Ticks are external parasites that are capable of infesting many different types of animals, including dogs, cats and people. These parasites attach to the skin of their hosts via special mouth parts and feed off their host's blood once attached. If infested by large numbers of ticks, dogs and other infested animals may even become anemic due to large volumes of blood being consumed.
Diseases may be Carried and Transmitted to Dogs by Ticks
In addition to the risk of blood loss and the discomfort caused by a tick infestation, ticks may also carry a number of diseases that are readily transmitted to a dog when an infected tick feeds on the dog. These diseases include:
- Lyme disease,
- ehrlichiosis,
- anaplasmosis,
- Rocky Mountain Spotted Fever,
- babesiosis,
- and others.
Lyme Disease can be Transmitted to Dogs Through Tick Bites
Lyme disease is probably the most well-known of the tick-borne diseases. Lyme disease is caused by a spirochete bacteria called Borrelia burgdorferi. Dogs become infected when an infected tick attaches and feeds.
Many dogs become infected with Lyme disease without ever showing clinical signs. When symptoms do occur, signs may include lameness and joint pain which may shift from one leg to another in addition to a fever. Less commonly, the kidneys may become involved, essentially causing nephritis and kidney failure.
Most cases of Lyme disease are relatively easily treated with appropriate antibiotics. However, Lyme disease nephritis is typically more difficult to treat and may become life-threatening.
Ehrlichiosis: Another Tick-Borne Disease in Dogs
Ehrlichiosis is also known as "tropical pancytopenia". Caused by a rickettsial organism, ehrlichiosis is introduced when an infected tick feeds on a dog. Once infected, the organism infects and destroys the red blood cells of the infected dog, leading to severe anemia. The nervous system is also frequently involved and neurological symptoms are common in dogs with ehrlichiosis.
Anaplasmosis in Dogs
Anaplasmosis is similar in many ways to ehrlichiosis and until recently, the bacteria that causes anaplasmosis was classified as an Ehrlichia species. Both diseases are caused by rickettsial organisms, are carried by ticks and produce similar symptoms in infected dogs.
Rocky Mountain Spotted Fever Infection in Tick-Infested Dogs
Rocky Mountain Spotted Fever is still another tick-borne disease that can be transmitted to dogs. The disease is caused by an organism known as Rickettsia rickettsii.
Rocky Mountain Spotted Fever may affect any organ system in an infected dog and the clinical signs will vary from dog to dog depending on which organs or organ systems are attacked. Disease may range from mild to life-threatening.
Babesiosis Infection in Dogs
Babesiosis is caused by a bacteria known as Babesia. When an infected tick feeds on a dog, the infection is transmitted. The Babesia organisms then infect the red blood cells of the dog, causing an immune-mediated hemolytic anemia. Platelets may also be destroyed, leading to clotting abnormalities, and liver disease and neurological symptoms are also possible in infected dogs.
Ticks, Zoonotic Disease and the Risk of Transmission to People
Tick-borne diseases can infect people very easily, though people are unlikely to become directly infected by any of these diseases by contacting an infected dog. Dogs may, however, function to transport ticks into the home or environment, where the ticks can then feed on human family members in the same fashion that they feed on the canine family members.
Lyme disease, ehrlichiosis, anaplasmosis, Rocky Mountain Spotted Fever and babesiosis are all tick-borne diseases with the potential to infect people as well as dogs. In addition, other tick-borne diseases, such as tularemia, which rarely infect dogs can infect people.
Ticks are dangerous to dogs not only because they feed off of the blood of the dogs they infest but also because they serve as disease vectors, spreading various diseases, including Lyme disease. These same ticks can also pose a threat to human health by feeding on people and transmitting disease to their human hosts.
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