Milk has classically been the primary vehicle for transmission of which disease from cattle to humans?

• A. Brucellosis
• B. Glanders
• C. Melioidosis
• D. Pontiac fever

Answer: (A)

Milk is classically a vehicle for brucellosis transmission from cattle to humans because Brucella bacteria can be shed in the milk of infected cattle. People who consume unpasteurized milk or dairy products can acquire the infection, leading to a feverish, often chronic illness. Pasteurization inactivates Brucella, and cattle vaccination reduces shedding, which is why this route became much less common with dairy processing. The other diseases come from different sources: glanders is primarily linked to contact with infected horses or inhalation; melioidosis arises from environmental exposure to Burkholderia in soil and water; Pontiac fever is caused by inhalation of aerosolized Legionella from water systems. Thus, milk has classically been the primary vehicle for brucellosis transmission.