Características epidemiológica e ambiental dos casos de dengue ocorridos nos anos de 2000 a 2010, em Araguaína -Tocantins.

Abstract

Dengue fever is an infectious disease caused by an RNA virus. Four serotypes have been identified: DEN-1, DEN-2, DEN-3 and DEN-4. The objective of the present study was to describe the epidemiological profile of dengue fever and its environmental characteristics in a historical series covering 11 years (2000- 2010). This is an observational, analytical, ecological study performed using secondary data obtained from the databases and reports of the Tocantins State Departments of Health and Agriculture. A total of 13,969 suspected cases were notified during the study period and 4,657 (33.3%) were confirmed. Of these, 63 (1.4%) were classified as severe. The highest incidence of dengue fever occurred in individuals of 20-40 years of age (44.1%), while the highest incidence of the severe form of the disease was found in children of 6-12 years of age (36.5%). Women were the most affected group (53.5%; p = 0.03). The vast majority of cases (98.1%) occurred in urban areas. The most common diagnostic criteria were based on epidemiological and clinical features (58.5%), while the severe cases of the disease were confirmed by laboratory tests. Of the confirmed cases of the disease, 99.8% had a favorable clinical course. One hundred and twelve samples were collected for isolation of the virus, with 10 cases testing positive (1 case of DEN-1, 2 cases of DEN-2 and 7 cases of DEN- 3). The greatest number of confirmed cases occurred in the years 2004 (n = 477; 10.2%), 2006 (n = 465; 10.1%), 2007 (n = 724; 15.7%) and 2008 (n = 1,398; 29.5%), comprising a total of 65.5% of all the cases registered in the period. The proportion of cases of classic dengue was higher between January and May (77.8%), while the severe forms of the disease were more common between the months of September and December (82.5%), when the rates of uninspected households were also highest. Between 2001 and 2010, statistically significant correlations were found between the occurrence of cases of dengue and the house index (p = 0.003; r = 0.76) and the rate of uninspected households (p = 0.0005; r = -0.84), while between 2000 and 2010 a correlation was found between the number of cases of dengue fever and mean monthly rainfall (p = 0.003; r = 0.76). No statistically significant correlation was found between the occurrence of cases of dengue fever and temperature (p = 0.5; r = -0.19). In conclusion, in Araguaína, the house index, the rate of uninspected households and monthly rainfall are factors associated with an increase in the occurrence of cases of dengue, highlighting the need to monitor indicators constantly and to develop multi-sectorial actions to improve control of the incidence of dengue in this municipality.