wherever it has been looked for in Europe but not always in juxtaposition with suitably pathogenic bacteria. Because it is rare in Ireland, it is often not correctly diagnosed.
Examples of pathogenic tick passengers include
- Borrelia burgdorferi causes Lyme Disease, named for the village in Connecticut where it was first identified. Its range is limited to two hotspots New England-Delaware on the East Coast and Minnesota and Wisconsin in the Upper Midwest. Its incidence has been climbing steadily from about 10,000 cases in 1995 to 30,000 in more recent years. Lyme disease won't kill you (it has appeared on 100+ US death certificates over those 30 years but only in 25 cases as principal cause of mortality) but may make you feel crook for years. One of the issues is that your doctor may declare you cured but you know you ain't right and you weren't neurotic before you got bitten.
- Borrelia spp. including B. miyamotoi or B. parkeri cause Relapsing Fever, which all cause similar symptoms, rather different from those of Lyme Disease
- Rickettsia rickettsii which causes Rocky Mountain Spotted Fever which has experienced 4-5x a surge of cases (to about 2000 per year) since the turn of the century. That's bad news but fatalities have fallen from 25% to less than 1% with effective antibiotic treatment.
- Francisella tularensis will give you Tularemia [aka rabbit fever, deer fly fever, lawnmower's fever to suggest where you might catch it] which, in contrast to Lyme Disease and RMSF, has been falling off from about 900 cases in 1950 to 150 cases nowayears. Tularemia can be fatal if untreated but let's not get excited about that until antibiotic resistant strains of F. tularensis emerge.
- Viruses including Tick-borne meningoencephalitis virus; Colorado tick fever virus; Crimean-Congo hemorrhagic fever virus; Heartland virus. These viruses come from widely separated branches of the viral evolutionary tree; their only commonality being that they can be carried by ticks and cause pathology in humans.
- Protozoa. Main badboy here is Babesia microti or B.venetorum. They cause, !surprise!, Babesiosis aka Texas cattle fever, Nantucket fever or redwater fever. These names are informative, because the vector is likely to be Ixodes scapularis, the deer tick (which favours cattle too) and one of the symptoms is the release of haemoglobin breakdown products in the urine - redwater geddit. Babesia is a protozoan in the Phylum apicomplexa which also contains the causes of malaria Plasmodium spp, and the water-borne runs Cryptosporidium. Babesiosis also took a bit of a leap up in incidence, which doubled between 2012 (N=900) and 2013 (N=1800) the most recent years for which data is easily available.