Purpose of review: Relapsing fever has the highest incidence of any bacterial disease in Africa and a massive epidemic potential due to current political turmoil in the Horn of Africa. This review focuses on recent advances in diagnostics, molecular biology and host-pathogen interactions.
Recent findings: Complete relapsing fever genomes have recently been published, and the first site-specific genetic knockout complementation has been performed. Relapsing fever has gone from being a neglected disease to garnering interest in aspects such as tissue invasion, membrane biochemistry and complement evasion. Relapsing fever symptoms are variable, and the disease is commonly misdiagnosed as, for example, malaria. Although relapsing fever is considered a transient disease, it persists as a residual infection in the brain, which can be reactivated on immunosuppression. Therefore, single-dose antibiotic treatment should be avoided. Instead, treatment should cover a longer period, similar to the recommended regime for Lyme disease. Relapsing fever is a common cause of pregnancy complications such as intrauterine growth retardation and placental damage with spirochaetes crossing the maternal-foetal barrier, resulting in congenital infection.
Summary: Although relapsing fever remains a big problem, recently described host-pathogen interactions, diagnostics and molecular biology advances such as completed genome sequences and the dawn of genetic tools have brought relapsing fever research into the 21st century.