Distribution of Trypanosoma cruzi discrete typing units in Bolivian migrants in Spain.

Chagas disease is caused by the protozoan Trypanosoma cruzi. This parasite is transmitted to humans mainly through the faeces of infected triatomine "kissing" bugs, by blood transfusions or organ donation from infected donors, and can be transmitted from mother to child. This disease is endemic in the Americas, where Bolivia has up to 28.8% prevalence in general population. Increased migration to Europe has made it emerge in countries where it was previously unknown, being Spain the second country in number of patients after the United States. T. cruzi is an organism with a rich genetic diversity, what has been grouped into six discrete typing units (DTUs). Some authors have linked these DTUs either to specific geographical distribution or to the different clinical presentations. Nevertheless little is known about its distribution in migrant populations. Our aim was to describe the T. cruzi strains isolated from a population of chronically infected Bolivian patients attending our clinic in Madrid. Thirty-three consecutive patients meeting this condition were selected for the study. Molecular characterization was performed by an algorithm that combines PCR of the intergenic region of the mini exon-gene, the 24Sα and 18S regions of rDNA and the variable region of the satellite DNA. A descriptive analysis was performed and associations between epidemiological/clinical data and the different DTUs were tested. Twenty-seven out of thirty-three patients had their DTU detected. Mean age was 36 years (IQR 31-43.3) and 23 were women (76.7%). The median time since arrival to Spain was 60 months (IQR 43-81). The most common DTU were TcV, TcIV and TcI. Four patients had cardiac involvement: 2 had TcV and 2 could not have their DTU determined. TcIII was not isolated from any patient. DTUs distribution in migrant population seems to be similar to that observed in the patients' countries of origin.