By the Numbers

Ticks

Over the past few decades, a tiny insect has added a level of fear to summer months. The fear is wellfounded: Many ticks carry a bacteria that causes Lyme disease, an infection that may last for months if the bite isn’t spotted early enough. In May, health authorities warned that rates of tick-borne illnesses—which have skyrocketed over the past decade—show no signs of abating.

50 percent

Estimated amount of adult female deer ticks carrying Lyme disease bacteria. About 20 percent of immature ticks are infected.

24 hours

Amount of time a tick can be attached to a host with a minimal risk of passing the Lyme pathogen.

7

Number of tick species in the U.S. known to bite humans. These include the blacklegged tick (the deer tick that spreads Lyme disease in the Northeast, midatlantic and North Central U.S.); brown dog (Gulf Coast); lone star; Rocky Mountain wood; and western blacklegged (which spreads Lyme disease on the Pacific Coast).

2

Average size of the rash that appears ɿve to seven days after a tick bite, signifying Lyme disease in about 0 percent of cases. 2ther symptoms: fatigue, chills and fever, headache, muscle and joint pain and swollen lymph nodes.

16

1umber of diseases that ticks carry. In addition to Lyme, these include anaplasmosis, ehrlichiosis (caused by the lone star tick, which can also trigger an allergic reaction to meat) and 5ocky Mountain spotted fever.

1 to 2 mm

Approximate size (about as big as a poppy seed) of immature deer ticks, or nymphs, which feed during spring and summer. Adults are longer, more like a sesame seed, and those ɿlled with blood can be 10 millimeters.

1975

Year that Lyme disease was first recognized in the U.S., after a large number of people in Lyme, Connecticut (thus, the name), developed unexplained arthritis.

300000 ,

Estimated number of people diagnosed with Lyme disease each year in the U.S. In 2015, it was the sixth most common nationally notifiable disease reported to government authorities.