Tick-Borne Diseases

 

A single tick can transmit multiple infections at one time. The presence of multiple infections tends to further complicate diagnosis and treatments.

 

Lyme disease

Lyme disease is the most common tick-borne infection in the United States and one of the fastest growing infectious diseases in North America, with the highest prevalence in the northeast. Transmitted by the bite of a tick, Lyme disease is a bacterial infection caused by the spirochete (spiral shaped bacteria) Borrelia burgdorferi (Bb). Lyme disease can also be transmitted from an untreated mother to her unborn baby. The primary tick that transmits lyme disease (Borrelia burgdorferiI) is known as the black-legged tick Ixodes scapularis.

In a 2013-2014 New Hampshire study examining ticks collected during the fall and spring months more than 50% of adult blacklegged ticks collected in Belknap, Grafton, Hillsborough, Merrimack, Rockingham and Strafford Counties carried Bb. Not enough ticks were collected in Carroll, Cheshire, Coos or Sullivan Counties to reliably estimate infection rates. Sampling from this time period showed that the statewide infection prevalence rate of adult blacklegged ticks remained close to 60% for Bb. Maps for both of these testing events may be found at www.dhhs.nh.gov/dphs/cdcs/lyme/publications.htm.

Lyme disease begins with a bite of a tick, with 36-48 hours of black-legged tick attachment the disease can be transmitted. The transmission efficiency increases with the duration of the blood meal. Most humans are infected from the bits of the tiny nymphs late May through July. The first reaction that could occur (27-80% of the time) is a red circular rash called erythema migrans (EM). It usually appears three to 30 days after being bitten by an infected tick, and it slowly expands in size, then fades. Don’t confuse this red zone with the red spot that appears within hours where you’ve removed a biting tick. The Lyme disease rash is often ring-shaped and may be warm to the touch.In fact Bb, can spread throughout the bloodstream even without a rash, and even Bb DNA can be detected in spinal fluid. Early dissemination is characterized by a period of inflammation and flu-like symptoms, such as headache, stiff neck, mild fever or chills, swollen glands, muscle aches, and fatigue. B. burgdorferi enters the skin at the site of the tick bite. The infection may spread in lymph, producing regional adenopathy. From the site of entry the spirochetes spread to further distant tissues during the following weeks and months. Late stage damage potentially includes chronic or relapsing problems of the skin, joint, muscle, eye, heart, bladder, spleen, and gastrointestinal ailments are also present. By the time these more severe symptoms appear, the disease can be hidden in the body, difficult to diagnose, and much harder to treat. Later symptoms also imitate other illnesses and can be misdiagnosed.

Diagnosis recommendation by CDC: https://www.cdc.gov/lyme/diagnosistesting/labtest/twostep/index.html

Treatment is most successful in the early stages, and antibiotics (doxycycline preferred) are used. During late stage Lyme disease treatment options vary and CDC posts complications here: https://www.cdc.gov/lyme/postlds/index.html and this is also a pretty good reference. https://www.lymedisease.org/lyme-basics/lyme-disease/chronic-lyme/


Anaplasmosis is the most prevalent tick-borne disease worldwide because there are several species including Anaplasma phagocytophilum which infects humans. Anaplasma phagocytophilum is the causative agent for human granulocytotropic anaplasmosis formerly called HGE (human granulocytic ehrlichiosis). The number of reported cases has been rising for several years, with the highest incidence in people over 60. In 2010, the highest incidence was reported from Minnesota, Wisconsin, New York, New Jersey, Delaware, Connecticut, Rhode Island, Vermont, New Hampshire and Maine. From 2010 through 2014, 320 cases of Anaplasmosis were reported in New Hampshire. The number of cases increased each year.

In the eastern United States, blacklegged tick is the vector. Deer and wild rodents are thought to be the reservoirs for this disease.

People with anaplasmosis commonly report flu-like symptoms (headaches, chills, fever, muscle aches), with the onset of symptoms one to two weeks after being bitten. A. phagocytophilum is an obligate intracellular bacterium which primarily attacks neutrophil granulocytes but also eosinophils of different species, including dog, cat, cattle, sheep, goat, horse, deer, rodents and birds. Monocytes and lymphocytes act as secondary host cells.

“The diagnostic criteria for confirmed human granulocytic anaplasmosis are clinical signs and laboratory findings suggestive of granulocytic anaplasmosis together with

  1. detection of morulae within neutrophils (rarely eosinophils) on blood smears combined with a single positive reciprocal antibody titer to A. phagocytophilum (or a positive PCR result ),

  2. a 4-fold increase or decrease in the antibody titer within 4 weeks;

  3. a positive PCR test result using specific A. phagocytophilum primers

  4. isolation of A. phagocytophilum from blood.

These criteria can also be applied to dogs and other species, however, isolation is not used routinely for diagnosis.” From www.cvbd.org

Physicians treat the disease with antibiotics: doxycycline, rifampin, and levofloxacin are most effective.

Anaplasmosis


Babesiosis is a human disease caused by a protozoan (most commonly Babesia microti, although other species are known to cause disease) that attacks red blood cells.

Rhipicephalus sanguineus is the primary vector for Babesia in warmer regions worldwide, like in Southern Europe, Southern USA, Australia and Latin America. In Western and Central Europe, the main vectors for Babesia are Dermacentor ticks, esp. Dermacentor reticulatus. The blacklegged tick is the main vector in NH, and reservoir is primarily the white-footed mouse. Most human cases occur during summer, when blacklegged tick nymphs are active, but adults can also spread the disease.

Many people who are infected with Babesia do not have symptoms.The main pathogenesis associated with babesiosis is hemolytic anemia.

From 2010 to 2014, 107 cases of human babesiosis were reported in New Hampshire. The number of cases increased each year.

reference: https://extension.unh.edu/resources/files/Resource000528_Rep1451.pdf

Babesiosis


The lone star tick, Amblyomma americanum rarely turns up in New Hampshire. It is unclear whether the specimens that are encountered actually overwintered here, or if they “hitchhiked” from farther south. Its reported range reaches to coastal Connecticut and Rhode Island. The adult females are red-brown, with a prominent white dot.

The lone Star tick is the vector for Ehrlichia chaffeensis, the agent of human monocytic ehrlichiosis (HME), and Ehrlichia ewingii, which causes human and canine granulocytotropic ehrlichiosis. Lone star ticks cannot spread Lyme disease. There have been cases correlating lone star tick bites to a red-meat allergy called “alpha-gal”. Only 6/70 people were seen to have symptoms of a meat allergy where difficulty breathing and other allergic symptoms occurs uniquely 3-6 hours after meat consumption.

Reference: https://extension.unh.edu/resources/files/Resource000528_Rep1451.pdf

https://www.nih.gov/news-events/news-releases/niaid-scientists-link-cases-unexplained-anaphylaxis-red-meat-allergy

Lone Star Tick


There have been cases correlating lone star tick bites to a red-meat allergy called “alpha-gal”. Only 6/70 people were seen to have symptoms of a meat allergy where difficulty breathing and other allergic symptoms occurs uniquely 3-6 hours after meat consumption.

https://www.nih.gov/news-events/news-releases/niaid-scientists-link-cases-unexplained-anaphylaxis-red-meat-allergy

https://www.niaid.nih.gov/news-events/niaid-scientists-link-cases-unexplained-anaphylaxis-red-meat-allergy

https://www.ncbi.nlm.nih.gov/pubmed/29161766

Allergies from ticks