Relapsing Fever Borreliae: A Global Review

Relapsing fever borreliae were notorious and feared infectious agents that earned their place in history through their devastating impact as causes of both epidemic and endemic infection. More recently they are considered more as an oddity and their burden of infection is largely overshadowed by other infections such as malaria, which presents in a similar clinical way. Despite this, they remain the most common bacterial infection in some developing countries. Transmitted by soft ticks or lice, these fascinating spirochaetes have evolved a myriad of mechanisms to survive within their diverse environments.

Refugee crisis and re-emergence of forgotten infections in Europe

Makeshift shelters are becoming increasingly evident in European cities as a consequence of the momentous influx of refugees seeking asylum in European countries. These individuals have endured long gruelling journeys to reach their target countries, often having to have survived appalling living conditions (figure 1a). One of the routes chosen by migrants is that from East Africa, through Sudan and Libya before reaching North Africa and eventually Europe (see figure 1b). Not unsurprisingly, this has led to the introduction of infectious diseases rarely encountered in developed nations, most notably louse-borne relapsing fever (LBRF).

A Case of Canine Borreliosis in Iran Caused by Borrelia persica

Tick-borne relapsing fever is an endemic disease in Iran, with most cases attributed to infection by B. persica, which is transmitted by Ornithodoros tholozani soft ticks. Here, we report spirochetemia in blood of a puppy residing in Tehran, Iran. The causative species was identified by use of highly discriminative IGS sequencing; the 489 bp IGS sequence obtained in our study showed 99% identity (100% coverage) when compared with Borrelia persica sequences derived from clinical cases or from Ornithodoros tholozani ticks. Our IGS sequence also showed 99% similarity over 414 bp (85% coverage) with a strain from a domestic dog, and 96% over 328 bp (69% coverage) with a strain from a domestic cat. Pet-keeping in cosmopolitan cities like Tehran has become increasingly popular in recent years. Animals are often transported into the city in cages or cardboard boxes that might also harbour minute tick larvae and/or early stages of the nymphs bringing them into the urban environment. This may pose a threat to household members who buy and keep these puppies and as a result may come into close contact with infected ticks.