Leprosy in Mexico.

The time of the settlement of leprosy in Mexico is uncertain, however recent studies pointed out that leprosy was probably brought by Asian's migration at about 12,000 years ago and not by the Europeans conquerors during XVI and XVII centuries. Registration of leprosy has been done since the colonial era and the disease was considered as a public health problem until the year 2004 in Mexico when the incidence was achieved to be less than 1 per 10,000 as defined by the world health organization (WHO). Although the national epidemiological parameters like prevalence show the leprosy are controlled well, there are still 49 prefectures with higher prevalence in Mexico. In addition, the incidence in last 10 years has not been stably reduced, in other words the infection cycle has not been interrupted. Therefore, it is necessary to keep the careful epidemiological monitoring, and to increase the search and follow-up of new cases and their contacts in order to eliminate leprosy in this country.

Polymorphism in the rpoT gene in Mycobacterium leprae isolates obtained from Latin American countries and its possible correlation with the spread of leprosy.

The genotypes of Mycobacterium leprae isolates originating from Mexico, Peru and Paraguay were analysed for the polymorphism of short tandem repeats in the rpoT gene. The genotype with four copies of the six-base tandem repeats in the rpoT gene was prominently predominant in Mexico, but the genotype of all isolates from Peru and Paraguay contained three copies of the six-base tandem repeats. These obvious different distributions might reflect the spread of leprosy by the different strains of M. leprae harboured by the various human races that moved to the American continent, as has been demonstrated in other infectious diseases.