Pathogen spread and globalization: The case of Pestivirus heterogeneity in southern Italy

Pestiviruses are responsible for widespread diseases affecting cattle, pigs and other ruminants, presenting a wide range of clinical manifestations, with significant impact on animal production. Given the recent various reports of a relatively high number of new strains and atypical genomic variants, in the present study, ninety-seven genomic sequences from southern Italy have been evaluated applying the palindromic nucleotide substitutions method, based on 5'-UTR secondary structure alignment and computing genetic distance among strains in the internal ribosome entry site. Sequence analysis revealed a highly heterogeneous virus population, indicating the introduction of virus variants of Bovine viral diarrhea virus and Border disease virus species from foreign countries. The application of different analytical procedures was useful to avoid interpretation difficulties. Circulation of heterogeneous virus populations showed the need for more accurate epidemiological investigations and stringent veterinary controls to protect animal health and welfare.

Development and evaluation of real-time RT-PCR using ear hair for specific detection of sheep persistently infected with border disease virus (BDV)

The aim of this study was to develop an improved border disease virus (BDV) specific real time RT-PCR and to evaluate its performance on manually plucked hairs from sheep persistently infected with BDV that may act as a non-invasive alternate sample. The BDV real time RT-PCR assay reported here showed a high analytical sensitivity (10^0.6 TCID50/ml), specificity (no reactivity with BVDV-1, BVDV-2, HoBi-like pestivirus and CSFV) and reproducibility. When the assay was validated on 210 samples from BDV-infected and uninfected sheep, it showed a 100% diagnostic sensitivity and specificity with virus isolation. Further evaluation of the assay on manually plucked hair follicles from ear (mid-lateral, mid-medial) and tail tip from sheep persistently infected with BDV showed that a minimum of 20 hair follicles need to be tested for correct diagnosis of BDV. The BDV load was comparatively higher in hairs from mid-medial ear than those from other tested locations. Evaluation on other samples from PI sheep demonstrated that the test performance was similar to that of pestivirus generic real-time RT-PCR, but improved than the currently available BDV specific real-time RT-PCR. Although more number of PI animals need to be evaluated, the results of the study showed that manually plucked hairs from mid-medial ear pinna is a suitable alternative sample in real-time RT-PCR for detection of BDV persistently infected sheep. Use of the non-invasive ear hair samples and the improved BDV specific real-time RT-PCR reported here may be useful for BDV surveillance in several sheep rearing countries.

Border disease in cattle

Within the family Flaviviridae, viruses within the genus Pestivirus, such as Border disease virus (BDV) of sheep, can cause great economic losses in farm animals. Originally, the taxonomic classification of pestiviruses was based on the host species they were isolated from, but today, it is known that many pestiviruses exhibit a broad species tropism. This review provides an overview of BDV infection in cattle. The clinical, hematological and pathological-anatomical findings in bovines that were transiently or persistently infected with BDV largely resemble those in cattle infected with the closely related pestivirus bovine viral diarrhoea virus (BVDV). Accordingly, the diagnosis of BDV infection can be challenging, as it must be differentiated from various pestiviruses in cattle. The latter is very relevant in countries with control programs to eradicate BVDV in Bovidae, as in most circumstances, pestivirus infections in sheep, which act as reservoir for BDV, are not included in the eradication scheme. Interspecies transmission of BDV between sheep and cattle occurs regularly, but BDV in cattle appears to be of minor general importance. Nevertheless, BDV outbreaks at farm or local level can be very costly.

First description of enhanced expression of transforming growth factor-alpha (TGF-α) and glia maturation factor-beta (GMF-β) correlate with severity of neuropathology in border disease virus-infected small ruminants

Border disease (BD) is caused by Pestivirus and characterized by severe neuropathology, and histopathologically observed severe hypomyelination. We have previously shown that small ruminants infected with border disease virus (BDV) play an important role for neuropathology and pathogenesis of severe oxidative damage in brain tissue, neuronal mtDNA; in the production of high pathologic levels of nitric oxide; in glial cell activation and stimulation of intrinsic apoptosis pathway. This study aimed to investigate the relationship between glia maturation factor beta (GMF-β) and transforming growth factor alpha (TGF-α) expressions and the causes of BDV-induced neuropathology and to investigate their role in neuropathogenesis in a way that was not presented before. Expression levels of GMF-β and TGF-α were investigated. Results of the study revealed that the levels of GMF-β (P < 0.005) and TGF-α (P < 0.005) expression in the brain tissue markedly increased in the BDV-infected animals compared to the non-infected healthy control group. While TGF-α expressions were predominantly observed in neurons, GMF-β expressions were found in astrocytes, glial cells and neurons. These results were reasonable to suggest that BDV-mediated increased GMF-β might play a pivotal role neuropathogenesis and a different type of role in the mechanism of neurodegeneration/neuropathology in the process of BD. The results also indicated that increased levels of GMF up-regulation in glial cells and neurons causes neuronal destruction, suggesting pathological pathway involving GMF-mediated brain cell cytotoxicity. It is clearly indicated that the cause of astrogliosis is due to severe TGF-a expression. This is the first study to demonstrate the expression of GMF-β and TGF-α in neurons and reactive glial cells and its association with neuropathology in BD.

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): Border disease

Border disease has been assessed according to the criteria of the Animal Health Law (AHL), in particular criteria of Article 7 on disease profile and impacts, Article 5 on the eligibility of Border disease to be listed, Article 9 for the categorisation of Border disease according to disease prevention and control rules as in Annex IV and Article 8 on the list of animal species concerned by Border disease. The assessment has been performed following a methodology composed of information collection and compilation, expert judgement on each criterion at individual and, if no consensus was reached before, also at collective level. The output is composed of the categorical answer, and for the questions where no consensus was reached, the different supporting views are reported. Details on the methodology used for this assessment are explained in a separate opinion. According to the assessment performed, Border disease can be considered eligible to be listed for Union intervention as laid down in Article 5(3) of the AHL. The disease would comply with the criteria as in Sections 3, 4 and 5 of Annex IV of the AHL, for the application of the disease prevention and control rules referred to in points (c), (d) and (e) of Article 9(1). The animal species to be listed for Border disease according to Article 8(3) criteria are mainly sheep and other species of the family Bovidae as susceptible and reservoirs.

Pestivirus in alpine wild ruminants and sympatric livestock from the Cantabrian Mountains, Spain

Bovine viral diarrhoea virus (BVDV) and Border disease virus (BDV) were investigated at the wildlife-livestock interface in the distribution area of chamois in the Cantabrian Mountains, North-Western Spain. From 2010 to 2014, sera from sympatric wild (n=167) and domestic (n=272) ruminants were analysed for pestivirus antibodies by cELISA, virus neutralisation test (VNT) and for the presence of pestiviral RNA using a reverse transcription (RT)-PCR. Results showed a higher seroprevalence in cattle (59.4 per cent, 13/13 of herds) than in domestic small ruminants (5.9 per cent sheep, 2/8 of flocks; 0 per cent goats of 4 flocks) and wildlife (10.8 per cent in red deer, 0 per cent in roe deer and 0 per cent in Cantabrian chamois). High VNT titres were detected in two cattle herds, suggesting the circulation of BVDV-1 and BVDV-2 strains. BVDV-1 RNA was detected in one cattle calf by RT-PCR and sequencing. Conversely to other similar grazing systems, sheep flocks did not play a relevant role in the pestivirus epidemiology in this region. Pestivirus infections in wild ruminants were sporadic and most probably dependent on a domestic source.