How do most mosquito-borne diseases spread in the environment?

Most mosquito-borne diseases spread primarily through the bite of infected mosquitoes. When a mosquito bites a host, it can transfer pathogens—such as viruses or parasites—present in its saliva into the bloodstream of that host. This method of transmission is efficient because mosquitoes frequently feed on blood from numerous hosts, thereby facilitating the spread of diseases like West Nile virus, Zika virus, and malaria among different populations.

The other methods outlined in the options do not significantly contribute to the transmission of these diseases. For example, soil contamination is not a common route for mosquito-borne pathogens to spread to humans. Airborne transmission typically refers to pathogens spread through the air via droplets, which is not how these diseases operate, as they rely on direct contact through a mosquito bite. Similarly, contact with infected surfaces does not play a role in this type of disease transmission; instead, the disease's spread largely depends on the physiological interaction between mosquitoes and potential hosts.