Maximizing detection of dengue virus serotypes by a modified reverse transcription-polymerase chain reaction assay in India: presence of co-infection with multiple serotypes

Background: Lumpy skin disease (LSD) is an emerging pox disease that can cause serious losses in cattle industry due to decreased productivity, cost of veterinary treatments, death, and impact on the international trade of live animals and animal products. The disease originated from Africa, but it has spread to countries of the Middle East and poses a serious threat to Europe and Asia. Recently, field veterinarians in Jordan reported a range of clinical signs seen after the LSD vaccination in cattle. Methods & Materials: During the outbreak of LSD in Jordan, farmers outside the outbreak governorate (Irbid) were recommended to vaccinate their cattle of all ages, types and sexes using a sheep pox virus (SPPV) RM65 vaccine, Jovivac. After the vaccination campaign was initiated, post vaccinal reactions were suspected. Affected farms were investigated and data collected about animals on each farm that practiced vaccination against LSD. Results: Sixty-three dairy cattle farms, with a total of 19,539 animals, were included in the study. Of those, 56 farms reported adverse clinical signs after vaccine administration. The duration between vaccine administration and appearance of adverse clinical signs ranged from 1 to 20 days (Mean = 10.3, SD 3.9). Clinical signs were similar to those observed with natural cases of lumpy skin disease. These included fever and variable sized cutaneous nodules that could be seen anywhere on the body. Some cattle had swollen lymph nodes, while a few pregnant animals aborted. The percentage of affected cattle ranged from 0.3 to 25% (Mean = 8, SD 5.1). Fever, decreased feed intake, and decreased milk production were seen in 83.9, 85.7, and 94.6% in cattle on the affected farms, respectively. All affected cattle displayed skin nodules over their entire bodies. No mortalities were reported due to vaccine adverse reactions. Duration (course) of clinical signs ranged from 3 to 20 days (Mean = 13.7, SD 4.1). Conclusion: LSD vaccines can be associated with severe reaction that can be confused with natural infection. Further studies are warranted to identify safe vaccines for this disease.