A new study published in Infectious Disease Modelling examines the relationships between incidence, prevalence, and total infection burden for Lyme borreliosis (LB) using sentinel canine and human seroprevalence data.
The researchers developed two models to estimate LB cases. One analyzed seroprevalence of Borrelia infections in human samples, applying corrections for false negative and false positive results from published test sensitivity and specificity measures. The second modeled Borrelia infections in sentinel dogs to quantify the prevalence of LB infections in humans. For this model, the researchers referenced human and canine infections in Germany as a baseline.
Both models were conservative and referenced published data based on medical insurance records coded for erythema migrans. The researchers used linear model growth rates rather than the common exponential growth models. The mean of the two models was applied to create estimates for various countries and continents.
For the year 2018, examples from the analysis for estimated LB include: incidence – USA 473,000/year, Germany 471,000/year, France 434,000/year and UK 132,000/year; prevalence – USA 2.4 million, Germany 2.4 million, France 2.2 million and UK 667,000; total infections – USA 10.1 million, Germany 10.0 million, France 9.3 million and UK 2.8 million. World estimates for 2018 are: incidence 12.3 million/year; prevalence 62.1 million; and total infection burden 262.0 million (Cook & Puri 2020).
The researchers conclude that, “These figures are considerably higher than officially published data and reflect not only the underestimation of diagnosed cases, which is acknowledged by health agencies, but also undiagnosed and misdiagnosed cases.”