The Yellow Fever Collection (YFC) is composed of 498 thousand cases (liver samples collected by viscerotomy between the thirties and the seventies). Each case is presented as a piece preserved in formaldehyde solution, paraffin block, and stained histological section(s) in slide(s). Additionally, the collection has a wide variety of written, printed and iconographed documents, which mainly include research protocols, case forms, histopathology reports, and pictures of people or sample collection sites. These documents are kept by Casa de Oswaldo Cruz (Oswaldo Cruz House).

Block cabinet (how the collection was originally stored).	Slide cabinet drawer.	Paraffin block detail (original storage manner and control number).	Slide cabinet detail.

The Yellow Fever Collection (YFC) corresponds to the collection created by the Histopathology Laboratory established in 1931, when the contract between the Brazilian government and Rockfeller Foundation had been renewed, and the North-Americans assumed responsibility for the anti-yellow fever campaign in almost the entire Brazilian territory by means of the Yellow Fever Cooperative Service.

Previous disease fighting campaigns were reformulated. Post mortem diagnosis, associated to retrospective diagnosis of survivors, began to grow. Innovations introduced by the Rockfeller Director, Fred Soper, such as viscerotomy and protection tests in mice, broadened the confirmation possibilities of Yellow Fever (YF) in Brazil.

In the Cooperative Service, a fragment of each viscerotomy was converted into a paraffin block, which then originated diagnosis slides. Thus, a unique collection started being formed, stored in the Histopathology Laboratory, in Manguinhos.

After the end of Rockfeller Foundation partnership in 1939, the Brazilian government continued the campaign and created the National Yellow Fever Service (SNFA) in the same facilities, in Manguinhos campus. In 1949, the entire collection of SNFA Yellow Fever Histopathology Laboratory was transferred to Oswaldo Cruz Institute (IOC). Due to a crisis affecting the Institute in the sixties and seventies, part of the collection (paraffin blocks and slides) was deteriorated or lost. On the other hand, all samples in formaldehyde solution were preserved.

In addition to the biological samples, there is also a wide variety of written, printed and iconographed documents, which mainly include research protocols, case forms, histopathology reports, and pictures of people or sample collection sites. These documents reflect the activities carried out for urban YF eradication in Brazil, which have been organised by the File and Document Department of Casa de Oswaldo Cruz (COC) – Fiocruz. These documents compose a rare and unique collection of inestimable value.

Due to its size, the collection will be distributed in two Fiocruz buildings. The samples (498 samples) are stored in Lauro Travassos Pavilion, under the responsibility of Instituto Oswaldo Cruz Pathology Laboratory, and the documents are stored in temperature and humidity controlled rooms, in the Expansion Building, under the responsibility of Casa de Oswaldo Cruz File and Document Department.