A health worker prepares a vaccine against measles at the Benito Juarez international airport in Mexico City

A health worker prepares a vaccine against measles at the Benito Juarez international airport in Mexico City July 22, 2011. Health officials started a vaccination campaign against measles after detecting the first case of the disease in four years, local media reported. An 18-months-old baby, who arrived on July 10 from France, showed symptoms of the disease and the neighbourhood where she lives in is under watch. REUTERS/Bernardo Montoya (MEXICO – Tags: HEALTH SOCIETY)