Anaplasmosis in the USA (Maine)

There were 411 cases of anaplasmosis   in Maine from January to September 2017. Case numbers have risen in recent years, from a total of 94 in 2013.

Anaplasmosis is caused by the bacterium Anaplasma phagocytophilum, part of the Rickettsia group of bacteria that cause Rocky Mountain spotted fever and typhus. The infection is transmitted by the same deer ticks that transmit Lyme disease, Ixodes scapularis in the eastern USA and Ixodes pacificus in the west.

While the disease is rarely fatal, it tends to be more severe in those who are elderly, immunosuppressed or have other health problems. Influenza-like symptoms are typical.

Doxycycline is the first line of treatment.

Prevention in Travellers

There is no vaccine against anaplasmosis.

Travellers should be aware of this infection, particularly if they are in rural parts of endemic countries. Ticks are more common from April to October.

At risk travellers should be advised to:

• Take precautions against tick bites including the use of insect repellents on the skin and insecticide impregnated clothes covering the skin as much as possible (long sleeves and long trousers tucked into socks).
• The skin should be inspected daily for ticks, ticks may brush onto clothing but keep crawling for hours to find suitable skin to feed on, particularly in the groin, axillae and behind the knees.
  • Any ticks seen should be removed as quickly as possible by grasping the tick as near to the skin surface as possible and applying gentle traction (without twisting).
• If an eschar or rash develops at the site of a tick bite, medical advice should be sought.