Department of Pathology Faculty of veterinary medicine

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

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

BOVINE EPHEMERAL FEVER * The 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.

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 characterized by muscle stiffness

(Definition)

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

(Etiology)

Etiology Family: Rhabdoviridae Genus: 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. *Sheep, goats, and other animals are not known to become infected

(Epidemiology)

Epidemiology *The disease was first recorded in East*The disease was first recorded in East Africa in Africa in * 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* It does not occur in Europe or the Americas. Americas.

BOVINE EPHEMERAL FEVER In Egypt

In Egypt,In Egypt, *BEF was first described in 1895 & 1924.*BEF was first described in 1895 & *subsequent outbreaks have been occurred in summer of*subsequent outbreaks have been occurred in summer of 1991,2000,2001 and ,2000,2001 and 2004.

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

*A second outbreak of BEF occurred in summer 2000, whereas it included several governorate in*A second outbreak of BEF occurred in summer 2000, whereas it included several governorate in lower and upper Egypt.lower and upper Egypt. and characterized byand characterized by 50% morbidity and 50% morbidity and 2.5% mortality 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 pH levels below 5 (7). Such acidic levels are attained rapidly in bovine muscle after death.

Incubation period 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

Clinical Signs Mild cases

*Fever ( C ( F) with biphasic or triphasic fever spaced hrs.)

*Discharge from the eyes

* Discharge from the nose

*Muscle tremor

*Temporary lameness.

Clinical Signs Moderate cases

* Animals lying down,* Animals lying down,

Subcutaneous oedema *Subcutaneous oedema.

Joint swelling, *Joint swelling,

Loss of appetite, *Loss of appetite,

Depression, *Depression,

Loss of rumen motility * Loss of rumen motility

Clinical Signs Severe case

Muscle stiffness*Muscle stiffness

Drag feet when forced to walk *Drag feet when forced to walk

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

P aralysis of limbs * P aralysis of limbs.

May lead to coma and death * May lead to coma and death

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

Pneumoniai) Pneumonia from secondary infection Causes of the death

ii)Muscle damaged and inflammation from long period lying down Causes of the death

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

(lesions)

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

Small amounts of fibrin-rich fluid in the pericardial 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 *The lungs may have patchy edema.

*Lymphadenitis

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

( biochemical event )

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

Prevention PreventionandControl

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