Abstract

Nearly 60% of China’s ex situ giant panda population is currently located in two facilities. The potential vulnerability of these concentrated groups to infectious diseases is of concern. As a first step to evaluate disease risks, a serologic survey of giant pandas was conducted, with a comparative assessment made for a red panda population maintained in the same facility. All serum samples for the survey came from the Chengdu Research Base for Giant Panda Breeding, which currently maintains 26 giant pandas and 35 red pandas. Serum samples from 19 giant pandas (total 44 samples; ages 3–18 y) were banked from 1998, 1999, 2000, 2001 and 2003, mostly during the breeding season (March–May). The eight red pandas (1–5 y of age) were sampled in 2003. At this facility, adult giant and red pandas were generally vaccinated with a product from China developed for domestic dogs that included attenuated distemper, parvo, rabies, herpes and parainfluenza viruses; since 2002, the vaccine also has contained coronavirus. Vaccination of cubs generally began after 1 y of age.

Serum samples were tested for antibody titers to canine distemper (CDV), adeno (CAV) and corona (CCV) viruses by serum neutralization assay; parvovirus (CPV-2) by hemagglutination inhibition assay; Toxoplasma gondii by indirect hemagglutination assay; Neospora caninum, Leptospira interrogans (serovars Pomona, Hardjo, Icterohaemorrhagiae/Copenhageni, Grippotyphosa, Canicola), and canine herpes (CHV) and canine parainfluenza (CPIV) viruses by indirect fluorescent antibody assay. All samples were negative for Leptospira, CPIV, CCV, CAV, CHV and Neospora. Positive titers to T. gondii ranged from 1:40 to 1:160; 57% of giant panda and all red panda samples were negative. All but 6 (13%) giant panda samples had significant titers to CDV, ranging from 1:16 to 1:2,560, with 50% in the range of 1:24 to 1:160. Six giant pandas with low titers are known to have been vaccinated within 2 months of at least two of the sampling dates. All red panda samples had titers (1:24 to 1:10,240) with the highest titers occurring in unvaccinated yearlings. Titers to CPV-2 were ≥1:20 in all but one sample (range 1:20 to 1:10,240), with 80% of giant panda and 75% of red panda samples ≥1:80. The high degree of variation in titers to CDV and CPV and the lack of vaccine response to CCV, CPIV and CHV suggest that alternative measures must be considered to more effectively protect giant and red pandas in China’s ex situ population against these agents of infectious disease.