Climate change has extended peak seasons for ticks in Ireland which brings increased risk of Lyme disease and other diseases, according to research published by The Irish Medical Journal.
Migratory patterns of birds enable ticks to transfer with ease from one region to another, while “global warming has precipitated the spread of ticks which host an increasing number of pathogens”, concludes infectious diseases consultant Prof Jack Lambert.
Ticks usually peak in Ireland during the spring and autumn, while they carry many different organisms, “not just Borrelia burgdorferi — the bacteria of Lyme disease”, he notes in the IMJ paper. While deer are known to host ticks, some carrying Lyme and other infectious agents, smaller animals and birds are also vessels for ticks.
Until there is better education for GPs and consultants in Ireland on the complexities of tick-borne infections, backed by better diagnostics and investment in research to improve understanding of these conditions, “patients will continue to be left undiagnosed and untreated”, he warns.
Diagnosis of Lyme disease is imperfect, he says — patients may experience a classic rash associated with the infection; migratory arthritis or Bell’s palsy, “but many may have atypical neurological, rheumatological or cardiological symptoms”. Equally, they may not entertain Lyme as a possible diagnosis, says Prof Lambert who is based at the Mater hospital, Dublin.
While there are parts of Ireland where Lyme is well recognised, nowhere is immune, he says. “Lyme disease does not just affect rural dwellers — dogs may bring home ticks and infect those living in urban settings also. Therefore Lyme disease will continue to be the ‘great imitator’. It is not easy to diagnose and not easy to treat.”
It was reported in one study that only 14 per cent of patients recalled a tick bite, only 50 per cent get “the classic bullseye rash”, and only about 50 per cent have a positive standard Lyme antibody test. “In some patients the infection does not clear, and it triggers a cascade of infection, inflammation and dysimmunity that may cause ongoing and long-term complications.”
He adds: “There is no current mechanism to test for co-infections; the only infection addressed in the UK and Ireland is Lyme disease. As ticks carry many pathogens, it is likely that other tick-borne infections are contributing to patients’ symptoms.”
Prevention and early recognition is the best way to thwart the consequences of chronic Lyme/co-infections, says Dr Lambert. “Educating the public on the importance of tick prevention, covering exposed body parts, using insect repellent, and checking for ticks upon return from the outdoors, are key messages that should be reinforced.”
As bacteria circulate in such small numbers, it is not possible, as a rule, to develop a PCR test or antigen test sensitive enough to detect replicating organisms. “Thus we are dependent on inadequate immunological tests … to measure the host immune systems response to an infection.”
People with suspected infections may consult with different specialists “but, without multisystem involvement, they may not entertain Lyme as a possible diagnosis. Treatment should be initiated immediately when a rash occurs following a tick bite, or indeed even in cases where the patient is symptomatic without a rash,” he advises.
While textbooks say Lyme disease is easy to diagnose and treat, and most patients are cured with short-course antibiotics, this is not always the case, adds Prof Lambert.
Spread of ticks
Global warming has precipitated spread of ticks which host an increasing number of pathogens. “The changes in our ecosystem are pushing us, as humans, into closer contact with ticks. Apart from Borrelia, multiple other bacteria are likely infecting humans, and the reported cases to public health authorities are likely to be grossly underestimated.”
Many patients are diagnosed with other conditions (chronic fatigue syndrome, ME, FND [functional neurological disorder], fibromyalgia, chronic headaches, etc) without Lyme disease being part of the differential, he says.
“We are increasingly learning more about ‘long covid’ because of the investment of research monies into this condition. Sadly, no research monies have been put into better understanding ‘long Lyme’,” says Prof Lambert.
On levels of Lyme disease in Ireland, the paper highlights only cases of neuroborreliosis are reported — a neurological disorder of the central nervous system and manifestation of the disease. “This represents only 10 cases annually although, the relevant health authority concedes there ‘may be’ up to 200 cases per year, which conflicts with modelling that estimates 2,500 annual infections,” says Prof Lambert.
