Vector-borne disease testing: Midwest
Beat the bite with leading-edge testing
In the Midwestern United States, warmer springs enable earlier emergence of the smallest disease-carrying creatures. Notably, ticks and mosquitoes flourish in the prairies and woodlands of the Midwest. The Ixodes scapularis, or the black-legged tick, is the most common disease-causing tick in the Midwest and can transmit multiple pathogens that cause several different illnesses, such as anaplasmosis, babesiosis, and Lyme disease. Importantly, given that babesiosis requires a different treatment regimen as compared to other tick-borne infections, it is imperative to accurately diagnose the various tick-borne pathogens.
Tick-borne illness
While Lyme disease and anaplasmosis are the most prevalent vector-borne illnesses in the Midwest, with both transmitted by Ixodes scapularis or the black-legged tick, other tick-borne infections have increased in prevalence as new species move into the area. For instance, the migration of the lone star tick, or Amblyomma americanum, into the Midwest has resulted in cases of spotted fever group Rickettsia, ehrlichiosis, tularemia, and alpha-gal syndrome. Clarifying which infection is affecting a patient through laboratory testing is the first step toward optimizing patient care.
Tick-borne disease testing
Mosquito-borne illness
West Nile virus, which is transmitted by Culex and other mosquito species, is the most prevalent mosquito-borne disease in the Midwest. With symptoms that include headache, body aches, vomiting, diarrhea, fatigue, and skin rash, West Nile infections can evolve to more serious neurological forms, including encephalitis or meningitis, if left untreated.
California serogroup viral infections, such as La Crosse virus, are transmitted by several mosquito species and were also reported in 2024. While most patients with La Crosse virus infections are asymptomatic, those who develop symptoms will present with fever, headache, nausea, fatigue, and vomiting; in a small number of patients, the disease can progress to encephalitis or meningoencephalitis.4 Although targeted antiviral medication is not available for these viruses, accurate diagnosis is essential to discontinue unnecessary antibiotics, allow physicians to provide prognostic information, and increase our understanding of the epidemiology of these pathogens.
Mosquito-borne diseases testing
References
- Lyme disease surveillance data. Lyme disease. U.S. Centers for Disease Control and Prevention. https://www.cdc.gov/lyme/data-research/facts-stats/surveillance-data-1.html. Page updated 2/11/25. Page accessed 5/14/25.
- Epidemiology and statistics. Anaplasmosis. U.S. Centers for Disease Control and Prevention. https://www.cdc.gov/anaplasmosis/hcp/statistics/. Page updated 3/3/25. Page accessed 5/14/25.
- Data and maps for West Nile. West Nile Virus. U.S. Centers for Disease Control and Prevention. https://www.cdc.gov/west-nile-virus/data-maps/index.html. Page updated 6/18/24. Page accessed 5/14/25.
- Clinical signs and symptoms of La Crosse virus disease. La Crosse virus. U.S. Centers for Disease Control and Prevention. https://www.cdc.gov/la-crosse-encephalitis/hcp/clinical-signs/index.html. Page updated 5/15/24. Page accessed 5/14/25.