Spatial-temporal patterns and risk factors for respiratory infection outbreaks among mountain gorillas of Volcanoes National park in 2016

Abstract

This study was done to determine spatial-temporal patterns, selected risk factors for viral pathogens influencing the incidence, morbidity and persistence of respiratory infection outbreaks among mountain gorillas of Volcanoes National Park in the period of January-December 2016. Spatial temporal patterns were obtained using geo-references data collected during routine health monitoring of twenty one groups of human habituated mountain gorillas. Further, ten saliva and twelve feacal samples were collected from symptomatic individuals for molecular-based detection of selected viral respiratory pathogens. Risk factors were determined through fieldbased observations particularly on age of affected individuals, intergroup social interactions, and identity of groups sharing home range, incidents of gorillas’ movement outside the park, morbidity and persistence of respiratory infections within gorilla groups. Retrospective data on climate patterns collected from 1st January to 31st December 2016 were obtained from Rwanda Meteorological Authority. Also one hundred twenty trackers were interviewed using a structured questionnaire to determine the potential role of selected public interfaces in transmission of respiratory infections. Similarly, annual data on the burden of respiratory infections in humans in areas where trackers live was collected from three health centers. Results revealed that five outbreaks occurred in the southern part of the park whereas three were observed within the northern sector of the park and the annual distribution was equal among the two half of the year with four outbreaks occurring in each. In addition, Human Adenovirus was detected in two of the outbreaks in the northern sector. Overall, morbidity was influenced by age (P = 0.013) and seasonality (P = 4.32 x 10-5). Surprisingly, symptoms of respiratory infections were not observed in 80% of the cases involving groups that had previous social contact and shared home range with infected ones. Further, results showed high diversity among social networks for trackers revealing that markets (social network density = 0.174) were the public interfaces that trackers shared most whereas religious venues (social network density = 0.014) were the public interfaces that trackers shared least. Generally, this study suggests that the incidence, persistence and morbidity due to respiratory infections could be influenced by a complex interaction of multiple factors. The conservation and public health implications of this study’s findings are discussed and further steps like characterizing the detected adenovirus are recommended.