Brucellosis

Brucellosis is an illness caused by different types of Brucella bacteria, which particularly infect livestock like cattle, pigs, goats, dogs, and sheep. The disease can be contracted by humans through direct contact with infected animals, consuming contaminated products of animals, or inhaling contaminated air. Ingesting milk which is unpasteurized or cheese made from infected goats or sheep is a common source of infection for humans.

Brucellosis is a zoonotic disease that can be found in many regions and presents a significant threat to public health. The growth of the livestock sector and urban development, combined with poor hygiene practices in animal husbandry and food processing, have all contributed to the persistence of brucellosis as a public health concern.

Recent Outbreak, Prevalence, and Disease Status in Pakistan

The incidence of human brucellosis in Pakistan is relatively low, although it has been reported as 21.7% in high-risk groups such as slaughterhouse employees. Furthermore, various investigations have revealed changing prevalence rates in different species of animal in Pakistan and nearby regions, with some cattle herds exhibiting a prevalence rate of up to 19%.

1. A 2021 research conducted in Sindh, the third largest province of Pakistan and the second most populous, found that brucellosis primarily affects cattle and camels in Karachi and Hyderabad, while no cases were reported in sheep and goats. The seroprevalence rates in cattle ranged from 17.5% to 25%, while in camels, it varied from 12.12% to 32.35%.

2. The prevalence of brucellosis in small ruminants and cattle has been documented in Khyber Pakhtunkhwa, a province situated in northwestern Pakistan, where seropositivity rates vary from 0% to 13.4% in bovines and bubaline, and from 3.2% to 16.67% in ovine and caprine.

3. In the districts of Quetta and Turbat, estimates of seroprevalence in cattle and buffaloes ranged from 0.26% to 5.9%, while in sheep and goats it ranged from 2% to 2.67%.

4. In the northern region of Pakistan, specifically in the capital city of Islamabad, Brucellosis has been frequently observed in both cattle and small ruminant herds. The seroprevalence in cattle and buffaloes ranges from 1.6% to 8.3%, while in sheep and goats it ranges from 2.2% to 13.1%.

5. Gilgit-Baltistan, a region in northern Pakistan encompassing the Himalayas, the Hindu Kush, and the Karakoram Mountains, has reported brucellosis cases in both cattle (10.93%) and wild animals.

6. In a study conducted in AJK, a self-governing region of Pakistan situated in the southern part of the Himalayan mountain range, it was found that 13.33% of goats were seropositive for brucellosis.

In 1979, the first research on human brucellosis in Pakistan was published. At present, the largest proportion of cases is believed to occur in Punjab, where the reported incidence ranges from 5.8% to 10.7% in hospitals and 6.87% to 38.94% in occupational settings. Similarly, in Khyber Pakhtunkhwa, hospital-based studies have found prevalence rates of 2% to 36.4%. Nonetheless, brucellosis is still widely underestimated and misdiagnosed in the country.

Zoonotic Potential of Brucellosis

Brucellosis is a zoonotic disease that can be passed from animals to humans and is caused by a type of bacteria. It can be contracted by coming into contact with animals infected animals or their surroundings which are contaminated. A common way for humans to get the disease is by using unpasteurized dairy products that have been contaminated. Another way is by direct exposure to tissues or fluids from infected animals. Brucellosis is the most easily transmitted zoonotic disease, second only to rabies.  

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References;

ONE HEALTH ZOONOTIC DISEASE PRIORITIZATION & ONE HEALTH SYSTEMS MAPPING AND ANALYSIS. (2017). (p. 3). Islamabad: CDC, USD.

WHO. (2023). Retrieved from https://www.who.int/news-room/fact-sheets/detail/brucellosis#:~:text=sheep%20and%20dogs-,Brucellosis%20is%20a%20bacterial%20disease%20caused%20by%20various%20Brucella%20species,or%20by%20inhaling%20airborne%20agents.