Tick-borne diseases, which afflict humans and other animals, are caused by infectious agents transmitted by tick bites. They are caused by infection with a variety of pathogens, including rickettsia and other types of bacteria, viruses, and protozoa. The economic impact of tick-borne diseases is considered to be substantial in humans, and tick-borne diseases are estimated to affect ~80 % of cattle worldwide.As of 2020  18 tick-borne pathogens have been identified in the United States according to the Centers for Disease Control and at least 27 are known globally. New tick-borne diseases have been discovered in the 21st century, due in part to the use of molecular assays and next-generation sequencing.The occurrence of ticks and tick-borne illnesses in humans is increasing. Tick populations are spreading into new areas, in part due to climate change. Tick populations are also affected by changes in the populations of their hosts (e.g. deer, cattle, mice, lizards) and those hosts predators (e.g. foxes). Diversity and availability of hosts and predators can be affected by deforestation and habitat fragmentation.Because individual ticks can harbor more than one disease-causing agent, patients can be infected with more than one pathogen at the same time, compounding the difficulty in diagnosis and treatment. As the incidence of tick-borne illnesses increases and the geographic areas in which they are found expand, health workers increasingly must be able to distinguish the diverse, and often overlapping, clinical presentations of these diseases. Prevention
Exposure
Ticks tend to be more active during warmer months, though this varies by geographic region and climate.
dammini), I. pacificus, I. ricinus (Europe), I. persulcatus (Asia))
Endemic to: The Americas and Eurasia
Symptoms: Fever, arthritis, neuroborreliosis, erythema migrans, cranial nerve palsy, carditis, fatigue, and influenza-like illness
Treatment: Antibiotics - amoxicillin in pregnant adults and children), (doxycycline in other adults
Relapsing fever (tick-borne relapsing fever, different from Lyme disease due to different Borrelia species and ticks)
Organisms: Borrelia species such as B. hermsii, B. parkeri, B. duttoni, B.  miyamotoi
Vector: Ornithodoros species
Regions : Primarily in Africa, Spain, Saudi Arabia, Asia in and certain areas of Canada and the western United States
Symptoms: Relapsing fever typically presents as recurring high fevers, flu-like symptoms, headaches, and muscular pain, with less common symptoms including rigors, joint pain, altered mentation, cough, sore throat, painful urination, and rash
Treatment: Antibiotics are the treatment for relapsing fever, with doxycycline, tetracycline, or erythromycin being the treatment of choice. Typhus Several diseases caused by Rickettsia bacteria (below)
Rocky Mountain spotted fever
Organism: Rickettsia rickettsii
Vector:  Wood tick (Dermacentor variabilis), D. andersoni
Region (US): East, Southwest
Vector: Amblyomma cajennense
Region (Brazil): São Paulo, Rio de Janeiro, Minas Gerais. Symptoms:Fever, headache, altered mental status, myalgia, and rash
Treatment: Antibiotic therapy, typically consisting of doxycycline or tetracycline
Helvetica spotted fever
Organism: Rickettsia helvetica
Region(R. helvetica): Confirmed common in ticks in Sweden, Switzerland, France, and Laos
Vector/region(s)#1: Ixodes ricinus is the main European vector. Symptoms: Most often small red spots, other symptoms are fever, muscle pain, headache and respiratory problems
Treatment: Broad-spectrum antibiotic therapy is needed, phenoxymethylpenicillin likely is sufficient.