Imported cases of malaria in Spain: observational study using nationally reported statistics and surveillance data, 2002–2015

Abstract

Background Malaria was eliminated in Spain in 1964. Since then, more than 10,000 cases of malaria have been reported, mostly in travellers and migrants, making it the most frequently imported disease into this country. In order to improve knowledge on imported malaria cases characteristics, the two main malaria data sources were assessed: the national surveillance system and the hospital discharge database (CMBD). Methods Observational study using prospectively gathered surveillance data and CMBD records between 2002 and 2015. The average number of hospitalizations per year was calculated to assess temporal patterns. Socio-demographic, clinical and travel background information were analysed. Bivariate and multivariable statistical methods were employed to evaluate hospitalization risk, fatal outcome, continent of infection and chemoprophylaxis failure and their association with different factors. Results A total of 9513 malaria hospital discharges and 7421 reported malaria cases were identified. The number of reported cases was below the number of hospitalizations during the whole study period, with a steady increase trend in both databases since 2008. Males aged 25–44 were the most represented in both data sources. Most frequent related co-diagnoses were anaemia (20.2%) and thrombocytopaenia (15.4%). The risks of fatal outcome increased with age and were associated with the parasite species ( Plasmodium falciparum ). The main place of infection was Africa (88.9%), particularly Equatorial Guinea (33.2%). Most reported cases were visiting friends and relatives (VFRs) and immigrants (70.2%). A significant increased likelihood of hospitalization was observed for children under 10 years (aOR:2.7; 95% CI 1.9–3.9), those infected by Plasmodium vivax (4.3; 95% CI 2.1–8.7) and travellers VFRs (1.4; 95% CI 1.1–1.7). Only 4% of cases reported a correct regime of chemoprophylaxis. Being male, over 15 years, VFRs, migrant and born in an endemic country were associated to increased risk of failure in preventive chemotherapy. Conclusions The joint analysis of two data sources allowed for better characterization of imported malaria profile in Spain. Despite the availability of highly effective preventive measures, the preventable burden from malaria is high in Spain. Pre-travel advice and appropriately delivered preventive messages needs to be improved, particularly in migrants and VFRs.

Spatiotemporal Distribution of Malaria in Spain in a Global Change Context

“…It would be interesting to analyse whether there have been changes in the national system of records or in administrative aspects that can explain these fluctuations. In this respect, a very recent study [23] shows that the compulsory reported disease records indicate some discrepancies with hospital records, as is the case in other countries. Moreover, it is important to consider that hospital records may be overvalued due to readmissions and/or erroneous classification in certain years [23].…”

“…In this respect, a very recent study [23] shows that the compulsory reported disease records indicate some discrepancies with hospital records, as is the case in other countries. Moreover, it is important to consider that hospital records may be overvalued due to readmissions and/or erroneous classification in certain years [23]. The global analysis of the evolution of the migration flows and economic tendencies, in both the period of increased national productivity for real estate development (1986)(1987)(1988)(1989)(1990)(1991)(1992) and the more recent economic crisis of 2008-2014, did not directly show any clear relationship that links migratory or touristic movements with endemic countries.…”

“…The data of imported malaria were taken from SSIbase [14], from the epidemiological bulletins of the Carlos the Third Institute and Spanish National Epidemiology Surveillance Network [21] and the Sistema Básico de Vigilancia Comunitat Valenciana [22]. Epidemiological data show small differences depending on whether records from the national surveillance system or the hospital discharge database are used [23]. Therefore, other complementary sources with historical data for the 20th and 21st centuries were also consulted [24][25][26].…”

“…The first cases were recorded in 1973, although this study only shows the cases from 1975. From that date, the number of cases recorded has made malaria the most frequently imported disease in Spain, mainly by travellers and migrants [23], among whom about 700 imported malaria cases are reported annually. Figure 2a represents the general tendencies of imported malaria from 1975 to 2018, and Figure 2b shows the specific disparity index of imported malaria for that period.…”

“…In Spain, imported malaria cases generally correspond to immigrants, immigrants who return to visit their friends and relatives and international travellers returning from endemic areas. These areas are mainly in sub-Saharan Africa, particularly Equatorial Guinea, a former Spanish colony [23,53,54]. Other countries, such as France, Italy and the United Kingdom, have also seen a greater number of imported malaria cases from former colonies with which they have historical and economic ties [55,56].…”