The fact that Zika virus has reached Australia is a reminder that infectious disease is one of the major global challenges. The current ‘standby, wait, and watch’ attitude of the developed world is failing us, writes Peter Curson.
Having survived the human drama of SARS, Avian Flu, Swine Flu, and Ebola – are we now headed for another infectious disease disaster?
The Zika virus, rapidly spreading around the world and now detected in Australians returning from South America, may very well turn out to be our next health crisis.
The Department of Foreign Affairs and Trade has now issued a new advice warning to Australians, particularly pregnant women, to reconsider plans to travel to 22 countries affected by the virus.
Zika is a mosquito-borne flavivirus, closely related to dengue to which its symptoms are very similar. Like both the dengue and Chikungunya viruses, the disease is transmitted by aedes mosquitoes and results in rashes, fever, headaches and severe joint pain.
In the case of Zika only one in five of those infected will go on to develop symptoms but there is a possibility that the infection can produce microcephaly (abnormal smallness of the head) in newly born infants.
While the evidence is still not conclusive there is little doubt that the number of young children born with microcephaly has substantially increased in countries such as Brazil where over the last year Zika has spread widely.
Zika is named after a forest in Uganda where the disease was first isolated in a rhesus monkey in 1947. It was first found in humans in Nigeria in 1954.
Before 2013 only a handful of Zika cases had been recorded but during 2015 the disease spread rapidly, producing a number of significant outbreaks in the Pacific Islands, South America and South East Asia. Recently the infection has also been recorded in Puerto Rico, and cases are now beginning to appear in the USA and UK among travellers returning from Latin America.
The large-scale outbreak in Brazil, that seems to have commenced in 2015, has virologists linking the infection to the birth defect microcephaly for the first time. In parts of Latin America women are now being advised to postpone becoming pregnant for at least six months.
Like many infections, the disease accompanies international travellers around our world, particularly those who had spent time in Latin America or the Pacific Islands. This, allied to the fact that the aedes mosquitoes responsible for spreading dengue throughout the world are also widespread in parts of Australia, places us at risk. Also, like dengue, there is no cure for Zika and treatment simply focuses on relieving the symptoms.
It is still unclear as to why Zika, which until recently was relatively rare, seems to be spreading so quickly. Many believe that human mobility and intrusion into infected areas plays a critical role but some argue that increasing temperatures, changing the breeding pattern and distribution of mosquito populations, may also be to blame.
There is little doubt that we are living in a highly mobile world where millions of people move every day across international borders in pursuit of holidays, education and business – or fleeing from natural disasters or civil unrest.
In addition, more people are seeking to visit remote rural locations in Latin America and the Pacific, possibly exposing them to encounters with infected mosquitoes. It would also seem true that both increasing temperatures and a higher frequency of tropical downpours may well influence the number and distribution of aedes mosquitoes.
But are we witnessing the early stages of a ‘pandemic in progress’? If an epidemic of Zika was to break out in Australia, would it produce the same reaction and fear that we saw with SARS and Avian and Swine Flu?
Possibly not given that we have been living with dengue for well over 100 years. But on the other hand, the possible implications for mothers giving birth would most certainly engender considerable fear and apprehension.
There is little doubt that infectious disease is one of the major challenges facing our world today. Looking back on the last 15 years, have we learnt anything about the identification and control of infectious disease outbreaks? I very much doubt it.
Given our experience with dengue and other mosquito-borne infections we tend to be governed by the rubric: ‘If it kills us, then we do something about it. Whereas, if it just debilitates and incapacitates, we tend to live with it’.
If this was untrue we would have had a cure or vaccine for dengue decades ago. Presumably the same might apply to Zika. The ebola outbreak in West Africa also indicated how poorly we react and respond to epidemic crises. The ‘standby, wait, and watch’ attitude of the developed world seems to be based on a belief that epidemics in underdeveloped countries will eventually burn themselves out and that unless they directly threaten North America or Europe we do not need to react and respond.
We still do not have an international response and reaction agency charged with quickly identifying and responding to epidemics wherever they might occur in the world. With respect to infectious disease there is still much we have to do to ensure a safe and secure world.
By Peter Curson