ABSTRACT:The purpose of this experiment was to describe early behavioural responses to illness in rabbits and their relation with physiological changes to improve early detection of infection by Taenia pisiformis in rabbits. Twenty adult female New Zealand rabbits were randomly allocated to 2 groups to determine whether changes in behaviour and some physiological parameters can be induced in rabbits after a T. pisiformis infection. Infected animals were orally inoculated with 3000 eggs of T. pisiformis, while controls received only saline solution. Behavioural activity was recorded daily from 19:00 to 21:00 h starting 2 d before infection. Mate choice and rank status were assessed, and blood samples were collected at −2, 7, 14 and 25 d post infection (dpi) for hematological and hepatic function determinations. All animals were observed for clinical signs every other day from the beginning of the experiment and euthanised 25 dpi after last sampling. Infected animals spent more (P<0.01) time lying stretched (3.78±1.77 vs. 0.77±0.03%) and less (P<0.01) time grooming (1.95±1.31 vs. 2.58±0.10%) and at the watering trough (1.20±1.13 vs. 3.35±0.02%) than controls. These differences were noticeable 6 dpi and remained until the end of the experiment. No changes (P>0.05) were observed in the time spent at the feeder, rank status or mate choice. Leukocyte and lymphocyte concentrations increased (P<0.05), while heterophil counts decreased in infected rabbits as the experiment progressed. Furthermore, infected animals had larger concentrations of alkaline phosphatase as soon as 7 dpi. No clinical signs of the disease were detected. Necropsy fi ndings corroborated hepatic lesions and presence of the parasite in all infected animals. It was concluded that an infection with 3000 eggs of T. pisiformis induced changes in behavioural and physiological parameters that may improve early detection of sick rabbits.

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Sexual dimorphism is a well-documented phenomenon observed at all levels of the animal kingdom, with the inclusion of both sexes in clinical trials and basic research becoming mandatory. Regarding parasitosis, in several animal species, the signs and virulence of the disease may change depending on the sex of the affected animal. In the cestodiasis caused by Taenia solium and Taenia crassiceps, females are more susceptible to experimental infection than males. Cysticercosis by Taenia pisiformis in rabbits has acquired relevance due to its economic impact, namely affecting welfare and production. In America, specifically in Mexico, there are no formal reports on the infection with T. pisiformis metacestodes in populations of wild rabbits, despite being the country with more endemic species (about 15 species), among them, the volcanoes rabbits or the endangered teporingo (Romerolagus diazi). In this study, 31 wild rabbits were obtained by hunters of some regions of Morelos state during several hunting seasons, and sex, physiological stage, and number of metacestodes were recorded. A high frequency of infection by T. pisiformis metacestodes (67.7%) was found. Also, a higher susceptibility to this infection was observed in does (80% infected) compared to bucks (40%), finding 84.2% of metacestodes (235 metacestodes) in does and 15.8% of metacestodes (44 metacestodes) in bucks. The percentage of infection was higher in lactating compared with pregnant and non-pregnant does, with metacestodes lodging mainly in the uterus. Increasing our knowledge regarding parasitic infections can help us better understand transmission circles as well as the parasite-host interaction of these increasingly at risk rabbit species.

Bacillus thuringiensis is a gram-positive soil-dwelling bacterium that is commonly used as a biological pesticide. This bacterium may also be used for biological control of helminth parasites in domestic animals. In this study, we evaluated the possible ovicidal and cestocidal effects of a total protein extract of B. thuringiensis native strains on the zoonotic cestode parasite of dogs, Dipylidium caninum (D. caninum). Dose and time response curves were determined by coincubating B. thuringiensis proteins at concentration ranging from 100 to 1000 μg/mL along with 4000 egg capsules of D. caninum. Egg viability was evaluated using the trypan blue exclusion test. The lethal concentration of toxins on eggs was 600 μg/ml, and the best incubation time to produce this effect was 3 h. In the adult stage, the motility and the thickness of the tegument were used as indicators of damage. The motility was inhibited by 100% after 8 hours of culture compared to the control group, while the thickness of the cestode was reduced by 34%. Conclusively, proteins of the strain GP526 of B. thuringiensis directly act upon D. caninum showing ovicidal and cestocidal effects. Thus, B. thuringiensis is proposed as a potential biological control agent against this zoonosis.

BackgroundParasitic diseases are important in animal production because they cause high economic losses. Affected animals often exhibit stereotypical behavioral alterations such as anorexia and inactivity, among others. Among the diseases that commonly affect domestic rabbits is mange, which is caused by the mite Psoroptes cuniculi. Therefore, within the context of the host-parasite relationship, it is critical to understand the mechanisms involved in the alteration of host behavior, in order to better utilize sick animal behavior as a strategy for diagnosis and treatment of disease.MethodsRabbits were infested placing mites in the ear conduct. We characterized changes in exploratory behavior and scent marking evoked by acute (1-9 days) and chronic (25-33 days) experimental infestation. Behavior was recorded during ten minutes while the animals were in a 120 cm × 120 cm open field arena divided into 9 squares. Serum cortisol was measured individually using radioimmunoassay kits. Locomotor activity, chinning, rearing and body weight were compared using a Friedman test, the effect of treatment (infested versus non-infested) across time was analyzed using a repeated measures ANOVA, and the Pearson test was used to determine whether chinning and ambulation scores were significantly correlated. Serum cortisol levels and food consumption were analyzed with a Kruskal-Wallis test and body temperature was analyzed with an ANOVA test.ResultsWe observed a significant decrease in rearing behavior as early as two days post-infestation, while chinning and locomotor activity were significantly decreased four days post-infestation. Chronic infestation was associated with decreased food intake, significant weight loss, and a trend toward increased serum cortisol levels, while no changes were observed in body temperature.ConclusionsThe presence of visible lesions within the ear canal is commonly used to detect mite infestation in rabbits, but this is possible only after chronic infestation. The behaviors described here may be a useful and economic tool in guiding the early diagnosis of parasitic infestation by P. cuniculi, allowing for early treatment and the application of control measures before significant weight loss occurs, thereby avoiding economic losses.