Which of the following illnesses is important to control to protect soldiers' health in the field?

Controlling arthropod-borne illnesses is crucial for protecting soldiers' health in the field due to the significant impact these diseases can have on military readiness and overall troop effectiveness. Arthropod-borne illnesses, such as malaria, dengue fever, and Zika virus, are transmitted through vectors like mosquitoes and ticks, and can lead to severe health complications and even fatalities.

In a military context, where personnel may be deployed in close quarters and in environments that facilitate the spread of these vectors, it is essential to implement control measures, such as insect repellent, proper sanitation, and use of protective clothing, to minimize the risk of infection. Keeping soldiers healthy and preventing outbreaks is vital for maintaining operational capabilities and ensuring mission success.

In contrast, while the common cold, seasonal flu, and allergies can affect soldiers, they typically do not pose the same level of threat to overall health and operational effectiveness as arthropod-borne illnesses. Therefore, the focus on controlling arthropod-borne diseases is a key element of field sanitation and public health measures in military operations.