During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever 39°C lasting >2 days with three or more symptoms (i. e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years. The situation is an example of:
a. human reservoirs.
b. a vector.
c. a zoonosis.
d. a nonliving reservoir.
e. a focal infection.

The answer is C.

Explanation:

In the example given in the question, it is stated that 20 of the 2000 sheep are tested and 15 are positive for the disease's antibodies. This indicated that the disease was transmitted to humans from the sheep and it is an example of zoonosis which is used to describes diseases that can be passed on to humans from animals.

I hope this answer helps.

Zoonosis

Explanation:

A disease is termed zoonotic when is transmitted by animals mainly vertebrates to humans. The animals carry the pathogen that causes such diseases and they might not show signs that they are affected by the disease. These diseases affect humans when they have close contact with the infected animals or through the agents of dispersion.

In the illustration, the sheep that are infected with the Coxiella burnetti transfers the disease via an agent of dispersion, which is the wind in this case to humans. This is a case of zoonosis