The tragic increase of microcephaly cases in Brazil, currently linked to the Zika virus, some people are convinced, is the creation of a British biotech company called Oxitech, which has been releasing genetically modified (GM) mosquitoes in Brazil.
However, the largest release of the GM mosquitoes was in Piracicaba, which is 2700 kilometers from Recife, where there is the greatest concentration of microcephaly cases. The Zika mosquito rarely travels more than one kilometer in its lifetime. Brazilian health officials and scientists say the Oxitec program has reduced mosquito populations in affected areas by up to 90 percent. While the program continues to release GM mosquitoes, its expansion is being held up by the government for technical reasons.
Discover magazine is among the authoritative sources that have disproved the allegation that the GM engineered mosquitoes are behind the Zika outbreak. Still, the idea has been picked up and expanded by scores of other outlets, including the anti-Western website Russia Today, the British tabloid The Daily Mail, and conspiracy-minded websites like Natural News.
The latest theory attempting to explain the rise of microcephaly is being broadcast by a group of Argentine doctors. Their idea has flooded the Internet, asserting that a larvicide, not the Zika virus, is to blame for a surge in cases of the birth defect. Social media is buzzing about this group of doctors, PhRed Universitária de Ambiente y Salud (University Network of Environment and Health), particularly after the Health Secretary of the state of Rio Grande do Sul announced a ban on the use of this larvicide, pyriproxyfen, in its drinking water. The larvicide is sold in Brazil by the Sumitomo company.
The ban was enacted after the doctors’ group and the Brazilian Collective Health Association, (Abrasco), questioned whether the larvicide might be linked with microcephaly. Rio Grande do Sul Health Secretary João Gabbardo said that despite the fact that a relationship between the larvicide and microcephaly has not been proven, the “suspicion” that there may be a linkage had led him to decide to suspend the use of the chemical. “We cannot run that risk,” Gabbardo said.
Numerous websites such as Tech Times immediately picked up on the banning story. After the Tech Times article was published, blaming the chemical company Monsanto for the outbreak of microcephaly, Monsanto issued a statement noting that the company doesn’t make larvicides, and only works with Sumitomo to sell herbicides and pesticides.
Pyriproxyfen (brand name Sumilarv) is a larvicide (kills insect larvae) that most Americans have probably used before. In the US, it is marketed as Nylar, an anti-flea product used generally by pet owners. It has been marketed since 1996 and has been subjected to a variety of toxicology tests.
Brazil’s health ministry issued a statement saying: “Unlike the relationship between the Zika virus and microcephaly, which has had its confirmation attested in tests that indicated the presence of the virus in samples of blood, tissue and amniotic fluid, the association between the use of pyriproxyfen and microcephaly has no scientific basis.”
Ian Musgrave, a senior lecturer in the Faculty of Medicine, School of Medicine Sciences at the University of Adelaide in Australia, explained in a statement that although pyriproxyfen does regulate growth, it “is not plausible” that the substance could cause birth defects in humans.
“Pyriproxyfen acts by interfering with the hormonal control growth cycle of insects from hatching, to larvae, to pupa,” Dr. Musgrave said. “This hormone control system does not exist in organisms with backbones, such as humans, and pyriproxyfen has very low toxicity in mammals as a result.”
Meanwhile, even though scientists and health officials insist there is no link between microcephaly and the chemical larvicide, the rumors about it are frustrating the Brazilian authorities, as they grapple with a poorly understood pathogen whose origins and implications are still a mystery. In a statement on February 15, the government noted that microcephaly was also growing in communities that did not use the larvicide, and declared bluntly, “The association between the use of pyriproxyfen and microcephaly has no scientific basis.”
Graham B. White, a medical entomologist who is a consultant to the United States Defense Department on disease-carrying insects, called the Argentine doctors’ assertion “ridiculous and not credible.” Mr. White said that the larvicide did not work through the nervous system, the part of the developing fetus affected by microcephaly. He noted that the chemical had been approved by the World Health Organization and had been widely used for years to treat drinking water in places where mosquitoes breed throughout the world, including in the US, where no connection to microcephaly has been made.
Brazil, where mistrust of government is high, is fertile ground for conspiracy theories based on rumors and gossip. Last week, the Brazilian government used Twitter to counter another popular rumor making the rounds: that vaccines for chickenpox and rubella were to blame for the increase in cases of microcephaly. The Health Ministry posted that such vaccines are not given to pregnant women.
Authorities are also attempting to combat another vaccine-related theory: A bad batch of the measles, mumps and rubella vaccine failed to protect against rubella, and the increase in cases of microcephaly was caused by an unreported rubella outbreak, not by Zika. (An outbreak of rubella among pregnant women occurred in the US decades ago and was connected to birth defects in newborns. During the 1964-65 rubella outbreak, 12 million Americans contacted the rubella virus.)
The vaccine rumors are exasperating Patricia Ismael de Carvalho, general director of information and strategic actions in epidemiological surveillance for the Pernambuco State Secretariat of Health. She insisted that vaccines present no danger to pregnant women, and that there is nothing to support the theory. “It’s impossible. Vaccinations given to pregnant women are all inactivated viruses. There is nothing active in the vaccine, nothing to cause harm,” she said.
Claudio Maierovitch, the Brazilian Health Ministry’s director of surveillance of communicable diseases, said there was a danger that fear, gossip, and scant scientific information would lead people to ignore the government’s exhortations about protecting themselves from mosquito bites and removing standing water that allows mosquitoes to breed. “Everything about Zika is new, and there is an aura of mystery about it, which leaves everyone open to new stories and new ideas about where it came from,” Dr. Maierovitch said.
Brazil’s Health Minister, Marcelo Castro, said he has “100 percent certainty” that a link exists between Zika and microcephaly. Michel Misse, a sociologist at the Federal University of Rio de Janeiro, said that rumors and conspiracy theories played an outsize role in Brazilian society, and that the spate of crises buffeting the Brazilian government made people question and doubt authority. “Given the political moment we are living in,” he said, “a lot of people are not happy with our government, and it definitely plays a role when it comes to believing rumors that blame the government for things that are going wrong.”
Another unknown factor in the Zika virus explosion is whether it’s a coincidence that the increase of Zika cases is happening during the hottest year in the historical record. Scientists say it will take them years to figure that out, and pointed to other factors that may have played a larger role in starting the crisis, such as increased deforestation and urbanization. But these same experts added that the Zika epidemic, as well as the related spread of dengue, should be interpreted as warnings of another danger posed by global climate change. Over the coming decades, global warming is likely to increase the range of the Zika mosquito and speed their life cycle, encouraging their spread deeper into temperate countries like the United States.
“As we get continued warming, it’s going to become more difficult to control mosquitoes,” said Andrew Monaghan, who is studying the interaction of climate and health at the National Center for Atmospheric Research in Boulder, Colorado. “The warmer it is, the faster they can develop from egg to adult, and the faster they can incubate viruses.”
Transported by slave ships from Africa, the Aedes aegypti mosquito that carries Zika and other diseases arrived in Brazil in the late 18th century and quickly established itself across South America, spreading disease in its wake. In 1928, a yellow fever outbreak caused by this mosquito in Rio killed more than 1,000 people in one month. In the 1940s and ’50s, Brazilian authorities began an eradication effort that relied on the pesticide DDT and intrusive home inspections that were carried out by the authoritarian government of Getúlio Vargas.
By 1958, the Pan-American Health Organization (PAHO) declared the Aedes aegypti mosquito vanquished in Brazil, and in the years that followed, in much of the continent. In 1947, an outbreak of yellow fever prompted the PAHO to launch a Continental Campaign for the Eradication of the Aedes aegypti mosquito. Yet victory was short-lived, and by the late 1960s, the deadly mosquito had returned to Brazil, according to Rodrigo Cesar da Silva Magalhães, a historian who has tracked the centuries-long war against the mosquito. Aedes aegypti reappeared in Belém in 1967, and then began to spread across Brazil in the late 1970s and early 1980s.
The World Health Organization (WHO) declared Zika a global public health emergency on February 1, 2016, only the fourth time in its history that it has raised such an alert. On February 13, the Brazilian government launched a nationwide prevention drive, with 220,000 military troops accompanied by mosquito control teams handing out pamphlets on how to prevent the spread of the virus. President Dilma Rousseff traveled to Rio to oversee the effort. She also dispatched Cabinet members to each of Brazil’s 27 states for the “National Day of Mobilization Zika Zero.” The Education Ministry said nearly 190,000 basic education schools, universities, and vocational training centers were visited on Friday, February 19.
The national campaign reflects the growing urgency among Brazilian officials who are battling both the spread of the virus and international alarm that could dampen attendance at the Summer Olympics. The government’s message being distributed by military personnel is “that Brazilians are largely responsible for controlling mosquitoes in and around their homes.” The message has received mixed reactions from residents, some of whom said they hoped that the government might play a more direct role in reducing mosquito populations through the application of insecticides, or by improving sanitation in impoverished communities.
In communities with unreliable water supplies, many residents collect water in rooftop tanks or containers, providing ideal nurseries for the mosquito larvae if left uncovered. Still, many Brazilians are reluctant to let government agents into their homes, and there have been reports of thieves masquerading as health visitors. As a result, some official teams were either barred from entering certain properties, or found no one there to let them in, leading authorities to use drones to access such sites in several cities in Brazil.
The question these days is how effective the government will be in its efforts at eradication of the dangerous mosquito. Americo Freire, a contemporary history professor at the Getúlio Vargas Foundation in Rio noted, “Rousseff is trying to present herself as the head of state. This terrible public health crisis could be an element to give her some political and moral support.”
While Brazil’s regional and national administrations should be held responsible for sanitation measures that would have controlled mosquito populations, Zika isn’t a “unique failing of Brazil’s health system,” said Eric Farnsworth, vice-president of the Council of the Americas.
Brazil’s Minister of Cities says there is a “strong link” between the country’s woeful sanitation system and the current outbreak of the Zika virus. Minister Gilberto Kassab said that while the country has made progress over the past decade, sewage and water delivery systems leave “much to be desired,” and he promised that basic sanitation will continue to be a government priority.
Sewage often flows through open channels into stagnant waters, and a lack of piped water service leads many Brazilians to rely on tanks that create a habitat for the mosquito that transmits Zika. Kassab conceded the virus spread “has a strong link with the absence of sanitation,” in quotes carried by Estado de S. Paulo.
Trata Brasil, a Sao Paulo-based pro-sanitation organization, says 35 million Brazilians, or around 18 percent of the population, do not have regular access to tap water. The group estimates that more than 60 percent of raw sewage nationwide flows untreated into rivers and the South Atlantic ocean.
Authorities aren’t escaping blame, especially the current Health Minister Marcelo Castro, who was appointed last year. When the connection between Zika and microcephaly began drawing attention in November, Castro’s apparently flippant response — “sex is for amateurs, pregnancy is for professionals” — angered many Brazilians. His confession that Brazil is “badly losing” the war on mosquitoes wasn’t well-received either.
Any setback to Brazil this year would be a fresh blow to the country’s shrinking economy and the government. Dilma Rousseff’s chief of staff Jaques Wagner said that it’s “not recommended” for pregnant women to travel to Rio for the Olympics, but he said there’s no chance Brazil will cancel the games.
Some scientists have a different approach to solving the Zika health emergency. Rather than mosquito eradication or a Zika vaccine, a growing number of infectious disease experts say that delaying pregnancy could work as an effective strategy against the virus, and may be the most effective way to break the back of this global epidemic. Such a strategy would not stop the spread of the mild illness that Zika causes in adults, or the surge in cases of Guillain-Barré paralysis syndrome linked to those. But waiting through at least one hot, wet, high-transmission summer season may save thousands of newborns from Zika’s terrifying suspected consequences.
The reason delaying pregnancy can be so important is because of something scientists call “herd immunity.” Non-pregnant women who are bitten, infected, and recover become immune and can later have a baby safely, experts said. And if everyone around a young woman becomes immune that way, she is safer even if she is not immune because mosquitoes cannot get the virus from them to give to her. This is herd immunity. A healthy mosquito passes the Zika virus to humans by first contracting it from biting a human who has the virus already. Additionally, if women can delay getting pregnant for as long as two years, a vaccine may arrive.
The most complicated problem, scientists say, is that no one knows exactly how much of a population must be sick and recover to create herd immunity. The Zika virus moves quickly, suggesting that immunity would build quickly. Yap Island, in Micronesia, had a 2007 Zika outbreak that lasted less than six months but infected 73 percent of the population, presumably immunizing all of them. Other Pacific Island outbreaks petered out in five to eight months, suggesting a tipping point had been reached.
After first being discovered in Uganda in 1947, the Zika virus seemed to disappear. For more than half a century there were no confirmed outbreaks of Zika, and only 14 confirmed human cases. Then, in 2007, Zika appeared on the island of Yap and nearby islands in Micronesia, 800 miles east of the Philippines, where nearly 50 people had been infected. Six years later, it showed up in French Polynesia, 5,000 miles to the southeast, where thousands contracted the virus. Today, it’s conceivable that more than one million have been infected in Brazil alone.
Doctors and researchers are continuing to investigate the dramatic increase in the documented cases of microcephaly in Brazil. The roots of the microcephaly surge will be tested as part of a case-controlled study underway at IMIP, a maternal and infant care hospital in Recife, said Dr. Adriana Scavuzzi, the hospital’s women’s health coordinator. Researchers will interview 200 women, half mothers of babies with confirmed microcephaly, and half mothers of apparently healthy children, about their lives and health history — including their vaccination history. Dr. Scavuzzi said she is “almost convinced” of the microcephaly-Zika connection, but that certainty will only come when more data is available. At this point, she said, scientists can only say the microcephaly outbreak is “highly likely” to have been caused by Zika.
US and Brazilian researchers are heading to João Pessoa in the state of Paraíba today, February 22, to recruit mothers and babies in one of the biggest government-led studies to understand whether the Zika virus is linked to microcephaly. The study has been in the planning stages for several weeks. It will pair researchers at the US Centers for Disease Control and Prevention (CDC) with Brazilian experts from the Health Ministry to examine babies already born with microcephaly and their mothers to determine whether Zika or some other infection caused their malady. The team will also try to determine the most common characteristics of microcephaly that might be specifically associated with Zika, and they will research whether other abnormalities might result from exposure to the virus.
Dr. Bruce Aylward, the WHO’s head of emergency response, said at a news conference in Geneva that the evidence was already so strong that “at this time, the virus is considered guilty until proven innocent.” Experts, he said, are waiting for a cohort of about 5,000 pregnant women, most of them in Colombia, to give birth. Those women, all of whom had Zika infections early in their pregnancies, were enrolled in a large clinical trial that effectively started in October, so most are expected to start giving birth in June. They will be tested to be sure they do not have any other known causes of microcephaly, such as rubella, toxoplasmosis, or genetic mutations. Researchers will compare their babies to those of a large group of pregnant women who did not have Zika.
On another front, Brazil has signed an agreement with the University of Texas to develop a vaccine against the Zika virus, adding the goal is for the vaccine to be ready for clinical testing within 12 months. Health Minister Marcelo Castro said at a news conference that the government will invest 1.9 million dollars (7.6 million reais) in the research, which will be jointly conducted by the University of Texas Medical Branch in Galveston and the Evandro Chagas Institute in Belem. The Health Ministry also has reached vaccine partnerships with the US Centers for Disease Control and Prevention and is looking to work with pharmaceutical giant GlaxoSmithKline because of its role developing a vaccine against Ebola.
Marie-Paule Kieny, WHO’s assistant director-general for health systems and innovation, said that 15 companies or groups have been identified as possible participants in the hunt for a Zika vaccine. A top official from the WHO said that a vaccine was approximately 18 months away.
Minister Castro says WHO chief Margaret Chan is expected to visit Brazil on February 23 to help coordinate the government’s response with other agencies around the world. An initial delegation of 15 researchers from the CDC (Centers for Disease Control) in the US arrived in Brazil on February 12.
Two US-Brazilian studies on whether the Zika virus is causing birth defects and other neurological disorders will yield initial results by May, a senior US public health official has said. The WHO says it could take four to six months to prove the link.
Colombia has emerged as the second front in the battle against Zika in the Americas. At least 25,000 Colombians have contracted the virus, a number officials say could surge to 600,000. Zika has already spread to 250 cities and towns in Colombia. The first cases of Zika were detected only in October of 2015. Most pregnant women who have contracted the disease in Colombia have not given birth yet, and no cases have been confirmed of infants born microcephaly.
Today, nearly 3,000 pregnant women with Zika in Colombia are in an agonizing position. While all have recovered from Zika, they now are faced with the moral dilemma of considering whether to abort their fetuses. Unlike in Brazil, in Colombia some expecting mothers are being given the choice to end their pregnancies under laws that allow abortions in these cases. Even if Zika does cause microcephaly, there is often no way to predict how a baby will be affected. Infants with microcephaly can endure a wide range of mental and physical disabilities, while some, about 10 percent, have no limitations whatsoever.
Honduras has registered 4,785 cases of Zika, according to the deputy health minister, who added that no cases of birth defects associated with the virus have yet been detected. Nevertheless, it is possible that more Zika cases may exist in Honduras since 75 percent of those infected do not show any symptoms and thus do not report the illness.
There have been more than 50 cases of Americans infected abroad, and most experts believe that by summer, the continental United States will have some of its own homegrown cases, meaning that domestic mosquitoes will have the virus. The United States’ best defense against Zika is its air-conditioning and window screens. Yellow fever and malaria killed tens of thousands of Americans through the end of the 19th century, but higher living standards helped stop it. Screens and round-the-clock air conditioning block virus transmission by keeping healthy mosquitoes from biting infected people and spreading the virus. They also prevent infected mosquitoes from biting healthy people.
As the Zika virus spreads in Latin America, Catholic leaders are warning women against using contraceptives or having abortions, even as health officials in some countries are advising women not to get pregnant because of the risk of birth defects. Nearly 70 percent of adults in Latin America still identify as Catholic, but that is down from 94 percent in 1950, according to a study by the Pew Research Center. Much of the fall-off has occurred in just the last generation.
South America happens to be the continent with the highest proportion of Catholics who already disagree with the church on abortion and birth control, according to a large international poll commissioned by Univision in 2014. Seventy-three percent of Catholics in Latin America said that abortion should be allowed in some or all cases, and 91 percent supported the use of contraceptives — a higher percentage even than in Europe or the United States. On February 18, Pope Francis, while flying back to Rome after a visit to Mexico, welcomed questions from journalists who were on the flight with him. When asked about Zika, he declared that contraceptives could be used to prevent the spread of Zika, which is a strong departure from official Vatican policy.
In conclusion, there is still a great deal yet to be learned about Zika. The virus is poorly understood by scientists. Early studies of the virus indicate that as many as 80 percent of those infected are asymptomatic, so pregnant women with no symptoms may still be infected with the virus and pass it to their fetus without realizing it. Even those people who experience symptoms of the illness report it is mild.Still to be determined is whether all infected women pass the virus to the fetus, and if all infected fetuses are damaged by the virus.
Brazilian officials reported a nearly 50 percent jump in cases of dengue fever reported over a three-week period in January. “This is a very strong indication that the Zika cases are increasing and that the combat against the mosquito is not being efficient,” said Marcos Lago, an associate professor of infectious diseases and pediatrics at the State University of Rio de Janeiro. “We will probably have a dengue epidemic,” Lago said. “And this dengue epidemic will be accompanied by a Zika epidemic.”
Here are the facts we currently know: 1) Zika is increasing rapidly, but the virus symptoms are not nearly as serious as dengue or yellow fever. 2) Poor people, particularly in the Northeast of Brazil, are at much greater risk because of weather and sanitary conditions. 3) The Brazilian government has a vested interest in keeping misinformation and panic to a minimum because it hinders efforts at eradication as well as tourism, which is a major issue this year with the Olympics.
4) Scientists have discovered evidence indicating a link between microcephaly and Zika, but a direct causal relationship has yet to be scientifically proven. The Zika virus or its antibodies have been found in the brain tissue, the amniotic fluid, or the spinal fluid of at least 41 babies in Brazil with microcephaly. Scientists still can’t say for sure whether there is a connection between microcephaly and Zika or how it happens. Nevertheless, says Eric Rubin, an infectious disease researcher at Harvard University, “The evidence is pretty good, and we don’t need absolute proof in order to act.” The type of study required to prove causation, however, takes a lot of time, money, and study volunteers to complete. So far, scientists have only carefully analyzed a handful of cases of microcephaly in babies born in Brazil. “I don’t think we’re going to have a definitive answer in the near future,” says Larry Kociolek, an infectious disease specialist at the Lurie Children’s Hospital of Chicago.
5) The Zika mosquito had been declared eradicated in Brazil in the 1950s, thanks to a massive government effort. In the decades since then, little has been done to control the Aedes aegypti mosquito population. However, there has been some recent success, such as in the northern state of Acre, which managed to slash the incidence of dengue fever to 350 cases last year from over 30,000 in previous years.
Looking forward amid the mystery and panic, there are some positive developments. First, while a vaccine is still probably years away, in 1958 Brazil was declared free of the Zika mosquito. Such a mass eradication program could be attempted again now.
Second, because the Zika virus is not that powerful, the population could develop an immunity to it as happened in Micronesia, an immunological phenomenon known as “herd immunity.”
Spanish Olympic gold medalist Marina Alabau says she got Zika while training in Brazil in December. However, the windsurfer said she was never hospitalized and the virus won’t stop her from competing in the Rio Games in August. Ms. Alabau won a gold medal in windsurfing in the London Olympics in 2012. She says by the end of January she was back in competition, first in Miami and now in Israel. “Some athletes ask me about it, and I say it isn’t as serious as they say,” she said. “It’s not as bad as a flu or a cold.”
Third, a group of Brazilian researchers has developed a molecular exam for diagnosing Zika within five hours, a much shorter time than current exams, and the new test will be used to facilitate studies on methods to combat the virus. The exam, which is 100 percent accurate, detects Zika in samples of blood, saliva, and urine, the University of Campinas announced, where scientists developed the test in association with colleagues at the University of São Paulo and the University of São Paulo State. The test differentiates among Zika, dengue, and chikungunya, all of which are transmitted by the same mosquito and have similar symptoms.
Also, Brazilian scientists in Rio have obtained the genome sequence of the Zika virus. The scientists were able to identify, “the full order of the virus’s genetic data, a significant step towards understanding how Zika behaves in the human body and how to develop a vaccine as well as new tests,” Agencia Brasil reported on February 20.
Iván Darío Vélez, a tropical disease specialist at the University of Antioquia in Colombia, said scientists there had successfully bred a mosquito that was resistant to Zika, dengue, chikungunya and yellow fever. To create the strain, Dr. Vélez infected mosquitoes with bacteria that block the insects from picking up the virus. When the mosquitoes breed with ones that are susceptible to the disease, their progeny are shielded.
Fourth, while Zika and dengue and yellow fever have been around for a long time, this is the first time any of those viruses have been connected with birth defects, such as microcephaly, or death through paralysis as in Guillain-Barré syndrome. No one knows why suddenly these conditions are arising alongside the rise in Zika, or why these more serious conditions are not occurring in other countries that have outbreaks of Zika. It’s possible that the cases of microcephaly and Guillain-Barré will be linked to other factors, such as environmental elements that could be rectified more readily than eliminating the mosquito for developing a vaccine.
[Research for this article comes from The New York Times, PBS Frontline, the Associated Press, the Washington Post, Reuters, the Latin American Herald Tribune, Fortune, and the websites of LiveScience, Pacific Standard, and Metabunk.]