What Are Parasitic Microorganisms Carried by Fleas, Lice, Ticks & Mites?

Lyme disease, passed by deer ticks, is communicable to both pets and humans. This bacteria can cause stiff joints, lameness, fever, fatigue and loss of appetite. The symptoms may not begin to show for more than a month after the contact with the tick occurred. If you are concerned that your dog may have Lyme disease, contact your veterinarian immediately. The infection is persistent; long-term antibiotics may be necessary.

Ticks can carry a number of dangerous bacteria that will cause illnesses in their host. Canine ehrlichiosis, carried by the brown dog tick, is one of the more common and most dangerous of these conditions. The symptoms include depression, weight loss, runny nose, loss of appetite, fever and nosebleeds. Rocky mountain spotted fever can cause stiffness, lameness, skin lesions and neurological problems. Canine anaplasmosis can cause fever, stiff joints, vomiting, diarrhea and seizures. Less common tick-borne illnesses include canine babesiosis, hemoplasmosis, tick-borne encephalitis and canine hepatozoonosis. Broad-spectrum antibiotics usually treat all of these conditions, as they are bacteria-based.

Canine bartonellosis is a bacteria carried by fleas and ticks. It can have serious symptoms when it presents in dogs. The disease is often opportunistic and may especially affect dogs with weakened immune systems. Symptoms include nosebleeds, inflammation of the heart, anemia and polyarthritis. Healthier dogs may be carriers of the disease and can pass it on to cats, who are more susceptible to the infection. Fleas can also carry tapeworm, most commonly presenting with weight loss in a dog, and spotted fever, which presents as fatigue, diarrhea and vomiting.

Scrub typhus is a serious condition that can pass to humans from mites and lice. The infected mite will often leave a skin ulcer where it bit the skin. You may also suffer from sudden fever, headache, sweating and a rash on the torso. Scabies or mange is a condition caused by the mites burrowing under the skin and laying eggs. Both dogs and humans can suffer from this severely itchy condition.