Environmental enrichment interaction for laboratory beagle dogs used in research.

Experimental animal facilities can have a negative impact on the well-being of animals owing to confinement. To mitigate this, environmental enrichment (EE) is implemented confinement. The purpose of EE is to enhance the complexity of an animal's natural environment. The objective of this study was to identify the types of EE most enjoyed by dogs used in experimental research and housed in individual kennels. A total of six adult Beagle dogs, housed at the Laboratório de Quimioterapia Experimental em Parasitologia Veterinária (LQEPV) at the Universidade Federal Rural do Rio de Janeiro (UFRRJ) were included in the study. The EE tools used included Petball® toys, a grassy outdoor area, interaction with other dogs and with a team member, a "pool" made of plastic bottles, and dog's wet food ice cream. A team member assessed the usage of these tools every 5 min for a 30-min period, six times per day, one day per week, over the course of eight weeks. The study revealed that the grass area was the tool most commonly used for physical enrichment, accounting for 58% of the occurrences (p < 0.05). Social and food enrichment were enjoyed in second and third place, with 23% and 19% of occurrences, respectively. that the study findings suggest that dogs housed in individual kennels enjoy engaging in their natural behaviors.

Os animais de biotério podem viver em situações que afetem o seu bem-estar, como o confinamento. Um dos métodos que buscam para reduzir os impactos negativos é o Enriquecimento Ambiental (EA), o qual objetiva a promoção da complexidade do ambiente dos animais. Foi possível, com esta pesquisa, atingir o objetivo de identificar quais tipos de EA são mais aproveitados por cães utilizados em pesquisas experimentais que viviam em canis individuais. Foram utilizados seis cães adultos, Beagles, oriundos do Laboratório de Quimioterapia Experimental em Parasitologia Veterinária (LQEPV) da Universidade Federal Rural do Rio de Janeiro (UFRRJ). Como ferramentas de EA foram utilizados brinquedos Petball®, área de grama ao ar livre, interação com outros cães e com uma pessoa da equipe, "piscina" de garrafas plásticas e sorvete de ração úmida. Um membro da equipe avaliou o uso a cada 5 minutos, por período de 30 minutos (6 avaliações) por dia, um dia por semana ao longo de 8 semanas. O estudo revelou que a ferramenta mais usufruída pelos cães foi a área de grama através do enriquecimento físico, quantificado em 58% de ocorrência (p<0,05). Os enriquecimentos sociais e alimentar, foram usufruídos em segundo e terceiro lugar, com 23% e 19% de ocorrência, respectivamente. Pode-se concluir que os cães mantidos em canis individuais individualizados mais necessitam exercer seu comportamento natural específico, para que seu grau de bem-estar seja mantido em nível satisfatório e em consequência sua saúde mental.

Ultrastructural characterization and quantification of hemocytes in engorged female Amblyomma sculptum ticks.

Amblyomma sculptum (formerly Amblyomma cajennense) ticks have been implicated in the transmission of pathogens that cause diseases in animals and humans. Their wide geographic distribution and high impact on animal health and zoonotic disease transmission highlight the importance of studying and implementing effective control measures to mitigate the risks associated with this tick species. The aim of this study was to quantify and characterize the morphology and the ultrastructure of different types of hemocytes in the hemolymph in engorged A. sculptum females fed on rabbits. The hemolymph samples were collected by perforation of the cuticle in the dorsal region. Hemocyte types, sizes, and differential counts were determined using light microscopy, while ultrastructural analysis of hemocytes was performed using transmission electron microscopy. The average number of total hemocytes in the hemolymph was 1024 ± 597.6 cells µL-1. Five morphologically distinct cell types were identified in A. sculptum females: prohemocytes (6 % ± 8.8), plasmatocytes (10 % ± 7.7), granulocytes (78 % ± 12.2), spherulocytes (5 % ± 4.48), and oenocytoids (1 % ± 1.6). In general, prohemocytes were the smallest hemocytes. The ultrastructural morphology of A. sculptum hemocytes described in the present study agrees with the findings for other hard ticks. This is the first study to investigate ultrastructural characteristics of hemocytes of female A. sculptum ticks.

Cavia porcellus (Rodentia: Caviidae) as host for Ctenocephalides felis felis (Siphonaptera: Pulicidae) in artificially infestation.

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.

Endoparasites of Leopardus pardalis (Carnivora, Felidae) rescued in the State of Rio de Janeiro.

Wild cats play an important role as top predators in the food chain and act as ecosystem regulators. However, in recent decades, many studies have demonstrated the potential effects of parasitic diseases on wild carnivore populations, including cats. This study reports on the endoparasites found in an injured and rescued specimen of Leopardus pardalis in the state of Rio de Janeiro. Fecal samples were collected and processed using five coproparasitological techniques: a simple flotation centrifugation, a zinc sulfate flotation centrifugation, a formalin-ether sedimentation centrifugation, a conical centrifuge tube technique, and a modified Ziehl-Neelsen staining technique for fecal smears. Helminth eggs belonging to the families Trichuridae and Diphyllobothriidae and the genus Toxocara were found in both sedimentation flotation techniques. Protozoan oocysts belonging to the genus Cryptosporidium were identified by modified Ziehl-Neelsen staining. These findings show that ocelots can harbor potentially zoonotic and pathogenic endoparasites. Further studies on the helminths and protofauna of these animals are necessary.

Os felinos selvagens desempenham um papel importante como predadores de topo na cadeia alimentar e atuam como reguladores do ecossistema. No entanto, nas últimas décadas, muitos estudos demonstraram os efeitos potenciais de doenças parasitárias em populações de carnívoros selvagens, incluindo gatos. Este estudo relata os endoparasitos encontrados em um espécime ferido e resgatado de Leopardus pardalis no estado do Rio de Janeiro. Amostras fecais foram coletadas e processadas usando cinco técnicas coproparasitológicas: uma centrifugação por flotação simples, uma centrifugação por flotação com sulfato de zinco, uma centrifugação por sedimentação com éter de formalina, uma técnica de tubo de centrífuga cônica e uma técnica modificada de coloração de Ziehl-Neelsen para esfregaços fecais. Ovos de helmintos pertencentes às famílias Trichuridae e Diphyllobothriidae e ao gênero Toxocara foram encontrados em ambas as técnicas de flotação por sedimentação. Oocistos de protozoários pertencentes ao gênero Cryptosporidium foram identificados pela coloração de Ziehl-Neelsen modificada. Esses achados mostram que jaguatiricas podem abrigar endoparasitas potencialmente zoonóticos e patogênicos. Mais estudos sobre os helmintos e a protofauna desses animais são necessários.

Fluazuron orally administered to guinea pigs: pharmacokinetic and efficacy against Amblyomma sculptum.

BACKGROUND: Brazilian spotted fever (BSF), the most lethal tick-borne disease in the Western Hemisphere, is caused by the bacterium Rickettsia rickettsii and transmitted by the bite of Amblyomma sculptum. Capybaras are considered primary hosts of this tick and amplifier hosts of R. rickettsii, generating new infected lineages of A. sculptum in BSF-endemic areas. To define a possible treatment regimen for controlling the tick A. sculptum in capybaras, the aim of this study was to establish an effective fluazuron (FLU) dose to control A. sculptum larvae 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 with A. sculptum larvae, 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 control A. sculptum and also to prevent BSF in areas where capybaras have been shown to play a primary role.

Efficacy of a dinotefuran, permethrin and pyriproxyfen combination product in the treatment of rabbits (Oryctolagus cuniculus) naturally infested by Psoroptes ovis.

The main of this study was to evaluate the efficacy of dinotefuran, pyriproxyfen and permethrin-combination (Vectra 3D-CEVA) in the topical treatment of rabbits naturally infested with P. ovis. Adult New Zealand rabbits (n = 18) with plaques of crust in both ears were divided into three groups (one control and two treated). On day 0, the animals belonging to the treated groups received a single dose of a commercial ectoparasiticide formulation, recommended for use in dogs. The control group (G1) (n = 6) received no treatment, the treated group (G2) (n = 6) received one drop in each ear, and the remaining volume was applied along the back of the animal in the dorsal midline with the commercial formulation. In the other treated group (G3) (n = 6), animals received the same product used in G2, but all the volumes of 0.5 mL were applied only to the back of the animal (dorsal midline). On days 0, +7, +14, +21, +28 and +35, lesion scores and mites per gram (MPG) of each ear scab were evaluated. Statistical analysis was performed using the statistical software Bioestat 5.01. As the Shapiro-Wilk test determined that the data were nonparametrically distributed, the Kruskal-Wallis test was performed, followed by the Student-Newman-Keuls test, to determine the significance levels among the mean values of mite counts per gram of crusts compared to the three experimental groups. The efficacies for remission of lesion scores were 19.87 % on day +7 to 83.44 % on day +35 for G2 and 70.67 % on day +7 to 92.20 % on day +35 for G3. The efficacies obtained by evaluation of MPG were 100 % on day +7 to 99.86 % on day +35 for G2 and from 93.05 % on day +7 to 99.89 on day +35 for G3. The topical administration of the combination of dinotefuran (4.95 %), pyriproxifen (0.44 %) and permethrin (36 %) on the ears and back or only on the back in rabbits was shown to be effective in naturally controlling mite infestations by P. ovis.

Oral pharmacokinetic profile of fipronil and efficacy against flea and tick in dogs.

Fipronil (FIP) is an ectoparasiticide of the phenylpyrazole class, used in veterinary medicine in topical form. Supported by evidence of uncontrolled human exposure to FIP and environmental damage caused by commercially available formulations, its use by oral administration has become promising. The effectiveness of FIP against the flea Ctenocephalides felis felis and the tick Rhipicephalus sanguineus and its pharmacokinetics and main active metabolite, fipronil sulfone (SULF) were evaluated after single oral administration of tablets in three different doses (2, 4, and 6 mg/kg) in dogs. Through the plasma concentration curves, it was possible to observe that the FIP showed rapid absorption and metabolization and slow elimination. The values of Cmax (ß = 0.7653) and AUC0- t (ß = 0.3209) did not increase proportionally with increasing dose. At 48 h after treatment, doses of 4 mg/kg (AUC0- t  = 442.39 ± 137.35 µg/ml*h) and 6 mg/kg (AUC0- t  = 421.32 ± 102.84 µg/ml*h) provided 100% and 99% efficacy against fleas, and 95% and 98% against ticks, respectively. The estimated EC90 of FIP +SULF was 1.30 µg/ml against C. felis felis and 2.16 µg/ml against R. sanguineus. The correlation between the FIP pharmacokinetic and efficacy data demonstrated its potential for oral administration in the form of tablets for the control of ectoparasites in dogs, as a safer alternative for animals, humans, and the environment, aligned with the One Health concept.

Platynosomum illiciens (Trematoda: Dicrocoeliidae) in a hybrid marmoset (Callithrix sp.) in the Municipality of Seropédica, RJ, Brazil - Case report.

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.

In vitro acaricidal activity of different ectoparasiticide classes against Amblyomma sculptum larvae.

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.

Activity of Syzygium aromaticum essential oil and its main constituent eugenol in the inhibition of the development of Ctenocephalides felis felis and the control of adults.

The aim of this study was to evaluate the in vitro activity of Syzygium aromaticum essential oil (SAEO) and its main constituent eugenol (EG) against adult fleas and their action in the maturation of eggs into adults of Ctenocephalides felis felis. In order to evaluate the pulicidal activity, 10 adult fleas were exposed to a filter paper impregnated with SAEO and EG at increasing concentrations of 0.047; 0.094; 0.188; 0.375; 0.750; 1.50; 3.00; 6.00; 12.00 and 24.00 µg cm-2. Flea mortality was evaluated 24 and 48 h after exposure. In order to evaluate the inhibition of the maturation of eggs into adults, 10 eggs were exposed to filter paper impregnated with SAEO and EG at the same concentrations used in the pulicidal test, and the evaluation was performed 30 days after incubation. Untreated repetitions were maintained in both studies (control group). The lethal concentration 50 (LC50) of pulicidal activity to SAEO was 5.70 µg cm-2 in 24 h and 3.91 µg cm-2 in 48 h. The LC90 was 16.10 µg cm-2 and 15.80 µg cm-2 in 24 and 48 h, respectively. The LC50 of inhibition of the maturation of eggs into adults was 0.30 µg cm-2 and the LC90 3.44 µg cm-2. The LC50 of pulicidal activity to EG was 2.40 µg cm-2 in 24 h and 1.40 µg cm-2 in 48 h; the LC90 was 8.10 µg cm-2 and 3.70 µg cm-2 in 24 h and 48 h, respectively. The LC50 of inhibition of the maturation of eggs into adults was 0.10 µg cm-2 and the LC90 0.68 µg cm-2. Based on the results obtained, it is possible to conclude that the both SAEO and EG have in vitro pulicidal activity as well as acting as inhibitors of the maturation of eggs into adults of the flea C. felis felis.

Fipronil Tablets: Development and Pharmacokinetic Profile in Beagle Dogs.

Increased human-pet interactions have led to concerns related to the prevention and treatment of ectoparasite infestations. Fipronil (FIP) is a widely used ectoparasiticide in veterinary medicine available for topical administration; however, its use may cause damage to the owners and the environment. The aim of the study was to develop immediate-release tablets of FIP, as well as to determine its pharmacokinetic properties after oral administration in beagle dogs. The prepared FIP tablets were evaluated for pre-compression (angle of repose, speed flow, and Carr's index) and post-compression (weight variation, friability, thickness, hardness, disintegration time, and dissolution rate) parameters. Orally administered FIP at a dose of 2 mg/kg was rapidly absorbed with Cmáx of 3.13 ± 1.39 µg/mL at 1.83 ± 0.40 h post treatment (P.T.) and metabolized with 1.27 ± 1.04 µg/mL at 2.33 ± 0.82 h P.T. for fipronil sulfone (SULF) (the primary metabolite). The elimination of FIP and SULF occurred slowly and had maintained quantifiable plasma levels in the blood for up to 28 days P.T. The goal of the study is aligned with the concept of One Health, which aims to collaboratively achieve the best health for people, animals, and the environment. Therefore, the use of FIP tablets for the control of ectoparasites in dogs may be a safer alternative for owners and the environment.

Laboratory evaluation of the efficacy of lotilaner (Credelio™) against Amblyomma cajennense (sensu lato) infestations of dogs.

BACKGROUND: The ixodid tick Amblyomma cajennense (sensu lato) complex, widespread throughout South and Central America, is also present in Mexico, Texas and Florida. As a vector of Rickettsia rickettsii, and potentially of other pathogens, infestations with A. cajennense present a substantial health risk to humans, dogs and other mammals. Oral administration of lotilaner flavored chewable tablets (CredelioTM, Elanco) to dogs was previously shown to rapidly provide killing activity of infesting ticks. This study investigated lotilaner's efficacy against A. cajennense (s.l.). METHODS: Twenty purpose-bred Beagles (10 male and 10 female) were ranked by Day -5 burdens of nymphal A. cajennense (s.l.) and randomized to either treatment with lotilaner or to a sham-treated control group. On Day 0, dogs were fed within approximately 30 min prior to oral lotilaner administration at as close as possible to 20 mg/kg, the minimum dose rate. For efficacy assessments, tick counts were completed 48 h post-treatment or 48 h after experimental challenge infestations with 200 nymphal A. cajennense (s.l.) on Days -7, -2, 7, 14, 21 and 28. RESULTS: Tick infestations in the control group dogs ranged from a low of 43 to 95, with the average infestation remaining above 25% at each assessment, thereby meeting the requirement for efficacy comparison with the treated group. Lotilaner efficacy was 100% within 48 h post-treatment, and at nine days post-treatment. Efficacy was greater than 99% at all subsequent assessments through Day 30. No treatment-related adverse events were observed. CONCLUSION: The results demonstrate that lotilaner, administered orally to dogs at a minimum dose of 20 mg/kg is well tolerated, provides rapid reduction of existing A. cajennense (s.l.) tick infestations, and provides sustained residual protection for at least 30 days against subsequent infestation by A. cajennense (s.l.).

Efficacy of a dinotefuran, pyriproxyfen and permethrin combination product against Ctenocephalides felis felis (Bouché, 1835) (Siphonaptera: Pulicidae) on artificially infested rabbits.

The aim of this study was to evaluate the efficacy of an insecticidal product in rabbits that combines the neonicotinoid dinotefuran with the pyrethroid permethrin plus the insect growth regulator pyriproxyfen. Adult New Zealand rabbits (n = 12) were infested with Ctenocephalides felis felis (50 males and 50 females per rabbit) at days -7, -2, +5, +12 and +19. The control group (n = 6) received no treatment and the treated group (n = 6) received the commercial formulation, indicated for use in dogs, which was applied topically on day 0. The animals were mechanically evaluated with combs (comb test), to assess pulicidal efficacy, on days -5, +2, +7, +14 and +21. All flea removals and counts were performed by region, following the order: head, ears, neck, forelegs, dorsum, abdomen, hind limbs and tail, in order to determine the preferred sites of parasitism by the C. felis felis flea in rabbits. The distribution of fleas prevailed in the head region (about 62%), followed by the neck and back (14 and 11%, respectively). The insecticidal efficacy was calculated using arithmetic means, showing effectiveness of 100% on days +2 and +7 and 82.2% and 81.6%, on days +14 and +21, respectively. Thus the present study has shown the combination to be a viable option in the treatment and control of rabbits infested by C. felis felis.