BOVINE EPHEMERAL FEVER- [Three Day Sickness]
by-DR RAJESH KUMAR SINGH, JAMSHEDPUR, JHARKHAND,INDIA
9431309542,rajeshsinghvet@gmail.com
Three Day Sickness in Cattle
Mansoon has arrived in the eastern states of India, after few days onset of mansoon, the disease which comes to notice occasionally is the Ephemeral fever or 3 day fever. Mostly indigenous cattle are affected with symptoms of lameness, pyrexia, staggering gaite n anorexia. Today i came across with the same case, so thought to give a brief description of this disease.
Bovine Ephemeral Fever (BEF) is a viral disease of cattle and buffalo. Typically, affected animals are only sick for a few days, hence the alternative name – Three Day Sickness. BEF is transmitted through mosquitoes and biting midges.
Clinical Signs————-
There is a sudden onset of fever- as high as 41oC compared with the normal temperature of about 38oC. The temperature returns to normal within 36 hours. The first sign in milking cows is a sudden and severe drop in milk production. Cows in advanced pregnancy may abort. This is probably because of the fever, rather than a specific effect of the virus.
Animals stop eating and drinking and become depressed. They usually drool saliva, develop a stringy nasal discharge, and may have watery eyes.
Affected animals may shiver and often become very stiff with a shifting lameness, and are reluctant to move. Lameness may not become apparent until the second day of illness. The joints may appear swollen and sometimes there is swelling around the jaw. Some animals – particularly the heavier ones – just lie down and refuse to move.
By day three the affected animal is usually standing again and will begin to eat. However, lameness and weakness may last for another two or three days.
In the vast majority of cases the disease runs a short course, followed by rapid and complete recovery. However, the disease can vary in severity. Some animals may show only slight symptoms for about 24 hours, while a small number may stay down for many weeks. The disease is usually milder in calves under 12 months of age.
Milk production usually drops by at least 50% in sick cows. In dairy herds it is the highest producing animals that are usually the most severely affected. Yield should return nearly to normal after about three weeks, but cows affected late in lactation often dry off. Mastitis sometimes develops, with a marked rise in the somatic cell count.
Bulls and fat cows tend to show more severe signs than other cattle. Such animals lose condition rapidly and are slow to regain their body weight. A proportion of bulls will suffer temporary infertility lasting from three to six months because of the high fever. Permanent infertility is uncommon but can occur.
A small proportion of animals that go down may suffer a permanent paralysis due to damage to the spinal cord- either as a direct effect of the virus, or due to injuries if they fall awkwardly.
Although most of the herd can be affected, deaths from ephemeral fever are uncommon and rarely involve more than 1% of the herd. Death is usually the result of misadventure or being down for a long period.
• MILD: stirry, lameness, fever, runny nose and sore eyes
• MODERATE: Cattle go down, fever, lack of appetite
• SEVERE: Paralysis, cattle stay down and can die
Diagnosis———————
BEF is usually diagnosed from history and clinical signs. Diagnosis can be made from the sudden onset of fever lasting for 2-5 days followed by spontaneous recovery.
Confirmation of diagnosis can be made by the laboratory either by isolation of the BEF virus or detecting the antibody level. One blood sample can be taken during the fever and isolation of BEF virus from the blood confirms BEF infection. Antibody level can be tested by taking two blood samples, one during the illness and another one two or three weeks later. BEF infected cattle will have much higher BEF antibody levels in the second sample compared to the first.
Transmission————–
BEF is caused by a virus known as rhabdovirus, it is also referred to as arbovirus. BEF is a viral disease transmitted by mosquittoes and biting midges. The spread of the disease is dependant on season and weather conditions.Diagnosis
When an outbreak occurs, a diagnosis can be made from the clinical signs and a blood test with also confirm the presence of a virus.
CAUSE—————–
The Bovine Ephemeral Fever virus is the cause of BEF. The BEF virus is transmitted between cattle by flying insects. The transmitting insects (vectors) have not been definitely identified but it is thought that mosquitoes and biting midges (especially sandflies) are responsible.
.
Typically, three stages of the disease are recognised. The acute febrile stage appears suddenly, especially noticeable in dairy cattle. Cattle show signs associated with a fever. Their rectal temperature will generally be over 40oC. Approximately 50% of sick animals shiver. Sick cattle will stand with their backs arched and heads held low with muzzles extended, drooling saliva. Often there is a discharge from the eyes and nostrils. Feeding and cud chewing stop and milk production, especially in dairy cows, is reduced.
The second stage is muscular stiffness and lameness in one or more limbs. Some degree of secondary bloat may also occur due to general inflammation of the abdominal cavity and ruminal stasis. The lameness may shift between limbs. Joints may be visibly swollen.
During the recovery stage, the great majority of affected animals resume eating and drinking. Animals may go down, with heavy animals in good condition being most affected. Some animals remain down due to muscle damage or damage to the spinal cord. Generally, about 1% die or are destroyed because they cannot get up, although this figure may be as high as 10%. Some animals that recover from ephemeral fever will have the staggers due to spinal cord damage. Pregnant cows may abort due to the high fever and heifers with young calves may mismother their calves.
Post mortem examination of cattle that die is important to rule out other acute febrile diseases that often occur under the same conditions as ephemeral fever and present in a similar manner, such as tick fever.
.
Complications—————–
Recovery is usually rapid and complete unless the affected animals are exposed to extreme weather conditions or aspiration of the stomach content. If affected cattle are without shade and water, they may suffer from severe dehydration.
Occasionally affected bulls are temporary infertile (up to 6 months) because of the high fever. Permanent infertility is uncommon but can occur.
A small proportion of affected animals may suffer permanent paralysis due damage to the spinal cord, either from effect of the virus or injury as the animal goes down.
Deaths from BEF are uncommon, and usually because of misadventure or being down for a long period.
TREATMENT AND PREVENTION—————-
Treatment———
Animals that have gone down should be provided with adequate shelter and shade, water and food, as cattle left exposed in hot weather are much more likely to die. It is important to get the animal back on its feet as quickly as possible to prevent muscle damage. Bulls, high producing dairy cows and valuable stock that go down should be treated quickly.
Anti-inflammatory medications aer recommended as soon as signs develop and provide producers the best treatment and chance of saving stock. This form of treatment is only available through veterinary prescription. Read the label carefully for withholding periods and dose rates.
Treatments are usually effective if given in the early stage of the disease. The affected cattle should be rested during the acute phase of the disease. Symptomatic treatment with anti-inflammatory drugs , nervine inj like neuroxin12 or nuerokind having methylcobalamine, inj of phosphorus like, Tonophosphone, for 3 days to 5 days has been found to be beneficial. Various antibiotics can be used if there is a suspicion of secondary bacterial infection.
Animals that have gone down should be provided with adequate shelter, water and food, as cattle exposed to hot weather are much more likely to die. They can be rolled over several times a day to maintain the blood circulation and avoid permanent muscle damage on the down side. It is important to get them back on their feet as soon as possible. Calcium injection can be given as it often helps to get recumbent cattle back on their feet.
BEF affects the swallowing reflex, therefore during the acute phase of illness; no medication should be given orally to avoid inhalation pneumonia.
Control and prevention————————
In most cases, cattle that have been infected with BEF are resistant to the infection for life. However, some animals, especially older animals may lose immunity after a few years.
.
Complete rest is the most effective treatment, and recovering animals should not be stressed or worked because relapse is likely. Anti-inflammatory drugs given early and in repeated doses for 2–3 days are effective. Oral dosing should be avoided unless the swallowing reflex is functional. Signs of hypocalcemia are treated as for milk fever. Antibiotic treatment to control secondary infection and rehydration with isotonic fluids may be warranted
