Table 1.

Zoonoses of known public health significance likely to be affected by future climatic and land use changes

Disease	Reservoir host/vector	Pathogen	Main transmission route to humans	Annual global incidence (estimated cases)	Socioecological context and current trends	Potential sensitivity to climate and land change
Lassa fever	Rodent (single species)	Lassa arenavirus	Contact with rodent contaminated food and surfaces	100 000-300 000	Seasonally endemic in rural west Africa, where rodent reservoir host is common around fields and villages. Reported cases have steadily increased over past twodecades	Increasing rainfall and agricultural expansion across much of west Africa may expand suitable habitat for reservoir host. Future shifts in rainfall seasonality may affect reservoir host population cycles and seasonality of human risk
Leptospirosis	Rodents (numerous species)	Leptospira spp	Contact with rodent contaminated environment (water, soil)	~1 million	Found in rodents globally, but human exposures and burden are highest in poor communities in the tropics9 (eg, subsistence farms, informal urban areas). Flooding after extreme weather events can lead to large human outbreaks	Climate change is increasing the frequency and intensity of extreme weather events. Agricultural expansion and unplanned urbanization can increase both rodent-human contact and susceptibility to flooding
Lyme borreliosis	Wild vertebrates (numerous species), ticks	Borrelia burgdorferi spp	Tick bite	Unknown but ~30 000 in US alone	Maintained in forested areas across Palaearctic in complex, multispecies transmission cycles. Disease in humans arises through infectious tick bites. Reported incidence increasing	Forest degradation and fragmentation often favors more competent host communities, increasing hazard for humans.10 Geographic distributions of tick vectors are likely to shift as climates change
Zoonotic malaria	Primates, Anopheles mosquitoes	Plasmodium knowlesi	Mosquito bite	Unknown; seems to be increasing	Maintained among macaques and mosquitoes in forests of South East Asia. Spillover to humans occurs through infectious mosquito bites, in forests and around forest edges. Human incidence rising in recent decades	Ongoing rapid deforestation and forest fragmentation in South East Asia is increasing human exposure11
Rift Valley fever	Mosquitoes (several genera), ruminant livestock	Rift Valley fever phlebovirus	Mosquito bite, infected livestock body fluids	Variable; occurs in sporadic outbreaks	Maintained and transmitted by mosquitoes in Africa and Arabian peninsula. Periodic, explosive outbreaks occur in ruminant livestock (eg, cattle) and in humans through mosquito bites and contact with infectious livestock fluids (eg, through slaughtering)	Seasonal temperature and water availability shape mosquito populations and virus persistence.12 Future climate and land changes may affect hydrology, mosquito-virus interactions, and human/livestock exposure, which may increase the frequency, intensity, and geographic distribution of outbreaks
Ebola virus disease	Bat reservoir (species unknown), primate and duiker intermediate hosts	Zaire ebolavirus	Contact with infectious body fluids (wildlife or people)	Variable; occurs in sporadic outbreaks	Ebola reservoir not definitively identified but most likely bat populations in central and west Africa. Following initial spillover event(s), epidemics driven by extended human-to-human transmission chains, with high case fatality rates	Warmer and wetter climates in Africa, forest fragmentation and expansion of plantation ecosystems, may increase habitat suitability for reservoir hosts and facilitate human-bat contact13