Rift Valley Fever Bovine calves
Natural infection with RVF virus primarily occurs in livestock (small ruminants, cattle) and humans with rare clinical cases reported in camels, African buffalos and horses. Experimental infection has been recorded in mice, rats, hamsters, dogs, cats and macaques. Gross pathology in calves is characterized by; Diffuse hepatic necrosis with cholestasis (yellow discoloration) and capsular plus parenchymal haemorrhages. (Image top right).
Gastrointestinal haemorrhage with large suggillations in the abomasal serosa. (Image bottom right)
Nephrosis (image below) and splenomegaly.
Viral antigen is abundant in the RE system of multiple organs (liver, kidney, adrenals, GIT, brain, ovaries, endometrium) with virus persisting at these sites for many weeks, making them useful diagnostic samples for RT-PCR, virus isolation and antigen ELISA. Viraemia (virus in blood) lasts only2-5 days.