Rapid Risk Assessment: Louse-borne relapsing fever in the EU, 19 November 2015

Cases of louse-borne relapsing fever in migrants from countries of the Horn of Africa are not unexpected as the disease is present in north-eastern Africa, concludes a new rapid risk assessment. Five European countries have reported a total of 27 confirmed cases of LBRF diagnosed between July and October 2015 - Germany (15), Finland (1), Italy (8), the Netherlands (2) and Switzerland (1).

Most of the 27 cases are likely to have been exposed to body lice and become infected with LBRF in their country of origin or during their journey to Europe. However, two affected individuals have lived in Italy since 2011 and have not travelled to LBRF endemic regions. They are likely to have been infected while living in the same facility as newly arrived infected refugees, pointing to the possibility of locally acquired LBRF transmission.

Since 2014, there has been an increase of migrants arriving in the EU who either originate from or have travelled through LBRF-endemic areas, indicating that similar importation of cases and subsequent secondary transmission could occur. The risk of infection for relief workers caring for refugees is extremely low when appropriate hygiene measures, such as wearing gloves during medical examination, are taken.

The risk assessment highlights the importance considering LBRF as a differential diagnosis in refugees presenting with recurrent fever, particularly among those who have arrived via the East African and Central Mediterranean routes.

The rapid risk assessment also proposes several options for response to be considered including:

• When possible, prevent or minimise overcrowding in migrant reception centres, and promote and enable adequate hygiene for residents in those facilities.
• Raise awareness among migrants about lice infestation and possible louse-borne diseases.
• Raise awareness among clinicians of the possibility of louse-borne diseases among migrants.
• Check for signs of lice infestation during medical screening of migrants.

Refugees are vulnerable to body lice infestation because of the impoverished, overcrowded and unhygienic conditions under which many of them travel and live, both before and after entering the EU. Once in the EU, there is a risk of spread from infected individuals infested with body lice to other vulnerable population groups sharing the same living environment.

Louse-borne relapsing fever (LBRF) is caused by the spirochaete bacteria Borrelia recurrentis, a pathogen transmitted by the body louse Pediculus humanus humanus. Symptoms include high-grade fever, malaise, chills and sweats, headache, meningism, myalgia/arthralgia and non-specific gastrointestinal symptoms. The disease can be severe and death can occur in 10–40% of symptomatic cases in the absence of appropriate treatment, and in 2–5% of treated patients.