Many a mile comes plague

August ends with bad news. Twelve Greek municipalities - Farkadona, Trikala, Palamas, Tempe, Achaean and Thebes (central Greece); Evrotas and Andravida-Kyllini (Peloponnesus); Chalcis (Euboea); Marathon (Attica); and Lagada and Pylaia (Thessaloniki region) - have banned blood donations because of malaria.

Greece was declared free of malaria by the World Health Organization in 1974. From 1974 to 2010, an average of 39 cases per year - mainly imported - were reported. In 2016, 65 new cases of malaria had been detected. Most of them (50) concern immigrants coming from the Indian subcontinent or African states.  Eleven cases involve Greek citizens returning from malaria-affected countries. Yet there are alsofour domestic cases. Imported cases are not, per se, worrisome (e.g., the UK had 1,400 cases of malaria in 2015, all imported). Domestic cases, on the contrary, imply the actual presence of the malaria parasite in a given region. Greek and international newspapers commented that malaria's return – after 40 years -  is probably due to the fact that the Greek public authorities can no longer afford mosquito-spraying programs. In other words, malaria should be included among deleterious consequences of the crisis of the Euro zone. Some media also suggested that malaria have been probably brought over by the large influx of migrants who have entered the country in the last years. "Many a mile comes plague", to quote Shelley.

No doubts that poor economic conditions are likely to be one of the major causes of the reemerging of malaria infection in Greece. The suspension of mosquito-spraying programs is likely to have negatively impacted, together with an overall deterioration of public health and social wellbeing. It is also probable that the malaria parasite was reintroduced by immigrants (although genotypic data would be necessary to state it with certainty). There is, however, an important piece of information that most commentators omit to mention. 

Most municipal spraying schemes to combat mosquito-borne diseases have been cut back in early 2010 and current figures are not the worst on record. The Hellenic Center for Disease Control and Prevention reported 96 malaria cases (imported 54 -  domestic 42) in 2011; 93 (imported 73 -  domestic 20) in 2012; 25 (22 imported - domestic 3) in 2013; 38 (all imported) in 2014; 85 (79 imported –domestic 6) in 2015. Where is then the rationale of the current emergency? In case, a crisis should have been declared during 2011 outbreak. Instead one had to wait till 2016 (4 cases of domestic transmission against 42 in 2011) for seeing the health crisis officially declared and blood donations suspended in twelve districts. Rather bizarre, isn't it?

Would it be too mischievous to suspect that the malaria emergency is occurring now also because of the refugee political crisis? The health emergency caused by refugees is probably one of the cards played in the complex negotiation, directly involving the Greece borders, between the European Union and Turkey.

One of the main problems with risk communication in public health and, notably, in outbreaks is that politicians can hardly resist the temptation to use communicable diseases as political weapons, to blackmail other countries and internal political opponents.  To be sure, one is not morally authorized to call it "bioterrorism", nevertheless it would be worth inventing an appropriate word to stigmatize such a vile habit.

Crying Wolf

Olympic Games has started. After more than a week of competitions, Zika infection does not seem to be any longer a major concern for anyone. Yet still a few weeks ago, Zika seemed to threaten the existence of the Olympic Games themselves. Distinguished epidemiologists and public health experts were even suggesting to postpone or relocate the games and some athletes announced their will not to participate because of the risk of being infected.  Other athletes decided to freeze their sperm as a precautionary measure. The entire world was looking at the Olympic Games in Rio with trepidation and alarm. 

The pendulum started to swing towards June, when the World Health Organization, finally, realized that August is midwinter in Rio, that is to say, it is not the mosquito season. So, on June 14  the WHO declared "that there is a very low risk of further international spread of Zika virus as a result of the Olympic and Paralympic Games as Brazil will be hosting the Games during the Brazilian winter when the intensity of autochthonous transmission of arboviruses, such as dengue and Zika viruses, will be minimal and is intensifying vector-control measures in and around the venues for the Games which should further reduce the risk of transmission". This official statement did not revoke the alert but just downgraded the emergency crisis level. As a matter of fact, the WHO still recommended that " countries with travelers to and from the Olympic and Paralympic Games should ensure that those travelers are fully informed on the risks of Zika virus infection, the personal protective measures that should be taken to reduce those risks, and the action that they should take if they suspect they have been infected. Countries should also establish protocols for managing returning travelers with Zika virus infection based on WHO guidance". Were these recommendations truly necessary? Actually,  on June 9, the European Center for Disease Prevention and Control (ECDC) had already circulated an Olympics risk assessment   stating something different from WHO declaration.  According to the ECDC gastrointestinal infections were definitely  the first risk for travelers to the Olympic Games,  while risks related to Zika infection were considered almost negligible. ECDC's approach was confirmed by the US CDC  – on July 13 -  in  its own 2016 Olympic and Paralympic Game risk assessment,  which concluded that the worst-case scenario of Zika contagion would likely lead to a small number of cases, if any, in only 4 of the 206 participating countries and consequently "attendance at the Games does not pose a unique or substantive risk for mosquito-borne transmission of Zika virus in excess of that posed by non-Games travel".  

Finally, on July 26 -  only nine days before the opening of the games -  the Annals of Internal Medicine published a model that drastically rectified original catastrophic predictions. Considering, inter alia, that Rio is far from the epicenter of the Zika outbreak, the study argued that the 2016 Olympics definitely represented a low risk event for Zika infection, disease, and transmission. Authors wrote "Our calculation provides worst-case estimates of travel-associated Zika risk by assuming that visitors encounter the same infectious exposures as local residents. Under these pessimistic conditions, we estimate that an individual traveler's probability of acquiring infection in Rio de Janeiro ranges from 1 in 56 300 to 1 in 6200".  

Should we wait for the calculation provided by this new model?  Probably not.  Already on July 2015, the Lancet Infectious Diseases had published a study devoted to dengue transmission during the 2014 FIFA World Cup in Brazil. Dengue is a disease very close to Zika and it is transmitted by the same mosquito that transmits Zika. Brazil has one of the highest rates of dengue infection in the world and in July 2014 the Football World Cup was held in Rio. As today, the public health authorities were worried by the risk of an outbreak, yet of the million foreign tourists who went to Brazil for the sporting event, only three of them contracted dengue (and no one of them in Rio!).  It would have been enough to project this data on the current Zika outbreak, to understand that Zika risks were negligible.

Actually, extrapolating dengue 2014 FIFA World Cup data to Zika 2016 Olympic Games, the worst-case scenario is 3.2 Zika infections per 100,000 tourists, while the much more likely scenario  is 1.8 cases per million tourists. Indeed, on 10 May 2016, John McConnell, editor of the Lancet Infectious Diseases, wrote "unless new data emerge before August, we can say that compared with the risks usually associated with travel, such as gastrointestinal infections (on which we have written previously), traffic accidents, and falls, Zika virus represents a minimal threat to games visitors".  Should public authorities wait August 2016 for reaching the same conclusions? Couldn't they learn from dengue transmission? Is it ever possible that still in June 2016, the WHO seriously warned tourists who were about to travel to Brazil for the Olympic Games? 

Since SARS outbreak in 2003, scientists, public health authorities, and the media, have been systematically overestimating the risk of emerging epidemics. Zika and 2016 Olympic Games are just the last episode of an ongoing saga of risk assessment and communication errors. Given the recurrent nature of these episodes, it is likely that these errors are of systematic nature. It is more and more urgent to understand their origin in order to prevent them. Crying wolf is not only the worst way to communicate risks, but it also paves the way for catastrophic failures, once risks eventually materialize.

Information is not Communication

There it is! On August 5, the U.S. Food and Drug Administration issued a "Preliminary Finding of No Significant Impact (FONSI) In Support of an Investigational Field Trial of OX513A Aedes aegypti Mosquitoes".  In practice, this is the greenlight for releasing of genetically modified mosquitoes in a field trial in Florida Keys.  Genetically modified Aedes aegypti mosquitoes generate offspring that die if they are not exposed to the antibiotic tetracycline. It implies – according to researchers – that they will die outside a lab. The method aims to reduce radically mosquito populations that spread Zika and other viruses. According to the FDA  "the probability that the release of OX513A male mosquitoes would result in toxic or allergenic effects in humans or other animals is negligible based on the sponsor’s draft EA. Almost all of the OX513A mosquitoes released for the investigational field trial will be male, and male mosquitoes do not bite humans or other animals. They are therefore not expected to have any direct impacts on human or animal health". The release of GM mosquitoes is not expected immediately, various federal, state and local requirements are still to be met, including the final approval of the Florida Keys Mosquito Control District, yet the field trial is now in the final straight and it is just a matter of time till it starts.

Notwithstanding the massive information campaign carried out by public health authorities, the majority of residents is still objecting to the trial. According to a recent poll 58 percent of Key Haven residents oppose the project, and 168,000 people have signed an online petition against the test (admittedly most of them are not resident in the area).

What are the main reasons of public concerns? Opponents mention three main risks. First, they draw attention on a general risk, related to interventions which aim to alter complex ecosystems. They claim that it would be impossible to predict the potential impact of measures aiming at eradicating a species. This is a good argument, but it is too encompassing. Actually it could be used for any kind of attempt to fight Aedes aegypti mosquitoes and the sole possible answer to this argument would be to give up the fight against mosquitoes. The second argument is more specific.  Opponents argue that the method of separating males and females is not perfect and at least one in 10,000 GM mosquitoes (according to the figures provided by the company that produces GM Aedes aegypti) are female instead of male. Given that several hundred thousand mosquitoes have to be released, there is an actual risk that GM mosquitoes could bite human beings. Again, the argument would work if it did not take as granted that being bitten by a GM mosquito would be risky. Actually, such a risk is not supported either by any sound theoretical consideration, or by any experimental evidence. On the contrary, it has been proven that the genetically modified female mosquito bite is no different from that of a wild mosquito. Finally, opponents argue that – according to the producing company –  3 to 4 percent of the GM mosquito offspring would survive, and thus they are expected to disseminate the mutation, whose evolutionary impact is totally unpredictable. Still, this is a logic argument but is it strong enough to prevent a measure whose aim is to stop the outbreak of significant infectious diseases, such as Zika and Dengue?

There is  still another argument against the mosquito eradication strategy, which has not yet been used by  opponents but it is – at least to me – the most puzzling.  Evidences are accumulating that the passage through vectors contributes to mitigate the disease severity (virulence). If one eradicates today vectors, it is likely that – soon or later -  viruses will find new vectors, yet without benefiting any longer from existing attenuation mechanisms. Are we paving the way for  future, more severe, outbreaks?

As anyone could see, the scientific debate is anything but easy. Said so, it is also apparent that this debate did not penetrate into the public opinion, and changes are that the field trial will start with the majority of residents, at least the "active" majority of them, opposing the trial itself and thinking to be victim of a plan driven by multinational corporations. Oxitect, the British company, which produces  GM mosquitoes, carried out in 2012 a similar field trial in Brazil with the aim to prevent Dengue. Chance would have it that some initial Zika cases originated in the same area where GM mosquitoes were released,  therefore some people argued that GM mosquitoes were responsible for the emerging of  Zika. Indeed on February 2016, a poll conducted by the Annenberg Public Policy Center found that more than one-third of Americans believed Zika generated by GM mosquitoes. Oxitect was supported by the Bill and Melissa Gates Foundation, and the conspiracy theory went ahead by claiming  that Zika was purposely created within the wider scope of  an (alleged)  Bill Gates' depopulation agenda. The Florida field trial would thus close a circle initiated by the same companies and corporations that are now claiming to have the solution of the problem.

At the end of the story, disaffection towards science and technology will still grow. Would the prize be worth it? This is a difficult question. What is certain is that the gap between experts, policy makers, and the public opinion is  becoming wider instead of reducing. Once again, experts and policy makers confused information with communication, and  failed to make risk communication a true priority.