# A critical perspective of prion disease surveillance in Brazil

## TL;DR

This study examines the challenges in tracking prion diseases in Brazil, highlighting issues with underreporting and data management.

## Contribution

The paper provides a critical analysis of Brazil's prion disease surveillance system and identifies key limitations in data collection and reporting.

## Key findings

- 1,576 suspected CJD cases were reported from 2005 to 2021, with a significant underreporting compared to expected numbers.
- Confirmed cases were mainly identified through laboratory and clinical-epidemiological criteria.
- The surveillance system lacks a specific database for CJD, leading to data inaccuracies and limitations.

## Abstract

Prion diseases (PrD) are a group of rapidly progressive dementias. Among its subtypes, Creutzfeldt-Jakob Disease (CJD) is the most common, affecting around 1–2 individuals per million inhabitants yearly. In 2005, Brazil’s Ministry of Health (MH) initiated a surveillance program for CJD, creating a protocol to report the cases. Despite advances, the MH still struggles to make a reliable database to determine PrD profile in Brazil. Therefore, the aim of the present study was to understand the Brazilian PrD surveillance system.

This is a retrospective and descriptive study based on the epidemiological records of CJD surveillance from 2005 to 2021 in the Ministry of Health’s Epidemiological Bulletin published in 2022.

1,576 suspected cases of CJD were reported, concentrated in the Southeast, South and Northeast regions of Brazil. Among the notifications, the following age groups predominated: 55–74 years (60.2%), 45–54 years (15%), and 75–85 years (11.8%). Suspected cases were mainly represented by women (53.6%), white individuals (61.4%), and residents of urban areas (90%). 547 cases (34.7%) were confirmed based on the following confirmation criteria: laboratory (65.6%), clinical-epidemiological (29.4%), and not informed (4.9%).

In this period, the expected number of cases for the Brazilian population would be 3,200. Additionally to underreporting, the data shared by MH is limited due to the use of a database destined to mainly observe epidemic outbreaks and mismatches between official documents. Despite some progress since 2005, PrD surveillance in Brazil faces significant problems, due to the inaccurate treatment of these data and the lack of a specific database for CJD.