Rickettsial diseases in children.

In a tropical country like India, fevers are caused by different etiological agents. Rickettsial infections, which have a global distribution is one of the differential diagnosis in such cases and are reported from almost all parts of India. Rickettsial diseases widely vary in severity from self-limited mild illnesses to fulminating life-threatening infections. They are obligate intracellular gramnegative coccobacillary forms that multiply within eukaryotic cells which makes it difficult to culture them on artificial culture medium. With globalization there is rapid spread of disease across the continents and therefore, skills for diagnosis and management of the disease attains global importance. Rickettsial diseases can be clinically classified as Spotted Fever group, typhus group, distinctive clinical rickettsiae and emerging rickettsiae. The clinical course will have incubation period, stage non-specific clinical signs and symptoms followed by typical/classical features depending on the type of rickettsiae infecting a person. However the clinical manifestation varies from one geographical area to another area for same species. The rickettsial diseases once thought to have been eradicated from India are re-emerging in many parts of our country. Their presence has recently been documented in at least eleven states of our country. Greater clinical awareness, a higher index of suspicion, better use of available diagnostic tools would increase the frequency with which rickettsial diseases are diagnosed.

Aproximación clínica y principales rickettsiosis transmitidas por garrapatas presentes en Latinoamérica / Clinical approach and main tick-borne rickettsiosis present in Latin America

Tick-borne rickettsial diseases are potentially life threatening infections that in Latin America have an emerging and reemerging character. Until few years ago, Rickettsia rickettsia was the only tick-borne rickettsia present in America; but nowadays several other species such as R. parkeri and R. massiliae are causing disease in humans in the region. In addition, new species are being described; although their pathogenicity has not been confirmed they should be considered as potential pathogens. Since the microbiological diagnosis of rickettsioses can take days or weeks, a high clinical suspicion and early start of appropriate treatment are crucial. In this review the distribution and main clinical manifestations of tick-borne rickettsial diseases in Latin America are detailed. Since R. felis has been found in ticks and the role of this vector has not been clarified, we have included a section about this pathogen.

Las rickettsiosis transmitidas por garrapatas son infecciones potencialmente letales, que en Latinoamérica tienen carácter emergente y re-emergente. Hasta hace escasos años, la única rickettsiosis transmitida por garrapatas era causada por Rickettsia rickettsii, pero en la actualidad existen otras especies como R. parkeri y R. massiliae que están provocando enfermedad en humanos en la región. Por otro lado, se están describiendo candidatos a nuevas especies de Rickettsia, que aunque no han probado su patogenicidad deben considerarse como potencialmente patógenos. Dado que el diagnóstico microbiológico puede tardar días o semanas, resulta fundamental una alta sospecha clínica y la instauración precoz de un tratamiento adecuado. En esta revisión se detalla la distribución y principales manifestaciones clínicas de las rickettsiosis transmitidas por garrapatas en Latinoamérica. Se ha incluido una sección sobre la infección por R. felis, por haberse encontrado esta especie en garrapatas, y no haberse aclarado el papel de este vector en su ciclo epidemiológico.

Rickettsiosis transmitidas por garrapatas en las Américas: avances clínicos y epidemiológicos, y retos en el diagnóstico / Tick-borne rickettsioses in the Americas: clinical and epidemiological advances, and diagnostic challenges

Las rickettsiosis son entidades clínicas de tipo zoonótico, causadas por bacterias intracelulares estrictas de los géneros Rickettsia y Orientia, pertenecientes a la familia Rickettsiaceae. Su ecología está determinada por factores ambientales y la presencia de vectores específicos que condicionan el establecimiento y la epidemiología en diferentes regiones del mundo. En las Américas, durante el siglo XX, únicamente eran reconocidas tres de estas enfermedades: la fiebre manchada de las Montañas Rocosas, el tifus epidémico y el tifus endémico, Sin embargo, a partir del año 2000 se han descrito mas de 10 especies diferentes previamente desconocidas en este continente, tanto en artrópodos como en casos clínicos, hecho que permite clasificarlas como entidades clínicas emergentes y reemergentes. Dadas las manifestaciones clínicas de las enfermedades causadas por rickettsias, siendo la gran mayoría inespecíficas y, por lo mismo, compartidas con otras enfermedades infecciosas, especialmente virales y bacterianas, han sido enmarcadas entre los diagnósticos diferenciales del síndrome febril agudo, tanto en áreas urbanas como tropicales. En la actualidad, se cuenta con métodos diagnósticos directos e indirectos, que son útiles en la identificación del agente infeccioso, en este caso, causante de rickettsiosis.

Rickettsioses are a group of zoonotic diseases caused by strict intracellular bacteria of the genus Rickettsia and Orientia which belong to the Rickettsiaceae family. Their ecology is influenced by environmental factors and the presence of specific vectors that determine the establishment and epidemiology in different world regions. In America, during the 20 th century, only three of these diseases were recognized: Rocky Mountain spotted fever, epidemic typhus and endemic typhus. However, since 2000, more than 10 different species that had previously been unknown in this continent have been described, both in arthropods and in clinical cases, fact that classifies them as emerging and re-emerging diseases. Given the clinical manifestations of the diseases caused by rickettsias, being the majority unspecific and, therefore, shared with other infectious diseases, especially viral and bacterial, they have been framed within the differential diagnoses of acute febrile syndrome in urban and tropical areas. Nowadays, there are direct and indirect diagnostic methods, which are useful in the definition of the infectious agent, in this case, the cause of rickettsioses.