Final answer:
A zoo doctor assisted in confirming an outbreak of West Nile virus by correlating symptoms with epidemiological data and by laboratory confirmation of the virus in samples from affected animals.
Step-by-step explanation:
The doctor at the zoo helped the investigators determine that West Nile virus was the cause of the outbreak through a meticulous process that included clinical diagnosis, laboratory testing, and observation of the affected animals. By validating symptoms consistent with West Nile virus infection and using epidemiological data, such as the increase in neuroinvasive cases reported by the Centers for Disease Control and Prevention (CDC), the doctor could support the hypothesis of West Nile virus being responsible. Additionally, by collecting samples from infected animals and testing for the presence of the virus, the doctor provided concrete evidence that aligned with the known spread and symptoms of West Nile virus, eventually confirming the cause of the outbreak.