For their study, the CDC researchers looked at data from more than 17,600 laboratory-confirmed dengue cases for Puerto Rico from 1994 through 1999 and divided those patients into four age groups: infants (up to 23 months of age), youth (2 to 18 years old), adults (19 to 64 years old), and elderly (65 and older). The elderly persons were more likely than the youths and the adults to have been hospitalized, and only slightly less likely so than the infants. The same pattern was true for occurrences of a more severe form of dengue called dengue hemorrhagic fever (DHF): the elderly were more likely to have suffered DHF than either the youths or adults and only slightly less likely so than the infants. While the number of deaths was small among the dengue cases in Puerto Rico, a similar age pattern held: the death rate among the elderly was higher than among the youths and adults and statistically about the same as for the infants.
After being brought under control in many tropical areas of the world, dengue fever has been re-emerging over the last several decades, and some 2.5 to 3.0 billion persons now live in parts of the world where the disease is endemic. That increase in dengue is occurring at the same time that the proportion of the population that is elderly has been growing around the world. While deaths are generally uncommon from dengue, there is no vaccine available to prevent infection.
Among all of the confirmed dengue cases in the study, hemorrhages [discharge of blood from the blood vessels] were reported less frequently among the elderly patients on dengue case investigation forms that accompanied blood samples that clinics, hospitals, and laboratories sent to the CDC Dengue Branch for confirmation. Therefore, the researchers advise clinicians, "the clinical evaluation of elderly patients with suspected dengue must include a thorough clinical examination, in order to avoid complications that might result from delayed identification and treatment of severe dengue infection." The researchers encourage clinicians to check for mild hemorrhage, microhematuria [blood in the urine], occult blood in stools, and increased capillary permeability ["leakage" from the smallest blood vessels]. "If obvious bleeding is not evident, it should be sought," the researchers emphasized.
The article can be viewed for free in PAHO's On-line Bookstore Web site, at http://publications.paho.org. Additional information on dengue fever is available from the CDC Web site, at http://www.cdc.gov.
The "Revista Panamericana de Salud Pública/Pan American Journal of Public Health" is the main scientific and technical periodical published by PAHO and features research conducted in the Region of the Americas. PAHO, which also serves as the Regional Office for the Americas of the World Health Organization, was established in 1902. PAHO Member States include all 35 countries in the Americas. Puerto Rico is an Associate Member. France, the Kingdom of the Netherlands, and the United Kingdom of Great Britain and Northern Ireland are Participating States, and Portugal and Spain are Observer States.