Health policies to control Chagas disease transmission in European countries.

Abstract

Chagas disease (CD) is a highly prevalent parasitic disease in immigrants from Mexico, as well as all of Central and South America. The total number of infected people is estimated between eight and ten million [1], [2], of whom 30%–40% either have, or will, develop cardiopathy, gastrointestinal disease, or both [1]. Cardiac involvement is the main cause of death from this infection through arrhythmias and cardiomyopathy. Nifurtimox and benznidazole are the only available medicines with proven efficacy against Trypanosoma cruzi infection in acute, congenital infection and early chronic infection. Until recently the treatment of chronic disease, particularly of adult patients with indeterminate form, was controversial; but during the past decade there has been a trend to offer treatment to adult patients and those with early cardiomyopathy [3]. To understand the magnitude of the problem, some economic studies have calculated the global cost of the disease worldwide at around 7,200,000,000 American dollars per year [4], which is mainly due to cardiovascular disease and early mortality. This cost is similar to, or even higher than, other prominent conditions such as rotavirus disease or cervical cancer [4]. In endemic countries, the main transmission route to humans is vectorial transmission through the faeces of infected triatomine bugs [1]. Oral transmission also occurs in endemic countries when beverages or food are contaminated with triatomine faeces [5]. Transmission through blood transfusion, organ transplantation from an infected donor, or from mother to child are less common routes, although they are of increasing importance, particularly in nonendemic areas where vectorial and oral transmission do not occur [1]. Another sporadic route of transmission is through the syringe sharing among drug users [6]. During the past decade, the infection has become a public health problem in some nonendemic countries, mainly due to migration and the chronic carriage of T. cruzi infection among a proportion of immigrants from endemic Latin American countries [7]. Since the first report of a case of CD in Europe was published in 1981 [8], sporadic cases have been detected in different European countries [9]. Since 2000, the number of reported cases has alarmingly increased, particularly in Spain and, to a lesser extent, in Italy and Switzerland [9]–[15]. In Europe, the currently estimated number of people with CD is between 68,000 and 122,000, but by 2009 only 4,290 had been diagnosed (index of underdiagnosis 93.9%–96.4%) [16]. The risk of transmission of T. cruzi infection in nonendemic countries through blood transfusion and organ transplantation has been described in multiple studies in the USA and more recently in Europe [17]–[21]. Moreover, several confirmed cases of T. cruzi transmission have already been detected in Europe [9], [22]. Accordingly, some studies have shown that it is cost-effective to screen for T. cruzi infection at blood banks, but depending on the prevalence of the disease, a mass screening of subjects—testing all—or a more selected strategy with screening questions to determine the risk level—screening and testing—should be applied [23]. Regarding congenital transmission, several studies have reported a rate of seroprevalence in Europe from 1.53% to 9.7% in pregnant women with the Bolivian population showing the highest seroprevalence rate [10], [24], [25], and with a transmission rate to newborn of around 7.3% [10]. Moreover, the strategy of screening pregnant women to control and treat newly diagnosed infected newborns has also shown to be cost-effective [26]. In response, several nongovernmental and later governmental initiatives have developed strategies to tackle this public health problem in the last years. The main aim of these initiatives has been to control the main transmission routes in nonendemic countries. Accordingly, some European countries have implemented national or regional measures to control transmission [27], [28], but many countries still have no legislation about it. In 2009, the World Health Organization (WHO) convened a WHO informal consultation (jointly organized by WHO headquarters and the WHO Regional Office for Europe) that performed a comprehensive review outlining this specific issue in Europe [29]. In collaboration with WHO, a research group working on migrant health, COHEMI, (COordinating resources to assess and improve HEalth status of MIgrants from Latin America) has undertaken this study aimed at reviewing the health policies implemented in European Union countries with the highest disease prevalence, plus Switzerland, to control the transmission of CD through blood transfusion, organ transplantation, and the congenital route.