Study of Dry Beriberi in Mayotte, Comoro Archipelago

Inclusion Criteria: * patients * Native to the Comoro Archipelago (Grande Comore, Mayotte, Anjouan, Mohéli) * Fulfilling the clinical definition of the dry beriberi. * Both sexes. * Older than 15 years and 3 months (limit of the paediatrics). * Having signed and whose legal representatives signed the form of assent, having understood the information. * Benefiting from a social coverage regime. * Controls * Native to the Comoro Archipelago. * People living in the same household as the patient, sharing the same meals. * Both sexes. * Older than 15 years old and 3 months. * Free from beriberi. * With normal neurological examination. * Having signed and whose legal representatives signed the form of assent, having understood the information. * Benefiting from a social coverage regime. Exclusion Criteria: * Aged under 15-year-old and 3 months. * For the patients and the witnesses, the presence of pathologies known to increase needs in vitamin B1 (cancer, infectious diseases, fever, hyperthyroïdism, chronic alcoholism).