Less than 50% of the new emerging human infectious diseases have been vector-borne or zoonotic.

• A. True
• B. False
• C. Not enough data
• D. Uncertain

Answer: (B)

The key idea is how most new human infectious diseases originate. A large majority come from animals and rely on vectors or animal reservoirs to reach people. Global analyses of emerging infections show that roughly six in ten new infections are zoonotic, and many of these involve vector transmission. That means the combined share of diseases that are either zoonotic or vector-borne is greater than half. For example, HIV originated from simian viruses crossing into humans, and coronaviruses like SARS and MERS are linked to animal reservoirs; vector-borne examples include diseases transmitted by mosquitoes such as dengue and West Nile virus. Because the evidence shows that more than 50% of emerging infections are zoonotic or vector-borne, the statement is not correct.