How do pest animals directly affect the health of people and other animals?

The correct answer focuses on how pest animals can directly harm health by biting and parasitizing. This can lead to the transmission of diseases and infections, as many pest species are vectors for various pathogens. For example, mosquitoes can carry viruses such as West Nile virus and Zika virus, while ticks can transmit Lyme disease. These direct interactions with pest animals can cause significant health issues in both people and other animals, leading to illnesses and sometimes severe health complications.

The other choices do not accurately represent the primary direct impacts of pest animals. Providing beneficial services is not relevant since pest animals are typically regarded as nuisances that pose health risks rather than benefits. Stimulating immune responses may happen in some cases, but this is more of an indirect effect and does not characterize the direct health threats posed by pest animals. Hence, while the immune system may respond to pest-induced challenges, it does not align with the question's focus on direct health impacts.