rewarding stages of my professional career". Pereira then became interested in laboratory research. He married in 1946 and returned to Rio de Janeiro the following year, beginning work as a clinical pathologist at a government hospital. Pereira soon left this position to join a research team directed by J. Travassos at the Instituto Oswaldo Cruz, studying rickettsia as a part-time assistant. In contrast to his previous work in Rio de Janeiro, he described the environment as "highly stimulating". At the institute, Pereira helped demonstrate the presence of murine typhus and tick-transmitted Rocky Mountain spotted fever in the state of Rio de Janeiro. The team also developed new methods to study rickettsial antigen-antibody reactions. Later career Common Cold Unit Political interference at the institute frustrated Pereira, who moved back to Britain in 1951 to work at the Medical Research Council's Common Cold Unit at Harvard Hospital in Salisbury. He worked under Christopher Andrewes, head of bacteriology and virology at the National Institute for Medical Research. The team studied the issue of culturing the common cold virus in the laboratory, and Pereira was successful at the facility. He used equipment from the institute and its library, where he often met with other scientists in his field. During a 1953 study, Pereira propagated a common-cold virus in the laboratory for the first time. Unaware at the time of what he had achieved, he changed the direction of his work to adenoviruses. Pereira again did important work in this area, researching the reversal of the cytopathic effect of infected-cell extracts. When he was called an adenovirologist he often corrected the speaker, saying that he was an "adenovirologist type 5". Pereira spent several years working out the molecular structure of this icosahedral virus, including crystallising its subunits and producing images of the virus with electron microscopist Robin Valentine. In 1957, he became a naturalised British subject. His wife had been working at a Salisbury hospital in a division of the Public Health Laboratory Service. Pereira accepted a post in Andrewes' laboratory, and they moved their family back to Mill Hill. His wife moved to Virus Reference Laboratory of the Central Public Health Laboratory in Colindale. Pereira returned to Brazil in 1960 and worked at the University of Brazil, punctuating his stay with occasional visits to England. He had travelled to Italy to work with N. Nardelli and A. Rinaldi on avian influenza which was an