Diagnosis and phylogenetic analysis of a multifocal cutaneous orf virus with mixed bacterial infection outbreak in goats in Fujian province, China

Abstract

Outbreaks of orf virus on goat farms are common in China. In this study, we investigated a severe multifocal cutaneous orf virus outbreak with a correlative mixed bacterial infection which persisted for up to 6 months, and which had a high morbidity (93.7%) and mortality (15%) among kids in a herd of crossbreed goats in Fujian province in China. The disease was diagnosed as an orf virus (ORFV XD strain) infection associating with Streptococcus pluranimalium and Staphylococcus, identified using standard virological and bacteriological techniques. Multiple sequence alignments and phylogenetic analyses of the whole ORFV 011 (B2L), 059 (F1L), 032 and 080 genes revealed that the even though the virus phylogeny was clustered in branches of conventional orf virus strains, it nonetheless evidenced high variation within this subset. Furthermore, the sequences from the ORFV 080 gene allowed us to distinguish between the different strains at a higher resolution and these observations afforded us a comparative view of the ORFV 080 gene. This is the first report describing an outbreak of severe multifocal cutaneous orf virus with associated bacterial infection in China.

Survey and Dynamics of bacteria involved in secondary infections in sheep affected by orf virus

“…We can thus say that there is no connection between the sex, age or severity of the lesions and the number of species of bacteria that infect lesions caused by orf virus. Lesional scores of sheep with suprainfected orf lesions tended to cluster around 2 and 3 confirming that the bacteria that populate such lesions also complicate the course of the disease as noted by Fleming et al, 2015 andChi et al, 2017. However, as regards sex of the affected animals, females seemed to be more susceptible to a secondary infection, probably due to the fact that the disease developed in late spring, during the shearing when the stress caused by lamb suckling and shearing can decrease the immunity of mothers.…”

“…Following the determinations, we found that S. aureus and P. aeruginosa dominated in secon dary infections, underlying their highly infectious character if they encounter a breach in the organism (Zecconi and Scali, 2013). Contagious ecthyma being a disease that affects the skin, it creates breaches for S. aureus and can complicate the evolution of this disease (Chi et al, 2017). Being a bacteria that easily adapts to any biological environment can even cause treatment-resistant rebellious mastitis (Weese et Note: Correlations are being calculated at a 95% level of significance, P values higher then 0,05 indicating that correlations beween the two sets of values cannot be generalized and every correlation between two datasets is the result of hazard r-correlation coefficient al., 2010).…”

“…As shown in literature (Chi et al, 2017, Quinn et al, 2011 orf virus can create breaches for opportunistic bacteria to develop secondary bacterial infections. In our study study is stated that such bacterial infections can often occur, regarding that all 4 baterial species isolated can develop infections if they encounter discontinuities in natural barriers of the hosts.…”

“…The research was conducted in five herds, on 3 to 96 month old sheep, with orf lesions, scored from mild (1) to severe (3). The bacteria were isolated from the lesions and identified by cultivation on liquid and solid media plus identification by use of API galleries with related software.…”

Antibiotic Resistance Profile in Co-Infecting Bacteria Isolated from Sheep Dipslaying Orf Lesions

“…However, mortality may increase by 20% ~ 50% as a result of secondary bacterial infection, stress, immunosuppression or in concomitant evolution with other diseases and may exceed 90% in the case of malignant orf (Hosamani et al, 2009). Frequent suprainfections occur with bacteria such as Staphylococcus and Streptococcus (Chi et al, 2017) but also with other bacteria (Venkatesan et al, 2018). Scarification or microabrasions in the epidermis are a condition for the onset of the disease.…”