Debora Azevedo Borges

The tick Amblyomma sculptum is the vector of the bacterium Rickettsia rickettsii (which causes Brazilian Spotted Fever in humans). It can be found in domestic and wild animals, as well as humans. The objective of this work was to evaluate the efficacy of baits containing fluazuron in the control of A. sculptum in guinea pigs that were artificially infested. The work was conducted in two studies: descriptive pharmacokinetics and efficacy. Descriptive pharmacokinetics was assessed after administering one fluazuron-containing bait per animal (10 mg/kg). To determine the pharmacokinetic profile, blood samples were collected over several days. For the efficacy test, the animals were divided into four groups: a control group (untreated) and three treated groups that received a single dose of 10 mg/kg on days −21 (G1), −14 (G2) and −7 (G3). All animals were infested with A. sculptum larvae on day 0 and recovered on days +4, +5, +6, and +7. Fluazuron plasma concentrations increased rapidly, indicating rapid absorption, and decreased slowly. In all treated groups, engorged larvae with morphological and behavioral changes were observed. Although fluazuron did not show acaricidal efficacy, it was able to interfere with tick molting. Fluazuron was effective in controlling the A. sculptum tick in guinea pigs.

The number of guinea pigs is increasing as pet and their domestication necessitates the study of their pathology and emerging diseases. This study aimed to evaluate guinea pigs’ capacity to be infested by Ctenocephalides felis felis fleas, as it is a common parasite among pets that causes irritation, stress, and transmission of other pathogens. Seventeen guinea pigs were infested with C. felis felis. After 48 hours, the animals were combed, and the number of fleas was determined. Guinea pigs had a very low recovery (average of 5%), leading us to conclude that they are not good hosts for this species, despite some literature citing it as an accidental host if infested along with dogs or cats. Os porquinhos-da-índia como animal de estimação têm aumentado cada vez mais, e, sua domesticação trouxe a necessidade de estudos sobre suas patologias e doenças emergentes. Este estudo teve como objetivo avaliar a capacidade de infestação dos porquinhos-da-índia pela pulga Ctenocephalides felis felis, ectoparasita comum entre os animais domésticos que causa irritação, estresse e transmissão de outros patógenos. Dezessete animais foram infestados com C. felis felis. Após 48 horas, os animais foram penteados e o número de pulgas determinado. Os porquinhos-da-índia tiveram uma recuperação muito baixa (média de 5%), levando-nos a concluir que estes não são bons hospedeiros para essa espécie de pulga, apesar de algumas literaturas os citarem como hospedeiro acidental se conviverem juntamente com cães ou gatos infestados.

This study aims to evaluate the influence of free omental graft without vascular microanastomosis (FOGWVA) on experimental skin healing in rabbits. Through celiotomy, a 9cm2 free omental fragment was collected in 36 rabbits, with subsequent production of a deep linear cutaneous wound in the dorsal midline measuring 3cm. In 18 animals from the omental group (OG), the omental fragment collected was fixed subcutaneously with six simple interrupted stitches using a 4-0 polyamide thread. In both treated and control (CG) groups, intradermal dermorrhaphy was performed with 4-0 polyamide thread. Experimental wounds were clinically evaluated every day. Each of the groups was divided into three subgroups of 6 animals each for histopathological evaluation on the 7th, 14th, and 28th days of postoperative. In the OG wounds, the increase in volume (omentum activation) stood out after the second postoperative day. Macroscopy showed an organic reaction to the graft on day 7, with a progressive reduction in addition to neovascularization towards the omental graft. The intense presence of mononuclear cells and collagen deposition on day 7 demonstrated an accelerated process of tissue remodeling and repair. The FOGWVA omental graft remained viable and positively influenced the cutaneous healing of the experimental wounds in rabbits.

Background: Brazilian spotted fever (BSF), the most lethal tick-borne disease in the Western Hemisphere, is caused by the bacteriumRickettsia rickettsiiand transmitted by the bite ofAmblyomma sculptum. Capybaras are considered primary hosts of this tick and amplifier hosts ofR. rickettsii, generating new infected lineages ofA. sculptumin BSF-endemic areas. To define a possible treatment regimen for controlling the tickA. sculptumin capybaras, the aim of this study was to establish an effective fluazuron (FLU) dose to controlA. sculptumlarvae in artificially infested guinea pigs.Methods: In Study I (pharmacokinetic and pharmacodynamic analysis), 24 guinea pigs were divided into four equal groups: control group (CG; untreated) and treated groups receiving FLU administered by gavage in three doses: G1—1 mg/kg, G2—5 mg/kg and G3—10 mg/kg, once a day for 15 days (d0 to d + 14). Blood samples were collected from the animals of the treated groups before and at d + 1, + 2, + 4, + 7, + 15 and + 21. The guinea pigs were artificially infested at d + 7 withA. sculptumlarvae, and specimens were recovered at d + 11 to d + 14 and kept in a climatized chamber for 14 days. In Study II (evaluation of pharmacokinetic parameters), one group of eight animals received FLU administered by gavage in a single dose of 10 mg/kg, and blood samples were collected before and on day 0 (8 h after treatment), + 1, + 4, + 7, + 15, + 21 and + 28 after single FLU administration. FLU was analyzed in plasma samples by high-performance liquid chromatography with ultraviolet detection.Results: FLU plasma concentrations increased quickly, indicating rapid absorption, and decreased slowly. Some larvae from all treated groups exhibited morphological and behavioral changes. FLU interfered in molting, and the efficacy obtained was 100% for all treated groups.Conclusions: The results offer promising perspectives for the development of a palatable feed cube containing FLU for free-living capybaras to controlA. sculptumand also to prevent BSF in areas where capybaras have been shown to play a primary role.

Platynosomum illiciens is a liver trematode encountered infecting mainly felids although it has also been reported in birds and in additional mammalian species, including non-human primates. The current study reports a natural P. illiciens infection primate of the genus Callithrix. The diagnosis was made using a combination of copro-parasitological techniques, morphological evaluation of adult specimens recovered from the liver during necropsy, and molecular analyses. Eggs were brown in color, oval, operculated, and contained a miracidium. Adult specimens recovered during necropsy were measured and showed dimensions compatible with P. illiciens. Molecular characterization of the trematode involved amplification by polymerase chain reaction (PCR), in combination with nucleotide sequencing, of an approximately 900 base pairs fragment corresponding to 18S-ITS1-5.8S ribosomal DNA. Sequenced amplicons showed 100% nucleotide identity with sequences deposited in the GenBank database as derived from specimens of P. illiciens recovered from cats in Malaysia and Brazil. It was concluded that the morphological and molecular analyses presented herein, confirmed the identification of the trematode recovered as P. illiciens.

Zoonoses are major causes of morbidity and mortality worldwide. Among them, Brazilian Spotted Fever (BSF) is an important one that occurs in some regions of South America and can be transmitted by the “star tick” Amblyomma sculptum. Application of acaricides against the larval stage is important as strategy of population control. However, there is still a deficiency of studies on chemical control of A. sculptum and the present work aims to evaluate the in vitro acaricidal activity of cypermethrin, flumethrin, deltamethrin, fipronil, coumaphos and chlorpyrifos against A. sculptum larvae. Bioassays were performed using the larval immersion test method. A discriminatory analysis between the antiparasitic classes most used for tick control was carried out, which made it possible to determine the classes with higher potential for controlling A. sculptum larvae. Our results showed that A. sculptum larvae present highest sensitivity to the synthetic pyrethroid group, followed by the phenylpyrazole, organophosphate and macrocyclic lactone groups. These findings may support studies on improvement of tick control as in animals as in the environment.