The objective of this work was to evaluate the diversity of ticks associated with free-living animals and to investigate new host records for ticks. Ticks were collected from animals rescued during the flood of the Jamari River in the municipality of Ariquemes, state of Rondônia, North Region of Brazil. A total of 39 animals were captured, out of which 10 were amphibians, 19 were reptiles and 10 were mammals. A total of 127 ticks of the Amblyomma genus were collected from these animals, distributed among seven species: Amblyomma dissimile, Amblyomma geayi, Amblyomma humerale , Amblyomma longirostre, Amblyomma nodosum , Amblyomma rotundatum and Amblyomma varium. In addition, one specimen of Rhipicephalus (Boophilus) microplus was collected. Among these specimens, 85 were adults and 42 were nymphs, with A. rotundatum being the most prevalent species. An Amblyomma spp. larvae was also collected from a lizard (Uranoscodon superciliosus), and one Amblyomma calcaratum and one Amblyomma dubitatum were recovered from the environment, thus totaling 130 ticks. Among the Ixodidae collected from different hosts, we provide the first report for the species A. rotundatum parasitizing Rhinella major, U. superciliosus, Leptophis ahaetulla, Chironius multiventris, and Mastigodryas boddaerti, as well as of A. humerale parasitizing U. superciliosus, A. geayi parasitizing Choloepus didactylus, and Rhipicephalus (B.) microplus parasitizing Alouatta puruensis.

Background: The tick Rhipicephalus microplus (Ixodida: Ixodidae, Canestrini, 1888) causes substantial economic and health losses in cattle production and is the main vector of Babesia bigemina (Piroplasmidae: Babesidae, Smith & Kilborne, 1893). Babesia bigemina is responsible for a tick-borne disease known as babesiosis that can cause hemolytic anemia, fever and death. In the study reported here, we investigated the relationship between the number of ticks per animal and the number of B. bigemina cytochrome b gene (cbisg) copies in the blood of Brangus and Nellore cattle reared without acaricidal treatment in the Brazilian Cerrado biome over a 1-year period. Methods: Ticks on 19 animals (9 Brangus and 10 Nellore cattle) were counted every 18 days, and blood was collected every 36 days for 12 months. Serological samples were analyzed with an indirect enzyme-linked immunosorbent assay, and genomic DNA was analyzed by conventional PCR and quantitative PCR. The PCR products were sequenced by the Sanger method. Results: The Brangus and Nellore breeds showed similar weight development and no clinical signs of babesiosis. Statistically significant differences (P < 0.05) between the breeds were observed for the number of ticks and the number of B. bigemina cbisg gene copies. Conclusions: No correlation between the number of ticks and the number of circulating copies of cbisg was observed, although Nellore cattle presented with fewer ticks than Brangus cattle and the number of cbisg copies was higher for Nellore cattle than for Brangus cattle.

The present study evaluated the behavior of Rhipicephalus microplus naturally infesting Brangus cattle raised with Nellore animals in the municipality of Água Clara, state of Mato Grosso do Sul, Central Brazil. For the field experiment composed of a group with 15 Brangus animals and 15 Nellore animals and a control group with 30 Brangus cattle, all at the post-weaning stage. The 2 groups were kept for 6 months in 2 adjacent paddocks, naturally infested with ticks, at a stocking rate of approximately 0.6 of an animal unit per hectare (AU/ha). Every 18 days, the animals were weighed, and ticks on both sides of each bovine were counted. Every 36 days, blood was collected for hematocrit measurement and molecular diagnosis of the 3 pathogens that cause tick fever. The Brangus animals had 6.8 times more ticks than the Nellore cattle. No significant difference was observed in the weight gain of the Brangus and Nellore animals, and no correlation between the number of ticks and weight was observed in either group. During the 6 months of the study, all animals presented normal hematocrit, were positive for Babesia bigemina and Anaplasma marginale, and were negative for Babesia bovis. Animals in Group 1 produced 27% fewer ticks than the animals in Group 2. The production rate of engorged female ticks in Nellore and Brangus cattle was 0.83% and 2.01%, respectively. Considering the infestation pattern required to produce 10 engorged females/day/animal, the Nellore and Brangus animals required 1,204 and 497 larvae/day, respectively. Our estimates showed that Brangus cattle need only 11.3% of the larvae in the pastures with Nellore cattle to maintain the infestation level observed in the present study. Brangus animals raised with Nellore cattle do not have a lower parasitic load and continue to suffer from tick infestation. Finally, Nellore cattle raised with Brangus cattle do not act as a cleaner because this grouping does not contribute to a reduced infestation in the Brangus animals.

Amblyomma parvum Aragão (Acari: Ixodidae) is a tick species found with wide distribution in the Neotropical region. Even though it is a wildlife-related tick, it is also a frequent parasite of domestic animals, is aggressive to human beings and may harbor pathogenic microorganisms. Therefore, it is a target species for control on domestic animals, particularly those at the rural–wildlife interface. Herein, the efficacy of two isolates (E9 and IBCB 425) of an entomopathogenic fungus, Metarhizium anisopliae sensu lato, already evaluated for ticks that parasitize domestic animals, was tested against unfed A. parvum adults. Both isolates displayed high acaricidal efficacy after immersion in fungal conidial suspensions for 5 min. Isolate E9 killed all ticks by the 7th day post-treatment, and isolate IBCB 425 did so by the 11th day. Tick mortality of 80 and 90% was achieved as early as the 3rd and 4th days, respectively, with both treatments. Thus, if a commercial M. anisopliae s.l. acaricide against domestic animal ticks is developed, it would also be effective against A. parvum.

The present study aimed to contribute towards identification and registration of tick species that parasitize dogs in rural and urban areas of three mesoregions of Paraná, southern Brazil, and to estimate the rate of occurrence of each species. Fifty-six dogs with ticks living in three mesoregions: Metropolitana de Curitiba (MC), Centro Oriental (COP) and Centro Sul Paranaense (CSP), were used in the study. From these 56 dogs, 253 ticks were collected and were identified and morphologically characterized according to the species. Among all the ticks, 69.6% were identified as belonging to the species Rhipicephalus sanguineus sensu lato (s. l.); 28.1% as Amblyomma aureolatum and 2.4% as Amblyomma ovale. Among the dogs in MC that were evaluated, 57.7% were parasitized by R. sanguineus s. l., 38.5% by A. aureolatum and 3.8% by A. ovale; while in COP, 72.4% of the dogs were parasitized by A. aureolatum and 27.6% by R. sanguineus s. l.. In CSP, one tick was obtained, which was identified as A. aureolatum.

Estima-se em 3,2 bilhões de dólares/ano os prejuízos provocados pelos carrapatos à economia do país. Esse quadro se agrava com a introdução de raças taurinas e seus cruzamentos na composição racial de bovinos no país pela demanda de raças mais produtivas para atender às demandas do mercado internacional na próxima década, gerando rebanhos mais sensíveis aos carrapatos. Este artigo discute o impacto econômico da infestação pelo carrapato do boi, ancorando-se em dados da literatura e nos resultados de pesquisa deste Grupo. O carrapato do boi, ectoparasito que tem o bovino como principal hospedeiro, alimenta-se do sangue do animal, na fase parasitária, momento das maiores perdas econômicas. A infestação em raças taurinas mais produtivas causa impacto na produtividade do rebanho gerando a necessidade de um controle estratégico associado a políticas públicas para gerenciar esse gargalo. Para comparar as raças, foi elaborada uma “régua do carrapato” mostrando que, na raça Nelore (zebuína), os prejuízos ficam abaixo e, na raça Brangus (taurina), ficam acima do limiar econômico. As análises realizadas levaram à conclusão de que: o investimento em genética mais produtiva deve levar em conta que o controle estratégico beneficia o desempenho produtivo e econômico das propriedades; a resistência dos carrapatos aos acaricidas merece um monitoramento adequado; há demandas por práticas e formas de controle mais sustentáveis, sem produtos químicos, como o controle por meio do Sistema Lone Tick para garantir a sustentabilidade.