Sooner or later a person carrying the Ebola virus will arrive in Australia. She, or he, may not have come from Africa, or be aware of having touched or ingested bodily fluids of an Ebola victim, or even, at the time of entry have classic symptoms as likely to alert officials as the carrier. However it happens, it is likely that there will be fairly prompt recognition once symptoms are obvious, effective case-finding of most of the victim's contacts, and containment of any risk of an outbreak.
Australia's health and quarantine services, which have long feared the arrival of an epidemic from abroad, gather information about the detection and management of particular conditions, and have rehearsed responses, not only with Ebola, but with conditions such as SARS, bird flu and H1N1. Each of these, like Ebola, appear to have mutated from viruses present in animals into entities which affect humans. The animal, or bird, interface has a special significance in making it much more difficult for public health authorities to find all reservoirs of the virus.
It takes more than the mere existence of a virus in a human to present the risk of epidemic or pandemic. It must be able to spread, in infectious form, from person to person. In some cases (as with malaria but seemingly not with Ebola) that is via insects, spores or animals.
Generally, the virus will flourish only in the right conditions. Ebola seems to spread only by entry of bodily fluids, such as blood, body waste, or perhaps even sweat from a victim in his or her infectious stages, into another host, through mucous membranes of the body but most likely through the mouth . Some victims may have contracted Ebola by innocently putting a hand to his or her mouth after touching infectious material.
It seems the virus is not particularly infectious, but that its incubation and spread is potentiated by overcrowding, promiscuity, poor hygiene and facilities, high morbidity from other infectious conditions reducing immune responses and the propensity to travel.
Fatality rates are high, but if victims are innocently moving locations while not obviously infected, the disease can easily shift from being a slow-smouldering fire to one in which the number of victims increases exponentially. Of course almost all victims will have travelled short distances, only rarely within more than 100 kilometres from their homes. In this sense, the epidemic is only slowly spreading from where it most recently started. But bureaucrats, traders, aid workers, soldiers, diplomats, missionaries and others who travel in and out of such regions are not immune from risk.
The virus has shown that it can develop, and potentially spread, in other locales and conditions, eventually even threatening to break our quarantine lines. We could slightly reduce the risk to Australians by drastic action at the barrier – refusing the entry of everyone from West Africa, or Africa, for example. But such measures come at considerable cost, whether for enforcement at the barrier or in injustice to visitors and returning Australians, without any necessary improvement in protection. It is far from impossible that the first Australian victim will not have been anywhere near Africa.
Ebola, in its various forms, has so far been mostly a local African catastrophe, which has not directly threatened the western world. But, even if action has been slow, the risks are now being appreciated.
There is urgent international action focused at finding a vaccine and other forms of prophylaxis against the disease and its spread. As urgent, if not without risk to those involved, is international help for victims (many of whom will die), measures to protect others in their communities, to help restore some of the shattered infrastructure, to alleviate fear, panic and sometimes counter-productive government actions.
Australian assistance ought not be regarded as some international charity, as, perhaps after an earthquake far away. It is an act of world citizenship, as well as an investment in international public health and our own.
That said, active help by Australians on the ground, though welcome, is probably not nearly as important as helping to underwrite some of the costs to closer countries in a position to do it more effectively. Here is a case where aid dollars save lives.