*3.1.1 Unpasteurized milk and dairy products*

Consumption of tainted dairy products is the most common vector for the transmission of brucellosis in humans. Consumption of unpasteurized milk and dairy products is a major route for the transmission of *Brucella* species to humans, as these bacteria are spread from diseased animals to humans through the milk they produce. Unpasteurized cheeses, also known as "village cheeses," are very probably the foods that cause human brucellosis. This is especially true of goat and ewe cheeses. The usual lifespan of Brucella in this cheese is one month, but it can last for as long as three months [17, 18].

#### *3.1.2 Raw or undercooked meat products*

In societies where raw or undercooked meat or meat products are highly valued, meat may also be a major source of infection [19].

## **3.2 Environmental contact with infected animals or their products**

Direct inoculation occurs most frequently through cuts and abrasions in the skin. Veterinarians and those working in red meat processing factories or slaughterhouses run the risk of skin wound contamination. Animal tissue, fetal remains, birth

products, blood, urine, and vaginal discharges are all potential vectors for the transmission of disease [20].

Hunters can become infected with *Brucella* by cuts in the skin or from ingestion of the bacteria while cleaning wild pigs, moose, elk, and deer that they have entrapped.

Newly aborted animals or rains running off of contaminated land might contaminate water supplies like wells.

Brucellosis can also be contracted through the inhalation of infected dust, dried dung, or other noxious excrements. *Brucella* species can persist for extended durations in a wide variety of environmental conditions, including dairy, meat, aborted fetuses, dung, dust, soil, slurry, and water, making the problem complicated. A lot of factors, including the type of substrate, the quantity of Brucella, the temperature, the pH, the amount of sunshine, and the presence of other microbial contaminants, all play a role in determining an accurate duration of survival [21].

#### **3.3 Occupational exposure**

The risk of brucellosis infection is higher in certain professions. Infection can happen through inhalation, contamination of the conjunctiva, ingestion, contamination of the mucous membranes, contamination of the skin, particularly through cuts or abrasions, and unintentional self-inoculation with live vaccines [22]. These professions involve:


#### **3.4 Infection by the inhalation**

It is uncommon for people to become infected with *Brucella* bacteria through inhalation, but it can be a serious risk for those who work in particular occupations, such as medical labs, where staff members may be exposed to the aerosol while preparing samples for isolation, in addition to abattoir workers, and those who work with animals used in food production or in the meat business [23].
