A Nature analysis of 58,319 records for 32 diseases in 169 countries found that reported outbreaks tracked health-facility access more consistently than forest loss or warming. For the median disease, recording odds fell about a third per extra travel hour to care.
Researchers modeled travel time to the nearest health facility and built-up-land density to account for uneven surveillance. After that correction, modeled risk remained highest in forest-farm-settlement mosaics, especially for vector-borne diseases; long-term drying was repeatedly associated with dengue. Recent forest loss was significant in 6 of 29 disease systems where experts considered it plausible, and warming in 5 of 28.
Ecologist Jason Rohr disputed the scope of the conclusions: the study counted an outbreak as at least one reported case in a place during a year, he said, which measures detection rather than necessarily a spillover or outbreak. He also argued that comparisons among places can miss effects of forest clearing over time. The article notes that records for Ebola, Marburg, Nipah and MERS were too sparse for precise estimates; the findings do not rule out environmental drivers. Clinic access can also affect treatment and containment, not just reporting.
