RESUMEN
The study of rickettsial agents associated with ticks from wild felines is scarce. In Europe, three species of Rickettsia have been detected (Rickettsia helvetica, Rickettsia massiliae, and Rickettsia monacensis) in ticks collected from the Iberian lynx (Lynx pardinus). However, no studies have been conducted on another lynx species. For this reason, the aim of this study was to identify the diversity of Rickettsia species in ticks associated with bobcats (Lynx rufus) collected in the State of Tamaulipas, Mexico. During 1999 and 2004, nine bobcats from two municipalities of the state were trapped and visually inspected for the presence of ticks. A total of 95 ticks were collected from these lynxes. Ticks were preserved in 96% ethanol. Subsequently we identified the presence of Rickettsia DNA by the amplification of several fragments of genes 17â¯kDa, ompA and ompB. Recovered sequences were concatenated, aligned, and compared with those of reference deposited in GenBank. Additionally, a phylogenetic analysis was performed using the Maximum Likelihood method. The ticks were morphologically identified as belonging to the species Dermacentor variabilis. We selected a subset of 60 ticks which were examined, and 5% (3/60) were positive with an identity of 99% to sequences of R. rickettsii deposited in GenBank. The results obtained represent the first record of R. rickettsii in ticks associated with wild carnivores, and in particular with bobcats distributed in northeast of Mexico.
Asunto(s)
Dermacentor/microbiología , Lynx/parasitología , Rickettsia rickettsii/aislamiento & purificación , Animales , Femenino , Masculino , México , Filogenia , Rickettsia/clasificación , Rickettsia/aislamiento & purificación , Análisis de Secuencia de ADN/veterinariaRESUMEN
BACKGROUND: The northern limits of Trypanosoma cruzi across the territory of the United States remain unknown. The known vectors Triatoma sanguisuga and T. lecticularia find their northernmost limits in Illinois; yet, earlier screenings of those insects did not reveal the presence of the pathogen, which has not been reported in vectors or reservoir hosts in this state. OBJECTIVES: Five species of medium-sized mammals were screened for the presence of T. cruzi. METHODS: Genomic DNA was isolated from heart, spleen and skeletal muscle of bobcats (Lynx rufus, n = 60), raccoons (Procyon lotor, n = 37), nine-banded armadillos (Dasypus novemcinctus, n = 5), Virginia opossums (Didelphis virginiana, n = 3), and a red fox (Vulpes vulpes). Infections were detected targeting DNA from the kinetoplast DNA minicircle (kDNA) and satellite DNA (satDNA). The discrete typing unit (DTU) was determined by amplifying two gene regions: the Spliced Leader Intergenic Region (SL), via a multiplex polymerase chain reaction, and the 24Sα ribosomal DNA via a heminested reaction. Resulting sequences were used to calculate their genetic distance against reference DTUs. FINDINGS: 18.9% of raccoons were positive for strain TcIV; the rest of mammals tested negative. MAIN CONCLUSIONS: These results confirm for the first time the presence of T. cruzi in wildlife from Illinois, suggesting that a sylvatic life cycle is likely to occur in the region. The analyses of sequences of SL suggest that amplicons resulting from a commonly used multiplex reaction may yield non-homologous fragments.