Argentinians planning to travel to the northern part of the country, Brazil and Paraguay were lining up for vaccinations Tuesday, because of a yellow fever breakout that has killed at least 21 people in the region.

Paraguay experienced a sudden outbreak of yellow fever that didn’t plague the country for more than three decades.

Developing new strategies to prevent and control yellow fever and dengue fever has become more possible with the completion of the first draft of the genome sequence of Aedes aegypti mosquito by scientists led by Vishvanath Nene at The Institute for Genomic Research (TIGR) and David Severson at the University of Notre Dame. The genome is the complete set of genetic material including genes and other segments of DNA in an organism.

The effort to contain deadly yellow fever, recently resurgent in West Africa, received a boost today at the annual policy meeting of the United Nations health agency, with the launch of an immunization campaign backed by a $58 million contribution.