Which organism is mentioned as a vector that can transmit disease?

Rats are known vectors that can transmit various diseases to humans and other animals. They can carry pathogens that cause illnesses such as leptospirosis, hantavirus, and rat-bite fever. The role of rats as vectors primarily comes from their ability to live in close proximity to human populations and their capacity to harbor and spread diseases through their urine, droppings, and bites.

In contrast, butterflies, birds, and beetles are generally not recognized as significant vectors for diseases affecting humans in the same way. While some birds can carry pathogens, their transmission mechanisms and the diseases they spread are different from those associated with rats. This specific context highlights why rats are identified distinctly as a vector for disease transmission.