Anaplasma phagocytophilum infection

Also known as canine granulocytic anaplasmosis or canine anaplasmosis. It is a relatively new disease but is now becoming increasingly recognized both in the USA and Europe.

Anaplasmosis is an infection caused by the bacterium A. phagocytophilium and leads to signs of fever, lethargy, reduced appetite and signs of lameness.

A. phagocytophilum infection is tick-borne, spread by ticks of the Ixodes class (such as Ixodes ricinus in Europe and in the USA Ixodes pacificus on western coast and Ixodes scapularis in the north-eastern and southern coastal. Infection often occurs from spring to fall due to increased tick activity at this time of year.

Following an incubation period of 7-14 days, signs of infection may include loss of appetite, a fever, depression, reluctance to move and lameness or a stiff gait due weakness of swollen joints. Co-infections with Borrelia burgdorferi (Lyme disease) may be responsible for more severe clinical signs in some cases.

Prompt diagnosis and accurate diagnosis is important as signs of A. phagocytophilium infection can be very similar to a number of other more serious infections such as Lyme disease. Treatment of A. phagocytophilum infection will speed recovery, so should your dog develops these signs, call your vet as soon as possible.

The clinical signs associated with the disease are not specific; therefore, clinical signs alone cannot be used to diagnose the condition. Infection with other pathogens such as those that cause Lyme disease or Ehrlichiosis can present in a similar way so you vet will likely take a blood sample to assess your dog’s general health (looking for evidence of any anemia or organ dysfunction) as well as to confirm the presence of infection. Sometimes the infection can be confirmed by examining the blood of the dog to look for the parasites inside blood cells, however often these are quite hard to find. In these instances, detection of antibodies to the parasite (made by the dogs immune system) or finding very small amount of the parasite DNA using a test called PCR, confirms that an infection has occurred.

The parasite can be killed by some antibiotics. Usually the drugs tetracycline or doxycycline are used. Treatment must be given for several weeks. Most dogs will respond rapidly (within a day or two) to appropriate therapy. Sometimes recovery takes a number of weeks but this is usually associated with the presence of concurrent infections. In addition, other symptomatic medication such as pain relief and anti-inflammatories may be considered.

Controlling ticks will prevent transmission of the disease. Various veterinary preparations are available to kill ticks or prevent their attachment to the dog. If ticks are seen these should be removed using a tick hook as swiftly as possible. Avoid covering them in petroleum jelly, burning them or spinning them round with an alcohol soaked swab. Annoying a tick risks it regurgitating its gut contents, which can cause it to pass on disease.