That was all the time the team had, and they used every minute of it. They drew blood, implanted microchips, fitted radio collars and gave the injections. The team brought together field researchers from SPVS, a Brazilian wildlife research and environmental education society, and staff from Bio-Manguinhos, the vaccine unit of the Oswaldo Cruz Foundation, which made the dose. It uses the 17DD strain, descended from the vaccine that earned Max Theiler a Nobel Prize in 1951.
What Mangini remembers most is the moment afterwards. When the animals came round, they grabbed the branches and jumped back into the forest.
Science has known the black-faced lion tamarin, the mico-leão-caiçara, only since 1990. That year the biologists Maria Lúcia Lorini and Vanessa Guerra Persson described it after finding it on Superagui Island, off the coast of Paraná. It lives in the lowland restinga and swamp forests of the Atlantic Forest, and groups sleep together in tree hollows. It is one of four lion tamarin species, all found only in Brazil.
The other lion tamarins have captive populations that could restore them if wild groups collapsed. This species has none. A single disease outbreak could wipe it out, and people have already made the forest harder to live in. The Varadouro canal, dug in the 1950s, cut through the habitat and split the tamarins into separate populations in São Paulo and Paraná.
The danger is not hypothetical. Between 2016 and 2018, yellow fever swept through southeastern Brazil and killed thousands of brown howler monkeys. Golden lion tamarins in Rio de Janeiro state fell from about 3,700 in 2014 to about 2,500 in 2019. After that loss, the Associação Mico-Leão-Dourado worked with Fiocruz to vaccinate golden lion tamarins, and that project provided the model for the work on Superagui.
The programme now plans to vaccinate more groups and, in time, to set up a captive population as a safeguard. For now, three tamarins in the restinga carry radio collars and some protection against the virus.