Rickettsial infection in free-ranging capybaras (Hydrochoerus hydrochaeris) and their ticks (Acari, Ixodidae) in the Caatinga and Atlantic forest biomes, Northeastern Brazil.

Caatinga and Atlantic Forest are Brazilian biomes threatened by anthropogenic disturbances, which are a serious threat to biodiversity and favor the emergence of zoonotic pathogens. Capybara populations are increasingly present in urban and rural areas due to the loss of their natural habitats. There are no studies on the rickettsial infection in these rodents in Northeastern Brazil, although there are case records of Brazilian Spotted Fever (BSF) in this region. In this context, we evaluated rickettsial infection in capybaras and their ticks in four areas of the Atlantic Forest and Caatinga biomes in Northeastern Brazil. Blood sera from 21 capybaras were tested by indirect immunofluorescence assay (IFA) using Rickettsia rickettsii, R. parkeri, and R. amblyommatis antigens. Blood samples and ticks (Amblyomma sp., Amblyomma dubitatum and Amblyomma sculptum) were tested by PCR, targeting a fragment of the rickettsial gltA gene and R. bellii primers. Overall, 15 out of 21 capybaras (71.4%) reacted positively (titer ≥64) to at least one of the three Rickettsia antigens tested, with final titers ranging from 64 to 1024. No rickettsial DNA was found in capybara blood samples. Rickettsial DNA was detected in 22 of 31 adult tick pools using gltA gene, being all nine pools of A. sculptum and 16 of the 19 of A. dubitatum, but all samples were negative to R. bellii specific primers. All attempts to sequence the amplicon were unsuccessful, indicating a possible low rickettsial load in the tick samples. The present study reports for the first time the serological evidence of Rickettsia spp. infection in free-ranging capybaras and suggest the rickettsial infection in A. sculptum and A. dubitatum in the Caatinga and Atlantic Forest biomes in Northeastern Brazil.

Multi-elemental exposure assessment through concentrations in hair of free-ranging capybaras (Hydrochoerus hydrochaeris Linnaeus, 1766) in the Atlantic Forest remnants, Northeast of Brazil.

This study aimed to determine the mineral profile of hair samples of free-ranging capybaras (Hydrochoerus hydrochaeris) in remnants of the Atlantic Forest located in the Northeast of Brazil, and to evaluate the effects of origin, gender and age of the animals on their mineral accumulation in hair. Twenty hair samples from animals of different areas, genders and ages were prepared using microwave-assisted digestion, employing 5 mL of HNO3 and 2.5 mL of H2SO4 for 100 mg of sample. Digestion efficiency was assessed by residual carbon content. The digested samples were analyzed by inductively coupled plasma optical emission spectrometry (ICP OES). Principal component analysis (PCA) was performed considering the composition data of 11 elements (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mn, Mo, and Na). The digestion method applied was efficient and the most abundant elements with their respective concentration ranges in mg kg-1 were Al (396-2746), Ca (36-3420), Fe (476-51180), K (115-4843), and Na (72-473). ANOVA and PCA differentiated among the capybaras regarding age (adults) and origin (A3), both associated with higher concentrations of Al, Cd, Fe, and K. Although a higher metal bioaccumulation was observed in adult animals, it is important to highlight that this result could have been affected by diet and physiological parameters. The results suggest that A3 was the most anthropized remnant area due to agricultural and urban influences. Multi-elemental determination in hair can be used as a non-invasive method to assess heavy metal contamination in capybaras.