3-Day Sickness (Ephemeral Fever)Local Names: Gabbra: Butt / Kipsigis: miotap butusiek somok / Samburu: lakirkir / Somali: tuhyaCommon Names: Three Day Sickness, Stiff SicknessDescription: Flies and mosquito borne disease

Introduction

Ephemeral Fever is an insect-transmitted, non-contagious, viral disease of cattle and water buffalo found in Africa, the Middle East, Asia south of the former USSR, and Australia. Infections with no illness can also occur in wild buffalo, waterbuck, hartebeest, wildebeest, deer and possibly goats. 

Mode of Spread The virus is insect-borne and is not contagious. This virus does not persist in recovered cattle and most recovered cattle have life-long immunity. The insects responsible for spread are several species of midge and mosquitoes. Outbreaks may be more common when conditions favour multiplication of the midge and mosquito populations. Wind may spread the responsible midges over large areas. 

The prevalence and severity of the disease may vary from year to year. The disease tend to disappear for long periods, to return when the resistance of the population is diminished. Recurrence depends primarily on suitable environmental conditions for the increase and dissemination of the insect vector. During periods of inactivity, the disease is still present but the number of animals affected is very low. Clinical cases may occur without being recognised. Outbreaks may depend on a change in the virulence of the virus or an increase in the insect population. 

During epidemics many animals may be affected within days or 2-3 weeks. 

Signs of Ephemeral Fever

Signs 

After an incubation period of 2-10 days the virus causes inflammation in tissues such as joints, muscles and lymph nodes.

There is a fever of up to 40.5°C - 41°C (105°F - 106°F) lasting for 2 days, an increased respiratory rate, difficulty in breathing, muscle stiffness and pain.

There is a sudden decrease in milk yield. (After recovery milk production does not return to normal levels until the following lactation.)

Affected animals refuse to eat, drool saliva from the mouth, have difficulty in swallowing and have muscle tremors.

There is often an excessive production of tears, a nasal discharge and occasionally constipation or diarrhoea.

The most characteristic signs, however, are the stiffness or lameness. Some animals become recumbent (lie down) and paralyzed from 8 hours to a week. In severe

cases animals suffer permanent paralysis, but this is uncommon. Above picture shows heifer with BEF virus unable to bear weight on its hind legs.

In most cases spontaneous recovery occurs after about 2 days, and is complete.

Bulls, heavy cattle, and high-yielding dairy cattle are the most severly affected, with animals less than 6 months of age showing no clinical signs. Pregnant cows may abort, especially those in late pregnancy. Bulls may suffer temporary infertility. 

Diagnosis This is based on the clinical signs. This should pose no problem during an outbreak but can cause difficulties in isolated cases, when it may be confused with Laminitis, milk fever or a foreign body in the reticulum. After a few days however, the spontaneous improvement should aid diagnosis. 

Prevention - Control - Treatment

Prevention and Control Control of the insect carriers is not possible. Inactivated and live virus vaccine combinations are used in some parts of the world, such as South Africa and Australia and appear to be effective. Such vaccines should, however, only be used in endemic areas. 

Treatment Generally, no treatment is required, but in individual cases anti-inflammatory drugs, such as injectable phenylbutazone or flunixin will help recovery. Animals should be rested and not stressed, as this may cause the disease to come back. No drugs should ever be given by mouth to an animal with Ephemeral Fever as many animals are unable to swallow and to do so will cause pneumonia. Antibiotic treatment to control secondary infection and rehydration with isotonic fluids may be warranted in some cases.

Bovine Ephemeral Fever

Overview

Bovine ephemeral fever (BEF), commonly known as three day sickness, is a disease of cattle and occasionally buffaloes, marked by short fever, shivering, lameness and muscular stiffness. Caused by an insect borne virus, the disease is widespread in northern Australia.

It causes serious economic losses through deaths, loss of condition, decreased milk production, lowered fertility of bulls, mismothering of calves, delays in marketing and restrictions on the export of live cattle.

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. Spread of the disease depends on the season and weather conditions - rain and prevailing easterly and southerly winds are necessary for the survival and dispersal of the vectors which spread the virus. The National Arbovirus Monitoring Program (NAMP) monitors the spread of ephemeral fever virus within Australia. For further information and maps showing the previous extent of BEF in Australia click here

In most years, BEF cases start at the beginning of the wet season in northern Australia and then spread south and east down the east coast, into southern Queensland and central and coastal New South Wales. Occasionally, outbreaks will occur in northern Victoria.

Impact and Incidence

In northern Australia, older cattle generally have immunity from previous exposure to BEF, with introduced or young growing cattle being most susceptible to disease. Once exposed to the virus, cattle develop a long lasting immunity. Calves are relatively immune to ephemeral fever until they are about six months old.

Levels of herd immunity will vary depending on location of the herd relative to the normal distribution of BEF and prevailing seasonal conditions. Outbreaks of disease affecting cattle of all ages can occur at the end of a series of drought years or in herds on the southern fringes of the normal BEF distribution.

Clinical signs

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.

Diagnosis

The diagnosis of ephemeral fever during epidemics is made on the presence of lameness, muscular stiffness, pain, rapid spread of the disease through herds and short fever. The BEF virus can often be identified from a blood sample taken from animals in the fever stage of the disease. Alternatively, two blood samples, the first obtained during the fever stage and the second fourteen days later can be examined for development of antibodies to ephemeral fever virus.

Treatment and Prevention

A vaccine is registered for the prevention of BEF. It is only available through your veterinarian as it is a prescription only product. It is a two part vaccine, with frozen and liquid components that must be mixed prior to administration. Great care must be taken with this vaccine if the full benefit is to be obtained. It must be kept frozen, mixed up immediately prior to administration and used straight away.

Two injections of the vaccine 4 weeks apart under the skin of the neck are necessary for long-lasting protection. Annual boosters are recommended.  It is advisable to commence vaccination in the winter months so that cattle are fully immunised prior to summer rains.

The vaccine has provided good levels of protection against BEF. Field observations have shown that some vaccinated cattle can develop mild disease, however the severity and duration of illness is very much less than in unvaccinated cattle.

Treatment with anti-inflammatory drugs has been shown to reduce the course of the disease and calcium injections may aid animals that are down. Most animals will recover if provided with water and shade, however, in extensive management situations this is often impossible to provide.

Related species

Three day sicknessYou are here: Home /  Livestock production / Animal health, welfare and biosecurity / Diseases / Infectious / Three day sickness

Three day sickness, or bovine ephemeral fever, is a viral disease of cattle that is spread by mosquitoes and biting midges. It occurs in northern Australia and along

the eastern seaboard south to the NSW-VIC border. It is called three day sickness because the clinical signs of the disease usually last for three days.

Conditions when three day sickness is likely to occur

Young stock are more commonly affected because infection provides life-long immunity.

Wetter northern regions (more sporadic in southern cooler regions). Following big wet seasons, especially if it follows several dry years (under these

conditions a much higher proportion of older animals will become infected).

Identifying and diagnosing three day sickness

Diagnosis of three day sickness will require assistance from a veterinarian.

Clinical signs that would lead producers to suspect three day sickness include the following:

Depression. Lameness, muscle stiffness, shivering, twitching, droopy ears. Drooling saliva, watery eyes, runny nose. Recumbency. Reduced water and food intake. Abortion. Heavier and older animals are more severely affected because long periods of

recumbency leads to muscle damage.

Prevention strategies for three day sickness

Prevention strategies for three day sickness rely largely on vaccination.

3 DAY SICKNESS IN CATTLE. (Bovine ephemeral fever. BEF)

 Bovine ephemeral fever (BEF), commonly known as three day sickness, is a disease of cattle that causes serious economic losses through deaths, loss of condition, decreased weight gains and reduced fertility in bulls. Three Day is marked by a short fever, shivering, lameness and muscular stiffness and is caused  

by a virus and is widespread in Queensland.

 Spread of BEF

BEF is transmitted between cattle by flying biting insects. The transmitting insects have not been definitely identified, though it is thought that mosquitoes and biting midges (sandflies) are responsible. The spread of the disease depends on the season and weather conditions.

In most years, BEF cases start at the beginning of the wet season in northern Australia, and then spread south and east down the east coast. It then spreads into southern Queensland, and central and coastal New South Wales. Occasionally, as in 2010, outbreaks occur in southern NSW and northern Victoria.

 Animals at risk

Once exposed to the virus, cattle develop a long-lasting immunity. Calves are relatively immune to BEF from maternal protection until they are about six months old. Older cattle generally have immunity from previous exposure, with introduced or young growing cattle being most susceptible to disease.

However, outbreaks of disease affecting cattle of all ages can occur at the end of a series of drought years because lack of rain will have prevented the breeding of insect vectors during the drought. Cattle born during the drought will not have been exposed to the virus as younger animals and older immune animals will have been sold off.

 Clinical signs

Cattle show signs associated with a fever where their temperature will generally be over 40oC. Sick animals shiver and stand with their backs arched and heads held low with muzzles extended, drooling saliva. Often there is a discharge from the eyes and nostrils.

Cattle develop muscular stiffness and lameness in one or more limbs. The lameness may shift between limbs. Joints may be visibly swollen. . 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 from constant struggling. Up to 10% of animals may die or be destroyed because they cannot get up. Some animals that recover from BEF have the staggers due to spinal cord damage. Abortions can occur in cows due to the fever.

 Diagnosis

In addition to the clinical signs BEF  a blood test can identify the presence of the virus, and is most successful when samples are collected in the first few days of clinical disease.

 Treatment

Treatment success has improved with veterinary intervention after the development of better anti-inflammatory medications to treat the signs of the virus. Consult your veterinarian as soon as signs develop for the best treatment and chance of saving stock from BEF.  

 Prevention

A vaccine is registered for the prevention of bovine ephemeral fever(BEF) Only cattle older than six months should be vaccinated. The vaccine is available only from veterinarians as it is a modified live vaccine.

This vaccine has provided good levels of protection against BEF. Field observations have shown that some vaccinated cattle can develop mild disease even after vaccination. However, the severity and duration of illness is very much less than in unvaccinated cattle.

Two injections of the vaccine, 2-4 weeks apart, under the skin of the neck are necessary for long-lasting protection. To ensure that animals are fully immune before insect populations have the opportunity to breed, it is recommended that you complete vaccination before the spring, especially in northern Australia.

 

Talk to any of the Vet Cross vets for advise and information on 3 Day Sickness and heard health programs.

 

BAGUS

I.       PENDAHULUAN

A.    Latar Belakang

            Ternak ruminansia besar (sapi) merupakan salah satu komoditas ternak yang strategis,

karena selain dapat digunakan sebagai ternak pekerja, juga dapat dijadikan sumber

pendapatan/tabungan serta menjadi sumber protein hewani berupa daging. Oleh karena itu,

kesehatan ternak harus selalu dijaga agar kondisi tubuhnya baik dan dapat berproduksi

dengan baik pula. Tiga faktor yang saling berkaitan dalam permasalahan timbulnya suatu

penyakit, yaitu : faktor agen penyakit, hospes (ternak itu sendiri) dan lingkungan.

            Bovine Ephemeral Fever (Demam Tiga Hari) merupakan penyakit yang bersifat

ringan yang umumnya menyerang pada sapi dan ditandai dengan demam tinggi rasa sakit

otot  dan pincang. Sapi yang menderita penyakit ini cepat sembuh bila tanpa komplikasi.

Penyakit klinis berjalan sangat singkat biasanya tidak lebih dari tiga hari. Akan tetapi, pada

pejantan penyakit ini bisa belangsung selama lima bulan.

            Bovine Ephemeral Fever (Demam Tiga Hari) dapat menyebabkan terjadinya

gangguan produksi susu pada sapi perah produktif.  Merupakan penyakit pada sapi yang

banyak sekali ditemukan dilapangan. Kasus yang terjadi di lapangan kebanyakan memiliki

angka kesakitan yang tinggi ,akan tetapi dengan angka kematian yang rendah.

            Penyakit Demam Tiga Hari banyak ditemui pada ternak sapi dan secara umum resiko

ekonomi yang ditimbulkan tidaklah besar apabila penanganan medis secara cepat telah

dilakukan untuk mencegah terjadinya komplikasi dengan penyakit lain. Penyakit ini biasa

menyerang pada musim pancaroba atau peralihan dari kemarau ke hujan.

            Bovine Ephemeral Fever (BEF) disebabkan oleh virus Rhabdovirus, yang termasuk

dalam familia yang sama dengan penyakit rabies dan vesicular stomatitis. Virus tersebut

dapat ditularkan melalui serangga.  Penyakit Demam Tiga Hari disebarkan oleh Cullicoides sp. dan nyamuk Cullicoides yang terinfeksi dapat menyebarkan penyakit mencapai jarak

2.000 KM. Ada dugaan penyebaran dapat pula terjadi melalui angin. Walau sampai saat ini

belum ditemukan penyebab ataupun pembawa penyakit BEF secara pasti, hal tersebut

mungkin disebabkan karena jumlah sampel yang diperiksa tidak cukup banyak. Mungkin

juga karena jangka waktu penyakit ini juga relatif pendek. Penyemprotan terhadap ternak

sebaiknya dilakukan secara kontinyu menggunakan insektisida dan sanitasi kandang

dilakukan secara rutin. Ha ini diharapkan untuk meminimalisir adanya vektor pembawa

penyakit.

II.    PEMBAHASAN

A.    Pengertian

            Bovine Ephemeral Fever (Demam Tiga Hari) adalah suatu penyakit viral pada sapi

atau kerbau yang ditandai dengan terjadinya demam tinggi, rasa sakit otot, dan kepincangan

(Akoso, 1996). Penyakit klinis berjalan sangat singkat, biasanya berakhir tidak lebih dari tiga

hari, dengan morbiditas tinggi tetapi mortalitas rendah. Penyakit ini dapat menimbulkan

gangguan yang hebat terhadap produksi susu pada sapi perah dan jasa kerja pada ternak

pekerja (Ressang, 1986).

            Bovine Ephemeral Fever hanya menyerang sapi dan kerbau dan tidak dapat menulari

dan menimbulkan penyakit pada hewan lain. Angka kematian sangat kecil sekali tidak

sampai 1% tetapi angka kesakitam tinggi (Deptan, 2001). Penyakit ini dapat menimbulkan

kerugian ekonomi yaitu dapat menurunkan produksi susu dan pertambahan berat badan

masing-masing sebesar 43% dan 10kg (Soleha et al., 1992).

            Berdasarkan pengertian diatas dinyatakan bahwa BEF hanya dapat menyerang ternak

sapi dan kerbau saja. Penyakit ini hanya menyerang dalam jangka waktu yang sangat singkat,

akan tetapi penyakit ini dapat mengakibatkan gangguan produksi susu pada sapi perah serta

pertambahan bobot badan. Oleh karena itu, walaupun penyakit ini tidak berbahaya dari segi

kesehatan, tetapi sangat berbahaya dari segi ekonomi yang mengakibatkan kerugian bagi

peternak.

B.     Penyebab

            Penyakit pada ternak pada umumnya terdiri atas penyakit infeksius dan penyakit non

infeksius. Penyakit infeksius adalah penyakit yang disebabkan oleh agen-agen infeksi. Agen-

agen penyebab infeksi antara lain adalah virus, bakteri, jamur, parasit, dll. Sedangkan

penyakit non infeksius adalah penyakit yang disebabkan selain oleh agen infeksi, misalnya

defisien nutrisi, vitamin, mineral, ataupun karena keracunan (Triakoso, 2009).

Penyakit BEF disebabkan oleh virus. Penyebab penyakit ini adalah virus dari genus

yang tidak ada namanya, tetapi masuk dalam keluarga Rhabdoviridae dari virus RNA. Masa

inkubasi penyakit ini berkisar antara 7-10 hari (Akoso, 1996). Berdasarkan morfologinya

virus BFE diklasifikasikan sebagai Rhabdovirus yang berbentuk peluru. Virus ini hanya bisa

diamati menggunakan mikroskop elektron. Infektivitas virus dapat hilang sangat cepat pada

pH 2,5 dan 12 dan hilang dengan cepat pada pH 5 dan pH 9 (Ressang, 1986).

            Berdasarkan pengertian diatas BEF merupakan penyakit infeksius. Hal ini sesuai

dengan pendapat Triakoso (2009) dan Akoso (1996). Akoso (1996) menyatakan

bahwa  penyakit BEF disebabkan oleh virus. Sedangkan Triakoso (2009) menyatakan bahwa

penyakit infeksius adalah penyakit yang disebabkan oleh agen-agen infeksi. Agen-agen

penyebab infeksi antara lain adalah virus, bakteri, jamur, parasit, dll sehingga dapat

disimpulkan bahwa BEF merupakan penyakit infeksius karena disebabkan oleh virus yang

berasal dari keluarga Rhabdoviridae.

C.    Penularan

            Penyebaran penyakit Bovine Ephemeral Fever tidak terjadi karena adanya kontak

secara langsung. Kemungkinan penyakit ini ditularkan melalui vektor. Lingkungan alam yang

berupa sawah dan banyak terdapat genangan air sangat baik untuk vektor ini (Soeharsono., et

al, 1983).

            Sapi maupun kerbau tidak pernah terbukti bertindak sebagai hewan pembawa virus

dalam jangka waktu panjang. Penyebaran lebih ditekankan pada peranan vektor ataupun

angin. Angina yang bersifat basah dan lembab diduga dapat memindahkan virus dan vektor

penyakit ini (Subronto, 1989).

            Penyakit Demam Tiga Hari disebarkan oleh Cullicoides sp (serangga pengisap darah)

dan nyamuk. Cullicoides yang terinfeksi dapat menyebarkan penyakit mencapai jarak 2.000

KM (Akoso, 1996).

            Berdasarkan pengertian diatas dapat disimpulkan bahwa penyakit BEF tidak

ditularkan melalui kontak langsung dengan penderita. Penyakit ini ditularkan oleh vektor

pembawa yaitu Cullicoides sp (serangga pengisap darah) dan nyamuk. Cullicoides yang

terinfeksi dapat menyebarkan penyakit mencapai jarak 2.000 KM.

D.    Hewan Rentan

            Bovine Ephemeral Fever hanya menyerang sapi dan kerbau dan tidak dapat menulari

dan menimbulkan penyakit pada hewan lain. Angka kematian sangat kecil sekali tidak

sampai 1% tetapi angka kesakitam tinggi  (Deptan, 2001).

            Berdasarkan pengertian diatas dapat diambil kesimpulan bahwa BEF hanya

menyerang sapi dan kerbau. Akan tetapi, kejadian yang banyak terjadi adalah pada sapi yang.

Serta penyakit ini tidak ditularkan secara langsung.

E.     Gejala Klinis

            Tanda-tanda ternak yang terjangkit penyakit ini antara lain adalah:

a. Demam (39 sampai 420C)

b. Lesu

c. Kekakuan anggota gerak sampai pincang

d. Kelemahan anggota gerak sampai tidak sanggup berdiri.

e. Keluar liur yang berlebihan

f. Sesak nafas

g. Gemetar

h. Keluar sedikit cairan dari mata dan hidung.

i. Pada sapi  menyusui, produksi air susu turun atau terhenti sama sekali (Deptan, 2001).

            Kepincangan merupakan tanda-tanda klinis yang menonjol dan lebih jelas terlihat

pada demam hari kedua. Kepincangan ini akan mengakibatkan hewan harus berbaring secara

terus-menerus dalam waktu yang lama. Sapi jantan yang berat dan sapi perah akan

mengalami hal ini. Pada kejadian ini, kesembuhan sempurna jarang terjadi meskipun sapi

sudah mau makan dan minum dengan normal. Kebanyakan sapi yang terserang BEF namun

tidak sampai berbaring akan mengalami kesembuhan setelah 2-3 hari dengan tanda-tanda

penyakit yang relatif ringan (Ressang, 1986).

            Sapi dewasa yang menderia penyakit ini akan lebih menderita daripada hewan muda.

Angka kesakitan tinggi tetapi angka kematian rendah. Bila terjadi komplikasi, sapi bunting

dapat abortus atau terjadi kemajiran sementara. Sapi pejantan penyakit ini dapat menyerang

selama 5 bulan (Akoso, 1996).

Kesembuhan mulai tampak pada hari ke-3 dan kesembuhan sempurna pada hari ke-5

setelah munculnya gejala klinis. Penderitaan yang bersifat kurang berat terkadang ditemukan

pada pedet yang berumur kurang dari 6 bulan. Pejantan yang berat dan sapi-sapi yang besar

paling menderita apabila terserang BEF. Angka kematian biasanya kurang dari 1% dan

kebanyakan disebabkan oleh factor-faktor sekunder (Subronto, 1989).

Berdasarkan pengertian diatas dapat disimpulkan bahwa gejala yang ditunjukkan pada

ternak yang menderita penyakit ini antara lain mengalami demam dan kekakuan anggota

gerak bahkan sampai mengalami kepincangan. Sapi yang menderita penyakit ini biasanya

mulai menampakkan kesumbuhannya pada hari ke 2-3 setelah terjangkit. Angka kematian

yang ditimbulkan dari penyakit ini sangat kecil yaitu kurang dari 1%.

F.     Pengendalian dan Pengobatan

            Pencegahan penyakit ini dapat dilakukan dengan cara sebagai berikut:

            1. Menjaga kebersihan lingkungan

            2. Pemakaian insektisida untuk membunuh vektor panyakit disekitar daerah terjangkit

             3. Mengisolasi hewan sakit

(Deptan, 2001).

            Pengobatan terhadap ternak yang menderita penyakit ini dilakukan dengan

memberikan obat simtomatik dan pencegahan terhadap timbulnya infeksi sekunder. Vaksin

yang efektif belum ada (Akoso, 1996).

            Sampai saat ini belum ada pengobatan yang efektif, namun demikian pemberian

spectrum luasperlu dianjurkan untuk mencegah infeksi sekunder dan pemberian vitamin

untuk menghindari stress (Deptan, 2001).

            Hewan yang menderita diusahakan agar terjadinya komplikasi sekunder dapat

diperkecil. Pemberian minum dengan alat (drench, contang) hendaknya dihindarkan, karena

dalam fase akut beberapa penderita mengalami kesukaran menelan (Subronto, 1989).

            Sapi yang pernah terinveksi virus BEF akan mendapat kekabalan tubuh dalam jangka

waktu yang panjang terhadap infeksi berikutnya. Akan tetapi, adanya penemuan bahwa BEF

tidak hanya disebabkan oleh satu serotip menimbulkan dugaan bahwa infeksi oleh satu

serotip belum tentu memberi perlindungan terhadap serotip lain (Ressang, 1986).

            Pencegahan yang bisa dilakukan peternak antara lain adalah menjaga kebersihan

kandang, penyemprotan insektisida agar tidak ada vektor yang bisa menyebarkan penyakit

ini. Walaupun penyakit ini tidak ditularkan secar kontak langsung dengan penderita,

sebaiknya ternak yang terjangkit tetap dipisahkan untuk menghindari mudahnya vektor untuk

menyebarka penyakit ini pada ternak yang sehat.

            Pengobatan yang bisa dilakukan apabila terjadi penyakit ini adalah pemberian

antibiotik untuk mencegah perkembangan virus dalam induk semang. Sapi yang pernah

terinveksi virus BEF akan mendapat kekabalan tubuh dalam jangka waktu yang panjang

terhadap infeksi berikutnya. Akan tetapi, adanya penemuan bahwa BEF tidak hanya

disebabkan oleh satu serotip menimbulkan dugaan bahwa infeksi oleh satu serotip belum

tentu memberi perlindungan terhadap serotip lain.

G.    Perubahan Pascamati    

            Perubahan pascamati sangat ringan dan tidak mencolok. Perubahan yang paling sering

terjadi adalah terdapatnya eksudat berfibrin pada pleura, pericardial, dan dinding rongga

perut. Kelenjar limfe busung dan paru dapat mengalami busung lokal, serta otot dapat

mengalami nekrosis setempat (Akoso, 1996).

            Berdasarkan pengertian diatas dapat disimpulkan bahwa sapi yang menderita penyakit

ini secara mencolok tidak mengalami perubahan fisik. Akan tetapi, pada beberapa kejadian

setelah penderita mati terdapat peubahan pada kelenjar limfe serta dinding rongga perut.

Beberapa kejadian juga menunjukkan adanya otot yang mengalami nekrosis.

H.    Pemotongan Hewan

            Ternak penderita BEF dapat dipotong dan dagingnya boleh dikonsumsi atau

diperdagangkan. Namun, mengingat angka kematian yang relatif rendah maka sebaiknya

pemotongan hanya dilakukan pada keadaan yang sangat terpaksa ditinjau dari segi medis dan

atas anjuran dari dokter hewan. Sisa pemotongan beserta sisa pakan yang masih tertinggal

harus dibakar dan dikubur dalam-dalam. Tempat pemotongan dibersihkan dan disucihamakan

(Akoso, 1996).

            Berdasarkan pendapat Akoso (1996) dagimg yang berasal dari sapi yang menderita

penyakit BEF dapat dikonsumsi. Akan tetapi, angka kematian yang rendah ternak yang

menderita BEF jarang dipotong kecuali pada kondisi yang sangat mendesak. Sisa pakan serta

bekas tempat pemotongan sapi penderita BEF harus dibersihkan serta disucihamakan.

III.       PENUTUP

A.    Kesimpulan

Bovine Ephemeral Fever (Demam Tiga Hari) adalah suatu penyakit viral pada sapi

atau kerbau yang ditandai dengan terjadinya demam tinggi, rasa sakit otot, dan kepincangan.

Penyakit klinis berjalan sangat singkat, biasanya berakhir tidak lebih dari tiga hari, dengan

morbiditas tinggi tetapi mortalitas rendah. Penyakit ini dapat menimbulkan gangguan yang

hebat terhadap produksi susu pada sapi perah dan jasa kerja pada ternak pekerja. Bovine

Empheral Fever hanya menyerang sapi dan kerbau dan tidak dapat menulari dan

menimbulkan penyakit pada hewan lain.

BEF merupakan penyakit infeksius karena disebabkan oleh virus yang berasal dari

keluarga Rhabdoviridae. Masa inkubasi penyakit ini berkisar antara 7-10 hari.

Penyebaran penyakit Bovine Ephemeral Fever tidak terjadi karena adanya kontak

secara langsung. Kemungkinan penyakit ini ditularkan melalui vektor. Penyakit Demam Tiga

Hari disebarkan oleh Cullicoides sp (serangga pengisap darah) dan nyamuk Cullicoides yang

terinfeksi dapat menyebarkan penyakit mencapai jarak 2.000 KM.

BEF hanya menyerang sapi dan kerbau. Akan tetapi, kejadian yang banyak terjadi

adalah pada sapi yang. Serta penyakit ini tidak ditularkan secara langsung.Tanda-tanda ternak

yang terjangkit penyakit ini antara lain adalah:

a.       Demam (39 sampai 420C)

b.      Lesu

c.       Kekakuan anggota gerak sampai pincang

d.      Kelemahan anggota gerak sampai tidak sanggup berdiri.

e.       Keluar liur yang berlebihan

f.       Sesak nafas

g.      Gemetar

h.      Keluar sedikit cairan dari mata dan hidung.

i.        Pada sapi  menyusui, produksi air susu turun atau terhenti sama sekali

Kepincangan merupakan tanda-tanda klinis yang menonjol dan lebih jelas terlihat

pada demam hari kedua. Kepincangan ini akan mengakibatkan hewan harus berbaring secara

terus-menerus dalam waktu yang lama. Sapi jantan yang berat dan sapi perah akan

mengalami hal ini. Pada kejadian ini, kesembuhan sempurna jarang terjadi meskipun sapi

sudah mau makan dan minum dengan normal. Kebanyakan sapi yang terserang BEF namun

tidak sampai berbaring akan mengalami kesembuhan setelah 2-3 hari dengan tanda-tanda

penyakit yang relatif ringan. Pencegahan penyakit ini dapat dilakukan dengan cara sebagai

berikut:

a.    Menjaga kebersihan lingkungan

b.   Pemakaian insektisida untuk membunuh vektor panyakit (serangga pengisap darah dan

nyamuk) disekitar daerah terjangkit

c.    Mengisolasi hewan sakit

Pengobatan yang bisa dilakukan apabila terjadi penyakit ini adalah pemberian

antibiotic untuk mencegah perkembangan virus dalam induk semang. Sapi yang pernah

terinveksi virus BEF akan mendapat kekabalan tubuh dalam jangka waktu yang panjang

terhadap infeksi berikutnya. Akan tetapi, adanya penemuan bahwa BEF tidak hanya

disebabkan oleh satu serotip menimbulkan dugaan bahwa infeksi oleh satu serotip belum

tentu memberi perlindungan terhadap serotip lain.

Sapi yang menderita penyakit ini secara mencolok tidak mengalami perubahan fisik.

Akan tetapi, pada beberapa kejadian setelah penderita mati terdapat peubahan pada kelenjar

limfe serta dinding rongga perut. Beberapa kejadian juga menunjukkan adanya otot yang

mengalami nekrosis.

Ternak penderita BEF dapat dipotong dan dagingnya boleh dikonsumsi atau

diperdagangkan. Namun, mengingat angka kematian yang relative rendah maka sebaiknya

pemotongan hanya dilakukan pada keadaan yang sangat terpaksa ditinjau dari segi medis dan

atas anjuran dari dokter hewan.

Bovine ephemeral fever is an insect-transmitted, noncontagious, viral disease of cattle and water buffalo that is seen in Africa, the Middle East, Australia, and Asia. Inapparent infections can develop in Cape buffalo, hartebeest, waterbuck, wildebeest, deer, and possibly goats. Low levels of antibody have been recorded in several other antelope species and giraffe, but the specificity has not been confirmed.

Etiology and EpidemiologyBovine ephemeral fever virus (BEFV) is classified as a member of the genus Ephemerovirus in the family Rhabdoviridae (single-stranded, negative sense RNA). The virus is ether-sensitive and readily inactivated at pH levels below 5 and above 10. Although no evidence of immunogenic diversity is reported, antigenic variation has been demonstrated using panels of monoclonal antibodies and by epitope mapping. Several closely related ephemeroviruses (including Berrimah virus, Kimberley virus, Malakal virus, Adelaide River virus, Obodhiang virus, Puchong virus, kotonkan virus, and Koolpinyah virus) have been identified. However, of these, only kotonkan virus (isolated in Nigeria) has been associated with clinical ephemeral fever in cattle.BEFV can be transmitted from infected to susceptible cattle by IV inoculation; as little as 0.005 mL of blood collected during the febrile stage is infective. Although the virus has been recovered from several Culicoides species and from Anopheline and Culicine mosquito species collected in the field, the identity of the major vectors has not been proved. Transmission by contact or fomites does not occur. The virus does not appear to persist in recovered cattle, which often have a lifelong immunity.The prevalence, geographic range, and severity of the disease vary from year to year, and epidemics occur periodically. During epidemics, onset is rapid; many animals are affected within days or 2–3 wk. Bovine ephemeral fever is most prevalent in the wet season in the tropics and in summer to early autumn in the subtropics or temperate regions (when conditions favor multiplication of biting insects); it disappears abruptly in winter. Virus spread appears to be limited by latitude rather than topography or availability of susceptible hosts. Morbidity may be as high as 80%; overall mortality is usually 1%–2%, although it can be higher in lactating cows, bulls in good condition, and fat steers (10%–30%). However, reported overall mortality rates have exceeded 10% in outbreaks in several countries in recent years.Clinical FindingsSigns, which occur suddenly and vary in severity, can include biphasic to polyphasic fever (40°–42°C [104°–107.6°F]), shivering, inappetence, lacrimation, serous nasal discharge, drooling, increased heart rate, tachypnea or dyspnea, atony of forestomachs, depression, stiffness and lameness, and a sudden decrease in milk yield. Clinical signs are generally milder in water buffalo. Affected cattle may become recumbent and paralyzed for 8 hr to >1 wk. After recovery, milk production often fails to return to normal levels until the next lactation. Abortion, with total loss of the season's lactation, occurs in ~5% of cows pregnant for 8–9 mo. The virus does not appear to cross the placenta or affect the fertility of the cow. Bulls, heavy cattle, and high-lactating dairy cows are the most severely affected, but spontaneous recovery usually occurs within a few days. More insidious losses may result from decreased muscle mass and lowered fertility in bulls.Lesions

Bovine ephemeral fever is an inflammatory disease. The most common lesions include polyserositis affecting pleural, pericardial, and peritoneal surfaces; serofibrinous polysynovitis, polyarthritis, polytendinitis, and cellulitis; and focal necrosis of skeletal muscles. Generalized edema of lymph nodes and lungs, as well as atelectasis, also may be present.Diagnosis

Diagnosis is based almost entirely on clinical signs in an epidemic. All clinical cases have a neutrophilia with the presence of many immature forms, although this is not pathognomonic. Serofibrinous inflammation in the tendon sheaths, fascia, and joints, together with pulmonary lesions, may substantiate a presumptive diagnosis.Laboratory confirmation is by serology, rarely by virus isolation. Whole blood should be collected from sick and apparently healthy cattle in affected herds and must be sufficient to provide two air-dried blood smears, 5 mL of whole blood in anticoagulant (not EDTA), and ~10 mL of serum. A differential WBC count on blood smears can either support or refute a presumptive field diagnosis.Virus is best isolated by inoculation of mosquito (Aedes albopictus) cell cultures with defibrinated blood, followed by transfer to baby hamster kidney (BHK-21 or BHK-BSR) or monkey kidney (Vero) cell cultures after 15 days. Suckling mice may also be used for primary isolation by intracerebral inoculation. Isolated viruses are identified by PCR, neutralization tests using specific BEFV antisera, and ELISA using specific monoclonal antibodies. The neutralization test and the blocking ELISA are recommended for antibody detection and give similar results. A 4-fold rise in antibody titer between paired sera collected 2–3 wk apart confirms infection.Treatment and ControlComplete 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 (see Parturient Paresis in Cows). Antibiotic treatment to control secondary infection and rehydration with isotonic fluids may be warranted.Attenuated virus vaccines appear to be effective but should be used only in endemic areas. Inactivated virus vaccines have not produced longterm protection against experimental challenge with virulent virus and cannot guarantee lasting immunity, but they may boost the immunity produced by live virus vaccine. Although a subunit vaccine that protects against field and laboratory challenge has been described, it is not commercially available. The efficacy of vector control remains uncertain, because the insect vectors have not been fully identified. There is no evidence that people can be infected.Last full review/revision October 2014 by Peter J. Walker, BSc, PhD, DS

Penyebab Sapi Pilek/FluMusim pancaroba yang biasa terjadi setiap pergantian musim sering kali meresahkan para

peternak sapi. Hawa yang terkadang dingin kemudian panas dan gerah setiap harinya membuat

daya tahan tubuh menurun, tidak hanya pada peternaknya namun juga pada sapi-sapi yang

dipeliharanya. Sapi-sapi tersebut biasanya terlihat lesu, demam dan nafsu makan menurun.

Leleran hidung yang menyertai terjadinya gejala lainnya menjadikan penyakit ini khas disebut

peternak “sapi pilek” atau sapi flu, sedangkan di dunia kedokteran hewan lebih umum dikatakan

sebagai penyakit “demam tiga hari”.

Demam 3 Hari Sapi

Penyakit yang bersinonim dengan Bovine Ephimeral Fever (BEF) ini merupakan penyakit yang

bersifat akut (terjadi dengan cepat dalam hitungan hari), dengan angka kejadian penyakit yang

tinggi, namun angka kematian dibawah 1%. BEF secara alami terdapat di benua Afrika, dan

Asia. Pada tahun 1963 diketahui mulai memasuki benua Australia yang mana disinyalir berasal

dari Indonesia.

BEF disebabkan oleh virus Rhabdovirus, satu family dengan virus penyebab penyakit Rabies.

Virus tersebut menyebar melalui bantuan vector / agen pembawa, yaitu serangga dan nyamuk.

Di dalam tubuh nyamuk, virus tidak hanya terangkut dan berpindah namun juga bertumbuh

kembang menjadi banyak. Sapi menjadi sakit apabila mengalami kontak langsung berupa gigitan

dengan vector, terlebih saat hawa berangin basah dan lembab yang dapat menyebarkan vector

hingga radius 100 Km, bahkan lebih.

Ciri-ciri Sapi Bovine Ephimeral Fever

Ciri-ciri BEF

Sapi yang mengalami BEF, akan terlihat lesu, nafsu makannya dan minumnya menurun, agak

gemetar, demam sekitar 2-40C lebih tinggi dari suhu normal, lebih sering tiduran, frekuensi nafas

dan detak jantung meningkat, terdapat leleran hidung dan mata, terjadi kepincangan sehari

setelah demam dimana kaki yang pincang dapat berbeda setiap harinya, kontraksi rumen

terhenti, kadang disertai diare atau konstipasi, dan pada sapi perah produksi terjadi penurunan

jumlah susu yang dihasilkan secara drastik.

Pencegahan dan Pengobatan BEFPada dasarnya tidak terdapat metode pengobatan secara khusus pada penyakit ini. Apabila

keadaan ternak baik, masih mau makan minum meski tidak sebanyak biasanya saat sehat,

demam tiga harinya akan mulai membaik di hari ke-3 dan sembuh seperti semula pada hari ke 5.

Untuk mendukung kondisi tubuh ternak dalam proses penyembuhan, pemberian vitamin A,D,E,

B dan C dalam air minum dapat dilakukan oleh peternak selama 3-5 hari.

Saat kondisi demam, sapi lebih sering memilih makanan, lebih menyukai makanan yang segar

dan berair seperti hijauan, dan mengacuhkan makanan kering seperti konsentrat. Makanan

beraroma kuat, manis dan disukai sapi seperti buah nangka dan jagung muda dapat diberikan

untuk meningkatkan nafsu makan ternak, namun tidak berlebihan, cukup sebagai topping atau

taburan diatas pakan hijauan.

Infeksi Sekunder BEFPenyakit BEF dapat menjadi berbahaya apabila disertai dengan infeksi sekunder. Saat virus

penyebab BEF menurunkan kekebalan tubuh sapi, bakteri disekitarnya akan mudah menginfeksi

dan terjadilah demam yang semakin lama dan disertai kondisi ternak yang memburuk setiap

harinya. Oleh karena itu, apabila peternak melihat kondisi sapinya semakin lesu, atau tidak

menyentuh makanan sama sekali sehari penuh, maka sebaiknya peternak memanggil dokter

hewan setempat, sehingga dapat dilakukan terapi infeksi sekunder dan supportif pada hewan

penderita.

Introduction

Bovine Ephemeral Fever is caused by an RNA virus – a rhabdovirus. Typically there is a sudden onset of fever with a sudden milk drop. It is transmitted rapidly with evident lameness, depression and often anorexia. Recovery is often rapid – 3 day fever. Morbidity can be up to 100% but mortality is low (1-2%).

Due to its geographical distribution and association with heavy precipitation, BEF can occur simultaneously with epizootics of Rift Valley Fever.

BEF is not zoonotic.

This disease is notifiable to the World Organisation for Animal Health (OIE).

Distribution

The virus occurs in Asia, Africa, Australia and Pacific islands. It is transmitted by a range of insect vectors including mosquitoes and midges. This is the ONLY route of disease transmission.

Signalment

Cattle and buffalo appear to be the only natural host of BEF. The disease is more severe in fat, lactating and heavily pregnant cows and bulls/steers.

In tropical regions, disease occurs in the wet season, while in temperate countries, it tends to present throughout Spring, Summer and Autumn.

When outbreaks occur annually or semi-annually, younger animals tend to be infected and so the economic impact is often less. Hence, the less frequent epidemics are, the more severe they tend to be.

Clinical Signs

The main clinical signs are very high fever, dehydration and animals often refuse to drink. Many signs are attributable to the hypocalcaemia caused by BEF.

Lymphadenopathy may be a feature as well as stiffness and lameness in the limbs with tremors/spasms and possible recumbency.

Gastrointestinal disease may present as hypomotility and constipation but occasionally there can be diarrhoea. Pregnant cattle may abort whilst infertility can occur in either sex. Cows may develop agalactia.

Other signs may include dullness, depression, lethargy and coma in severe cases. Some animals develop respiratory disease and subcutaneous emphysema, oedema and crepitation.

Hot, moist weather increases mortality in epidemics.

Mild cases - <18mo old, ocular and nasal discharge, lameness, inappetance, fever, recovery in 1-2days.

Moderate – Severe depression, recumbency, respiratory signs, salivation and dehydration, rumenal atony, milk reduction.

Severe – lateral recumbency, paralysis, reflex loss, subcutaneous emphysema, tachycardia and tachypnoea, mortalities. Residual paralysis may remain after resolution of fever.

Viraemia usually lasts 3-5 days after which recovery is rapid and natural immunity is long lasting.

Diagnosis

Diagnosis is often based on clinical observations of various stages of disease present simultaneously and history of sudden onset outbreaks on the farm or neighbouring units.

Isolation of virus from blood taken during pyrexic phase is the gold standard laboratory method of diagnosis, but is demanding. Molecular diagnosis is preferred these days. The virus can also be identified by immunofluorescence or immunostaining.

A rising antibody titre when sampled during fever and 2 weeks later is also confirmatory.

On post-mortem, generalised inflammatory changes are evident with neutrophilic infiltration of tissues and muscle necrosis. Straw coloured fibrinous fluid is often present in several cavities.

Treatment

Calcium borogluconate and/or NSAIDs will resolve many clinical signs and reduce pyrexia. All should be injected as swallowing reflex may be dysfunctional.

Draught cattle need rest for at least one week after recovery or further mortalities may occur.

Control

Vaccines are available in Japan, Australia and South Africa. Annual boosters are essential to maintain immunity. All are expensive for use in developing countries.

Vector control is theoretical and almost impossible. Quarantine also has no impact upon local spread due to vector transmission. Movement regulations vary with country and time and should be adhered to.

Cattle in good health usually recover quickly and have a long lasting immunity.

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.

How is BEF spread?

A virus known as a rhabdovirus causes BEF. It is also referred to as an arbovirus because biting insects spread it. The most likely insects to transmit the disease in NSW are mosquitoes, such as Culex annulirostris. Biting midges may also play a role in disease spread, and there may be other vectors that have not been identified.

The distribution of these insects varies with climatic conditions, and this in turn will influence the pattern of disease spread and time of occurrence.

Where does the disease occur?

Before 1975, BEF occurred infrequently in explosive epidemics that swept from north to south throughout eastern Australia - from Queensland, sometimes to Victoria. Large numbers of cattle were affected. These outbreaks occurred at intervals of 10 to 15 years. In the years between these epidemics, the disease was virtually unknown.

BEF has become established now in parts of eastern Australia, with localised outbreaks occurring on the north coast of NSW, or in the Hunter Valley. Depending on the seasonal conditions, the disease has then spread from these centres. Sometimes there is a north-south moving wave of infection from Queensland through NSW but this is now uncommon. The usual pattern consists of sporadic cases for one or two years followed by an outbreak.

Cases in inland NSW are much less common but occasional outbreaks can occur in the north west of the State - usually associated with spread from Queensland. The disease is rare in southern NSW and Victoria but occasional cases have been observed.

When does it occur?

BEF usually occurs between January and April, with the greatest number of cases in March. However, cases can occur from December through to early June. Cases in the winter or spring months, even in coastal districts, are rare.

Diagnosis

When an outbreak occurs in unvaccinated cattle not previously exposed to the virus, a diagnosis of BEF can often be made based on clinical signs and the brevity of illness.

However, when most animals are immune and occasional cases occur, laboratory confirmation of the cause of illness may be required. Usually this is done by taking

two blood samples - one during the very early stages of the illness, and another three weeks later. If BEF is responsible, BEF antibody levels will be much higher in the second test than in the first.

Treatment

Medical treatment is often unnecessary for non-lactating stock. However, bulls and high producing cows in early to peak production should be treated promptly. Animals that have gone down should be provided with adequate shelter, water and food, as cattle left exposed in hot weather are much more likely to die.

They should be rolled over several times a day to help avoid loss of circulation to the underside limbs, which will result in permanent muscle damage. The heavier the animal is, the more critical it is to get it back on its feet as quickly as possible. Bulls, high producing dairy cows and other valuable stock that become recumbent should be treated as soon as they are found. Any animals that go down should be given a calcium injection as soon as possible. This will help them to rise.

The use of anti-inflammatory drugs is recommended for any animals that become recumbent, and would be useful for any clinically affected animals. This treatment is only available through veterinary prescription. Long withholding periods may apply to some anti-inflammatory drugs, so read the label carefully.

BEF can impair the swallowing reflex, so affected animals should not be drenched or force fed. This may result in the inhalation of food or water, which can cause pneumonia.

Immunity

Once cattle have been infected with the disease, most are resistant to infection for many years or for life. However, some animals lose immunity after a few years, especially older animals.

Severe disease can occur in animals of any age that are introduced to districts where the disease is frequently observed from areas where the disease is uncommon.

Prevention

Both live and inactivated vaccines against BEF are available:

The live vaccine requires a veterinary prescription. It gives at least 12 months protection after two doses. The live vaccine is a freeze-dried preparation that must be kept frozen and then requires reconstitution immediately before use.

The killed vaccine is a refrigerated bulk product like most other vaccines. It is easier to use and is cheaper, but only gives about six months protection.

With either vaccine, two doses are required four weeks apart to achieve adequate protection. Animals can be vaccinated from six months of age and should then be revaccinated each year to ensure continued protection.

The second dose of vaccine can be given only two weeks after the first, if protection is required urgently. This only gives 10 weeks of protection and not all animals are protected quickly. If the BEF season turns out to be a long one, a third vaccination will need to be given after 10 weeks to give longer lasting protection.

The choice of vaccine will depend on:

the number of animals to be vaccinated, the predictability of BEF outbreaks in the region in question, and the farmers’ attitude to risk.

Some producers may decide to protect only their more valuable heavy animals, such as bulls and stud cows. Others may only vaccinate if BEF occurs in cattle to the north, or antibodies for BEF are detected in sentinel cattle close to their properties.

Due to the severe drop in milk production, vaccination is often worthwhile in dairy herds. Local knowledge of the frequency of outbreaks will assist decisions on the age of stock to be vaccinated. However, vaccination of bulls and very high producing cows is strongly recommended.

Vaccination in a commercial beef herd may or may not be worthwhile. It will depend on the stage of the management cycle when risk occurs. For example:

Fever may cause heavily pregnant cows to abort if they are not protected. If steers are close to finished weights, the loss of condition if they are

infected with BEF may make it economic to vaccinate (if given enough warning). If they are not close to market weight, vaccination may not be worthwhile.

Monitoring of arboviruses

NSW Agriculture and Local Land Services are involved in testing cattle for a National Arbovirus Monitoring Program (NAMP). Sentinel herds at various locations throughout Australia are blood sampled at regular intervals, to see if the cattle have been exposed to viruses carried by insects. Insect populations are also monitored by collections in special traps.

This allows animal health and quarantine authorities to demonstrate freedom from certain diseases to importing countries, to satisfy export requirements, and possibly give producers warning of the possible spread of disease south from endemic areas.

Nature of the disease

 BEF is an acute infectious arthropod-born non contagious viral disease of cattle and water buffalo characterized by transient fluctuating fever, depression, stiffness, lameness, and rapid recovery.

The name fits the sudden onset, short course of the disease, and the animal's abrupt recovery.

BEF incidence and severity fluctuates from year to year, depending on the immune status of the local cattle populations from previous contact with the disease.

BEF can causes serious economic losses through loss of condition, marked drop in milk production in dairy herds, temporary sterility in bulls, restrictions on the export of live cattle, and deaths which may occur due to concurrent infection.

BEF prognosis is good where spontaneous recovery usually occurs after 4 days "self-limiting disease" and most recovered cattle have life-long immunity.

 History and Occurrence

        The disease was first recorded in East Africa in 1867. In Egypt, BEF was first described in 1895 by piot, 1924 by Rabagliati , and subsequent outbreaks have been occurred in summer of 1991, 2000, 2001, and 2004. BEF is widely distributed in tropical and subtropical areas; it 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 .

 Etiology

The BEF virus is a single-stranded RNA, ether-sensitive Ephemero virus of the family Rhabdoviridae.

There are four serotypes with some antigenic variation; all of them are closely associated with leukocyte platelet fraction of the blood. Serological cross-reactions were detected between viruses of BEF and other Rhabdoviruses of cattle as rabies and rabies related viruses without significant cross protection.

BEF virus is pH-liable and the pH changes in muscles following death

as well as atmospheric temperature inactivates it, thus the virus does not survive long out side its host.

BEF virus is best isolated on mosquito cultures inoculated with defibrinated blood and transferred to several types of cell cultures as BHK 21 or Vero cells after 15 days.

 Hosts

Clinical disease has only been observed in cattle and water buffalo. 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.

 Transmission

The virus is present in blood of infected animals during the early febrile stage.

BEF virus is transmitted by several species of culicoides and mosquitoes. Viral development in the insect is suspected to be cyclic. Spread by wind-born carriage of vector is possible.

Direct i.v inoculation; as little as 0.002 ml of virulent blood in susceptible cattle is infective.

The reservoir host, other than cattle, has not been identified. Transmission by contact or fomites does not occur.

 Key signs

In cattle and buffalo, there is an incubation period 2-4 days and sometimes longer up to 10 days, and the course 3 - 5 days. The morbidity rate is about 35% or more, and fatality is low, seldom exceeding 1%.

The disease can vary in severity but the vast majority of cases run a short course, followed by rapid and complete recovery.

Clinical signs include sudden onset of fever (41-42 °C) which usually biphasic or poliphasic, shivering, inappetence, depression, lacrimation, serous nasal discharge, and lactation may decline suddenly or completely in dairy cows. Signs of stiffness and lameness typically occur on the second day of the disease. Some affected cattle may become recumbent and paralyzed for 8 hrs to more than 1 week, and a very small number may stay down for many weeks.

Clinical signs are severe in lactating cows, heavily conditioned animals and mature cattle.

BEF deaths are rare and could be attributed to complications arising from being down for long periods.

BEF complications may include subcutaneous emphysema, aspiration pneumonia, mastitis, abnormal gait, hindquarter paralysis, non-specific abortions, and temporary infertility in bulls up to 6 months.