LIBERIA — Chimpanzees formerly used in hepatitis B vaccine experiments received health checks at the Second Chance Chimpanzee Refuge in central Liberia. The examinations provided medical attention to animals that spent decades in research facilities before retiring to the sanctuary.

The health examinations included dental cleaning, X-rays, pedicures, blood tests, fecal tests, ultrasounds, and assessments of the heart, lungs, nervous system, bones, muscles, and joint mobility. Veterinarians performed these comprehensive checks under anesthetic to ensure the safety of both the animals and the medical staff during the procedures.

Liliana Pacheco Ricote is the director of the Second Chance Chimpanzee Refuge. She noted the severity of the animals' past experiences. "They were used in very invasive research and went through a lot of experiments and pain," Ricote said.

Belen Perez Hernando is the veterinarian at the Second Chance Chimpanzee Refuge. She emphasized the importance of the current medical interventions for the group. "The health checks are a vital part of caring for these chimpanzees who have been through so much," Hernando said.

Ricote expressed satisfaction in providing improved living conditions for the survivors. "Seeing how much they hurt about what we’ve done, it gives me a lot of pleasure to give them this second chance to live with dignity the life that they deserve," Ricote said.

The average age of the chimpanzees is 30 to 35 years. These animals reside on a series of mangrove forest-covered islands at the sanctuary, where they live in a naturalistic environment away from laboratory settings.

More than 400 chimpanzees were used by American researchers in Liberia for hepatitis B vaccine experiments from the 1970s until the early 2000s. Many of the chimpanzees used in the research were captured from the wild as infants, removing them from their natural habitats at a young age.

Humane World for Animals assumed permanent responsibility for 60 chimpanzees remaining at the end of the research program in 2015. This transfer marked the conclusion of the experimental phase and the beginning of long-term sanctuary care for the surviving subjects.

Findings from the health assessments are not yet concluded. Plans are in place to carry out health checks on the remaining chimpanzees to ensure all residents receive similar medical evaluations.

Why It Matters

West African chimpanzees (Pan troglodytes verus) are classified as critically endangered by the IUCN Red List due to rapidly declining numbers. This conservation status shows the vulnerability of the species in the wild, where populations face threats from habitat loss and other pressures.

Liberia has the second-highest number of chimpanzees in West Africa, after Guinea. The presence of these former research subjects in a Liberian sanctuary connects local conservation efforts with the legacy of international biomedical research conducted in the region during the late twentieth century.