Epidemics in a Changing World - Department of Innovation, Industry ...

Mobility of humans, animals and food
Increased mobility of humans, animals and agricultural produce carries with it the risk of
exotic disease importation into Australia, and rapid worldwide spread of infection. Even
with border controls and quarantine requirements in place, infectious agents can still enter
Australia, for example in asymptomatic human or animal carriers.
EpidemICs in a Changing World
Report of the Expert Working Group
12
There are numerous examples of how increased mobility has led to the spread of infection, or
to the introduction of exotic diseases into Australia. One is the rapid spread of human influenza
viruses along travel routes, as seen in the current 2009 A(H1N1) epidemic. Another is equine
influenza: prior to 2007, Australia was one of only three countries worldwide considered free of
this disease 43 (Text Box 6).
Text Box 6: Equine influenza 2007
An example of the effect of globalised trade on animal epidemics
Globalisation with the resulting increase in the trade of animals and animal products
has increased the risk of spread of infectious diseases. For example, equine influenza
was introduced through the importation of thoroughbred stallions. This epidemic led to
the infection of nearly 80,000 horses across New South Wales and Queensland before
the disease was contained and eradicated. 44 This is the first time that any country
has been able to eradicate this disease. CSIRO, NSW DPI, QDPI&F, DAFF, AHA and
the AB CRC all played critical roles in the eradication program. Direct costs to the
Australian Government were approximately AU$ 350 million. However, indirect costs to
both industry sectors and government were also high. For example, the thoroughbred
industry estimated indirect costs to their industry of AU$ 1 billion. 45 Significant social
costs were also borne by all sectors of the horse industry. 46
A subsequent inquiry (the Callinan Inquiry) 47 found that the failure of existing processes
led to the introduction of the virus.
Dengue fever is another example of population movement being associated with disease
transmission. Increased potential for dengue transmission is associated both with increased
mobility due to more affordable jet travel, and with increasing rural to urban migration
(especially in Asia).
Since its re-emergence in 2003, the highly pathogenic avian influenza A(H5N1) (“bird flu”)
virus has caused devastating disease in domestic poultry, leading to the death from disease
or culling of hundreds of millions of ducks and chickens. The virus is known to have infected
more than 420 humans with about 60% mortality. Today highly pathogenic H5N1 is endemic in
poultry in some countries, notably Indonesia, and continues to cause serious human infections,
including at least 23 in Egypt in 2009 to date. Although migratory birds are thought to have
contributed, the most important factors in the spread of this virus throughout south east and
central Asia into Europe and Africa have been the mingling of birds in live bird markets and the
transport of infected poultry or poultry products. The dependence of many people in developing
countries on poultry for income and food, and the difficulties in controlling cross-border trade,
mean that there is currently little prospect of controlling the spread of this virus in large areas
of the world and it remains a significant pandemic threat.