Saturday, July 14, 2018

A long fuse: 'The Population Bomb' is still ticking 50 years after its publication



File 20180709 122271 1ubedx.jpg?ixlib=rb 1.1
Slums like this one in Rio de Janeiro embody the problems Paul Ehrlich warned of in ‘The Population Bomb.’ dany13, CC BY

“The battle to feed all of humanity is over,” Stanford biologist and ecologist Paul Erhlich declared on the first page of his 1968 best-seller, “The Population Bomb.” Because the “stork had passed the plow,” he predicted, “hundreds of millions of people are going to starve to death.”

Ehrlich’s book identified dramatically accelerating world population growth as the central underlying cause of myriad problems, from a food crisis in India to the Vietnam War to smog and urban riots in the United States. It sold more than 2 million copies and went through 20 reprints by 1971. Ehrlich appeared more than 20 times on NBC’s “The Tonight Show Starring Johnny Carson”, and became the first president of Zero Population Growth, a Washington D.C.–based advocacy organization, while remaining a professor at Stanford.

“The Population Bomb” created more space to hold radical views on population matters, but its impact was fleeting, and maybe even harmful to the population movement. By the early 1970s, many critics were savaging Ehrlich and the larger goal of achieving zero population growth. And the politics of “morning in America” in the 1980s successfully marginalized Erhlich as a doomsdayer.
However, as a historian who has studied debates about population growth throughout U.S. history, I believe that Ehrlich’s warnings deserve a new and less hysterical hearing. While Ehrlich has acknowledged significant errors, he was correct that lowering birth rates was – and remains – a crucial plank in addressing global environmental crises.

Paul Ehrlich in 2010. Paul R. Ehrlich, CC BY

A Malthusian warning

Ehrlich drew on nearly 200 years of thinking inspired by British pastor and political economist Robert Thomas Malthus. In his 1798 study, “An Essay on the Principle of Population,” Malthus famously predicted that “geometric” population growth would overwhelm “arithmetic” gains in agricultural production, leading to wars, famines and societal collapse.

Fears of the potentially dangerous social and ecological effects of population growth intensified after World War II. Global population surged as public health improved greatly in developing nations, increasing life expectancy. At the same time, the new science of ecology demonstrated the fragility of Earth’s interconnected systems. And the Cold War promoted worries that population-induced poverty would breed communism.

Mainstream advocates of arresting population growth emphasized better access to family planning and education, but Ehrlich had no use for such baby steps. “Well-spaced children will starve, vaporize in thermonuclear war, or die of plague just as well as unplanned children,” he wrote.

It took 200,000 years for Earth’s human population to reach 1 billion – and only 200 years to reach 7 billion. But growth has begun slowing as fertility rates decline.

Technological optimists pointed to the “Green Revolution” in agriculture, which had vastly increased crop yields up until the late 1960s. But Erhlich, echoing a growing chorus of farmers and agricultural scientists, warned that pesticides ruined the environment and would eventually backfire as weeds and pests developed resistance.

Erhlich never called population the only variable. With physicist John Holdren, he proposed the I = P x A x T formula, which describes human impact as the product of population, affluence (the effects of consumption) and technology.

Nonetheless, Ehrlich believed that population was the key multiplier and massive reductions in global population were critical for human survival. He hoped that a combination of policy carrots and sticks would reduce fertility sufficiently and preserve voluntary family planning. But he held out the possibility that coercive measures, including compulsory sterilizations, might be needed.

Backlash and a new population politics

Millions of Americans shared Ehrlich’s anxieties in 1968. Concerns about the ecological impact of global population growth had helped birth modern American environmentalism. Feminists cited overpopulation to buttress the case for reproductive and abortion rights. Politicians on both sides of the aisle urged action to lower birth rates, and Republican President Richard Nixon signed into law a Commission on Population Growth and the American Future.

But the “culture wars” of the 1970s subsumed and reconfigured population issues. On the right, the “pro-life” movement that crystallized in the wake of the Supreme Court’s 1973 Roe v. Wade decision considered any talk of population reduction anathema.

China’s one-child policy, launched around 1980, led to serious human rights abuses that allowed anti–family planning conservatives to paint all population programs in a negative light. Conservatives subsequently ignored China’s significant reforms to the policy, as well as research indicating that slowing population growth contributed to China’s economic miracle.

Moreover, newly ascendant anti-Keynesian economists rejected an older consensus that slowing population growth would yield economic benefits. These market-oriented economists asserted that denser populations created economies of scale, and that individual fertility decisions would adjust to any temporary population problems. President Ronald Reagan, who once had dabbled with Malthusianism, tellingly labeled advocates who worried about scarce resources “Doomsday prophets.”

As nations develop economically, couples have fewer children and fertility rates decline. CC BY-ND

After Congress eliminated national-origin immigration quotas in 1965, immigration rose steadily and accounted for a growing share of population growth in the U.S. In this context, white liberals increasingly risked being branded racist for supporting population reduction.

By the late 1970s, both liberals and conservatives had bought into exaggerated talk of an “aging crisis” – too few workers to pay for the bulge of baby boomers headed toward retirement. This perspective bolstered calls for higher birth rates and further reduced the sting of the overpopulation critique.

An unsolved equation

Today Ehrlich is a largely forgotten prophet, although some small population-centric organizations continue to tilt at windmills and the mainstream press occasionally dips its toes in the water. After some very public rifts over immigration policy, mainstream environmental groups generally avoid or downplay the issue. Meanwhile, the Right continues to dismiss talk of population problems.

Looking back with the benefit of time, it’s clear Ehrlich was wrong to view population as all-encompassing. In addition, the global total fertility rate has declined more than he anticipated – although the development and modernization that has helped lower birth rates, a process known as the demographic transition, comes at great environmental cost.

Ehrlich underestimated human ingenuity. And for now, one can reasonably argue that food insecurity remains primarily political rather than technological. In Ehrlich’s own words, the book’s weaknesses were “not [focusing] enough on overconsumption and equity issues.”

The demographic transition is a pattern in which countries tend to transition from high birth and death rates to lower birth and death rates as they industrialize. Max Roser, CC BY-SA

But he got much right, even if many details and his timing were off. Global population has increased at a remarkably steady rate since 1968, and the United Nations projects that it will reach 9.8 billion by 2050 and 11.2 billion by 2100. Scientists continue to extend his prescient warnings that efforts to feed all these people through pesticide-intensive monoculture may backfire. And although Ehrlich exaggerated the threat of mass starvation, about 8,500 young children die from malnutrition every day.

Human-driven climate change is an overriding threat, and is unambiguously worsened by population growth. The Intergovernmental Panel on Climate Change estimates that limiting warming in this century to 3.6 degrees Fahrenheit (2 degrees Celsius) would require cutting global greenhouse gas emissions 40 to 70 percent by 2050 and nearly eliminating them by 2100. “Globally, economic and population growth continue to be the most important drivers of increases in CO2 emissions from fossil fuel combustion,” the panel observes.

The ConversationThere lies an enduring flaw in Ehrlich’s approach. If impact equals people times affluence times technology, then reducing population alone is not sufficient to solve our ecological crises. But reducing affluence is neither possible nor desirable, since it would condemn millions to lifelong poverty. Ultimately, “The Population Bomb” offered no road map for transitioning away from capitalism without causing human ruin as serious as the environmental ruin that seems to be our destiny.
Derek Hoff, Associate Professor, Lecturer in Business and Humanities, University of Utah
This article was originally published on The Conversation.

Revisiting Jimmy Carter's truth-telling sermon to Americans



File 20180712 27039 n5e3lw.jpg?ixlib=rb 1.1
Employees at a gas station in Los Angeles watch President Jimmy Carter giving his energy speech over national television on July 15, 1979. AP Photo/Mao

Nearly 40 years ago, on July 15, 1979, President Jimmy Carter went on national television to share with millions of Americans his diagnosis of a nation in crisis. “All the legislation in the world,” he proclaimed, “can’t fix what’s wrong with America.” He went on to call upon American citizens to reflect on the meaning and purpose of their lives together.

Carter made several specific policy prescriptions. But in a presidency animated by spirituality perhaps more than any other in American history, this speech called more generally for national self-sacrifice and humility.

At a time when political strongmen, hypernationalism, and xenophobia have risen in the U.S. and the world, Carter’s speech offers a powerful counterexample to these trends.

A nation in ‘very serious trouble’

In 1979, Jimmy Carter was three years into his presidency. The burdens were many. Leading a divided Democratic Party, he faced a staunch and growing Republican opposition. The nation suffered from stagflation, a combination of economic stagnation and 12 percent inflation.

In 1973 the OPEC cartel, comprised mostly of Middle Eastern countries, had cut oil production and imposed an embargo against nations that supported Israel. In the late 1970s production declined again. Coupled with high global demand, this generated an energy crisis that increased gasoline prices by 55 percent in the first half of 1979.

In protest, truckers set bonfires in Pennsylvania, and Carter’s approval rating sank to 30 percent. An anxious Carter cut short his overseas trip to Vienna where he was holding nuclear-arms talks with the Soviet Union’s Leonid Brezhnev.

After a brief stop in Washington, the President retreated to Camp David for ten days. As he considered the severe and interlocking problems facing his administration, Carter read the Bible, historian Christopher Lasch’s The Culture of Narcissism, and economist E.F. Schumacher’s Small Is Beautiful, a meditation on the value of local community and the problems of excessive consumption.
He also invited representatives from many sectors of American life – business and labor leaders, teachers and preachers, and politicians and intellectuals – to consult with him. By the end of his retreat, Carter had concluded that the country faced more than a series of isolated problems. Collectively they comprised a fundamental cultural crisis.

The malaise speech



Having cloistered himself for an unprecedented length of time, the President emerged from Camp David with great drama on July 15, 1979. In a nationally televised speech that was watched by 65 million Americans, Carter intoned an evangelical-sounding lament about “a crisis of the American spirit.”

He said,
“In a nation that was proud of hard work, strong families, close-knit communities and our faith in God, too many of us now worship self-indulgence and consumption.”

Indeed, the President’s sermon expounded at length about excess. “Human identity is no longer defined by what one does but by what one owns,” he preached. But “owning things and consuming things does not satisfy our longing for meaning.”

It was a penetrating cultural critique that reflected Carter’s spiritual values. Like the writers of the New Testament, he called out sin. Like the prophets of the Old Testament, he confessed to personal and national pride.

In the mode of theologian Reinhold Niebuhr, he noted the limits of human power and righteousness. In this moment of national chastening, he committed himself and the nation to rebirth and renewal.
As a scholar of American religious history, this so-called “malaise speech” (though Carter never actually used the word “malaise”) was, in my opinion, the most theologically profound speech by an American president since Lincoln’s Second Inaugural Address.

A squandered opportunity

This articulation of economic and political humility sounded the perfect pitch for a nation whose confidence in civil institutions had been shaken. The Watergate scandal had revealed corruption in the nation’s highest political offices. The Vietnam War had ended with a Communist victory.

The “malaise speech” was a continuation of a long-running theme for Carter. In his 1977 inaugural address, he intoned, “We have learned that ‘more’ is not necessarily ‘better,’ that even our great nation has its recognized limits, and that we can neither answer all questions nor solve all problems … we must simply do our best.”

Popular memory suggests that the nation reacted negatively to his speech. In The Age of Reagan, historian Sean Wilentz writes that Carter appeared to be blaming the American citizens for their problems. Others panned Carter’s idealistic approach to the energy crisis as naïve.

Soon after the speech, Carter got a bump in his approval ratings. AP Photo/Harry Cabluck

But that was not how most Americans received the speech. In fact, Carter enjoyed an immediate 11 percent bump in his job approval rating in the days that followed. Clearly many agreed with Carter’s line that the nation was mired in a “moral and spiritual crisis.”

The President, however, failed to capitalize on the resonance with his meditation. Just two days after his speech, Carter fired his entire cabinet, which seemed to suggest that his government was in disarray.

The President’s poll numbers immediately melted. As Time magazine described it, “The President basked in the applause for a day and then set in motion his astounding purge, undoing much of the good he had done himself.” Reagan soon capitalized on the disillusionment. “I find no national malaise,” said Carter’s successor, who campaigned on a platform of America as “a shining city on a hill.

About to win the Cold War, America was ready for some exuberant nationalism, not a plain-style president who insisted on carrying his own garment bag aboard Air Force One.

New resonance

Forty years later, national jingoism pervades both political parties. Republicans and Democrats alike speak of the United States as a "city on a hill,” and Donald Trump’s “America first” rhetoric has lifted hubris to new heights and alienated allies around the world.

The ConversationJimmy Carter’s sermon of humility speaks more than ever to crises of our times.
David Swartz, Associate Professor of History, Asbury University
This article was originally published on The Conversation.

Tuesday, July 3, 2018

Are we alone? The question is worthy of serious scientific study


File 20180625 19411 1bdn3yc.png?ixlib=rb 1.1
US F/A-18 footage of a UFO (circled in red). Creative Commons Attribution-Share Alike 4.0 International license. Parzival191919, CC BY-NC-SA

Are we alone? Unfortunately, neither of the answers feel satisfactory. To be alone in this vast universe is a lonely prospect. On the other hand, if we are not alone and there is someone or something more powerful out there, that too is terrifying.

As a NASA research scientist and now a professor of physics, I attended the 2002 NASA Contact Conference, which focused on serious speculation about extraterrestrials. During the meeting a concerned participant said loudly in a sinister tone, “You have absolutely no idea what is out there!” The silence was palpable as the truth of this statement sunk in. Humans are fearful of extraterrestrials visiting Earth. Perhaps fortunately, the distances between the stars are prohibitively vast. At least this is what we novices, who are just learning to travel into space, tell ourselves.

Cover of the October 1957 issue of pulp science fiction magazine Amazing Stories. This was a special edition devoted to ‘flying saucers,’ which became a national obsession after airline pilot Kenneth Arnold sighted a saucer-shaped flying objects in 1947.

I have always been interested in UFOs. Of course, there was the excitement that there could be aliens and other living worlds. But more exciting to me was the possibility that interstellar travel was technologically achievable. In 1988, during my second week of graduate school at Montana State University, several students and I were discussing a recent cattle mutilation that was associated with UFOs. A physics professor joined the conversation and told us that he had colleagues working at Malmstrom Air Force Base in Great Falls, Montana, where they were having problems with UFOs shutting down nuclear missiles. At the time I thought this professor was talking nonsense. But 20 years later, I was stunned to see a recording of a press conference featuring several former US Air Force personnel, with a couple from Malmstrom AFB, describing similar occurrences in the 1960s. Clearly there must be something to this.

With July 2 being World UFO Day, it is a good time for society to address the unsettling and refreshing fact we may not be alone. I believe we need to face the possibility that some of the strange flying objects that outperform the best aircraft in our inventory and defy explanation may indeed be visitors from afar – and there’s plenty of evidence to support UFO sightings.

The Fermi paradox

The nuclear physicist Enrico Fermi was famous for posing thought provoking questions. In 1950, at Los Alamos National Laboratory after discussing UFOs over lunch, Fermi asked, “Where is everybody?” He estimated there were about 300 billion stars in the galaxy, many of them billions of years older than the sun, with a large percentage of them likely to host habitable planets. Even if intelligent life developed on a very small percentage of these planets, then there should be a number of intelligent civilizations in the galaxy. Depending on the assumptions, one should expect anywhere from tens to tens of thousands of civilizations.

With the rocket-based technologies that we have developed for space travel, it would take between 5 and 50 million years for a civilization like ours to colonize our Milky Way galaxy. Since this should have happened several times already in the history of our galaxy, one should wonder where is the evidence of these civilizations? This discrepancy between the expectation that there should be evidence of alien civilizations or visitations and the presumption that no visitations have been observed has been dubbed the Fermi Paradox.

This photograph was taken in Wallonia, Belgium. J.S. Henrardi

Carl Sagan correctly summarized the situation by saying that “extraordinary claims require extraordinary evidence.” The problem is that there has been no single well-documented UFO encounter that would alone qualify as the smoking gun. The situation is exacerbated by the fact that many governments around the world have covered up and classified information about such encounters. But there are enough scraps of evidence that suggest that the problem needs to be open to scientific study.

UFOs, taboo for professional scientists

When it comes to science, the scientific method requires hypotheses to be testable so that inferences can be verified. UFO encounters are neither controllable nor repeatable, which makes their study extremely challenging. But the real problem, in my view, is that the UFO topic is taboo.

While the general public has been fascinated with UFOs for decades, our governments, scientists and media, have essentially declared that of all the UFO sightings are a result of weather phenomenon or human actions. None are actually extraterrestrial spacecraft. And no aliens have visited Earth. Essentially, we are told that the topic is nonsense. UFOs are off-limits to serious scientific study and rational discussion, which unfortunately leaves the topic in the domain of fringe and pseudoscientists, many of whom litter the field with conspiracy theories and wild speculation.

I think UFO skepticism has become something of a religion with an agenda, discounting the possibility of extraterrestrials without scientific evidence, while often providing silly hypotheses describing only one or two aspects of a UFO encounter reinforcing the popular belief that there is a conspiracy. A scientist must consider all of the possible hypotheses that explain all of the data, and since little is known, the extraterrestrial hypothesis cannot yet be ruled out. In the end, the skeptics often do science a disservice by providing a poor example of how science is to be conducted. The fact is that many of these encounters – still a very small percentage of the total – defy conventional explanation.

The media amplifies the skepticism by publishing information about UFOs when it is exciting, but always with a mocking or whimsical tone and reassuring the public that it can’t possibly be true. But there are credible witnesses and encounters.

Why don’t astronomers see UFOs?

I am often asked by friends and colleagues, “Why don’t astronomers see UFOs?” The fact is that they do. In 1977, Peter Sturrock, a professor of space science and astrophysics at Stanford University, mailed 2,611 questionnaires about UFO sightings to members of the American Astronomical Society. He received 1,356 responses from which 62 astronomers – 4.6 percent – reported witnessing or recording inexplicable aerial phenomena. This rate is similar to the approximately 5 percent of UFO sightings that are never explained.

As expected, Sturrock found that astronomers who witnessed UFOs were more likely to be night sky observers. Over 80 percent of Sturrock’s respondents were willing to study the UFO phenomenon if there was a way to do so. More than half of them felt that the topic deserves to be studied versus 20 percent who felt that it should not. The survey also revealed that younger scientists were more likely to support the study of UFOs.

UFOs have been observed through telescopes. I know of one telescope sighting by an experienced amateur astronomer in which he observed an object shaped like a guitar pick moving through the telescope’s field of view. Further sightings are documented in the book “Wonders in the Sky,” in which the authors compile numerous observations of unexplained aerial phenomena made by astronomers and published in scientific journals throughout the 1700s and 1800s.

Evidence from government and military officers

Some of the most convincing observations have come from government officials. In 1997, the Chilean government formed the organization Comité de Estudios de Fenómenos Aéreos Anómalos, or CEFAA, to study UFOs. Last year, CEFAA released footage of a UFO taken with a helicopter-mounted Wescam infrared camera.

Declassified document describing a sighting of a UFO in December 1977, in Bahia, a state in northern Brazil. Arquivo Nacional Collection

The countries of Brazil, Canada, Denmark, Ecuador, France, New Zealand, Russia, Sweden and the United Kingdom have been declassifying their UFO files since 2008. The French Committee for In-Depth Studies, or COMETA, was an unofficial UFO study group comprised of high-ranking scientists and military officials that studied UFOs in the late 1990s. They released the COMETA Report, which summarized their findings. They concluded that 5 percent of the encounters were reliable yet inexplicable: The best hypothesis available was that the observed craft were extraterrestrial. They also accused the United States of covering up evidence of UFOs. Iran has been concerned about spherical UFOs observed near nuclear power facilities that they call “CIA drones” which reportedly are about 30 feet in diameter, can achieve speeds up to Mach 10, and can leave the atmosphere. Such speeds are on par with the fastest experimental aircraft, but unthinkable for a sphere without lift surfaces or an obvious propulsion mechanism.

1948 Top Secret USAF UFO extraterrestrial document. United States Air Force

In December 2017, The New York Times broke a story about the classified Advanced Aviation Threat Identification Program, which was a $22 million program run by the former Pentagon official Luis Elizondo and aimed at studying UFOs. Elizondo resigned from running the program protesting extreme secrecy and the lack of funding and support. Following his resignation Elizondo, along with several others from the defense and intelligence community, were recruited by the To the Stars Academy of Arts & Science, which was recently founded by Tom DeLonge to study UFOs and interstellar travel. In conjunction with the launch of the academy, the Pentagon declassified and released three videos of UFO encounters taken with forward looking infrared cameras mounted on F-18 fighter jets. While there is much excitement about such disclosures, I am reminded of a quote from Retired Army Colonel John Alexander: “Disclosure has happened. … I’ve got stacks of generals, including Soviet generals, who’ve come out and said UFOs are real. My point is, how many times do senior officials need to come forward and say that this is real?”

A topic worthy of serious study

There is a great deal of evidence that a small percentage of these UFO sightings are unidentified structured craft exhibiting flight capabilities beyond any known human technology. While there is no single case for which there exists evidence that would stand up to scientific rigor, there are cases with simultaneous observations by multiple reliable witnesses, along with radar returns and photographic evidence revealing patterns of activity that are compelling.

The ConversationDeclassified information from covert studies is interesting, but not scientifically helpful. This is a topic worthy of open scientific inquiry, until there is a scientific consensus based on evidence rather than prior expectation or belief. If there are indeed extraterrestrial craft visiting Earth, it would greatly benefit us to know about them, their nature and their intent. Moreover, this would present a great opportunity for mankind, promising to expand and advance our knowledge and technology, as well as reshaping our understanding of our place in the universe.

Kevin Knuth, Associate Professor of Physics, University at Albany, State University of New York
This article was originally published on The Conversation.

Humans are to blame for the rise in dangerous viral infections



Today, we hear about dangerous viral infections around the world on a regular basis. Social media and internet access may be an obvious explanation for their seeming increase.

But it doesn’t just seem this way. The number of viruses and the infections they cause are truly increasing. Scientific advances, the way humans live today and virus biology all contribute to the rise of viruses.

Read more: Health Check: when are we most likely to catch viral diseases?

New viruses, all the time

It seems viral infections are everywhere these days. Starting from January 2018, Nigeria has been experiencing an unusually large outbreak of haemorrhagic fever caused by Lassa virus. There have been more than 400 confirmed infections and 100 deaths to date.

The southern Indian state of Kerala is battling an outbreak of the rare Nipah virus, which causes severe inflammation of the brain and claimed the lives of 14 people in May.

The Brazilian outbreak of viral yellow fever that began in late 2017 has moved into highly populated areas near São Paulo and Rio de Janeiro. One-third of the 723 people with confirmed infections have so far died from the illness.

We’re no doubt more aware of such serious diseases after the unprecedented 2014-2016 Ebola outbreak in West Africa that claimed more than 11,000 lives. And then the 2015-2017 Zika virus outbreak that closely followed during which 3,500 babies were born with nervous system or eye damage.

Read more: Zika, dengue, yellow fever: what are flaviviruses?

The first report of human virus infection was yellow fever in the US army at the turn of the 20th century. And now, estimates suggest three to four new species of human viruses are found each year and around 250 human virus species are yet to be discovered.

Discovery of a new virus today is complex and requires many steps. Typically, it involves describing its complete genetic code with a combination of intensive molecular sequencing work in the laboratory and computational analyses using enormous reference databases.

Medical epidemiological studies (that look at the distribution of disease) and biological experiments are then needed to understand any virus as a dangerous human pathogen. It may then take some time to link a virus with a particular human disease.

Human parechoviruses were only discovered in the 1950s. from shutterstock.com

For instance, human parechoviruses (which can cause severe disease in young children) were discovered in the 1950s. But they were only identified as a cause of disease in young children in 2004. And relatively large Australian epidemics since 2013 have highlighted their link to a serious sepsis-like illness and potential for developmental complications.

How humans contribute

Modern humans contribute to the success of dangerous viruses. A virus replicates only when inside the cell of a living being, and spreads most efficiently when there is contact between two individuals.

The United Nations measures current world population growth at more than 1% per year. From the virus’ perspective, potential incubators are increasing. The world’s population is also urbanising, which means people living in closer proximity, which is conducive to spread of a virus.

Domestic and international mass transport permit viruses to move between regional populations.
Many dangerous virus infections are zoonoses, which are diseases transmitted to humans from other animals. Bats are a common culprit – one theory is that a unique low-grade immune system allows them to carry a relatively high number of viruses without developing disease. Epidemics caused by severe acute respiratory syndrome (SARS) coronavirus probably began through bat-human contact.

Read more: Why bats don't get get sick from the deadly diseases they carry

Expanding settlement towards wilderness areas provides more opportunities for viruses to meet people. Domesticated livestock may carry viruses that infect humans, and the growing human population dictates increasing and more compact livestock production.

Influenza virus infects pigs, cattle and poultry as well as humans. The H7N9 strain that has infected more than 1,500 people in China and resulted in the death of one-third since 2013, first moved to humans from diseased poultry.

When it comes to numbers though, the most important viral transporter is the mosquito. The bite of certain Aedes mosquitoes, for instance, is the primary route for infection with dengue, Zika and chikungunya viruses. Queensland is home to these mosquitoes, so outbreaks of dengue occur annually, usually due to an infected traveller arriving from an endemic region.

Research conducted in the Amazon has linked expansion of the mosquito range in endemic areas to deforestation and low re-vegetation. Resistance to the relatively few available insecticides may also contribute to their population growth.

Why viruses are sneaky

The basic biology of viruses contributes to their capacity to cause disease. Most human viruses replicate almost instantaneously and in huge numbers. As a result, mutations arise at a high rate in the genetic code of a virus. This allows the virus to adapt quickly to an adverse environment, such as the human immune system or drugs. It may also allow a virus to jump from an animal host to humans.

Read more: New mosquito threats shift risks from our swamps to our suburbs

Some viruses establish a chronic infection, which extends the potential for transmission. After acute illness, Ebola virus hides for many months in parts of the body that generate weak inflammatory responses, such as the sexual organs, the brain and/or the eye.

And although human immunodeficiency virus (HIV) may cause an acute illness, there is usually a long delay between infection and the onset of any disease. Consequently infected people may pass on HIV for years before being aware that they carry the virus.

Mosquitoes are responsible for the most viral transmissions. from shutterstock.com

There are no specific drugs for most dangerous human viruses. This is in part because viruses are a fast growing and diverse group, with no common drug targets to exploit, as has been possible with antibiotics for bacteria.

But another challenge relates to the viral life cycle, which uses the infected person’s cell machinery. Drugs that target the growth of viruses therefore have effects on the person’s cell, which may result in drug side effects.

Read more: HIV latency: a high-stakes game of hide and seek

Also, the capacity of a virus to adapt implies the potential to develop resistance to a drug. Drug treatment for HIV infection involves a combination of drugs with different actions to address this problem.

Despite the many challenges associated with dangerous viruses, research continues to yield even more innovative solutions. The World Mosquito Program, run out of Monash University, is one example. This program is based on the discovery that a safe and natural bacteria, Wolbachia, stops viral growth in the mosquito. Insects in regions endemic with mosquito-borne diseases are being infected with Wolbachia to break the transmission cycle.

The ConversationUltimately, the cunning strategies used by dangerous viruses are no match for the wide breadth of human ingenuity.

Justine R. Smith, Professor of Eye & Vision Health, Flinders University and Jill Carr, Associate Professor, Flinders University
This article was originally published on The Conversation.