The Lancet, Vol. 363, No. 9412, March 2004
Prevalence of Lyme borreliosis
Sir--In their Seminar on Lyme borreliosis (Nov 15, p 1639),1 Gerold Stanek and Franc Strle mention little about prevalence. This aspect of the disease has also been neglected in other recent papers.2
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 syndromes3 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.4,5
Lyme borreliosis is often undetectable by serological techniques. In our practice, the passive haemagglutination 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 1 million--ie, 10% of the population.
Bela P Bozsik
Lyme Borreliosis Foundation, H-1119 Budapest XI, Hungary (e-mail:bpbozsik@freestart.hu)
1 Stanek G, Strle F. Lyme borreliosis. Lancet 2003; 362: 1639-47.
2 Steere AC. Lyme disease . N Engl J Med 2001; 345: 115-25. [PubMed]
4 Rowe PM. Chronic Lyme disease: the debate goes on. Lancet 2000; 355: 1436.