Which of the following pests is not known to be a vector for disease?

The head louse is not known to be a vector for disease in the same way that the other pests listed are. While head lice can cause discomfort and irritation through their feeding on human blood, they do not transmit pathogens that lead to infectious diseases. This distinct characteristic sets them apart from body lice, ticks, and fleas, which are all recognized vectors of various diseases.

Body lice are associated with serious diseases such as typhus and trench fever; ticks can transmit Lyme disease and Rocky Mountain spotted fever; and fleas are known carriers of the bubonic plague and other infections. Understanding the role of these different pests in disease transmission is important for managing and controlling them effectively in various environments.