While Lyme disease cases in Maine appear steady according to 5-year averages through September (1,039 cases YTD), another tick-borne disease has seen a dramatic increase in the past five years.

Image/ National Atlas of the United States
Image/ National Atlas of the United States

The bacteria infection, anaplasmosis has seen an increase in Maine from 94 cases reported in all of 2013 to 411 cases reported through September, according to Maine CDC statistics.

Transmitted by the same tick that transmits Lyme disease (in fact co-infections do happen), anaplasmosis is caused by Anaplasma phagocytophilum.

It is an intracellular pathogen that is part of the Rickettsia (the same group of bacteria that cause Rocky Mountainspotted fever amongst other diseases) family.

Formerly known as human granulocytic ehrlichiosis, and as the former name of the disease implies, it’s an infection of the white blood cells.

LISTEN: Tickborne diseases: Laboratory diagnosis and treatment

People get this infection through the bite of an infected tick. Depending on the part of the United States you are, the tick species is different: the eastern part of the country is the black-legged tick, Ixodes scapularis, and in the western part of the country, Ixodes pacificus, is usually involved. These are deer ticks that are also involved in the transmission of Lyme disease.

After a period of a couple of days to a few weeks, most people infected with Anaplasma show influenza- like symptoms(fever, malaise, headache, nausea, vomiting, diarrhea and respiratory symptoms such as a cough).Symptoms tend to be more severe in those that are immunosuppressed and the elderly.

The case fatality rate (i.e. the proportion of anaplasmosis patients that reportedly died as a result of infection) has remained low, at less than 1%.

Related: Lyme disease: 14 states classified as ‘high incidence’

Because A. phagocytophilum infects the white blood cells and circulates in the blood stream, this pathogen may pose a risk to be transmitted through blood transfusions. Anaplasma phagocytophilum has been shown to survive for more than a week in refrigerated blood.

Doxycycline is the first line treatment for adults and children of all ages and should be initiated immediately whenever anaplasmosis is suspected.