Is There an Association between Dryland Salinity and Ross River Virus Disease in Southwestern Australia?

Abstract

Land use change has the potential to cause severe ecosystem degradation and drive changes in disease transmission and emergence. Broadscale clearing of native vegetation for agriculture in southwestern Australia has resulted in severe ecosystem degradation, which has been compounded by the subsequent development of large areas of dryland salinity. The mosquito-borne disease, Ross River virus (RRV), has been noted as a potential adverse human health outcome in these salinity affected regions. The association between dryland salinity and RRV disease was therefore tested by undertaking a spatial analysis of disease notification records using standard and Bayesian techniques. To overcome inherent limitations with notification data, serological RRV antibody prevalence was also investigated. Neither method revealed a significant association with dryland salinity, however, the spatial scale imposed limited the sensitivity of both studies. Thus, further multidisciplinary studies are required to overcome these limitations and advance understanding of this ecosystem health issue, particularly using variables that can be investigated on a finer scale.

Dryland Salinity and the Ecology of Ross River Virus: The Ecological Underpinnings of the Potential for Transmission

“…Our model of epizootics assumes RRV is introduced into sites, where local transmission occurs, briefly, and is followed by local extinction of the virus. This assumption is consistent with observations of human cases by Jardine et al (2008). Arboviruses can be transported by infected vectors (Kay and Farrow 2000) and hosts (Aaskov et al 1981, Kelly-Hope et al 2002, Lindsay et al 1993c, McBride 2008, Ryan et al 1997.…”

“…camptorhynchus, may also promote potential for RRV activity at other times of the year (i.e., summer). However, human notification data does not currently reflect the salinity-RRV potential (Jardine et al 2008). It is possible the examination by Jardine et al (2008) of a sparse human population over a large geographical area may be an inappropriate scale of spatial variability in RRV transmission.…”

“…camptorhynchus breeding (Biggs and Mottram 2008, Lindsay et al 2007. This is supported empirically by studies of mosquito larvae (Carver et al submitted), but not supported by human clinical notifications (Jardine et al 2008). The host-vector ecology of RRV transmission, in relation to salinity, has not been assessed.…”

Rehabilitation of degraded dryland ecosystems – review

“…Some of the relevant issues presented in the literature which could be used in a cost-benefit analysis include: the economic case for government intervention and the overall cost of dryland degradation (Kirby and Blyth 1987;Beresford 2001;Roberts and Pannell 2009;Graham et al 2010), spatial modelling and identification of dryland areas affected by salinization (Graham 1992;Ive et al 1992;Horwood 1994;Kirkby 1996;Furby et al 2010), farmers and community perceptions about the salinization problem and the proposed alternatives (Greiner 1997;Hartley et al 1998;Kington et al 2003;Khan et al 2008;Kingwell et al 2008); landscape or river basin management options (Greiner 1998;Callow 2011Callow , 2012, modelling of on-farm management alternatives and economic trade-offs (John et al 2005;Cheng et al 2009;Finlayson et al 2010;Graham et al 2010), reintroduction of native trees and shrubs (Schofield 1992;Dorrough and Moxham 2005;Thrall et al 2005), and the effects of dryland degradation on human health (Jardine et al 2007(Jardine et al , 2008a(Jardine et al , 2008b(Jardine et al , 2011Speldewinde et al 2009Speldewinde et al , 2011.…”

Is restoring an ecosystem good for your health?

“…rooted perennial vegetation results in a rise in the water table bringing dissolved salts to the surface). These changes have resulted in ecosystem disruptions (Jardine et al, 2007), such that the vector for RRV, Aedes camptorhynchus, becomes dominant in saline affected areasdue to other mosquito species which may compete with A. camptorhynchus and macroinvertebrate predators of A. camptorhynchus being unable to tolerate the saline conditions (Carver et al, 2009b(Carver et al, , 2010Jardine et al, 2008). Environmental remediation of saline lands is underway in Western Australia through a variety of means, including revegetation and deep drainage (a process where drains are constructed that pierce the watertable draining away saline water).…”