Wild great apes habituated to human presence for research or tourism are susceptible to human respiratory viruses (Köndgen et al. 2008&2010, Palacios et al. 2011). While viral infections pave the way for secondary bacterial infections, the bacterial infection rather than the virus itself determines disease severity and outcome (Chi et al. 2007). In all reported cases of great apes dying from respiratory disease with the involvement of a human respiratory virus, Streptococcus pneumoniae was also present in lung tissues. With secondary infections potentially playing a pivotal role in the progression of disease, it remains unclear whether the relevant bacteria occur naturally in wild great ape populations or also stem from humans entering great ape habitats. Previously found S. pneumoniae strains were shown to be distinct from known human strains (Chi et al. 2007), yet it remains possible that simultaneous transmission of viruses and bacteria occur. The objective of this study was to characterize S. pneumoniae found in the lungs of deceased wild great apes that died from respiratory disease and compare them to known human strains to determine whether transmission occurs.
Lung tissue of three wild great apes undergoing habituation was tested for common human respiratory pathogens. Respiratory syncytial virus (RSV) and S. pneumoniae were detected; phylogenetic analysis revealed that RSV clustered firmly within known human strains. S. pneumoniae was characterized by multi locus sequence typing (MLST) using virtual clones. The allelic profile identified was identical with known human strains. Our results suggest that not only human respiratory viruses but also bacteria are being transmitted from humans to wild habituated great apes. This provides important information for the improvement of measures aimed at preventing disease transmission during habituation to protect these endangered animals.