Emerging Tickborne Diseases in New Hampshire

June 05, 2017

Key Points and Recommendations:

1. Blacklegged ticks transmit four different infections in New Hampshire (NH): Lyme, Anaplasma, Babesia, and Powassan. They may transmit other emerging infections.

2. NH has one of the highest rates of Lyme disease in the nation, and 50%-60% of blacklegged ticks sampled in NH have been found to be infected with Borrelia burgdorferi, the bacterium that causes Lyme disease.

3. Powassan was identified in two NH residents during past seasons: 2013 and 2016. While uncommon, Powassan can cause a debilitating neurological illness, so providers should maintain an index of suspicion for patients presenting with an unexplained meningoencephalitis.

  1. Testing for Powassan can be arranged through the NH Public Health Laboratories by calling the NH DPHS Bureau of Infectious Disease Control at the number below.

4. Providers should ask patients with suspected babesiosis whether they have donated blood or received a blood transfusion.

5. For any non-Lyme tickborne disease, providers should determine the most likely geographical area for exposure and report that information on the case report form, as this information will help define the location of tickborne disease in NH.

6. If testing for Lyme disease is negative, yet you still suspect a tickborne disease, consider testing for other pathogens, such as Borrelia miyamotoi.

7. Report all tickborne diseases, confirmed or suspected, to the NH DPHS Bureau of Infectious Disease Control at 603-271-4496 (after hours, 603-271-5300).


New Hampshire has evidence of local transmission of four tickborne diseases. Lyme disease (Borrelia burgdorferi), babesiosis (Babesia microti and other species), anaplasmosis (Anaplasma phagocytophilum), and Powassan virus are transmitted by the bite of the blacklegged tick (Ixodes scapularis), also known as the deer tick. Although the lifespan of this tick is two years, people are most likely to be infected between May and August when the aggressive nymph stage is active. Nymphs are very small (< 2 mm) and difficult to see unless they become engorged with blood. Household pets commonly bring ticks in from outdoors that can serve as a source of infection for their owners.

There are also other emerging tickborne diseases which have not yet been identified in NH, but should be considered in the appropriate setting:

1. Neighboring states have reported cases of Borrelia miyamotoi, which is also transmitted by the blacklegged tick.

2. Borrelia mayonii, which was identified as a disease-causing agent in 2013 in the Midwest, is also found in blacklegged ticks in upper Midwestern states.

3. Heartland virus has been identified in residents of Missouri and Tennessee, but one study demonstrated that NH deer and moose had serological evidence of Heartland virus infection. The vector for this in NH is currently unknown.


Lyme disease has been identified in all 10 New Hampshire counties and incident cases have been stable for the last five years. Anaplasmosis and babesiosis continue to increase across the state. Powassan virus is rare, with only two reported cases, one in 2013 and one in 2016. The last year for which complete data exists is 2015. Additional data, as well as our Tickborne Disease Bulletin, can be found on our website.

Table 1. Tickborne disease incidence in New Hampshire by year, 2011-2015

  2011 2012 2013 2014 2015
Lyme Disease 1321 1456 1691 1416* 1371*
Anaplasmosis 30 52 88 130 110
Babesiosis 14 19 22 40 53
Powassan Virus 0 0 1 0 0
*Due to staffing vacancies and elimination of positions, suspect cases of Lyme disease reported in 2014 and 2015 could not be confirmed. The number of cases in 2014 and 2015 was estimated based on the number of reports received and historical data.

Tick surveillance performed during 2013-2014 in NH counties showed that >50% of adult ticks tested in most counties were infected with the bacteria causing Lyme disease with the exception of Carroll, Cheshire, Coos and Sullivan counties, where very low numbers of ticks were collected, precluding prevalence assessment. Babesia and Anaplasma have been detected in ticks in NH, although reliable prevalence data for these pathogens in ticks is not available due to small sample size. Tick surveillance maps by county from 2013-2014 are available here. Borrelia miyamotoi was first identified in 1995 in ticks from Japan, and to date fewer than 60 human cases of have been documented in the United States. No cases have been identified in NH, but some have been identified in surrounding states. New Hampshire ticks have tested positive for B. miyamotoi. Borrelia mayonii is even less common, and from 2012-2014, six individuals tested positive in the upper Midwest of the United States as part of a retrospective serosurvey. Heartland virus has been diagnosed in only eight individuals in the U.S. in Missouri and Tennessee since March 2014. No cases have been identified in New Hampshire; however, deer and moose have demonstrated evidence of exposure to this virus. The full clinical spectrum and geographical distribution of these emerging infectious diseases are not well understood.

Tickborne Disease Symptoms

General: Many tickborne diseases present similarly with nonspecific symptoms that may include malaise, fever, chills, sweats, headache, stiff neck, muscle and joint pains, and lymphadenopathy. Some may also present with other systemic symptoms (neurological, cardiovascular, respiratory or gastrointestinal symptoms).

Powassan Virus: Powassan (POW) virus has an incubation period of 7-30 days following the bite of an infected tick. Although most infections are subclinical, symptoms may include fever, headache, vomiting, and generalized weakness that can progress to meningoencephalitis. About half of those that survive clinical disease have permanent neurological sequelae.

Borrelia miyamotoi: Symptoms of Borrelia miyamotoi include fever, chills, headache, body aches, joint pain, and fatigue. Rash is uncommon, occurring in about 8% of infected individuals.

Borrelia mayonii: Symptoms of early infection may include fever, headache, rash, and neck pain. Nausea and vomiting may also occur. Later stages of disease may cause arthritis-like symptoms.

Heartland Virus: Symptoms in the eight identified cases included fever, fatigue and thrombocytopenia. Some also experienced headaches, myalgia, diarrhea, anorexia and/or nausea. Most required hospitalization.

Tickborne Disease Diagnostic Testing:

For Lyme disease, anaplasmosis and babesiosis, use your already established testing networks. Powassan virus testing should be coordinated through New Hampshire's Public Health Laboratories. If you suspect another tickborne disease for which testing may be limited or not accessible, such as Borrelia miyamotoi or Heartland virus, please contact the Bureau of Infectious Disease Control at 603-271-4496 (after hours, 603-271-5300).

For testing information on Borrelia miyamotoi, please see attachment 1.

For tickborne disease treatment information, please see attachment 2 and attachment 3.

Reporting Tickborne Diseases

Clinicians should report suspected and confirmed cases of all tickborne diseases to the NH DPHS Bureau of Infectious Disease Control at 603-271-4496 (after hours, 603-271-5300). There is a specific Lyme disease case report form that should be used for reporting. Please record the date of symptom onset because this information is used to determine whether a case meets the CDC case definition for surveillance. When complete, please mail or fax to the number listed on the form. The form can be downloaded here.

Additional Resources

New Hampshire Tickborne Disease Page

Tickborne Diseases of the United States: A Reference Manual for Health Care Providers, Second Edition (CDC)

Tickborne Disease (CDC)

Powassan Virus (CDC)

Borrelia miyamotoi (CDC)

Borrelia mayonii (CDC)

Heartland Virus (CDC)

Heartland virus wildlife serosurvey article

Tickborne Disease Prevention

An individual's risk of tickborne disease depends on their outdoor activities and the abundance of infected ticks. All tickborne diseases are prevented the same way. There are options for personal protection through the use of appropriate clothing and repellents, as well as options for environmental management and control. The use of environmental management and control is successful in preventing tick encounters, thereby reducing the risk of tick bites. There are several resources available to educate your patients about how to reduce their risk of tick encounters and tick bites.

Prevention Messages for Patients:

  • Avoid tick-infested areas when possible and stay on the path when hiking to avoid brush.

  • Wear light-colored clothing that covers arms and legs so ticks can be more easily seen.

  • Tuck pants into socks before going into wooded or grassy areas.

  • Apply insect repellent (20%-30% DEET) to exposed skin. Other repellent options may be found here.

  • Outdoor workers in NH are at particular risk of tickborne diseases and they should be reminded about methods of prevention.

  • Perform daily tick checks to look for ticks on the body, especially warm places like behind the knees, the groin, and the back and neck.

  • Pets returning inside may also bring ticks with them. Performing tick checks and using tick preventatives on pets will minimize this occurrence.

  • Encourage landscape or environmental management to reduce tick habitat and encounters.

  • Shower soon after returning indoors to wash off any unattached ticks and check clothes for any ticks that might have been carried inside. Placing dry clothes in the dryer on high heat for ten minutes or one hour for wet or damp clothes effectively kills ticks.

  • Remove ticks promptly using tweezers. Tick removal within 36 hours of attachment can prevent Lyme disease, but transmission of other tick-borne diseases can occur with shorter periods of attachment time.

  • Monitor for signs and symptoms of tickborne diseases for 30 days after a tick bite. Patients should contact their healthcare provider if symptoms develop.

Additional background information about tickborne diseases and prevention can be found in the State of New Hampshire Tickborne Disease Prevention Plan.

The full text of this alert is available here.

For any questions regarding the contents of this message, please contact NH DHHS, DPHS,

Bureau of Infectious Disease Control at 603-271-4496 (after hours, 603-271-5300).


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: