Measles surveillance: El Salvador.
D000569:Americas; D002489:Central America; D003906:Developing Countries; D004194:Disease; D004544:El Salvador; D005069:Evaluation Studies as Topic; D007843:Latin America; D008457:Measles; D009656:North America; D014777:Virus Diseases
Americas; Central America; Developing Countries; Diseases; El Salvador; Evaluation; Latin America; Measles; Monitoring; North America; Viral Diseases