Prevalence of Lyme borreliosis

Abstract

Sir—In their Seminar on Lyme borreliosis (Nov 15, p 1639),1Stanek G Strle F Lyme borreliosis.Lancet. 2003; 362: 1639-1647Summary Full Text Full Text PDF PubMed Scopus (381) Google Scholar Gerold Stanek and Franc Strle mention little about prevalence. This aspect of the disease has also been neglected in other recent papers.2Steere AC Lyme disease.N Engl J Med. 2001; 345: 115-125Crossref PubMed Scopus (1042) Google ScholarLyme borreliosis has a high incidence throughout the Northern hemisphere. One of the reasons for this high rate is its chronic nature: patients with specific and non-specific symptoms or rare syndromes3Kristof V Bozsik BP Szirtes M Simonyi J Lyme borreliosis and Raynaud's syndrome.Lancet. 1990; 335: 975-976Abstract PubMed Scopus (7) Google Scholar can remain undiagnosed for years or even decades. Treatment with antibiotics does not always result in eradication of the organism, therefore without follow-up and repeated treatment at recurrence, Lyme borreliosis chronica can develop.4Rowe PM Chronic Lyme disease: the debate goes on.Lancet. 2000; 355: 1436Summary Full Text Full Text PDF PubMed Scopus (10) Google Scholar, 5Chow CC Evans Jr, AS Noonan-Toly CM et al.LD trends—Dutchess County, New York, 1992-2000.Mt Sinai J Med. 2003; 70: 207-213PubMed Google ScholarLyme borreliosis is often undetectable by serological techniques. In our practice, the passive haemag glutination method (Diagast, France) failed to detect more than 60% of cases, compared with the newer ELISA (Enzygnost, Behring, Germany). The primary and secondary errors of this passive haemagglutination method were calculated as 1·9% and 6·3%, respectively, from 50000 investigations. The significant difference between these diagnostic techniques highlights the need to assess other factors, especially clinical symptoms, in the evaluation of results and formulation of the definitive diagnosis.The occurrence of Lyme borreliosis can be estimated from the reported incidence of tick-borne encephalitis (TBE) and the bacterial (1:10) and viral (1:1000) infectivity rate of ticks (http://www.tbe-info.com). The estimated incidence of TBE in Hungary (population 10 million) is 200–400 cases per year, and the infectivity rate of ticks is 100 times higher for Borrelia burgdorferi sensu lato than for the TBE virus. Thus there could be more than 20000 new cases of Lyme borreliosis per year in Hungary. Given the subclinical nature of the disease, the problems with diagnosis, misunderstanding about criteria and diagnosis, and the mean age of patients being 60 years, the number of patients affected at any one time could be as much as 1million—ie, 10% of the population. Sir—In their Seminar on Lyme borreliosis (Nov 15, p 1639),1Stanek G Strle F Lyme borreliosis.Lancet. 2003; 362: 1639-1647Summary Full Text Full Text PDF PubMed Scopus (381) Google Scholar Gerold Stanek and Franc Strle mention little about prevalence. This aspect of the disease has also been neglected in other recent papers.2Steere AC Lyme disease.N Engl J Med. 2001; 345: 115-125Crossref PubMed Scopus (1042) Google Scholar Lyme borreliosis has a high incidence throughout the Northern hemisphere. One of the reasons for this high rate is its chronic nature: patients with specific and non-specific symptoms or rare syndromes3Kristof V Bozsik BP Szirtes M Simonyi J Lyme borreliosis and Raynaud's syndrome.Lancet. 1990; 335: 975-976Abstract PubMed Scopus (7) Google Scholar can remain undiagnosed for years or even decades. Treatment with antibiotics does not always result in eradication of the organism, therefore without follow-up and repeated treatment at recurrence, Lyme borreliosis chronica can develop.4Rowe PM Chronic Lyme disease: the debate goes on.Lancet. 2000; 355: 1436Summary Full Text Full Text PDF PubMed Scopus (10) Google Scholar, 5Chow CC Evans Jr, AS Noonan-Toly CM et al.LD trends—Dutchess County, New York, 1992-2000.Mt Sinai J Med. 2003; 70: 207-213PubMed Google Scholar Lyme borreliosis is often undetectable by serological techniques. In our practice, the passive haemag glutination method (Diagast, France) failed to detect more than 60% of cases, compared with the newer ELISA (Enzygnost, Behring, Germany). The primary and secondary errors of this passive haemagglutination method were calculated as 1·9% and 6·3%, respectively, from 50000 investigations. The significant difference between these diagnostic techniques highlights the need to assess other factors, especially clinical symptoms, in the evaluation of results and formulation of the definitive diagnosis. The occurrence of Lyme borreliosis can be estimated from the reported incidence of tick-borne encephalitis (TBE) and the bacterial (1:10) and viral (1:1000) infectivity rate of ticks (http://www.tbe-info.com). The estimated incidence of TBE in Hungary (population 10 million) is 200–400 cases per year, and the infectivity rate of ticks is 100 times higher for Borrelia burgdorferi sensu lato than for the TBE virus. Thus there could be more than 20000 new cases of Lyme borreliosis per year in Hungary. Given the subclinical nature of the disease, the problems with diagnosis, misunderstanding about criteria and diagnosis, and the mean age of patients being 60 years, the number of patients affected at any one time could be as much as 1million—ie, 10% of the population.