Neurogenic cardiomyopathy in rabbits with experimentally induced rabies

Cardiomyopathies have been rarely described in rabbits. Here we report myocardial necrosis of the ventricular wall in rabbits with experimentally induced rabies. Myocardial lesions were found only in rabbits with brain lesions, and the severity of the cardiac lesions was proportional to that of the brain lesions. Neither the frequency nor the cumulative dose of anesthesia was related to the incidence or the severity of the myocardial lesions. The myocardial lesions were characterized by degeneration and/or necrosis of myocardial cells and were accompanied by contraction band necrosis, interstitial fibrosis, and infiltration of inflammatory cells. The brain lesions due to rabies virus infection were most prominent in the cerebral cortex, thalamus, hypothalamus, brainstem, and medulla. Rabies virus antigen was not found in the hearts of any rabbits. Based on these findings, the myocardial lesions were classified as neurogenic cardiomyopathy.

Relationships among specific reasons for culling, reproductive data, and gross morphology of the genital tracts in gilts culled due to reproductive failure in Thailand

The present study aims to investigate genital organs of replacement gilts culled due to reproductive failure, and the relationship between gross morphological findings and historical reproductive data. The study was conducted from July 2005 to September 2006 and included a random sample of 200 genital organs from six swine herds in Thailand. Historical data and the reasons for culling were analyzed. Gross morphological examinations focused on the normality and abnormalities of the ovaries, as well as the remainder of the reproductive tract. Descriptive statistics and frequency analysis were conducted for all reproductive parameters. On average, the gilts were culled at 321.2+/-51.1d of age, at a body weight of 145.3+/-24.2kg. Gilts expressed first estrus at 253.2+/-32.7d and were artificially inseminated for the first time at 268.2+/-30.8d of age. The interval from entry to culling averaged 96.9+/-53.7d. Reasons for culling included anestrus (44.0%), vaginal discharge (20.5%), repeat breeding (15.5%), not being pregnant (10.0%), and miscellaneous causes (10.0%). Overall, 50.5% of gilts had normal genital organs, whereas 49.5% had at least one abnormality. Abnormalities of the ovary, oviduct, uterus, cervix and vagina-vestibule were found in 15.5%, 14.0%, 22.0%, 16.2%, and 17.6% of the gilts, respectively. The most common post-mortem abnormalities included endometritis (14.0%), cystic ovaries (10.5%) and congenital abnormalities of the reproductive tract (8.0%). Of the gilts culled due to anestrus, 52.2% were pre-pubertal. Most of the gilts culled due to vaginal discharge or repeat breeding had been cycling (90.2% and 96.8%, respectively).

Negative impact of porcine reproductive and respiratory syndrome virus infection on the efficacy of classical swine fever vaccine

Recent findings suggest that porcine reproductive and respiratory syndrome virus (PRRSV) possesses immunomodulatory properties. To investigate the effect of PRRSV infection on classical swine fever (CSF) vaccine efficacy, 17-day-old pigs were divided into five groups. The experimental group was infected with a Thai PRRSV (US genotype) a week before CSF vaccination and challenged with a virulent CSF virus (CSFV) 3 weeks following vaccination. The control groups received no PRRSV infection, no CSF vaccination, no CSF challenge, or in combination were included. The results demonstrated that PRRSV infection significantly inhibited host immune response that resulted in vaccination failure in the subsequent CSFV exposure. Following CSF challenge, the PRRSV-infected, vaccinated pigs exhibited clinical, virological and pathological features resembled to those of the non-vaccinated groups. The findings indicated that CSF immunization during an acute phase of PRRSV infection could result in vaccination failure.