Bovine ephemeral fever (BEF) also known as Three Day Sickness is an

arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

vector-borne disease of cattle and is caused by bovine ephemeral fever virus (BEFV), a member of the genus ''

Ephemerovirus ''Ephemerovirus'' is a genus of viruses in the family ''Rhabdoviridae'', order ''Mononegavirales''. Cattle and mosquitoes serve as natural hosts. Diseases associated with viruses in this genus include: sudden fever. Structure Ephemeroviruses ar ...

'' in the family ''

Rhabdoviridae ''Rhabdoviridae'' is a family of negative-strand RNA viruses in the order ''Mononegavirales''. Vertebrates (including mammals and humans), invertebrates, plants, fungi and protozoans serve as natural hosts. Diseases associated with member virus ...

''.

Virology

BEFV forms a bullet- or cone-shaped

virion A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1 ...

s that consist of a negative, single stranded RNA genome with a lipid envelope and 5 structural proteins. The envelope

glycoprotein Glycoproteins are proteins which contain oligosaccharide chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycos ...

G contains type-specific and neutralizing antigenic sites. There has been recent evidence which demonstrated that BEFV induces

apoptosis Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes incl ...

in several cell lines. It was however shown that apoptosis could be blocked by the

caspase Caspases (cysteine-aspartic proteases, cysteine aspartases or cysteine-dependent aspartate-directed proteases) are a family of protease enzymes playing essential roles in programmed cell death. They are named caspases due to their specific cystei ...

inhibitor (Z-VAD-fmk), indicating that BEFV induces caspase-dependent apoptosis in cultured cells.

Location

The virus has been found in tropical and subtropical regions of Asia, Africa and through eastern Australia. It is not found in the Americas, or in Europe (except western parts of Turkey).

Transmission

The virus is transmitted by an insect

vector Vector most often refers to: *Euclidean vector, a quantity with a magnitude and a direction *Vector (epidemiology), an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematic ...

. The particular

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

linked to the virus are the biting midges ''

Culicoides oxystoma ''Culicoides'' is a genus of biting midges in the family Ceratopogonidae. There are over 1000 species in the genus,Connelly, C. RBiting midges: ''Culicoides'' spp.Featured Creatures, Entomology and Nematology Department, University of Florida IFA ...

'' and '' C. nipponensis''.

Disease characteristics

The characteristics of the disease are the sudden onset of

fever Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...

stiffness Stiffness is the extent to which an object resists deformation in response to an applied force. The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is. Calculations The stiffness, k, of a b ...

lameness A limp is a type of asymmetric abnormality of the gait. Limping may be caused by pain, weakness, neuromuscular imbalance, or a skeletal deformity. The most common underlying cause of a painful limp is physical trauma; however, in the absence ...

and

nasal Nasal is an adjective referring to the nose, part of human or animal anatomy. It may also be shorthand for the following uses in combination: * With reference to the human nose: ** Nasal administration, a method of pharmaceutical drug delivery ** ...

and

ocular Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and con ...

discharges. BEF often causes

hypocalcaemia Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 mmol ...

which in turn generates clinical signs such as depression, cessation of rumination, muscle tremors and

constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...

. Although the pathogenesis of the disease is complex it seems clear that the host inflammatory responses, mediated by the release of

cytokines Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in autocrin ...

, are involved in the expression of the disease.

Diagnosis

The virus can be isolated from blood and can be identified by immunofluorescence and immunostaining. Rising levels of antibodies in two samples taken 2 to 4 weeks apart also indicate infection.

Treatment

Rest, and lack of stress, are important to aid recovery. Animals lying flat out on their side, unable to get up, should be rolled over several times each day to prevent loss of circulation and muscle damage. If the animal has signs of

hypocalcemia Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 mmol ...

, such as

rumen The rumen, also known as a paunch, is the largest stomach compartment in ruminants and the larger part of the reticulorumen, which is the first chamber in the alimentary canal of ruminant animals. The rumen's microbial favoring environment allow ...

stasis, then calcium borogluconate may be administered.

Non-steroidal anti-inflammatory drugs Non-steroidal anti-inflammatory drugs (NSAID) are members of a therapeutic drug class which reduces pain, decreases inflammation, decreases fever, and prevents blood clots. Side effects depend on the specific drug, its dose and duration of ...

can improve recovery. Rest is absolutely imperative, for a minimum of one week or death can still occur.

Control

A vaccine is available in Japan but is very expensive which limits its use. Movement regulations are in place in several countries. Ultravac BEF (from Zoetis) - is a vaccine to prevent bovine ephemeral fever. The product is registered in Australia, Israel and Egypt.

References

* * *

External links

* {{DEFAULTSORT:Bovine Ephemeral Fever Animal viral diseases Ephemeral Fever Rhabdoviridae