Rabbit antibody responses to experimental infestation with Dermatobia hominis.

The three larval stages of Dermatobia hominis (Linnaeus) have been evaluated for their immunogenicity by ELISA and immunodiffusion (ID) using sera from experimentally infested rabbits. During a primary infestation, first instar D. hominis were found to cause most reaction and allowed the earliest diagnosis by ELISA. An inhibition of the antibody response against second and third instars was observed. The inhibition disappeared after departure of the larvae from the host. In experimentally immunized hosts the antibody response, following challenge, was highest against second and third instar antigens. Antibody remained elevated during the infestation but fell immediately after the larvae had left the host.

Infestação experimental em girinos de Rana catesbeiana Shaw por copepoditos de Lernaea cyprinacea Linnaeus (Copepoda, Lernaeidae)

The Lernaea cyprinacea Linnaeus, 1758 copepodids experimental contamination on the Rana catesbeiana Shaw, 1802 ladpoles was analized. Sixty percent (12) of infested tadpoles was found parasitized. High mortality range, lower appetence, equilibrium loss and apathy were observed. The parasites showed the preference for the mouth and cloaca: in 72 hours lhe egg saes had already developed.

Farmacocinética e eficácia endectocida de uma nova formulação contendo doramectina 3,5% em bovinos

Pós-graduação em Medicina Veterinária - FCAV

Investigation of tick vectors of Hepatozoon canis in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Acaricidal effects of fluazuron (2.5 mg/kg) and a combination of fluazuron (1.6 mg/kg) + ivermectin (0.63 mg/kg), administered at different routes, against Rhipicephalus (Boophilus) microplus parasitizing cattle

The present study aimed to evaluate the acaricidal efficacy of fluazuron (2.5 mg/kg), administered as a pour-on, in comparison to an injectable formulation containing fluazuron (1.6 mg/kg) + ivermectin (0.63 mg/kg), against Rhipicephalus (Boophilus) microplus in naturally and experimentally infested cattle. Two studies were conducted with different tick strains, one with artificial infestations (Stall Test, using leight animals per group) and one with natural infestations (utilizing ten animals per group): In both studies, the animals were randomized, according to average tick counts performed on days -3, -2 and -1, into four groups: T01, negative control (saline solution); T02, pour-on fluazuron (2.5 mg/kg); T03: subcutaneous fluazuron (1.6 mg/kg) + ivermectin (0.63 mg/kg); and T04 subcutaneous ivermectin (0.63 mg/kg). Based on obtained results, and considering the utilized tick strains, it was possible to conclude that the pour-on fluazuron (2.5 mg/kg) formulation demonstrated high acaricidal efficacy, with protection periods ranging from 49 to 77 days against Rhipicephalus (Boophilus) microplus. On the other hand, for the injectable fluazuron (1.6 mg/kg) + ivermectin (0.63 mg/kg) formulation, it was not possible to observe elevated anti-R. (B.) microplus effect on both artificial and experimental infestation studies. Results observed for this combination were similar or inferior to those obtained by subcutaneous ivermectin (0.63 mg/kg). Future studies with this formulation containing fluazuron (1.6 mg/kg) + ivermectin (0.63 mg/kg), regarding pharmacokinetic and/or bioavailability profiles, or even studies analyzing both this active principles separately, are needed, seeking to better understand the effects of such combination against Rhipicephalus (Boophilus) microplus parasitizing cattle. (C) 2015 Elsevier Inc. All rights reserved.

Spittlebug infestation in sugarcane affects ethanolic fermentation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Morphological changes in the salivary glands of Amblyomma cajennense females (Acari : Ixodidae) in different feeding stages on rabbits at first infestation

This study examined salivary glands of unfed, partially engorged, and engorged females of the tick Amblyomma cajennense on rabbits at first infestation using histological and histochemical techniques. In type I acini, no significant changes were observed among the three feeding conditions. In type II acini of unfed females, c1, c2, and c4 cells were described for the first time in this species. In a comparison among the three feeding conditions, an increase in this acinus was observed, due to the increase in secretion in c1, c2, and c4 cells and the appearance of c3 cells. In engorged females, some cells were still active. Type III acini presented cells d, e, and f containing secretion in unfed females. In partially engorged females, these cells were devoid of secretion. In engorged females, type III acini exhibited a reduced lumen. After engorgement, all acini underwent a degenerative process, as observed in females after two to five days post-engorgement.

Influence of the physiological state on infestation by Rhipicephalus microplus in dairy cows

The purpose of this study was to identify the influence of physiological state, season, breed, number of lactations, dairy productivity, and stocking rate on infestation by Rhipicephalus microplus in dairy cows. Two hundred cows were selected through proportional representative sampling at the Seropédica Experimental Station (Pesagro-Rio), Brazil. Fully or partially engorged R. microplus females measuring between 4.5 and 8.0. mm were counted on the right side of each animal. The tick infestation prevalence data were analyzed in relation to the risk factors, using multiple logistic regression. Associations between prevalence and its possible influencing determinants were measured using odds ratios. The average tick count of cows during the peripartum and lactation periods was significantly higher (p<0.05; OR=4.82) than the count in dry cows. Taurine animals showed significantly higher infestation (p<0.05; OR=3.28) than pure zebuine animals. Among cross-bred animals, the infestation was higher (p<0.05) in F1 animals (1/2 taurine × 1/2 zebuine) than in Girolando animals (5/8 zebuine × 3/8 taurine). Primiparous cows (p<0.05) had significantly heavier infestations than multiparous cows. Dairy production showed a positive correlation with tick infestation (p<0.03; OR=2.94), such that the most productive animals were the most parasitized ones. Animals kept at high densities were significantly more heavily infested (p<0.05, OR=6.32) than animals kept at low density. First-lactation and high-productivity taurine animals were more vulnerable to R. microplus, thus comprising a high-risk group in dairy herds. © 2012 Elsevier GmbH.

Effects of Haematobia irritans infestation on weight gain of Nelore calves assessed with different antiparasitic treatment schemes

Effects of Haematobia irritans infestation on weight gain of 18 to 20 months old non-castrated Nelore calves, were investigated, under field conditions, using different antiparasitic treatments. Sixty animals were divided in three groups, with 20 bovines each: T01 (untreated control); T02 (treated with Cypermethrin 15 g + Chlorpyriphos 25 g + Citronellal 1 g, as a whole body spray, on days 0,30, 60, 90 and 120 post-treatment); and T03 (treated on day zero with an ear tag impregnated with Diazinon 6 g on the left ear). Counts of H. irritans were conducted on day 30, 60, 90, 120 and 150 post-treatment (DPT). On the same experimental dates, animals were individually weighed, seeking to evaluate the effects of parasitism on the development of animals in each group. From this study it is concluded that T03 had significantly higher efficacy (>90%, till 90 DPT), based on H. irritans fly counts, compared to T02 which showed little or no effect. At the specific conditions of the present study, an average of approximately 90 flies (mean difference of flycounts between groups T01 and T03) was associated with a difference of 20 kg/animal in 150 days. (C) 2014 Elsevier B.V. All rights reserved.