Final answer:
Rickettsias are the specialized bacteria spread by infected arthropods like fleas, ticks, and lice, and they're responsible for several zoonotic diseases, including Lyme disease and plague.
Step-by-step explanation:
The specialized bacteria spread by infected fleas, ticks, and lice that are considered biological hazards are known as Rickettsias. These are obligate intracellular pathogens that can cause a variety of zoonotic febrile diseases. For example, the bacteria responsible for Lyme disease, Borrelia burgdorferi, is transmitted to humans by tick bites, while Yersinia pestis is the bacterial pathogen that causes plague, spread by fleas. It's important to understand these vector transmission mechanisms as they are crucial for the spread of these bacterial diseases.