Fleas are a terrible nuisance to pets and humans alike. Fleas reproduce quickly, are difficult to control and can cause flea allergy dermatitis or even anemia in pets. Even worse, fleas can transmit parasites and dangerous diseases to animals and humans. Since it is virtually impossible to avoid fleas, both those who own pets and those who don’t should be aware of these diseases and their symptoms.
The most deadly flea-borne disease is the bubonic plague. Plague cases in humans are not common anymore; however, it is still exceptionally serious. Other flea-borne diseases include flea-borne typhus, bartonella henselae (cat scratch fever), several other bartonella strains including bartonella grahamii, bartonella taylorii and bartonella quintana.
The bacterium Yersinia pestis, which is carried by the rat flea, causes bubonic plague. Rat fleas prefer to infest rodents, such as mice, rats, and prairie dogs, but can infect and bite other animals, including rabbits, cats, dogs, and people. Cats contract plague either via fleabite from an infected flea or by eating an infected rodent. People contract plague via a fleabite or by exposure to blood or other fluids from those (human or animal) infected. Flea-borne typhus is caused by Rickettsia typhi (murine typhus) or Rickettsia felis (flea-borne spotted fever), and is spread mainly by the rat flea and cat flea. Bartonella henselae is the pathogen responsible for cat-scratch disease. As the name indicates, people usually acquire this infection via a bite or scratch from an infected cat. Cats get the disease from an infected flea. Fleas can also pass other strains of bartonella to animals or people.
Bubonic plague is quickly fatal if untreated. Symptoms of plague in humans include a painfully swollen lymph node or nodes, accompanied by sudden high fever and debilitating fatigue. Symptoms in domestic animals are similar to those in humans. Flea-borne typhus symptoms include fever, headache, muscle pain, red rash and stomach pain or nausea. Bartonella often only causes mild symptoms, if any, in cats. In people, bartonella henselae usually causes swollen lymph nodes and is not normally serious; however sometimes bartonella can be much more serious--especially in those suffering other chronic illnesses.
The most effective way to prevent flea-borne diseases is to keep your pets and home flea free. In addition, you should watch for signs and symptoms of flea-borne illness and treat the illnesses promptly. Cat owners in plague regions should keep cats indoors to prevent them from eating plague-infected rodents. Doctors treat plague and flea-borne typhus with doxycycline, or similar antibiotics. Human patients with bartonella may be prescribed the antibiotic ciprofloxacin or other antibiotics.
According to the Center for Disease control, most U.S. plague cases in humans are found in New Mexico, Arizona, Colorado, California, Oregon and Nevada. Around the world, plague cases are found in parts of Africa, Asia, and South America. U.S. cases of flea-borne typhus occur mainly in the southern states. Rickettsia typhi and Rickettsia felis are found in several other countries as well, including Brazil and Spain. Bartonella exists in most areas of the world.
Fleas also transmit tapeworm, a parasite that can cause anemia, diarrhea and other health problems in animals and in humans.