Pakistan has been renowned as an agricultural country. It is rich in livestock sector having fairly large populations of domestic animals. Among these, populations of cattle and buffalo are 38.3 and 33.7 million respectively. The importance of cattle and buffalo cannot be denied at any level as these are the principal farming animals and milk and beef are widely consumed locally in the country. The estimated annual milk production of cattle and buffalo include 17.372 and 30.462 million tonnes respectively and a combined 1.829 million tonnes beef for human consumption during 2012-2013 (Pakistan Economic Survey 2012-2013).
Brucellosis, a worldwide bacterial zoonosis, is one of the most serious diseases causing huge loss to national economy and human beings among developing countries (Wu et al. 2013). The disease is endemic in Middle East, Central Asia, Africa, Mediterranean region and parts of Latin America (Gwida et al. 2010). Brucellae are Gram-negative bacteria, facultative anaerobic and intracellular pathogens. These show a wide range of host specificity. These coccobacilli measure from 0.6 to 1.5 µm long and 0.5 to 0.7 µm wide. Eight species have been identified in the genus Brucella such asBrucella abortus(B. abortus affecting cattle and buffalo), B. melitensis (sheep and goats), B. ovis (sheep), B. suis (swine), B. canis (dog), B. neotomae (desert rats), B. ceti (cetaceans) and B. pinnipedialis (pinnipeds) (Blasco 2010). This wide range of species covers almost all domestic animals however cats have found resistant. Generally it is considered as a reproductive problem in both male and female animals (Ficht 2003).
Brucellosis has been listed as the second most serious zoonotic disease in the world after rabies by OIE (OIE 2009). B. abortus, the primary cause of Brucellosis in large ruminants, (cattle and buffalo), remains not only a significant threat as a source of human illness but also risks economy of the country (Makita et al. 2011). Present estimates of economic loss in meat and milk production resulting from Brucellosis are $800 million annually in the United States(OIE 2009). The incidence of the disease can be correlated to several factors including demographic and geographic factors(Soomro et al. 2014). Seroprevalence of the disease has been reported in different regions of Pakistan and ranges 3.25 to 4.4%(Naeem et al. 1990).
Brucellosis in cattle and buffaloes can be recognized clinically by an abortion usually occurring form 6 months and onwards i.e. last trimester of pregnancy (Soomro et al. 2014). Brucellosis is principally a disease of sexually mature animals as it affects mainly the reproductive system and fertility of the animals. It significantly reduces the survival rate of newborns and also the milk yield (Sikder et al. 2012). Greyish white mucoid or mucopurulent discharges from the vagina, prior to parturition of cow, may show the clinical patterns of disease along withnormal patterns of parturition like swelling of the vulva, relaxation of pelvic ligament, enlargement of udder and discharge from the vulva (Shafee et al. 2012).
Human infections as a result of Brucellosis range more than 500,000 annually round the world (Abo-Shehada and Abu-Halaweh 2011). Brucellosis can cause a wide range of symptoms similar to the flu and may also include fever (39-40°C), night sweats, headache, back pain and physical weakness. Severe form of infection may result in involvement of the central nervous system or the lining of the heart (Soomro et al. 2014). It is one of the principal public health problems for an agricultural country like Pakistan, where majority of the population is engaged in livestock farming (Shafee et al. 2012).
Brucellosis in humans is a severely debilitating condition that usually requires prolonged treatment involving a combination of strong antibiotics. The treatment results in permanent and disabling sequel, and also in significant medical expenses along with loss of income due to loss of working hours. Brucellosis can be transmitted to humans by ways of inhalation, direct contact with infected animals or contaminated products of conception and ingestion of unpasteurized dairy products and undercooked meat or meat products (Gwida et al. 2010; John et al. 2010). Brucellosis can also be transmitted from infected animals to human beings who are in close contact with animal secretions like infected vaginal secretions, blood, urine, feces, aborted fetus, or those who consume unpasteurized milk or other raw milk products. Shepherds, milkmen, butchers, knackers, veterinary assistants, and abattoir workers are at high risk (Agasthya et al. 2007)