1. Las características generales de estas enfermedades, así como las rickettsiosis más importantes transmitidas por piojos, pulgas y ácaros, han sido descritas en un trabajo anterior. En esta revisión se exponen las características más importantes, en especial aspectos epidemiológicos y clínicos, tanto en adultos como en niños, de las rickettsiosis más frecuentes transmitidas por garrapatas, como son la fiebre de las Montañas Rocosas, la fiebre botonosa mediterránea, la fiebre Q y la ehrlichiosis (AU)

Detection of the etiologic agent of human ehrlichiosis by polymerase chain reaction.

Polymerase chain reaction (PCR) primers derived from a variable region of the 16S rRNA gene sequence were used to amplify DNA specifically from Ehrlichia chaffeensis (the recently proposed name for the etiologic agent of human ehrlichiosis). The 389-bp product defined by the specific primers was not detected when DNA samples from any of the other recognized species of Ehrlichia were used as amplification templates. When the PCR was applied to five suitable blood specimens obtained from patients subsequently shown to be serologically positive for E. chaffeensis, all five were positive. The same technique was applied to a total of six control blood specimens, three from febrile patients who had no serologic evidence of infection with Ehrlichia or Rickettsia species and three from patients diagnosed with Rocky Mountain spotted fever, and all six were negative. A chemiluminescent, group-specific oligonucleotide probe was shown to hybridize only with the PCR products obtained upon amplification of the five blood specimens from patients serologically diagnosed as having human ehrlichiosis. The results indicate that PCR, coupled with a nonisotopic method of confirming the identity of the PCR product, is a highly specific and efficient method of detecting the agent of human ehrlichiosis in blood. The results also suggest that E. chaffeensis is the sole etiologic agent of human ehrlichiosis in the United States. The technique was also applied to four ticks that were positive by direct immunofluorescence for Ehrlichia species, and one tick was PCR positive, indicating that E. chaffeensis DNA can be detected in ticks harboring this organism, although the sensitivity may be low.

Relapsing illness due to Rochalimaea henselae in immunocompetent hosts: implication for therapy and new epidemiological associations.

Two previously healthy, immunocompetent men had persistent Rochalimaea henselae bacteremia with clinical relapses after courses of antibiotics to which the isolates were ultimately demonstrated susceptible in vitro. Both had sustained tick bites prior to their illnesses, thus demonstrating an association not previously identified, although suspected. The first patient had relapsing fever, constitutional symptoms, and an episode of aseptic meningitis despite therapy with amoxicillin, then with doxycycline, and then with ceftriaxone. Thereafter, he spontaneously became asymptomatic during a span of 2 months of persistent bacteremia. Finally, after 2 weeks of therapy with ceftriaxone plus gentamicin, followed by 4 weeks of therapy with oral ciprofloxacin, his bacteremia was cured. The second man had relapsing fever and constitutional symptoms after courses of tetracycline, then of chloramphenicol, and then of doxycycline. He became permanently asymptomatic after serial 2-week courses of chloramphenicol and erythromycin. The greater efficacy of lysis-centrifugation blood cultures in the recovery of R. henselae was noted.

Tres nuevos casos de Fiebre Manchada de las Monta¿as Rocosas en Costa Rica / Three new cases of Rocky Mountain Spotted Fever in Costa Rica

Se informa sobre tres nuevos casos de Fiebre Manchada de las Monta¿as Rocosas ocurridos en Costa Rica, dos en El Bosque, Limón y el otro en la Virgen, Sarapiquí, Heredia. Se incluyen, además, algunas consideraciones de orden epidemiológico que han caracterizado a esta rickettsiosis en Costa Rica tales como distribución geográfica, clínica, patología, diagnóstico de laboratorio y vectores

Increased pathogenicity of an Ehrlichia-like agent after passage through Amblyomma hebraeum: a preliminary report.

After being passaged through 3 generations of Amblyomma hebraeum, an Ehrlichia-like agent isolated from an adult Hyalomma truncatum female became more pathogenic and elicited a disease in sheep indistinguishable from heartwater. Cross-immunity between this agent and several stocks of Cowdria ruminantium and high levels of antibody elicited by the agent against 2 stocks of C. ruminantium in the indirect fluorescent antibody test, confirmed its close relationship to Cowdria.

Canine ehrlichiosis in Connecticut.

The first case of canine ehrlichiosis in Connecticut is reported. A female Brittany spaniel from Milford presented with lethargy, anorexia, fever, petechiae, splenomegaly, thrombocytopenia, anemia, elevated serum alkaline phosphatase, lymphopenia, and hypoalbuminemia. Serologic analysis revealed antibodies to Ehrlichia canis (titer, 1:2,560). This documents a more northern geographic distribution in the United States for this infectious agent than had previously been suspected.

Ehrlichiosis and polyarthritis in three dogs.

Three dogs admitted for evaluation of lameness were determined to be infected with a neutrophilic strain of Ehrlichia. Ehrlichia morulae were detected in low numbers in both synovial fluid and blood neutrophils. The dogs had rapid clinical improvement after appropriate antibiotic therapy. A diagnosis of canine ehrlichiosis easily could have been missed if morulae had not been identified. Ehrlichiosis should be considered in acutely lame dogs residing in areas enzootic for ehrlichiosis. A careful search for Ehrlichia morulae within synovial fluid and blood neutrophils should be performed. An E canis titer determination also may be helpful.

Unexplained febrile illnesses after exposure to ticks. Infection with an Ehrlichia?

The Ehrlichia are tick-borne rickettsial organisms that cause disease in animals throughout the world but that have been previously recognized as human pathogens only in Asia. We have identified six patients with serological evidence of recent infection with an Ehrlichia: a fourfold or greater rise or fall in titer to Ehrlichia canis. All of the patients reported recent tick bites. Rigors, myalgia, headache, nausea, and anorexia were each reported by five patients. Fever was present in all patients and was accompanied by relative bradycardia and leukopenia in five patients, thrombocytopenia and abnormal liver function test results in four, and anemia in three. Five of the six patients were treated with tetracycline hydrochloride, and all recovered. Infection with Ehrlichia should be considered in patients with unexplained febrile illnesses after tick exposure.

Experimental reproduction of Potomac horse fever in horses with a newly isolated Ehrlichia organism.

Potomac horse fever, a recently recognized disease of equines, characterized by high fever, leukopenia, and a profuse diarrhea, was studied for its etiology. An Ehrlichia organism was isolated in equine macrophage-fibroblast cell cultures and mouse macrophage cell cultures from the mononuclear cells of blood of infected horses. The agent was continuously propagated in mouse macrophage cell cultures. The organism multiplied in the cytoplasm of mouse macrophage cells and was identified by Giemsa staining, acridine orange staining, and by indirect immunofluorescence with convalescent sera from infected horses. The disease was experimentally reproduced in horses inoculated with Ehrlichia-infected cell culture material. The Ehrlichia organism was reisolated from the blood of these infected horses during the course of the disease. Antibody against the organism was detected in the sera of experimentally infected horses. This study confirmed that the new Ehrlichia organism is the etiological agent of Potomac horse fever.

Tick-borne fever: a review.

The literature on tick-borne fever is reviewed. Tick-borne fever is a rickettsial disease of sheep and cattle characterised by high fever and severe leucopaenia. The causative agent, Cytoecetes phagocytophila invades the neutrophils and monocytes and is transmitted by the tick Ixodes ricinus. There is very little information on the pathogenesis and immunogenesis of the disease but there is ample evidence that infected animals are predisposed to other diseases. Animals infected with tick-borne fever resist reinfection for a variable period of time. The organisms may persist in the blood of recovered animals for up to two years. Humoral antibodies are produced two weeks after infection and continue to be detected for many months but their significance on protective immunity is not clearly established.

Importation into the United States from Africa of Rhipicephalus simus on a boutonneuse fever patient.

Rhipicephalus simus Koch was removed from a human upon his return to Connecticut, U.S.A. from Kenya, Africa. This person became ill in Africa, exhibited clinical manifestations of boutonneuse fever and had a significant rise (greater than or equal to 8-fold) in IgM titer against spotted fever-group rickettsiae. Rickettsia conorii was probably the infectious agent.