Study of infection by Rickettsiae of the spotted fever group in humans and ticks in an urban park located in the City of Londrina, State of Paraná, Brazil

• Main Authors: Roberta Santos Toledo, Katia Tamekuni, Mauro de Freitas Silva Filho, Valeska Bender Haydu, Richard Campos Pacheco, Marcelo Bahia Labruna, John Stephen Dumler, Odilon Vidotto
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Medicina Tropical (SBMT) 2011-06-01
• Series: Revista da Sociedade Brasileira de Medicina Tropical
• Subjects: Amblyomma dubitatum; Amblyomma cajennense; Rickettsia; Epidemiologia; PCR
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0037-86822011000300010&lng=en&tlng=en

INTRODUCTION: Spotted fevers are emerging zoonoses caused by Rickettsia species in the spotted fever group (SFG). Rickettsia rickettsii is the main etiologic agent of Brazilian spotted fever (BSF) and it is transmitted by Amblyomma spp. ticks. METHODS: The study aimed to investigate SFG rickettsiae in the Arthur Thomas Municipal Park in Londrina, PR, by collecting free-living ticks and ticks from capybaras and blood samples from personnel working in these areas. Samples from A. dubitatum and A. cajennense were submitted for PCR in pools to analyze the Rickettsia spp. gltA (citrate synthase gene). RESULTS: All the pools analyzed were negative. Human sera were tested by indirect immunofluorescence assay with R. rickettsii and R. parkeri as antigens. Among the 34 sera analyzed, seven (20.6%) were reactive for R. rickettsii: four of these had endpoint titers equal to 64, 2 titers were 128 and 1 titer was 256. None of the samples were reactive for R. parkeri. An epidemiological questionnaire was applied to the park staff, but no statistically significant associations were identified. CONCLUSIONS: The serological studies suggest the presence of Rickettsiae related to SFG that could be infecting the human population studied; however, analysis of the ticks collected was unable to determine which species may be involved in transmission to humans.