Experimental infection of pregnant Pyrenean chamois (Rupicapra pyrenaica) with border disease virus subtype 4.

Border disease virus (BDV) causes high mortality in Pyrenean chamois (Rupicapra pyrenaica) on the French and Spanish sides of the Pyrenees Mountains. We investigated the pathology induced by BDV in pregnant chamois via experimental infection. Three females were inoculated during the second third of pregnancy with a BDV-4 subgroup strain isolated from a wild Pyrenean chamois during an acute epizootic. A fourth pregnant chamois and one nonpregnant ewe were kept as negative controls. Animals were monitored to assess clinical signs, hematology, viremia, and serology. Postmortem examinations included necropsy, histopathology, and quantification of viral RNA in organs. Pregnancy was unsuccessful in all inoculated animals. One died 24 days postinoculation (dpi) without showing any precursory clinical signs. The second animal had profuse diarrhea from 13 dpi to its death at 51 dpi. The third aborted at 46 dpi and was euthanized at 51 dpi. All animals were viremic from 4 dpi until death. Neutralizing antibodies against BDV-4 were detected from 12 dpi. Necropsies showed generalized lymphadenomegaly, associated in one case with disseminated petechial hemorrhages in the digestive tract. Seventy-eight of 79 organs from inoculated adults and their fetuses had detectable viral RNA. The main histologic lesions in adults were mild lymphohistiocytic encephalitis associated with moderate or moderately severe lymphoid depletion. Control animals remained negative for virus (in blood and organs), antibody, and lesions upon postmortem examination. BDV infection during pregnancy in Pyrenean chamois causes severe disease leading to abortion, then death. Despite 100% fetal death following inoculation, viral RNA was recovered from all organs of infected fetuses, suggesting that persistently infected offspring could be born. Our results may help explain the reported decrease in chamois populations in several areas and suggest that great care must be taken when interpreting infection status for wildlife.

Border disease virus among chamois, Spain.

Approximately 3,000 Pyrenean chamois (Rupicapra pyrenaica pyrenaica) died in northeastern Spain during 2005-2007. Border disease virus infection was identified by reverse transcription-PCR and sequencing analysis. These results implicate this virus as the primary cause of death, similar to findings in the previous epizootic in 2001.

Severe outbreak of disease in the southern chamois (Rupicapra pyrenaica) associated with border disease virus infection.

An outbreak of a previously unreported disease affecting southern chamois (Rupicapra pyrenaica) in the central Pyrenees (NE Spain) was recorded in 2001 and 2002. There was a marked temporal distribution, most animals being found between February and June. After the outbreak, the population was found to have decreased by about 42%, most probably due to the disease. We examined 20 affected chamois. Clinical manifestations included depression, weakness and movement difficulties in all cases. Three chamois presented abnormal behaviour, with absence of flight reaction, and 16 showed different degrees of alopecia with skin hyperpigmentation. At necropsy cachexia was observed in all animals, four chamois had abscesses in different parts of the body, four had pneumonia, one had an extensive subcutaneous infection on the head and neck and one had severe orchitis. Microscopic lesions were found in the brain, mainly edema, gliosis, espongiosis, cariorrexis and neuronal multifocal necrosis. A perivascular mononuclear inflammatory infiltrate was present in three of them. Skin lesions included marked follicular atrophy, mild to moderate epidermal hyperplasia with orthokeratotic hyperkeratosis and follicular hyperkeratosis, and hypermelanosis. In 13 chamois there were haemosiderin deposits in the spleen, and in three individuals kidney "cloissone" was observed. Intraeritrocitic parasites were detected either by direct observation or PCR in 8 of 17 chamois. A pestivirus was isolated and detected by RT-PCR from 12 of 13 affected chamois and antigenic characterized as border disease virus by monoclonal antibodies. This is the first time a border disease virus has been associated with an outbreak of a high-mortality disease in a wild species.

[Pestivirus as causative agent of abortion and perinatal mortality in cattle and sheep in Switzerland]. / Ursächliche Beteiligung von Pestiviren an Aborten und perinatalen Todesfällen bei Rindern und Schafen in der Schweiz.

The causal involvement of bovine viral diarrhoea virus (BVDV) and border disease virus (BDV) infection in bovine and ovine abortion and perinatal mortality remain unclear. From 1992 until 1994, 213 bovine and 31 ovine foetuses as well as 36 calves and 25 lambs which had died perinatally were investigated. Tissue samples were tested for the presence of pestiviruses and serum or fluid from the body cavities were analysed for the presence of pestivirus antibodies. Detection of pestiviruses was performed by (i) cell culture isolation, (ii) antigen ELISA and (iii) immunohistochemical staining for viral antigen. For antibody-testing an indirect ELISA was used. In nine bovine foetuses and in two calves BVDV was isolated. Pestiviruses, most likely BDV were detected in one ovine foetus and three lambs. In 6% of the bovine and 11% of the ovine foetuses anti-pestivirus antibodies were detected. However, clinical features and history of bovine cases did not show a correlation with the diagnostic results, In contrast, the presence of central nervous system signs in neonatal lambs and the detection of BDV was correlated.