Congenital tick-borne relapsing fever: report of a case with transplacental transmission in the Islamic Republic of Iran.

Tick-borne relapsing fever (TBRF) is an arthropod-borne infection found in the Middle East, Africa, Europe and North America. The disease is caused by several species of Borrelia and transmitted by various species of soft ticks [1,2]. Specific relationships usually exist between Borrelia species, the vector ticks and the distribution area [3]. Ornithodoros tholozani is distributed in the Middle East and is known as the main vector and sole reservoir for B. persica, which is often responsible for old-world TBRF. Ticks of this species live in close proximity with humans host and feed for short periods, through a painless bite, often at night [4]. TBRF is endemic in the north-west of the Islamic Republic of Iran where clinical and epidemiological studies have been conducted [5,6]. It is more prevalent in children under 5 years and pregnant women. In infected pregnant women, transplacental transfer of the microorganism is possible, which leads to neonatal infection. Although the mothers may have nonspecific febrile illnesses, the infected infants may present with severe disease. Most of the previous studies concern children and adults, whereas no studies have been published on neonatal borreliosis in the Islamic Republic of Iran [6,7]. In this study, we report the clinical and laboratory results of a neonate infected with B. persica.