Def: chronic highly contagious disease of sexually mature animals characterized by abortion, retention of placenta and high rate of infertility.
Brucellosis causes serious economic losses to livestock breeders due to abortion, decrease in milk yield and infertility.
Etiology & Susceptibility
The disease is caused by different species and serovars including:
- Brucella abortus
- Brucella melitensis
- Brucella ovis
- Brucella suis
- Brucella canis
They are Gram negative coccobacilli or short rods.
They grow intracellularly and intercellularly.
Sources of infection:
- uterine discharge, fetal membranes and aborted fetuses.
- milk of infected animals.
- contaminated litters, feed stuffs, water, pastures and utensils.
- contaminated clothes, shoes and gloves of workers.
- semen of infected animals.
- ingestion of contaminated food or water
- mucous membranes
- skin either contacted or abraded
- congenital transmission
- In highly susceptible non-vaccinated pregnant cattle, a storm of abortion occurs after the 5th month of pregnancy. in unprotected herds 40% to 80% of pregnant females may abort or give birth to very weak newborns.
- In subsequent pregnancies the fetus is usually carried to full term.
- Retention of placenta and metritis which often causes infertility.
- Some cows may die due to septic metritis.
- Orchitis and epididymitis in bulls.
- Lack of sexual activity.
- Hygroma of the joints especially of the knees.
depends on the use of efficient diagnostic procedures for detection of infected animals
Control of Brucellosis based on:
1- Removal of the source of infection.
2- Application of hygienic measures and management
3- Vaccination : Brucella abortus strain 19 vaccine – Brucella abortus strain RB51 vaccine – Brucella abortus strain 45/20 Duphavac, McCewen vaccine – Brucella melitensis Rev.I vaccine – Brucella melitensis H38 vaccine