Department of Pathology Faculty of veterinary medicine BOVINE

Department of Pathology Faculty of veterinary medicine

BOVINE RAL FEVER By • Dr. SHEREIN SAIED • Assistant professor, Pathology DPT.

(Three-day sickness, Bovine Epizootic Fever, Three-day stiff sickness),

BOVINE EPHEMERAL FEVER name ephemeral fever was • applied very early in the disease’s recorded history. *The disease is not ephemeral in the • sense of being hard to see. *The

Three-day sickness As clinical signs generally • persist for about three days then disappear suddenly with complete recovery – hence the name of the • disease

Bovine Epizootic Fever The disease is known • to be the same as Bovine epizootic fever • of japan.

Three-day stiff sickness, The disease is aracterized by muscle stiffness • •

(Definition)

Definition non contagious epizootic -A • . arthropod-born viral disease • -Affect cattle and water buffaloes. • -Characterized by; Sudden • set of fever, depression, • stiffness, lameness, and • rapid recovery. • •

(Etiology)

Etiology Family: Genus: Rhabdoviridae • Ephemerovirus Type Species: Bovine ephemeral fever virus

(Host Range)

Cattle and Water Buffaloes •

Host Range *All age groups of cattle are susceptible • but the disease is more common in age group of 6 -24 months. Inapparent infections may occur in some wild ruminants. and other animals are not known to become infected • •

(Epidemiology)

Epidemiology The disease was first recorded in East Africa in 1867. • • * BEF occurs enzootically in African countries including Egypt, in most of Asia, Middle East countries, Australia and Japan. It does not occur in Europe or the • Americas. •

BOVINE EPHEMERAL FEVER In Egypt

In Egypt, • BEF was first described • 1895 & 1924. ubsequent outbreaks • ve been occurred in of 00, 2001 and • 000, 2001 2004.

* In summer 1991, • a typical form of the • disease. has been recorded in different orates in lower Egypt.

*A second outbreak of BEF • occurred in summer 2000, whereas it included several governorate in lower and upper Egypt. • and characterized by • 50% morbidity and • 2. 5% mortality. •

(Transmission)

Transmission *In nature, Only by Insect bite • Culicoid-Mosquitoes. The disease will not spread from cow to cow by; close contact, droplet infection, bodily excretions, or by the transfer or injection of exudates.

Transmission *There is experimental evidence that BEF virus is not spread by semen. *Meat does not represent even a theoretical risk for transmission because the virus is rapidly inactivated at p. H levels below 5 (7). Such acidic levels are attained rapidly in bovine muscle after death. •

Incubation period

Incubation period *The incubation period following experimental intravenous inoculation of BEF virus varies between 2 and 4 days, and 9 days is the rare extreme. *The time is probably influenced by; the strain and dose used. *The natural incubation period can only be inferred but is probably similar.

Clinical Signs

Clinical Signs Mild cases

*Fever(40 -41. 5 C (105 -107 F) with • biphasic or triphasic fever spaced 12 -18 hrs. )

*Discharge from the eyes • •

*Discharge from the nose

*Muscle tremor

*Temporary lameness.

Clinical Signs Moderate cases

*Animals lying down, •

*Subcutaneous oedema.

*Joint swelling, • • •

*Loss of appetite, • • •

*Depression, • • •

*Loss of rumen motility • •

Clinical Signs Severe case

*Muscle stiffness •

*Drag feet when forced to walk

*Lying down(3 days), with hind • limbs outstretched-to relieve muscle cramp

Paralysis of limbs. • •

*May lead to coma and death • •

Morbidity and Mortality *Morbidity • may reach to 30% • *Mortality • Low •

Causes of the death i)Pneumonia from secondary infection •

Causes of the death uscle damaged and inflammation from long period lying down

Causes of the death iii)Pregnancy toxemia (fatty liver syndrome)

(lesions)

*Small amounts of fibrin-rich fluid • . in the pleural cavity •

*Small amounts of fibrin-rich fluid in • the peritoneal cavity. •

*Small amounts of fibrin-rich fluid • in the pericardial cavity. •

*Small amounts of fibrin-rich fluid in • . the joint capsules •

*The synovial surfaces of the spine. may have fibrin plaques •

*The lungs may have patchy edema.

*Lymphadenitis •

*Focal necrosis can be found in major • . Muscle groups in some cases •

(biochemical event )

Hematology * An absolute rise in leukocyte numbers • *A rapid fall in circulating lymphocytes • *A return to normal levels after 3 -4 days • •

Hematology *The serum fibrinogen level rises to 3 -4 times the normal level and returns to • . normal 1 -2 weeks after recovery • *The total serum calcium level falls to 1. 8 • mmol-1 during the febrile phases and • . returns to normal on recovery • • This is the biochemical event that • causes the reversible early • . paralysis •

(Diagnosis)

Diagnosis *Clinical signs • *Sero-conversion: • Paired serum; SN test & ELISA • *Gross lesion •

Differential Diagnosis *Blue tongue • *Babesiosis • *Black leg •

(Treatment)

Treatment *Recovery with no treatment* • *In severe cases • i)Anti-inflammatory drug: NSAIDs – ii)Fluid therapy and calcium – iii)Broad spectrum ABO –. 3 -4 wks Recovery period

Prevention and Control

Prevention and Control *Vector control • *Vaccine: • Attenuated lived virus vaccine (Australia) •

THANK YOU BY Dr/SHEREIN SAIED Assistant Prof. Pathology Dpt.