Amblyomma sculptum is a relevant tick species from a One Health perspective, playing an important role as a vector of Rickettsia rickettsii, the main agent of spotted fever rickettsiosis in Brazil. In this study, we evaluated the susceptibility of two A. sculptum populations from Goiás state (midwestern Brazil) to different acaricides. The first tick population (GYN strain) originated from an experimental farm, where the ticks are annually exposed to acaricides. The second (PNE strain) was collected in a national park (Emas National Park), where the ticks had not been exposed to acaricides. Immersion tests were conducted with 21-day-old laboratory-reared larvae and nymphs originating from adult ticks collected in the areas mentioned above. The chosen acaricides were two synthetic pyrethroids (cypermethrin and deltamethrin), one organophosphate (chlorfenvinphos), one formamidine (amitraz), and two combinations of pyrethroids and organophosphates (cypermethrin, chlorpyrifos and citronellal; cypermethrin, fenthion and chlorpyrifos). Mortality data were used to determine the lethal concentration (LC) values at which 50%, 90%, and 99% of the ticks died (LC₅₀, LC₉₀, and LC₉₉, respectively), and resistance ratios (RR) were calculated based on the LC values. The RR revealed differences between the acaricide-exposed (GYN) and unexposed (PNE) tick strains. The PNE strain larvae and nymphs were susceptible to all the tested acaricides. The GYN strain larvae were tolerant to cypermethrin, whereas the nymphs were tolerant to deltamethrin, chlorfenvinphos, and the combination of cypermethrin, chlorpyrifos, and citronellal (2 < RR ≤ 10). The GYN strain nymphs were resistant to amitraz (RR > 10). This is the first report of A. sculptum nymphs with resistance to amitraz and tolerance to deltamethrin, chlorfenvinphos, and the combination of cypermethrin, chlorpyrifos, and citronellal.

Among the parasitic and infectious diseases affecting cats, those caused by vector-borne pathogens deserve attention due to their ability to cause nonspecific clinical signs and clinicopathological abnormalities. We studied the presence of Cytauxzoon spp., Ehrlichia spp., and Mycoplasma spp. in blood samples from 135 cats referred to the veterinary teaching hospital of the Federal University of Goiás in midwestern Brazil. We also investigated co-infections with Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV) as well as the correlation between Mycoplasma spp. infection and cat variables, including age, sex, breed, and complete blood count abnormalities. Upon PCR testing, 20.7% (28/135) of samples were positive for Mycoplasma spp., 1.5% (2/135) for Cytauxzoon spp., and none for Ehrlichia spp. Co-infections with Mycoplasma spp. and Cytauxzoon spp. were detected in the two cats with the latter infection. Mycoplasma spp. infection was statistically associated with the simultaneous presence of thrombocytopenia and leukocytosis. This study confirms a high frequence of Mycoplasma spp. infection, with both M. haemofelis and ‘Candidatus Mycoplasma haemominutum’ circulating in this cat population. The clinical significance of Mycoplasma spp. infection in cats should be further explored and this infection should eventually be included in the differential diagnosis of thrombocytopenia and leukocytosis in otherwise apparently healthy cats.

Tick-borne piroplasmids are apicomplexan protozoa that infect a wide range of vertebrate hosts, with significant implications for animal and human health. This study investigated the occurrence and genetic diversity of piroplasmids in wild mammals, unconventional pets, and associated ticks in Goiás state, midwestern Brazil. Between April 2023 and January 2024, 105 blood samples, 22 tissue samples, and 300 ticks were collected from 21 mammalian species housed in wildlife screening centers, zoos, and veterinary clinics. Molecular screening targeting the 18S rRNA gene of piroplasmids detected a 25.7% (27/105) overall positivity, with gray brockets (Subulo gouazoubira) and South American tapirs (Tapirus terrestris) showing the highest infection rates. Three tick samples tested positive, including two Amblyomma sculptum nymphs and a male of Amblyomma dubitatum collected from a tapir and capybara (Hydrochoerus hydrochaeris). Cytauxzoon brasiliensis was reported, for the first time, in cougars (Puma concolor) from Goiás state, midwestern Brazil, indicating the role of this feline as a host of this parasite. Babesia goianiaensis was confirmed in a capybara, and Theileria terrestris in tapirs. Phylogenetic analyses clustered gray brockets-associated Theileria sequences with Theileria sp. previously detected in Neotropical deer from Brazil and Theileria cervi. While the phylogenetic analysis of amino acid sequences of the cytochrome c oxidase subunit III separated Theileria genotypes detected in S. gouazoubira from T. cervi, hsp70-based phylogenetic inferences clustered the genotypes detected in Tapirus terrestris with Theileria terrestris, suggesting host-specific evolutionary lineages. These findings contribute to the understanding of Piroplasmida diversity and circulation in South American wild mammals, emphasizing the need for enhanced molecular surveillance to elucidate transmission dynamics, assess potential health risks, and contribute to the establishment of wildlife conservation and One Health strategies.

Wild boars (Sus scrofa L.) are considered among the most harmful invasive species worldwide, causing irreversible ecosystem damage, acting as zoonotic spreaders and reservoirs, threatening human and animal health, and having an important economic impact. Accordingly, the present study has assessed the rickettsial exposure, tick infestation of wild boars, and rickettsial DNA presence in ticks from infested animals from the Cerrado biome in midwestern Brazil. Anti-Rickettsia spp. antibodies were detected in serum samples of wild boars by immunofluorescence assay. Overall, 106/285 (37.2%) wild boar serum samples from 13 to 18 (72.2%) municipalities showed seroreactivity to at least one of the four Rickettsia spp. antigens tested, the largest number of wild boars serologically tested to Rickettsia spp. in this type of study. Among the 106 seroreactive animals, 34 showed possible homologous reactions between R. parkeri, R. amblyommatis, and R. bellii, with endpoint titers between 128 and 512. A sample of 45 ticks collected from four culled wild boars was identified as Amblyomma sculptum, and all tested negative for rickettsial DNA presence. In conclusion, this study has provided a reliable sampling seroprevalence and indicated high exposure of wild boars to rickettsial agents, with a potential interaction with Rickettsia spp. from the spotted fever group within the Cerrado biome from midwestern Brazil.

This study sought to investigate the presence of anti-Rickettsia spp. antibodies in georeferenced serum samples from equids across all regions of the state of Goiás, while also presenting variables that indicate risk factors for the circulation of rickettsiae, and evaluating the presence of rickettsial DNA in ticks collected from equids and the surrounding environment in the municipalities of Uruaçu and Porangatu, located in the northern region of the state. A total of 1156 equid serum samples provided by the Goiás Agricultural Defense Agency (Agrodefesa) were analyzed for antibodies against 4 Rickettsia antigens. Additionally, 39 blood samples were collected from equids during a 3-day field expedition in January 2024, alongside 938 ticks collected from both animals and the environment. In total, 297 adult ticks were randomly selected for molecular analysis and tested by qPCR targeting the rickettsial gltA gene. Positive samples were further analyzed using cPCR to target the ompA and gltA genes. Results revealed that 9.6% (111/1156) of the serum samples were seroreactive to at least one Rickettsia antigen. Among these, 36% had antibodies against Rickettsia rickettsii, 18.9% against Rickettsia parkeri, 69.4% against Rickettsia amblyommatis, and 14.4% against Rickettsia bellii. Furthermore, the possible antigen responsible for a homologous reaction was found in 3.6% of equids for R. rickettsii, and in the same proportion for R. bellii, while 23.4% of animals showed antibodies for R. amblyommatis, and none exhibited a homologous reaction to R. parkeri. Meanwhile, 28.2% of the serum samples collected during the field expedition had antibodies against R. amblyommatis, with 72.7% identifying R. amblyommatis as the antigen involved in the homologous reaction. In the logistic regression analysis, the variables of education level, altitude below 500 m, and presence of female mules demonstrated a positive effect on seropositivity. Ticks from animals were identified as Amblyomma cajennense sensu lato, Amblyomma sculptum, Dermacentor nitens, and Rhipicephalus microplus, while environmental ticks were identified as A. cajennense s.l., A. sculptum, and Amblyomma nodosum. In the qPCR assays, two specimens of A. cajennense s.l., one of A. sculptum, and one of D. nitens amplified a fragment of the gltA gene. Of these, one A. cajennense s.l. specimen amplified a fragment of both the ompA and gltA genes, and one A. sculptum specimen amplified a fragment of the gltA gene through conventional PCR. Sequencing confirmed the detection of R. amblyommatis. These findings highlight the presence of anti-Rickettsia spp. antibodies in equid serum samples from all regions of the state of Goiás, emphasizing the important role of equids as sentinels for Rickettsia spp. To our knowledge, this study represents the largest effort to detect anti-Rickettsia spp. antibodies in equid serum samples in Brazil. Additionally, it is the first nationwide investigation of its kind conducted in collaboration with the Agricultural Defense Agency (Agrodefesa), serving as a significant example of the One Health approach.