[Indicators of the effectiveness of epidemiological surveillance for acute flaccid paralysis in Brazil from 1990 through 2000].
OBJECTIVE
To describe and compare indicators of the quality of epidemiological surveillance for acute flaccid paralysis (AFP) before Brazil's certification as a poliomyelitis-free area (1990 through 1994) and after that certification (1995 through 2000).


METHODS
The following variables were studied: minimum prevalence (reporting annually at least 1 case of AFP per 100 000 individuals younger than 15 years), negative reporting (weekly reporting of the absence of AFP cases by at least 80% of the reporting units in each region), time of investigation (investigating at least 80% of the AFP cases within 48 hours of their being reported), and diagnostic investigation (collection of two stool samples for viral culture in the 2 weeks following the onset of paralysis in 80% or more of the AFP cases). The results were categorized as adequate if they were equal to or higher than the value considered as being effective, or as inadequate if they were below this value. The percentage rate of adequate values was calculated for each of Brazil's 27 federal political divisions (26 states plus the Federal District) in each year, for each of the two periods studied. The final means per period, per federal political division, and per region were also calculated.


RESULTS
For Brazil overall, minimum prevalence decreased from 1.3 per 100 000 individuals younger than 15 years in the precertification period to 0.9 per 100 000 in the postcertification period, but the difference was not statistically significant (P > 0.08). While negative reporting was adequate in both periods (87% and 84%, respectively), the percentage rate of effectiveness was 6.6% lower in the postcertification period (P > 0.21). The effectiveness in the time required to investigate AFP cases increased from 60.7% to 71.6% (P > 0.06). The collection of stool samples was inadequate both before and after certification (54% and 52%, respectively).


CONCLUSIONS
Despite the absence of indigenous wild virus poliomyelitis cases in Brazil in the postcertification period, the quality of epidemiological surveillance indicators is still less than desirable. This may delay the detection and investigation of AFP cases and compromise the global poliomyelitis eradication effort. New information strategies that are being made available for the health system in Brazil may improve the effectiveness of the national poliomyelitis control program.
Teixeira-Rocha
Eduardo Souza
ES
Universidade Federal da Bahia, Faculdade de Medicina, Salvador (BA), Brasil. duda.teixeira@uol.com.br
Tavares-Neto
José
J
D000208:Acute Disease; D000293:Adolescent; D001938:Brazil / Q000453:epidemiology; D002648:Child; D006801:Humans; D009123:Muscle Hypotonia; D010243:Paralysis / Q000453:epidemiology*; D011051:Poliomyelitis / Q000453:epidemiology*; D011159:Population Surveillance; D015995:Prevalence; D011786:Quality Control