Murine typhus as the leading cause of non-focalized fever in the Canary Islands

Abstract

Purpose and methods: This prospective study aims to diagnose the etiology of non-focalized fever lasting between 5 and 28 days in the islands of La Palma and El Hierro (Canary Islands, Spain) during 2021, using serology and PCR. Results: The etiological profile described in this study aligns with that of fever of intermediate duration (FID), with zoonoses being the primary cause. Murine typhus (MT) is identified as the leading cause, followed by Q fever (QF). The incidence of MT is the highest reported nationally and comparable to the highest in Europe, with 39.6 cases per 100,000 inhabitants in La Palma and 79.7 cases per 100,000 inhabitants in El Hierro. Q fever, known to be endemic to the Canary Islands, presents incidences of 26.5 cases per 100,000 inhabitants in La Palma and 15.6 cases per 100,000 inhabitants in El Hierro. MT shows no gender differences and has a homogeneous geographical distribution. In contrast, QF is more prevalent in men and has a heterogeneous geographical distribution. Conclusions: The high incidence of MT found in both urban and peri-urban areas is particularly noteworthy. Its potential connection with climate change and/or the growth of the reservoir population in the Canary Islands remains unknown. MT's similarity to QF in terms of clinical signs and treatment, coupled with the absence of a specific protocol for early diagnosis, may have contributed to its underdiagnosis. MT can lead to significant health concerns, including risk of hospitalization, complications, and even death. Therefore, the registration of cases for epidemiological control is deemed essential.