Emerging infectious diseases
I came across a report of an outbreak of Human Metapneumonia Virus, that was quickly ramping up to epidemic proportions in the population. The outbreak of hMPV will never reach pandemic proportions, because the population that is infected with the disease are the Mountain Gorillas of Rwanada, Uganda, and the Democratic Republic of Congo. Reserves in these 3 countries are home to the less than 800 gorillas that remain in the wild.
Habitat encroachment and poaching remain the two most significant dangers to the closely watched population, however the second most common cause of death in the gorillas besides trauma is infectious disease, which accounts for about 20% of sudden deaths. The Centers for Disease Control report noted 4 respiratory outbreaks among human-acclimated gorilla groups, between May and August 2008, with an additional outbreak in one of the same groups the following summer.
In the group observed during 2009, 11 out of the 12 animals exhibited moderate to severe respiratory disease. Several of them were treated via remote administration of antimicrobial therapy, however one of the adult females succumbed while under observation. Post-mortem analysis of the gorilla indicated significant immune cell infiltration into the respiratory system, consistent with the presumed etiology of the disease. Microbiological analysis confirmed the presence of Streptococcus pneumoniae, Klebsiella pneumoniae, as well as genetic sequences from the aforementioned Human Metapneumonia Virus. Both S. pneumonia and K. pneumonia (unrelated organisms!) are found on humans in the absence of disease, but are significant opportunists. hMPV is an extremely common innocuous virus in humans, with an inferred prevalence of very close to 100% in most populations. None of these agents are particularly harmful in immunocompetent individuals, however we have a very different situation in the simian population, with an immune system that is best adapted to deal with simian pathogens.
Molecular analysis of the hMPV sequences indicated they were very closely related to virus strains of South African origin, and that it was very unlikely that they came from the immediate caregivers in the gorilla preserves. The CDC report notes:
Although HMPV transmission as a result of human intervention to treat sick animals in the group is possible, it does not explain HMPV in the adult female, which died early in the outbreak before any clinical interventions were conducted. Although human proximity to mountain gorillas is essential for their conservation, also crucial is minimizing the risk for human-to–great ape transmission of respiratory pathogens.
The situation will continue to degrade, as the habitats shrink and human contact expands. I have no bonus opportunity to offer for us here, but appreciate any comments.