Nasty diseases like Ebola and SARS are not something one picks up in the good old USA, particularly at a national park, like, say, Yosemite. Well that would be wrong. Three visitors have died this summer from something called the hantavirus. Infectious disease specialists have localized the most likely cause to a rustic tent site in Curry Village, popular with visitors to the park. Hantavirus is transmitted through the aerosolization of infected rodent feces and urine. The mortality rate is about one in three. This is not good.
You may be saying this is all very interesting, but hardly the subject for a blog about climate change. Well that would be wrong too.
Concerning a link between hantavirus outbreaks and climate change, researcher B. Klempa came to this conclusion:
The early effects of global warming have already been observed in different geographical areas of Europe. Elevated average temperatures in West-Central Europe have been associated with more frequent Puumala hantavirus outbreaks, through high seed production (mast year) and high bank vole densities. On the other hand, warm winters in Scandinavia have led to a decline in vole populations as a result of the missing protective snow cover.
B. Klempa, Hantaviruses and climate change, Clin. Microbiol. Infect. 15(6):518-23 (June 2009). Jan Clement and his colleagues looked at the rising incidence of nephropathia epidemica (NE), an emerging hantavirus-caused illness, which “has become the most important cause of infectious acute renal failure in Belgium, with sharp increases in incidence occurring for more than a decade.” Clement’s team reported:
NE, a zoonosis scarcely known before 1990, has been increasing in incidence in Belgium with a cyclic pattern, to reach statistically higher and even epidemic proportions since 2005. NE is a rodent-borne infection, implying that it is at least partly climate-dependent. … A higher availability of staple food for the rodent reservoir Myodes glareolus, together with a higher autumn-winter survival of this rodent, explains the higher and cyclic NE occurrence in Belgium and in neighbouring countries, Germany in particular. … The fact that the growing combined effect of hotter summer and autumn seasons is matched by a growing epidemic trend of NE in recent years, can be considered as an effect of global warming.
J. Clement et al., Relating increasing hantavirus incidences to the changing climate: the mast connection, International Journal of Health Geographics 8:1 (2009).
At Yosemite, what has been happening to the population of deer mice ? It has been increasing. Traps set for mice following the hantavirus outbreak caught mice at a rate at least twice what had been recorded previously. And it is hardly news that California’s winters have been milder and summers hotter. Climate change is alleged to be the culprit. See, e.g., California ex rel Lockyer v. General Motors Corp., No. 06-CV-05755, Complaint ¶¶ 47, 55 (N.D. Cal. filed Sept. 20, 2006) (one of the first climate change liability cases) (attached below).
The jury is still out on whether California's recent weather would cause an increase in the population of deer mice or not. But as we have written previously, proving the causative role of climate change is not our point, others can do that. We focus on what one can do in the face of climate change. Whether the hantavirus outbreak is climate-change driven or not, increases in the range and incidence of infectious disease is a predicted outcome. Businesses need to prepare. The first thing of course is to recognize that the fundamental feature of climate change is just that: change. And change means that there is no reason to believe that what was satisfactory in the past will continue to be satisfactory. For example, one of the news stories on the hantavirus outbreak demonstrates this repeatedly. The article reports criticism of park employees for failing to warn visitors after the first few cases were noted. Guests continued to be checked into the suspect tents for over a week after the park service began deep cleaning the tents. The tent design, with a space between the inner and outer fabric, permits mice to enter that space. The National Park Service, and likely its concessionaire, will undoubtedly be revisiting their procedures and their equipment.
One can also envision claims for failure to warn, negligence and product liability by injured visitors or their estates. And certainly, even without any claims, business is down at Yosemite. The concessionaire would do well to investigate its liability, property and business interruption insurance policies, although it is certainly too late now to do anything about the terms of coverage. That is not so for others, however. One typical exclusion, for example, that will make coverage difficult for hantavirus claims (or any disease claims such as SARS, or swine flu, or dengue fever) is the Mold, Fungus and Organic Pathogen Exclusion. As its name suggests, insurers certainly will assert that injury arising from exposure to the hantavirus is excluded. But that argument could be eliminated if the insured had simply negotiated for a Fungus or Bacteria Exclusion, such as ISO’s CG 21 67 12 04. In any event, reading from a new perspective whatever exclusion is proffered can only help a company to manage its risks better.
Some will say that the chances of a hantavirus outbreak affecting one’s business are vanishingly small. We don’t dispute that. What is not vanishingly small is the fact of climate change and that its effects are not vanishing.
2006 California ex rel. Lockyer v. General Motors Complaint.pdf (36.16 kb)