Underdiagnosis of dengue--Laredo, Texas, 1999

Dengue outbreaks have been reported in communities along the Mexico-U.S. border since 1980; however, during 1987-July 1999, no cases were reported from Laredo, Texas (1999 population: 162,000). During January-July 1999, approximately 300-325 dengue cases were reported from Nuevo Laredo, Tamaulipas, Mexico (1999 population: 274,000), a city across the Rio Grande from Laredo. To determine whether undiagnosed or unreported dengue cases had occurred in Laredo, the Texas Department of Health (TDH) reviewed medical records from five Laredo health facilities (the two city hospitals and the three largest of five community clinics). This report summarizes the findings of the review, which indicated that during July 23-August 20, 1999, 50% of suspected case-patients had undiagnosed dengue infection. Recognition of the diagnosis of dengue can be improved through heightened surveillance, professional and public education, and prompt reporting of cases by the health-care providers to local or state health departments.