Bovine ephemeral fever (BEF) is an arthropod-borne viral disease of cattle caused by a single
stranded RNA virus that belongs to the rhabdovirus group. The outbreak was diagnosed as
BEF on the bases of clinical signs and pathological lesions. In the present study, out of two
hundred and fifty cows, fourteen cows are died from BEF by mortality ratio 5.6%. The diseased
cows showed viraemia, inappetance, depression, salivation, lacrimation, nasal discharge,
lameness, and recumbency followed by death. Formalin-fixed paraffin-embedded
samples from naturally infected cows with BEFV were grossly and microscopically evaluated
and tested using immunohistochemistry. The main gross findings include grayish-white
streaks in the skeletal muscles, congestion and mottling of the lung surface with darkness
of the lobar septa, congestion of the tracheal mucosae with the presence of mucous exudate
in their lumen. The liver and kidneys were congested with edematous and enlarged lymph
nodes. The microscopical examination revealed various pathological changes in different
organs. Diffuse hemorrhage and pulmonary emphysema with alveolar atelectasis and catarrhal
bronchiolitis were observed in the lung. The skeletal muscle showed severe hyaline
degeneration and myomalacia with inter-muscular hemorrhage. Edema with marked lymphoid
depletion was observed in the pre-scapular and pre-femoral lymph nodes. Necrotic
changes were noticed in the renal and intestinal tissues. Diagnosis was confirmed by detecting
viral antigen in the spleen, lung, muscle, kidney, heart and lymph nodes with most
of the antigen appearing within macrophages and pericytes using immunohistochemistry. |
