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

arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

vector-borne disease of cattle and is caused by bovine ephemeral fever virus (BEFV), a member of the genus '' Ephemerovirus'' 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 virion (plural, ''viria'' or ''virions'') is an inert virus particle capable of invading a Cell (biology), cell. Upon entering the cell, the virion disassembles and the genetic material from the virus takes control of the cell infrastructure, t ...

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 (sugar) 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 a ...

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

apoptosis Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biol ...

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 cyste ...

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 * Disease vector, an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematics a ...

. The particular

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

linked to the virus are the biting midges '' Culicoides oxystoma'' and '' C. nipponensis''.

Disease characteristics

The characteristics of the disease are the sudden onset of

fever Fever or pyrexia in humans is a symptom of an anti-infection defense mechanism that appears with Human body temperature, body temperature exceeding the normal range caused by an increase in the body's temperature Human body temperature#Fever, s ...

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 ...

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 An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the eye ...

discharges. BEF often causes hypocalcaemia 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 Human feces, stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the ...

. 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 produced by a broad range of cells, including immune cells like macrophages, B cell, B lymphocytes, T cell, T lymphocytes ...

, 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 ...

, such as

rumen The rumen, also known as a paunch, is the largest stomach compartment in ruminants. The rumen and the reticulum make up the reticulorumen in ruminant animals. The diverse microbial communities in the rumen allows it to serve as the primary si ...

stasis, then calcium borogluconate may be administered. Non-steroidal anti-inflammatory drugs 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