Brote de poliomielitis en Haití y la Republica Dominicana debido a un virus derivado de la vacuna antipoliomielítica oral / Poliomyelitis outbreak caused by vaccine- derived virus in Haiti and the Dominican Republic

ABSTRACT

In October 2000,The ministries of health of the Dominican Republic and Haiti notified two cases of acute flaccid paralysis(AFP)in rural cases,one of them in a 9 year old female,respectively.Stool samples that were obtained from these cases,with ocured in July and August 2000,after a 9 year interruption of wild polivirus circulation in the western Hemisphere,revealed the presence of type 1 poliovirus.Genetic sequencing,wich was later performed at the centers for disease control and prevention,in Atlanta,Georgia,United States of America,revealed and atypical descendant of the virus used in the manufacture of the oral polio vaccine(OPV)but with 3 per cent genetic divergence with respect to the parent strain,Normally,viral isolates that derive from vaccine components show 99,5 per cent genetic agreement with the parent strain,in wild poliviruses,on the othe hand,this agreement is usually less tha 82,0 per cent.Thus,thw 3 per cent genetic divergence detected in this study suggests thar,in areas with low vaccine coveragemthe virus used in the vaccine remained in circulation for at least two years,during wich it recovered the neurovirulence and communicability of wild polivirus type 1.This report describes the characteristics and results of the active search for cases of AFP thar spaeked by the detection of the two indez cases.It also looks at the public health implications of this outbreak for the entire region of the Americas