Orf: an update on current research and future perspectives

Abstract

Orf is one of the most widespread viral diseases worldwide, affecting mostly small ruminants and, sometimes, other species, including wild animals. Of late, there have been an increasing number of reports of new species being affected by the disease, implying a dynamic host-pathogen interaction. The causative agent, orf virus, has been extensively investigated over recent years, owing to its zoonotic importance and ability to cross-infect other species sporadically. The evasive mechanisms that the virus has developed to adapt and grow in the presence of an active immune response helps to explain the ability of the virus to repeatedly reinfect the same host. The apparent diversity in the antigenic/immune targets of different orf virus strains involved in such repeat infections may also be contributing factors. Exposure of animals to stress or immunosupression as a result of therapy or primary viral infection can accentuate the severity of disease. Genes homologous to host cytokines or their antagonists, and which contribute to viral virulence, have been found in the viral genome. A combination of electron microscopy, histology and PCR is the most accurate laboratory approach for confirmation of the disease, although clinical signs are often typical. However, some infections may be confounded by similar clinical manifestations caused by other infections. This review presents, in brief, a recent understanding of the virus at the host-pathogen level, molecular biology of the virus, disease epidemiology, clinical manifestations in man and animals, diagnostic procedures, and the economic and environmental impact of the disease.

Effect of Stabilization and Reconstitution on the Stability of a Novel Strain of Live Attenuated Orf Vaccine (ORFV MUK59/05)

“…Adv., 10 (8): 365-375, 2015 udder or vulva may be affected including secondary bacterial infections with or without myasis (Housawi and Abu Elzein, 2000). Orf is considered as economically important due to its high morbidity in adult animals, repeated infection of hosts by subverting the host immunity, cross infectivity to other species and its zoonotic potential (Hosamani et al, 2009). Orf can be controlled by vaccination and live vaccines are used in some parts of the world.…”

Isolation and molecular characterization of contagious pustular dermatitis virus from Rajasthan, India

“…This helps to explain the ability of the virus to repeatedly reinfect the same host, a phenomenon also observed in an outbreak of ORFV infection during December 2012, followed by in August 2013 at the Central Sheep Breeding Farm (CSBF), Hisar, Haryana (Aman Kumar, personal communication). Exposure of Animals to stress or immune-suppression as a result of therapy or primary viral infection can accentuate the severity of disease [8]. Because of the persistence or repetition of ORFV infections, it is very difficult to eliminate this virus and hence CPDV infection is considered a re-emerging disease in India and other countries [2,4].…”

Occurrence and identification of contagious ecthyma in blackbuck

“…It affects sheep, goats and other domesticated/wild ruminants namely rein deer, musk ox, mule deer, white-tailed deer, pronghorn fawns and wapiti calves in natural captive/free ranging conditions as well as experimental infection [2,9,16]. It has also been reported in camelids, squirrels and seals [4]. Secondary bacterial and fungal infections are common [2] and sometimes associated with other viral infections namely PPRV [13] and goat pox [17].…”

“…Secondary bacterial and fungal infections are common [2] and sometimes associated with other viral infections namely PPRV [13] and goat pox [17]. Increasing number of reports of CE in sheep and goats has been noticed worldwide and it has been reported in all parts of India and endemic in nature [4,10]. This endemic disease incurs economic losses by causing severe morbidity in adults and mortality in young ones affecting farming community in India [10].…”

“…However, the presence of viral nucleic acid in skin tissue was identified by molecular diagnostics namely diagnostic PCR and B2L gene cloning/ sequencing. Multiple sequence alignment and phylogenetic tree based on complete B2L sequence have been performed to study the evolutionary relationship with other circulating virus strains/isolates in the country [1,4,18].…”