Lumpy skin disease (LSD) is a highly infectious disease of cattle caused by a virus belonging to the Capripoxvirus genus of the family Poxviridae. The purpose of this study is to place on record the first confirmation of LSD in the Sultanate. The disease was diagnosed and confirmed using polymerase chain reaction, histopathology, transmission electron microscopy and serum neutralization testing. The epizootic occurred in 2009 involving a large number of animals and covering a wide area including Nezwa, Alqabel, Sohar, Saham and Burimi. Morbidity and mortality rates of 29.7 and 26.3 %, and 13.6 and 15.4 % were observed at Nezwa and Sohar, respectively. The clinical signs were much more severe in Holstein–Friesian cattle compared to indigenous breeds and were characterized by multiple skin nodules covering the neck, back, perineum, tail, limbs and genital organs. Affected animals also exhibited lameness, emaciation and cessation of milk production. Oedema of limbs and brisket, and superficial lymph node enlargement were highly prominent. It is not known from where the virus originated, or how it spread to the Sultanate. The disease has become endemic in the country and is liable to extend to other Gulf Cooperation Council Countries and cause a pandemic. It is of major concern to the Omani dairy industry. Due to the widespread presence of screw worm, serious economic losses can follow outbreaks.
Influenza A strains emerging from wild birds are a constant threat to South Africa's valuable ostrich industry. In 2004 and again in 2006, low pathogenicity avian influenza H5N2 strains introduced from a wild bird reservoir mutated in ostriches to high pathogenicity avian influenza (HPAI), with serious economic consequences and export bans imposed by the European Union. Although no outbreaks of notifiable avian influenza have occurred in South Africa since 2006, the H9N2 virus caused a localized outbreak where ostriches displayed symptoms of green urine, depression, and mild morbidity. Most recently, an outbreak of H10N7 in farmed Pekin ducks (Anas platyrhynchos domestica) caused increased mortalities, but this was exacerbated by a secondary Escherichia coli infection, because an intravenous pathogenicity index of 0.00 was recorded. Each of the eight gene segments of the five strains isolated from 2007 to 2009 from farmed ostriches in the Oudtshoorn region (H6N8, H9N2), Pekin ducks (H10N7, Joostenburgvlakte region), and wild Egyptian geese (Alopochen aegypticus; H1N8, Baberspan wetlands; H4N2, Oudtshoorn region) were sequenced, genetically analyzed, and compared to previous South African isolates and viruses in the public data banks. An H5N8 strain was also detected by reverse-transcription PCR in cloacal swabs from swift terns (Sterna bergii) in the Mosselbaai region during 2007, although a virus could not be isolated. Initial phylogenetic results indicate that H6N8 and H9N2 ostrich and H10N7 Pekin duck viruses originated in the wild bird population that is geographically dispersed throughout southern Africa, based on the reassortment of viral genes from birds sampled outside of the ostrich farming areas. No evidence of internal genes associated with Asian HPAI H5N1 strains were detected in the South African isolates.
In an intensive ostrich farming area in South Africa with a history of ostrich influenza outbreaks, we conducted a survey of avian influenza virus (AIV) and Newcastle disease virus (NDV) in wild aquatic birds. During late autumn and winter 1998, the time of year when outbreaks in ostriches typically start to occur, 262 aquatic birds comprising 14 species were sampled and tested for both virus infections. From eight samples, AIV, serotype H10N9, could be isolated. All isolates were apathogenic as determined by the intravenous pathogenicity index (0.00). Conversely, none of 33 sera of these wild birds showed antibodies against H10. However, one bird was found serologically positive for H6 AIV. This AIV serotype was later isolated from ostriches during an avian influenza outbreak in this area. No NDV was isolated although 34 of 46 serum samples contained NDV-specific antibodies. This is the first H10N9 isolate to be reported from Africa. In addition, our data support the notion that wild aquatic birds may function as a reservoir for AIV and NDV in South Africa.
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