Important as veterinary point of view

1. Bovine Ephemeral Fever
(Three Day Sickness)
By
Mujahid Hussain

2. Hosts
It is a acute arthropod-borne 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.

3. Etiology
Rhabdoviridae => Ephemerovirus => Bovine ephemeral fever virus (BEFV)
BEFV is:
 Ether sensitive
 Inactivated at pH below 5 and above 10
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.
No transmission by contact or fomites
The virus does not appear to persist in recovered cattle, which often have
a lifelong immunity.

4. Epidemiology
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 (when
conditions favor multiplication of biting insects); it disappears abruptly in
winter.
Morbidity may be as high as 80%.
Overall mortality is usually 1–2%.

5. Clinical Findings
 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.
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.
Bulls, heavy cattle, and high lactating dairy cows are the most severely
affected, but spontaneous recovery usually occurs within a few days
(that’s why called Three Day Sickness). More insidious losses may result
from decreased muscle mass and lowered fertility in bulls.

7. 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 (collapse of an expanded
lung), also may be present.

8. Diagnosis
Diagnosis is based almost entirely on clinical signs in an epidemic.
Laboratory confirmation is by:
 Serology
 Virus isolation
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
weeks apart confirms infection

9. Treatment & Control
 Complete rest is the most effective treatment, and recovering animals
should not be stressed or worked because relapse is likely.
 NSAIDs given early and in repeated doses for 2–3 days are effective.
Oral dosing should be avoided unless the swallowing reflex is functional.
 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.
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.

10. Overview
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.
Etiology: The BEF virus is a single-stranded RNA, ether-sensitive Ephemero virus of the
family Rhabdoviridae
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
Transmission: 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.
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. Clinical signs include sudden onset of
fever (41-42°C) which usually biphasic or polyphasic, shivering, inappetence,
depression, lacrimation, serous nasal discharge, salivation, 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 hours to more than 1 week,
Treatment: A palliative treatment is possible with non-steroidal anti-inflammatory for
several days as early as possible.