Housed in one large enclosure, the monkeypox virus subsequently spread to several orangutans, chimpanzees, gorillas, guenons, squirrel monkeys, macaques, marmosets and gibbons.

In total, 11 of the 23 affected animals died, including six orangutans, the anteaters, three squirrel monkeys, the only one Asian gibbon and an American common marmoset.

[3][a] Ten days after the onset of sickness in the anteaters, two Asian orangutans that were housed in a glass cage nearby, developed small blisters.

[5] The disease spread to several other orangutans, who became unwell with yellow nasal discharge and lesions on their face, body and legs.

[5] Also affected, and all housed in one large enclosure, were chimpanzees, gorillas, guenons, squirrel monkeys, macaques, marmosets and gibbons.

[1] Affected animals typically had a generalised illness, some with skin lesions, and several died during early symptoms, before the spots appeared.

[5] In total, 11 of the 23 affected animals died, including in addition to the orangutans and anteaters, all three squirrel monkeys, the Asian gibbon and the severely ill American common marmoset.

[1] According to Isao Arita and Donald Henderson in 1976, how relevant that a strain of whitepox viruses, which resembled variola, were isolated from two cynomolgus monkeys at the National Institute for Public Health and the Environment three-months prior to the arrival of the anteaters was not clear.

[10] Six years after the outbreak, Gispen detected high levels of mpox neutralizing antibody in two of the surviving orangutans, and concluded that it lasts long after infection.