Current status of Leishmaniosis in the Balearic Islands

Abstract

Data on leishmaniosis and its vectors (sand flies) in the Balearic Islands are scarce and restricted mainly to Majorca. According to the official data, the overall rate of human leishmaniosis (HL) is 0.7-3.5 cases per year/100,000 inhabitants (for the period 2001-2015), and the reported prevalence of canine leishmaniosis (CanL) varies between 0 and 45%, depending on the island and the dog population tested. In the present study, we investigated the sand fly fauna and current status of CanL in the Balearic Islands. Four sand fly species were captured: Phlebotomus perniciosus, a known vector in the Mediterranean area, P. sergenti, P. papatasi and Sergentomyia minuta. P. perniciosus was found throughout the island of Majorca, from sea level to the mountains, being detected in 70% of the capture sites and with a density of 6.7 specimens/m2. The global density of P. perniciosus in Minorca was of 3.4 specimens/m2, which constitutes a significant decrease compared to the results of a previous study performed 20 years ago. The influence of environmental factors on the presence or density of P. perniciosus differed according to the physiography of the area studied. A standard questionnaire sent to the local veterinarians in the Balearic Islands revealed that 73.8% of veterinarians had confirmed CanL cases in the previous 12 months and thought the disease was increasing in Minorca. The global seroprevalence of CanL in Minorca was 24%, being 31% among animals who had never left the island, which shows the existence of an autochthonous focus of CanL unrelated with an increasing vector density.