Cystic echinococcosis in Spain: current situation and relevance for other endemic areas in Europe

Abstract

Cystic echinococcosis (CE) remains an important health problem in many regions of the world, both where no control measures have been implemented, and where control programs have been incompletely successful with ensuing re-emergence of the disease. In Spain, official data on CE show an increase in the proportion of intermediate hosts with CE during the last few years, and autochthonous pediatric patients have been reported, a sign of active local transmission of disease. A similar picture emerges from data reported to the European Food Safety Authority by other European countries. Nevertheless, several crucial aspects related to CE that would help better understand and control the disease have not been tackled appropriately, in particular the emergence of infection in specific geographical areas. In this respect, while some data are missing, other data are conflicting because they come from different databases. We review the current situation of CE in Spain compared with areas in which similar problems in the CE field exist, and offer recommendations on how to overcome those limitations. Specifically, we believe that the introduction of national registries for CE with online data entry, following the example set by the European Registry for Alveolar Echinococcosis, would help streamline data collection on CE by eliminating the need for evaluating and integrating data from multiple regions, by avoiding duplication of data from patients who access several different health facilities over time, and by providing much needed clinical and epidemiological data that are currently accessible only to clinicians.

Figure 1. Epidemiology of Echinococcus granulosus in Spain.

The main domestic cycle is maintained between dogs and sheep, with man as accidental intermediate host (a; white arrows). Wild cycles could occur between wolves, wild boars, and cervids, among others (b). The sylvatic cycle could be occasionally peridomestic (black arrow), since the G1 genotype, the most frequent in sheep and human patients, has been found in isolates from wild animals.

Figure 2. Age distribution of cystic echinococcosis human cases reported in Spain in 2006.

Source: National Statistics Institute. Five autochthonous CE cases are found in the age range 5–14 years, indicating active transmission of the parasite. The rest of the cases are distributed as follows: 11 cases among 15- to 24-year-old patients, 19 among those aged 25–34, 36 among those aged 35–44, 46 among those aged 45–54, 40 among those aged 55–64, 54 among those aged 65–74, 27 among those aged 75–84, and five among patients aged 85 years old or more.