ABSTRACT
From July to December 1998, a hospital- and health center-based surveillance system for dengue was established at selected sites in Nicaragua to better define the epidemiology of this disease. Demographic and clinical information as well as clinical laboratory results were obtained, and virus isolation, reverse transcriptase-polymerase chain reaction, and serologic assays were performed. World Health Organization criteria were used to classify disease severity; however, a number of patients presented with signs of shock in the absence of thrombocytopenia or hemoconcentration. Therefore, a new category was designated as "dengue with signs associated with shock" (DSAS). Of 1,027 patients enrolled in the study, 614 (60%) were laboratory-confirmed as positive cases; of these, 268 (44%) were classified as dengue fever (DF); 267 (43%) as DF with hemorrhagic manifestations (DFHem); 40 (7%) as dengue hemorrhagic fever (DHF); 20 (3%) as dengue shock syndrome (DSS); and 17 (3%) as DSAS. Interestingly, secondary infection was not significantly correlated with DHF/DSS, in contrast to previous studies in Southeast Asia. DEN-3 was responsible for the majority of cases, with a minority due to DEN-2; both serotypes contributed to severe disease. As evidenced by the analysis of this epidemic, the epidemiology of dengue can differ according to geographic region and viral serotype.
Subject(s)
Dengue Virus/classification , Dengue/epidemiology , Disease Outbreaks , Adolescent , Child , Child, Preschool , Dengue/blood , Dengue/diagnosis , Dengue/virology , Dengue Virus/isolation & purification , Enzyme-Linked Immunosorbent Assay , Female , Humans , Infant , Male , Nicaragua/epidemiology , Reverse Transcriptase Polymerase Chain Reaction , Seasons , Severity of Illness IndexABSTRACT
Leishmania chagasi, the causative agent of visceral leishmaniasis (VL) in the Americas, has recently been associated with atypical cutaneous leishmaniasis (ACL) in Central America; however, little comprehensive information about this disease is available. Clinical, epidemiologic, and parasitologic characteristics of 252 ACL cases and 44 VL cases in Nicaragua were analyzed. Visceral leishmaniasis is primarily associated with malnourished children less than five years of age, whereas ACL is found predominantly in children greater than five years of age and young adults. Genetically similar parasites are associated with both disease manifestations. The sand fly Lutzomyia evansi, in addition to Lu. longipalpis, may be involved in transmission of L. chagasi to humans. Our results indicate that ACL is more prevalent than previously thought, affecting up to 10% of a local population. The fact that the same parasite appears to cause both ACL and the potentially fatal visceral disease suggests that the host immune response is critical in determining the outcome of L. chagasi infection. The public health implications of the wide-spread presence of L. chagasi are discussed.