The accepted message is that humankind has largely conquered infectious disease with a mixture of antibiotics and vaccines yet it is becoming clear that chronic hidden or latent infections (crypto-infections) lie behind many of today’s big killers, including heart disease, dementia and cancer. From his experience as one of France's — and the world's — leading ID specialists, Dr Perrone examines the threats that both Lyme in particular and crypto-infections in general pose and how we can rise to the challenge.