Respiratory infection of camels associated with parainfluenza virus 3 in Sudan

This study was undertaken to investigate the role of parainfluenza virus 3 (PIV3) in respiratory infection of camels. A total of 273 lung specimens from camels with pneumonia lesions were collected from slaughterhouses in four different areas of Sudan. In addition, eight specimens were collected from outbreaks of respiratory infection in camels. Using antigen detection sandwich ELISA kits, six out of the 281 specimens tested were positive for the PIV3 antigen (2.1%); the highest prevalence was noted in Eastern Sudan (4.2%), then in Central and Northern Sudan (1.4%). The direct immunofluorescent test (FAT) was used to confirm the positive reactions for PIV3 by ELISA. The polymerase chain reaction (RT-PCR) was applied for the detection of the PIV3 genome in lungs of camels; two out of four samples which were positive by the PIV3 ELISA were also positive by RT-PCR. Virus isolation was attempted for PIV3 in MDBK cells; four specimens yielded cytopathic virus when inoculated onto the cell culture. The cytopathic effect (CPE) consisted of cell rounding, multinucleated cells, sloughing and elongation of cells, and some syncytia were observed on the 3rd to 7th day post-inoculation. Using commercially available indirect ELISA kits for antibodies to PIV3, 495 camel sera were tested, and the seroprevalence detected was 82.2%. The highest seroprevalence was observed in Central (92.6%), then in Eastern (92.2%) and Central to South Sudan (82.5%); the lowest prevalence was found in Northern Sudan (64.8%).