Neonatal Borrelia infections (relapsing fever): report of 5 cases and review of the literature.

Tick borne relapsing fever is an endemic disease in Sengerema district, Mwanza region, Tanzania, East Africa. Five cases of neonatal relapsing fever occurring in this endemic area are described. Two neonates showed signs of septicaemia, clumping of spirochetes (Borrelia index is uncountable) in the thick blood smear and they died the day of admission. Two neonates showed severe spirochetaemia (Borrelia index: 3). The neonate treated with low dose penicillin died, the other neonate, treated with erythromycin, survived. One neonate had only a mild spirochetaemia (Borrelia index is 0.5) and responded well to penicillin treatment. Jaundice was seen in four of the five cases, three of them died. Only twenty cases of neonatal relapsing fever were previously reported. Findings are discussed in comparison with those of former reports on relapsing fever in the literature. Based on the fact that in a relatively short time (1 year), 5 cases of neonatal relapsing fever were diagnosed in an endemic area in East Africa, we conclude that neonatal relapsing fever is probably underdiagnosed.