ABSTRACT
ABSTRACT The northern region of the Caldas department in Colombia is considered an endemic area for murine typhus. Recent studies in patients with acute febrile disease demonstrated infection with the spotted fever group's rickettsiae due to an increase in the IgG titer by indirect immunofluorescence in paired sera obtained from these patients. The objective of the current research was to identify the species of ticks present in domestic animals in the northern region of Caldas and establish the presence of rickettsial genomic material in the collected ticks. Ticks were obtained from bovines, horses, and dogs in seven municipalities in the north of Caldas. Ticks were stored in 90 % ethanol until processing and were identified using taxonomic keys, DNA was extracted using commercial techniques, and the gltA gene was amplified by conventional chain reaction polymerase (PCR). Seven hundred thirteen ticks were obtained from 593 domestic animals. The highest infestation occurred in cattle, followed by canines and horses. Ticks found corresponded to the species Riphicephalus microplus, Dermacentor nitens, Amblyomma sp., and Riphicephalus sanguineus s.l. In none of the tick samples, Rickettsia-specific gltA gene DNA was found. It can be inferred that the ticks obtained are not a source of rickettsial infection for people in this department region, despite finding different species associated with the transmission of this disease.
RESUMEN La región norte del departamento de Caldas, Colombia es considerada como una zona endémica de tifo murino. Estudios recientes realizados en pacientes con enfermedad febril aguda, demostraron la infección con rickettsias, del grupo de las fiebres manchadas, debido al aumento en el título de IgG, por inmunofluorescencia indirecta (IFI), en sueros pareados, obtenidos de dichos pacientes. El objetivo de la investigación fue el de identificar las especies de garrapatas presentes en animales domésticos, de la región norte de Caldas y establecer la presencia de material genómico de rickettsias, en las garrapatas recolectadas. En siete municipios, se recolectaron garrapatas de bovinos, de equinos y de caninos. Las garrapatas, se almacenaron en etanol al 90 %, hasta su identificación taxonómica. Se extrajo el ADN, utilizando técnicas comerciales y se amplificó por reacción de cadena de la polimerasa (PCR) convencional el gen gltA. Se obtuvieron 713 garrapatas de 593 animales domésticos. La más alta infestación se presentó en bovinos, seguido de los caninos y equinos. Las garrapatas encontradas correspondieron a las especies Riphicephalus microplus, Dermacentor nitens, Amblyomma sp. y Riphicephalus sanguineus s.l. En ninguna de las muestras, se comprobó la presencia de ADN del gen gltA específico de Rickettsia. Se puede inferir que las garrapatas obtenidas no serían una fuente de infección rickettsial para las personas, en esta región del departamento; sin embargo, su presencia es un factor de riesgo para la adquisición de rickettsiosis asociadas con las fiebres manchadas.
ABSTRACT
Background & objectives: In India, spotted fever group rickettsiae (SFGR) are an underdiagnosed cause of acute febrile illness (AFI). The non-specific Weil-Felix test is the first diagnostic modality for the diagnosis of SFGR in many laboratories due to the lack of advanced diagnostic facilities in developing countries. The aim of this study was to detect SFGR using molecular methods in the patients, presenting with AFI in a tertiary care centre in north India. Methods: Consecutive patients (>14 yr of age) with AFI were enrolled over a six month period. Standard investigations for common pathogens causing AFI in India (malaria, dengue, scrub typhus, leptospirosis and enteric fever) were carried out. In patients who were negative for all of the above investigations, blood was subjected to polymerase chain reaction (PCR) targeting outer membrane protein A (ompA) gene of Rickettsia. Results: Of the 51 patients with an undiagnosed aetiology, three were positive by ompA PCR. Two of the PCR products produced good sequences and BLAST identification confirmed them as Rickettsia conorii. The sequences of R. conorii reported from south India clustered with two previously reported novel rickettsial genotypes. The study sequences clustered in a group different from that of Rickettsia spp. of the south Indian sequences reported earlier. Interpretation & conclusions: This study showed the existence of R. conorii in north India. Testing for SFGR may be included in the diagnostic workup of AFI for better disease management.
ABSTRACT
In India the presence of Rickettsial disease in human is documented in many states however, the data on presence of Rickettsial infection in Andhra Pradesh is very scare. Therefore, a study was undertaken in Chittoor district (A.P.) to see the prevalence of Rickettsial infection in human and rodent population. 3-5 ml of human blood samples were collected from the patients attending the nearest hospitals of Tirumala, Tirupathi, Palmner and Chittoor areas. Live rodents were trapped and blood samples were collected from them during January and February 2008. Sera was separated and tested by Weil Felix test. Two hundred human sera samples were tested. Of these 39 samples were found reactive with Weil Felix antigen. Of the 39 reactive, 31 were male and 8 female. All the human samples were showing reactivity at 1:20 dilution. Out of the 343 rodents samples tested, only 24 samples were showing reactivity. These were reactive at 1:20, 1:40 and 1:80 dilutions with different types of Weil Felix antigens. Eight rodent sera samples were having titer 1:80 with Proteus OXK which is suggestive of presence of Scrub typhus in this region.