Why is wildlife health important?

Wildlife health and biosecurity is an important global issue (Daszak et al. 2000; Morner et al. 2002; Jones et al. 2008; The World Bank 2010). The risk of disease to, and arising from, wildlife continues to be of significant concern to environment, animal health and human health agen­cies, particularly the risk of EIDs (e.g.

Diseases originating from wildlife are a major source of emerging zoonotic diseases (Jones et al. 2008; Wool­house 2008; McFarlane et al. 2013). In some cases the dis­ease may affect both wildlife and humans (e.g. ABLV infection, angiostrongyliasis, tularaemia [see relevant chapters]), whereas some diseases have serious implica­tions for humans without any apparent effect on the wild animal carrying the disease (e.g. salmonellosis, leptospi­rosis, Q fever [see Chapter 16]) (Williamson et al. 1998).

Wildlife health is also important to the maintenance of environmental health and biodiversity. Wildlife dis­ease can contribute to the decline and extinction of vul­nerable, threatened and endangered species (Smith et al. 2006; Heard et al. 2013; Grogan et al. 2014; Peters et al. 2014; Hoyt et al. 2016; Preece et al. 2017). Some diseases may cause serious illness or death in free-ranging species (e.g. Tasmanian devil facial tumour disease, white-nose syndrome) or be more subtle, for example by affecting reproductive success (e.g. reproductive tract chlamydiosis in koalas [Phascolarctos cinereus]) (Blanshard and Bodley 2008; Ladds 2009; Klaassen et al. 2012; Cox-Witton and Iglesias 2017; see Chapter 35).

Disease in wildlife can also be an early indicator of changes in the environment, including the presence or increase of environmental contaminants, harmful algal blooms or overgrowth of toxic plant species (e.g. steroi­dal saponin toxicity and fluorosis in macropods [see Chapter 19]).

Disease agents with wildlife as part of their epidemiol­ogy, such as Brucella suis, and Hendra virus, can also affect domestic species, including production animals, as well as humans. These diseases may also impact upon trade and have economic consequences (Feare 2007; Nugent 2011; Wiethoelter et al. 2015; AHA 2021b). In some cases the disease of concern may affect both wildlife and domestic species, whereas in other cases wildlife may not be affected but the implications of spillover to domestic animals can be very serious (Williamson et al. 1998; Bunn and Woods 2005; Grillo 2014; Mor et al. 2016). This is primarily an issue around feral animals and exotic fauna, which are susceptible or act as reservoir hosts for important trade-sensitive diseases of livestock (e.g. foot-and-mouth disease, African swine fever, lumpy skin disease, rabies, screw-worm fly etc.). However, dis­ease in native wildlife can also affect trade and market access. For example, mass mortality and morbidity events involving large macropod species occur sporadically in Australia (Grillo et al. 2015a; Grillo et al. 2015b; Grillo et al. 2016). In some events, the geographic distribution of affected animals will span several states and territories. Disease investigations may reveal a primary diagnosis, but in some cases the disease event may be due to multiple factors. The response and investigation into macropod mortality events requires close collaboration between government field veterinarians, veterinary diagnostic laboratories and environmental officers, including those involved in macropod management, across the states and territories affected. In cases where animals are being found in areas used for commercial harvesting, govern­ment agencies may advise harvesters to cease activities until further information and investigation is under­taken. Though Australia’s kangaroo harvesting industry is relatively small, knowledge of the health status of wild populations is important for food safety and to maintain market access (Commonwealth of Australia and each of its states and territories 2007).

Several international standards, conventions and agreements recognise the importance of wildlife health, including those set by the WOAH and the WTO Agree­ment on Sanitary and Phytosanitary Measures. For exam­ple, the WOAH sets science-based standards and coordinates the flow of information regarding animal diseases of concern for international trade, and has a Wildlife Health Framework in recognition that manage­ment of wildlife health is important for safeguarding biodiversity and animal and public health.

Australia is a member of WOAH and a signatory to the WTO’s Agreement on Sanitary and Phytosanitary Meas­ures. Therefore, the implementation of adequate systems to determine Australia’s wildlife health status, and the ability to demonstrate freedom from specific diseases and manage wildlife disease, ensures Australia can fulfil its international obligations. For all of these reasons, wildlife health is an important issue both globally and for Aus­tralia (Bunn and Woods 2005).

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