Trends in the Epidemiology of Leishmaniasis in the City of Barcelona (1996-2019)

Abstract

Background: Leishmaniasis is a neglected zoonosis produced by 20 different flagellated parasites of the Leishmania genus, a protozoan transmitted to humans and other vertebrates by the bite of dipteran insects of the Phlebotominae subfamily. It is endemic in Mediterranean countries and the number of cases is expected to increase due to climate change and migration. Prioritizing public health interventions for prevention and control is essential. The objective was to characterize the epidemiology and temporal trends in the incidence of human leishmaniasis in the city of Barcelona, between the years 1996 and 2019. Methods: A population-based, analytical observational study among residents in the city of Barcelona was conducted of all the cases of leishmaniasis reported between 1996 and 2019 to the Public Health Agency. The epidemiological survey contains clinical, diagnostic, and epidemiological data, including contact with suspicious mammals or insects. Annual incidence-rates were calculated by sex, age, and country of origin. Chi-square tests were used to assess association between studied risk factors, periods of time and type of leishmaniasis. Results: During the study period a total of 177 cases of leishmaniasis were reported in Barcelona, being 74.6% (n = 132) of the total cases in Spanish born, although within the foreign-born population the incidence was higher. Median age was 34 years (IQR = 10-48) and 121 (66.8%) were male. The main type was cutaneous (46%) followed by visceral (35.1%). The cumulative incidence was 0.47 per 100,000 inhabitants, with the highest incidence found in 2017 (1.60 per 100,000 inhabitants). A higher incidence was observed in the 0-4-year-old group (1.73 per 100,000 inhabitants), but increased during the study period for all age groups. There was an increase of foreign origin cases, and a decrease in the number of cases associated to any immunosuppression. Conclusion: In Barcelona, leishmaniasis incidence continues to be higher in people under 5 years of age, and 25-64 years old males, but it has also increased in population from foreign country of birth. There is an increase of the cases since 2016, probably due to the changes in the notification system, increasing the diagnosis of cutaneous leishmaniasis. Improvements in the current surveillance system are needed. Notification of the disease, vector, and reservoir control activities are also essential for the control of the disease.

Keywords: One Health; Phlebotomus; infectious disease; leishmania; parasitology; public health surveillance; surveillance; zoonosis.