The proportion of recurrent tuberculosis (TB) cases caused by re-infection has varied widely in previous studies. The aim of the present study was to determine the relative frequency of relapse and exogenous re-infection in patients with second episodes of TB, using DNA fingerprinting.A population-based retrospective longitudinal descriptive study was conducted in Madrid (Spain) during 1992-2004. The study consisted of 645 patients with culture-confirmed TB. Of these, 20 (3.1%) were retained because they presented with a second isolate of Mycobacterium tuberculosis. Finally, 12 of these cases were excluded because they did not complete the full treatment prescribed. All strains were typed by restriction fragment length polymorphism analysis and some by mycobacterial interspersed repetitive unit-variable number of tandem repeats analysis. The patients with recurrent TB were compared with those without recurrent TB.For seven out of the eight patients, the restriction fragment length polymorphism patterns of the Mycobacterium tuberculosis strains from the episodes of recurrent disease showed identical initial and final genotypes, indicating relapse; the remaining recurrent case showed different genotypes, suggesting exogenous re-infection.Re-infection is possible among people in developed countries, but the rates are lower than those occurring in high-risk areas. The risk factors for recurrent tuberculosis should be taken into account in the follow-up of treatment and tuberculosis control strategies.

20 colonias de Apis mellifera L., se evaluó la eficacia de acaricidas sobre Varroa destructor. El experimento se realizó en diseño completamente al azar con cuatro tratamientos más un testigo sin aplicación y cuatro repeticiones. Los tratamientos evaluados fueron cumafós, amitraz, ácido oxálico y timol. En base a registros de infestación inicial y final de Varroa, se demostró que el cumafós y el timol, con eficacia de 94,85% y 84,68%, respectivamente, fueron los más eficaces, sin diferencias significativas entre ellos, pero sí con respecto al ácido oxálico y amitraz que resultaron menos eficaces con valores de 62,81% y 55,22%, respectivamente. Por otra parte, bajo el procedimiento del shock químico, cumafós y timol fueron los más eficaces con valores de 97,72% y 87,16%, respectivamente, sin diferencias significativas entre ellos, pero sí con el ácido oxálico y el amitraz que mostraron menor eficacia con valores de 68,12% y 58,12%, respectivamente. Ningún acaricida ensayado mostró impacto negativo sobre abejas adultas, crías y reserva alimenticia.

Tres tipos de colmenas relacionado a la crianza y el desarrollo biológico de reinas Apis mellifera Three types of hives related on queens rearing and biological development in Apis mellifera

Infestación, daño y enemigos naturales de Heteropsylla texana en algarrobo (Prosopis sp.) en Tongorrape (Motupe -Lambayeque)Infestation, damage and natural enemies of Heteropsylla texana on algarrobo (Prosopis sp.) in Tongorrape (Motupe-Lambayeque)Juan

Variación en la densidad de poblaciones de Apis mellifera L. en el cultivo de mandarinaVariation in population density of Apis mellifera L. on tangerine crop