How climate change could expose new epidemics

PARIS - Long-dormant viruses brought back to life; the resurgence of deadly and disfiguring smallpox; a dengue or zika "season" in Europe.

These could be disaster movie storylines, but they are also serious and increasingly plausible scenarios of epidemics unleashed by global warming, scientists say.

The COVID-19 pandemic that has swept the globe and claimed over 760,000 lives so far almost certainly came from a wild bat, highlighting the danger of humanity's constant encroachment on the planet's dwindling wild spaces.

But the expanding ecological footprint of our species could trigger epidemics in other ways too. 

Climate change -- already wreaking havoc with one degree Celsius of warming -- is also emerging as a driver of infectious disease, whether by expanding the footprint of malaria- and dengue-carrying mosquitos, or defrosting prehistoric pathogens from the Siberian permafrost.

'IGNORANCE IS OUR ENEMY'

"In my darkest moments, I see a really horrible future for Homo sapiens because we are an animal, and when we extend our borders, things will happen to us," said Birgitta Evengard, a researcher in clinical microbiology at Umea University in Sweden.

"Our biggest enemy is our own ignorance," she added. "Nature is full of microorganisms."

Think of permafrost, a climate change time bomb spread across Russia, Canada and Alaska that contains three times the carbon that has been emitted since the start of industrialization. 


Even if humanity manages to cap global warming at under two degrees Celsius, the cornerstone goal of the 2015 Paris Agreement, the permafrost area will decrease by a quarter by 2100, according to the UN's climate science panel, the IPCC.

And then there are the permafrost's hidden treasures.

"Microorganisms can survive in frozen space for a long, long time," said Vladimir Romanovsky, a professor of geophysics at the University of Alaska in Fairbanks.

AN ANTHRAX COMEBACK? 

As ground thaws, once-frozen soil particles, organic material and microorganisms that had been locked away for millennia are carried toward the surface by water flows, he explained.

"That's how thawing can spread these microorganisms into present day environments." 


There are already examples of ancient, long-frozen bugs coming to life.

"When you put a seed into soil that is then frozen for thousands of years, nothing happens," said Jean-Michel Claverie, an emeritus professor of genomics at the School of Medicine of Aix-Marseille University in France.

"But when you warm the earth, the seed will be able to germinate," he added. "That is similar to what happens with a virus."

Claverie's lab has successfully revived Siberian viruses that are at least 30,000 years old.

These reanimated bugs only attack amoebas, but tens of thousands of years ago there were certainly others that aimed higher up the food chain.

"Neanderthals, mammoths, woolly rhinos all got sick, and many died," said Claverie. "Some of the viruses that caused their sicknesses are probably still in the soil."


The number of bacteria and viruses lurking in the permafrost is incalculable, but the more important question is how dangerous they are.

And here, scientists disagree.

"Anthrax shows that bacteria can be resting in permafrost for hundreds of years and be revived," said Evengard.

In 2016, a child in Siberia died from the disease, which had disappeared from the region at least 75 years earlier.

2-MILLION-YEAR-OLD PATHOGENS

This case has been attributed to the thawing of a long-buried carcass, but some experts counter that the animal remains in question may have been in shallow dirt and thus subject to periodic thawing.


Other pathogens -- such as smallpox or the influenza strain that killed tens of millions in 1917 and 1918 -- may also be present in the sub-Arctic region.

But they "have probably been inactivated", Romanovsky concluded in a study published earlier this year.

For Claverie, however, the return of smallpox -- officially declared eradicated 50 years ago -- cannot be excluded. 18th- and 19th-century victims of the disease "buried in cemetaries in Siberia are totally preserved by the cold," he noted.

In the unlikely event of a local epidemic, a vaccine is available.

The real danger, he added, lies in deeper strata where unknown pathogens that have not seen daylight for two million years or more may be exposed by global warming.

If there were no hosts for the bugs to infect, there would not be a problem, but climate change -- indirectly -- has intervened here as well.

"With the industrial exploitation of the Arctic, all the risk factors are there -- pathogens and the people to carry them," Claverie said.

The revival of ancient bacteria or viruses remains speculative, but climate change has already boosted the spread of diseases that kill about half a million people every year: malaria, dengue, chikungunya, zika.

"Mosquitoes moving their range north are now able to overwinter in some temperate regions," said Jeanne Fair, deputy group leader for biosecurity and public health at the Los Alamos National Laboratory in New Mexico.

"They also have longer breeding periods."

'CLIMATE CHANGE APERITIF'

Native to southeast Asia, the tiger mosquito (Aedes albopictus) -- which carries dengue and chikungunya -- arrived in southern Europe in the first decade of this century and has been moving rapidly north ever since, to Paris and beyond.

Meanwhile, another dengue-bearing mosquito, Aedes aegypti, has also appeared in Europe. Whichever species may be the culprit, the Europe Center for Disease Prevention and Control (ECDC) has registered 40 cases of local transmission of dengue between 2010 and 2019.

"An increase in mean temperature could result in seasonal dengue transmission in southern Europe if A. aegypti infected with virus were to be established," according to the Europe Center for Disease Prevention and Control.

As for malaria -- a disease that once blighted southern Europe and the southern United States and for which an effective treatment exists -- the risk of exposure depends in large part on social-economic conditions. 

More than five billion people could be living in malaria-affected regions by 2050 if climate change continues unabated, but strong economic growth and social development could reduce that number to less than two billion, according to a study cited by the IPCC. 

"Recent experience in southern Europe demonstrates how rapidly the disease may reappear if health services falter," the IPCC said in 2013, alluding to a resurgence of cases in Greece in 2008.

In Africa -- which saw 228 million cases of malaria in 2018, 94 percent of the world's total -- the disease vector is moving into new regions, notably the high-altitude plains of Ethiopia and Kenya.

For the moment, the signals for communicable tropical diseases "are worrying in terms of expanding vectors, not necessarily transmission," said Cyril Caminade, an epidemiologist working on climate change at the Institute of Infection and Global Health at the University of Liverpool.

"That said, we're only tasting the aperitif of climate change so far," he added.

Agence France-Presse

Race for Zika vaccine gathers momentum as virus spreads

Vaccine is seen as months, if not years, away
U.S. CDC activates Zika emergency response center
Geneva-based WHO plans emergency meeting Monday

Companies and scientists are racing to create a Zika vaccine as concern grows over the mosquito-borne virus that has been linked to severe birth defects and is spreading quickly through the Americas.

Zika is now present in 23 countries and territories in the Americas. Brazil, the hardest-hit country, has reported around 3,700 cases of the devastating birth defect called microcephaly that are strongly suspected to be related to Zika.

The Geneva-based World Health Organization (WHO), stung by criticism that it reacted too slowly to West Africa's Ebola epidemic, convenes an emergency meeting on Monday to help determine its response to the spread of the virus.

The U.S. Centers for Disease Control and Prevention has activated an emergency operations center staffed around the clock to address Zika, agency officials told Reuters.

On Thursday, the WHO said as many as 4 million people in the Americas may become infected by Zika, adding urgency to the research efforts. Vaccine developers made clear a vaccine for widespread public use is at least months, if not years, away.

The closest prospect may be from a consortium including drugmaker Inovio Pharmaceuticals Inc that could have a vaccine ready for emergency use before year-end, according to one of its lead developers. Inovio's share price gained more than 15 percent in Friday trading.

Canadian scientist Gary Kobinger told Reuters on Thursday the first stage of testing on humans could begin as early as August. If successful, the vaccine might be used during a public health emergency by October or November, said Kobinger, who helped develop a trial vaccine for the Ebola virus.

Privately owned vaccine developer Hawaii Biotech Inc said it began a formal program to test a Zika vaccine last fall as the virus started to gain traction in Brazil, although it has no timetable yet for clinical trials.

"Right now, we are in the pre-clinical stage, as I suspect everyone is," Chief Executive Officer Dr. Elliot Parks told Reuters.

Another private vaccine developer, Boston-based Replikins Ltd, said it was preparing to start animal studies on a Zika vaccine in the next 10 days. Data from the trials on mice and rabbits would likely be out in the next couple of months, Replikins Chairman Samuel Bogoch told Reuters.

"No one has the $500 million on hand to take it (a vaccine) all the way to human trials. Somewhere along the course we hope to have big pockets join us," Bogoch said.

'FIGHT THE MOSQUITO'

Zika had been viewed as a relatively mild illness until Brazilian health officials identified it as a matter of concern for pregnant women. While a direct causal relationship has not been established, scientists strongly suspect a link between Zika and thousands of children born in Brazil with abnormally small heads, brain defects and impaired vision.

There is no treatment for Zika infection.

Efforts to combat Zika are focused on protecting people from being bitten and on eradicating mosquitoes, a tough task in many parts of Latin America, where people live in poverty and there are plentiful breeding grounds for the insect.

"We do not have a vaccine for Zika yet. The only thing we can do is fight the mosquito," Brazilian President Dilma Rousseff said on Friday, reiterating her call for a national eradication effort.

Rousseff said tests for the development of a vaccine would begin next week at the Butantan Institute, one of Brazil's leading biomedical research centers in Sao Paulo.

U.S. President Barack Obama spoke on Friday with Rousseff about the spread of the virus, the White House said.

"The leaders agreed on the importance of collaborative efforts to deepen our knowledge, advance research and accelerate work to develop better vaccines and other technologies to control the virus," the White House said in a statement.

Zika has hit Brazil just as it prepares to host the Olympic Games in Rio de Janeiro on Aug. 5-21, an event that draws hundreds of thousands of athletes, team officials and spectators. The International Olympic Committee (IOC) assured teams on Friday the Olympics would be safe from Zika, but urged visitors to carefully protect themselves.

U.S. lawmakers have begun to press the Obama administration for details of its response to Zika. At least 31 people in the country have been infected, all of them after travel to affected countries.

The U.S. Senate Health, Education, Labor and Pensions Committee is planning a hearing on Zika "very soon," said Republican Senator Lamar Alexander of Tennessee, who called the threat posed by the virus to the United States a "big concern."

Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Disease, said he did not expect the United States to be hit hard like other some countries in South America and the Caribbean.

"We prepare for the possibility of a major outbreak but we believe it is unlikely to happen," Fauci said.

(Reporting by Rod Nickel in Winnipeg, Manitoba; and Natalie Grover in Bengaluru; Additional reporting by Amrutha Penumudi in Bengaluru; Julie Steenhuysen in Chicago, Toni Clarke in Washington, Karolos Grohmann in Berlin, Anthony Boadle in Brasilia, Jeffrey Dastin in New York; Writing by Frances Kerry; Editing by Will Dunham and Lisa Shumaker)

source: www.abs-cbnnews.com

Obama calls for rapid Zika research as virus seen spreading

CHICAGO/WASHINGTON - President Barack Obama on Tuesday called for the rapid development of tests, vaccines and treatments to fight the mosquito-transmitted Zika virus, which has been linked to birth defects and could spread to the United States in warmer months.

U.S. health officials are stepping up efforts to study the link between Zika virus infections and birth defects, citing a recent study estimating the virus could reach regions where 60 percent of the U.S. population lives.

Obama was briefed on the potential spread of the virus by his top health and national security officials on Tuesday.

"The president emphasized the need to accelerate research efforts to make available better diagnostic tests, to develop vaccines and therapeutics, and to ensure that all Americans have information about the Zika virus and steps they can take to better protect themselves from infection," the White House said in a statement.

The virus has been linked to brain damage in thousands of babies in Brazil. There is no vaccine or treatment for Zika, a close cousin of dengue and chikungunya, which causes mild fever and rash. An estimated 80 percent of people infected have no symptoms, making it difficult for pregnant women to know whether they have been infected.

On Monday, the World Health Organization predicted the virus would spread to all countries across the Americas except for Canada and Chile.

In a blog post, National Institutes of Health Director Dr. Francis Collins cited a Lancet study published Jan. 14 in which researchers predicted the Zika virus could be spread in areas along the East and West Coasts of the United States and much of the Midwest during warmer months, where about 200 million people live.

The study also showed that 22.7 million more people live in humid parts of the country where mosquitoes carrying the virus could live year round.

Given the threat, Collins said "it is now critically important to confirm, through careful epidemiological and animal studies, whether or not a causal link exists between Zika virus infections in pregnant women and microcephaly in their newborn babies." Microcephaly results in babies being born with abnormally small heads.

There is still much to learn about Zika infections, experts said. For example, it is not clear how common Zika infections are in pregnant women, or when during a pregnancy a woman is most at risk of transmitting the virus to her fetus.

Collins said the National Institute of Allergy and Infectious Disease is conducting studies to more fully understand the effects of Zika in humans, and to develop better diagnostic tests to quickly determine if someone has been infected. The NIAID is also working on testing new drugs that might be effective against the virus.

The U.S. Centers for Disease Control and Prevention also announced new instructions for pediatricians treating infants whose mothers may have been exposed to the virus during pregnancy.

In those guidelines, the CDC made clear that it considers the Zika virus a nationally notifiable condition, and instructs doctors to contact their state or territorial health departments to facilitate testing of potentially infected infants.

Dr. Kathryn Edwards of Vanderbilt University, who serves on the American Academy of Pediatrics' committee on infectious disease, said the guidelines were intended to help establish whether Zika causes microcephaly and to help pregnant women who may have been infected with the virus.

Microcephaly is a lifelong condition with no known cure, the CDC website said. Symptoms range from mild to severe.

In mild cases, infants often have no symptoms other than small head size, but doctors still need to check their development regularly. In severe cases, babies may need speech, occupational and physical therapy.

The guidelines for testing infants affected by Zika infections follows CDC guidelines for caring for pregnant women exposed to Zika virus, which were first reported by Reuters. The CDC said last week it is trying to determine how many pregnant women may have traveled to affected regions in the past several months.

On Tuesday, the CDC added the U.S. Virgin Islands and the Dominican Republic to its list of countries and territories with Zika transmissions, bringing the total to 24.

The CDC has told pregnant women not to travel to countries and territories in Latin America and the Caribbean affected by Zika. Travel companies, including United Airlines, have begun offering refunds or allowing pregnant women to postpone trips to regions affected by Zika with no penalty.

There are no global estimates for how many people in the world have been infected by the Zika virus, World Health Organization spokesman Christian Lindmeier said on Tuesday.

He said that because Zika has such mild symptoms, the virus has "not really been on the radar."

Lindmeier said it was not yet clear whether the virus affecting Brazil and other countries in Latin America and the Caribbean was a mutated version of the virus that has caused prior outbreaks.

He said the WHO was working with the CDC, the Institut Pasteur in France and the London School of Hygiene and Tropical Medicine to establish that.

"There is a lot of effort going into this now, on the ground, in the laboratories, everywhere," Lindmeier said.

source: www.abs-cbnnews.com