Transactions of the Royal Society of Tropical Medicine and Hygiene (2007) 101, 169—175
available at www.sciencedirect.com
journal homepage: www.elsevierhealth.com/journals/trst
Clinical and epidemiological characteristics of yellow
fever in Brazil: analysis of reported cases 1998—2002
Suely Hiromi Tuboi
a,1
, Zouraide Guerra Antunes Costa
a
,
Pedro Fernando da Costa Vasconcelos
b,*
, Douglas Hatch
c
a
Secretaria de Vigilˆ ancia em Sa´ ude, Ministry of Health, Bras´ ılia, Distrito Federal, Brazil
b
Instituto Evandro Chagas, Department of Arbovirology, Ministry of Health, Bel´ em, Par´ a State, Brazil
c
Division of International Health, Epidemiology Program Office, Centers for Disease Control & Prevention, Atlanta, GA, USA
Received 9 January 2006; received in revised form 3 April 2006; accepted 3 April 2006
Available online 30 June 2006
KEYWORDS
Yellow fever;
Arbovirus;
Flavivirus;
Population
surveillance;
Brazil
Summary Yellow fever (YF), an arboviral infection of major public health importance in
Brazil, is associated with high mortality and high epidemic potential. We analysed confirmed YF
cases from the National Surveillance System from 1998—2002 and assessed risk factors for death
among hospitalised patients. Variables assessed included age, gender, clinical signs and labora-
tory findings. A logistic regression model was used to identify independent predictors of death
among hospitalised patients. From 1998—2002, among 2117 suspected YF cases reported to
Brazil’s Ministry of Health, 251 (11.9%) had confirmed YF, of whom 217 (86.5%) were hospitalised
and the case fatality rate was 44.2%. Factors associated with higher mortality in univariate anal-
ysis included male gender (relative risk (RR) 1.96, 95% CI 1.17—2.28), age >40 years (RR 2.61,
95% CI 1.25—5.45), jaundice (RR 2.66, 95% CI 2.12—3.35), serum aspartate aminotransferase
(AST) >1200 IU/l (RR 1.84, 95% CI 1.23—2.74), alanine aminotransferase >1500 IU/l (RR 2.09, 95%
CI 1.38—3.17), total bilirubin >7.0 mg/dl (RR 2.33, 95% CI 1.44—3.78), direct bilirubin >5.0 mg/dl
(RR 2.29, 95% CI 1.33—3.94) and blood urea nitrogen >100 mg/dl (RR 5.77, 95% CI 1.43—23.22).
In multivariate analysis, elevated AST and jaundice remained independently associated with
higher mortality. These findings suggest that selected clinical and laboratory indicators may
help clinicians recognise potentially fatal cases of YF.
© 2006 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights
reserved.
*
Corresponding author. Present address: Department of Arbovirology and Hemorrhagic Fevers, WHO Collaborating Center for Arbovirus
Reference & Research, Instituto Evandro Chagas/SVS/MS, Ave. Almirante Barroso, 492, 66093-020, Bel´ em, Par´ a State, Brazil.
Tel.: +55 91 3202 4609; fax: +55 91 3226 5262.
E-mail address: pedrovasconcelos@iec.pa.gov.br (P.F. da Costa Vasconcelos).
1
Present address: Infectious Diseases Epidemiology Research Unit, Graduate School of Public Health and School of Medicine, University
of Pittsburgh, Pittsburgh, PA, USA.
0035-9203/$ — see front matter © 2006 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.trstmh.2006.04.001