EpiCorpus-BR: A Named Entity Recognition Corpus for Epidemiological Documents in Portuguese

Christian Freitas, Lilian Berton


Abstract
This paper presents EpiCorpus-BR, the first annotated corpus for Named Entity Recognition (NER) in Brazilian Portuguese epidemiological surveillance documents, covering the annual SIREVA-SUS reports (2013–2024) and complementary documents from the Brazilian Ministry of Health. The corpus comprises 8,314 textual units across 22 documents (6,358 narrative text sentences and 1,956 table rows), with 4,159 entity mentions in the silver set. The tagset consists of eight specialized categories (PATOGENO, SOROTIPO, FAIXA_ETARIA, LOCAL, PERIODO_TEMPORAL, METODO_LAB, METRICA_EPI, MANIFESTACAO_CLINICA), annotated via few-shot prompting with GPT-4o-mini and manually reviewed in a stratified sample of 280 units (180 text sentences and 100 table rows) by two independent annotators (κ = 0.76). Strict IOB2 evaluation with seqeval yields a combined micro-F1 of 0.77. METRICA_EPI is absent from narrative text but reaches F1 = 0.89 on table rows, which shows why the tabular sub-corpus must be included in the evaluation. A BERTimbau baseline fine-tuned on the silver corpus, with the gold held out, reaches micro-F1 = 0.73, showing that the corpus supports training a dedicated NER model. The corpus and code are publicly available.
Anthology ID:
2026.stil-1.13
Volume:
Proceedings of the 17th Brazilian Symposium in Information and Human Language Technology
Month:
October
Year:
2026
Address:
Cuiabá, Mato Grosso, Brazil
Editors:
Bryan Khelven da Silva Barbosa, Aline Paes, Ariani Di Felippo
Venue:
STIL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
150–162
Language:
URL:
https://aclanthology.org/2026.stil-1.13/
DOI:
10.5753/stil.2026.26614
Bibkey:
Cite (ACL):
Christian Freitas and Lilian Berton. 2026. EpiCorpus-BR: A Named Entity Recognition Corpus for Epidemiological Documents in Portuguese. In Proceedings of the 17th Brazilian Symposium in Information and Human Language Technology, pages 150–162, Cuiabá, Mato Grosso, Brazil. Association for Computational Linguistics.
Cite (Informal):
EpiCorpus-BR: A Named Entity Recognition Corpus for Epidemiological Documents in Portuguese (Freitas & Berton, STIL 2026)
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PDF:
https://aclanthology.org/2026.stil-1.13.pdf