Every summer the concern about tick-borne diseases runs high. Lyme disease, which is carried by ticks, is quickly becoming a major public health concern.
To get a handle on where the areas of high risk were, the Bay Area Lyme Foundation in California partnered with Northern Arizona University and Colorado State University and hundreds of citizen scientists to track the number of ticks as well as the presence of ticks carrying bacteria that could cause illness. All over the country, observations were made and documented and the results showed that ticks carrying Lyme and other illnesses were showing up in 83 counties across the U.S. that had not seen these tiny yet dangerous arachnids before this year.
The study stands out from previous work in part because of the scale of the work. The study data was gathered from citizens scientists is 49 states and Puerto Rico and included more than 16,000 ticks. When the study began, investigators estimated they might be able to collect between 200—3000 ticks. The study was published in the journal PLOS One and shows the infiltration in many areas of the disease-carrying little buggers that had not been seen in these locations previously.
Lead author Nate Nieto is an associate professor in NAU’s Department of Biological Sciences. He explained, “The overwhelming study participation from residents throughout the country and the surprising number of counties impacted demonstrates that great interest and need exist throughout the country for this information. This study offers a unique and valuable perspective as it looks at the risk to humans that goes beyond the physician-reported infection rates and involves ticks that were found on or near people.”
Getting bit by a tick that carries Lyme disease is no small matter. It’s an infectious disease that results when a tick that’s been infected with a specific bacteria burrows under the skin of an animal or human host. The infection causes cognitive issues, fatigue, joint pain and fever. It is treated with antibiotics, but in some patients it can linger for months or even years causing potential disability. The latest data from the CDC, collected in 2015 reveals that there are more than 329,000 new cases of Lyme disease every year in the US. Those numbers are likely low because the symptoms are sometimes missed by healthcare professionals or misdiagnosed as influenza, viral illness or other conditions. Many patients don’t show the tell-tale bullseye rash from a Lyme-infected tick so they don’t think to ask for a Lyme test from their doctor.
The executive director of the Bay Area Lyme Foundation, Linda Giampa, stated, “Identifying geographic patterns of tick-human contact provides valuable insight that may help public health officials, patients and physicians become more vigilant about Lyme disease symptoms and increase early diagnosis. Based on these findings, it is critical that residents throughout the country take precautions and know the symptoms of tick-borne infections, even in areas where ticks have not previously been shown to cause disease.”
Ticks were collected by citizen science volunteers in every state except Alaska. They collected ticks January 2017 through August 2017 and sent them to researchers at NAU and Colorado State. The ticks were tested for four common strains of bacteria: Borrelia burgdorferi, which causes Lyme disease; Borrelia miyamotoi, which causes tick-borne relapsing fever; Anaplasma phagocytophilum, which causes human granulocytic anaplasmosis; and Babesia microti, the protozoan pathogen.
Two specific species of ticks are known for carrying Lyme disease. The isIxodes scapularis (deer tick) and Ixodes pacificus (Western black-legged tick) were discovered in the following 24 states: Alabama, Arizona, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Montana, Missouri, Nevada, North Carolina, Ohio, Oregon, South Carolina, Tennessee, Texas, Utah, Virginia, Washington and Wisconsin. These were areas that had not seen this kind of activity before. Part of that is that state health agencies don’t necessarily collect tick samples since Lyme disease has not been prevalent in the area. Without a history of tick-borne illnesses, some states and counties simply do not have reporting requirements or tracking programs.
It wasn’t just about Lyme disease either. Citizen scientists collected ticks carrying the parasite Babesia. It’s a microscopic invader carried by some ticks and it causes babesiosis, an illness that impacts red blood cells. It can destroy blood cells and cause flu-like symptoms, but in some populations like the elderly, those who don’t have a spleen or those with weakened immune systems are most at risk. Ticks carrying this parasite were found in 26 counties in ten states. While babesiosis is treatable, if it goes unnoticed, the destruction of red blood cells that it causes can lead to severe anemia or death. More information about the spread of tick-borne disease can be found in the video below, check it out.
Sources: CDC PLOS One Northern Arizona University