GM mosquito trial results in Cayman prove ineffective in tackling dengue
GM insect company Oxitec today published results of its trials of genetically modified (GM) mosquitoes in the Cayman Islands in 2010 (1). The results were originally submitted to the journal Science in January 2011 but have now finally been published in Nature Biotechnology (1). The paper shows that Oxitec has no clear baseline for claims made in the press that it achieved an 80% reduction in the target population of mosquitoes, and that to achieve the claimed effect it significantly increased the number of adult GM mosquitoes it expected to release and also released additional GM pupae at locations spaced at 70 to 90m apart across the release site.
|GM dengue mosquito – Wiki image|
“This poor quality paper pours cold water on the idea that Oxitec’s GM mosquitoes will be an effective way to tackle dengue” said Dr Helen Wallace, Director of GeneWatch UK. “Staff would be better employed using the well-established public health approach of removing mosquito breeding sites rather than in placing GM mosquito pupae at intervals across a site. Removing the flower pots and water containers where mosquitoes breed has the added benefit of reducing both mosquito species that spread dengue, not just one of them. It is hard to see how Oxitec can justify commercial releases of its GM mosquitoes based on such poor data.”
During the experiments, Oxitec increased releases of GM male mosquitoes from the expected 3,150 males per hectare per week to about 14,000. When local residents complained about the nuisance caused by the very large number of mosquitoes, Oxitec halved the number of adults released and deployed GM pupae at the site (2). Oxitec reports several different estimates of the reduction in the wild population of mosquitoes, ranging from 60 per cent to 85 per cent depending what comparisons are made. Because there is no baseline data on mosquito populations at the site there is considerable uncertainty in the results. At different times, Oxitec moved mosquito traps from one location to another and changed the size of the release site, adding to difficulties in interpreting the results.
This paper (published as Correspondence to the journal, two years after Oxitec press released its results) will increase the growing doubts about the efficacy of Oxitec’s approach and whether it will be a cost-effective way to tackle dengue fever.
Releasing such large numbers of mosquitoes adds to concerns that the small percentage of surviving GM mosquito offspring and accidental releases of GM female mosquitoes could pose unnecessary risks (3). Oxitec’s failure to publish and consult on a risk assessment and obtain informed consent from Cayman Islands’ residents before going ahead with its experiments remains unacceptable. Oxitec’s summary of the necessary regulatory requirements is misleading because it fails to mention that it should have sent a risk assessment which meets European standards to the EU and UK authorities before exporting GM mosquito eggs to the Cayman Islands (4). Informed consent to such experiments is not possible unless public information on the risks has been made available.
Progress on dengue vaccines and other approaches means that it is likely that more effective public health approaches can be combined with vaccination in the future. Impacts of vaccination on immunity and cross-immunity must be considered as part of the regulatory assessment for new vaccines, but these important issues have been ignored by Oxitec when it promotes its GM mosquitoes in dengue-endemic countries (3). Poorly effective approaches to reducing mosquito populations can actually increase the risk of the more severe form of dengue, due to the loss of cross-immunity to different serotypes of the dengue virus. Other risks include a possible increase in the numbers of the second mosquito species that transmits dengue (the Asian Tiger mosquito); and increases in the number of surviving GM mosquitoes over time.
“Plans to scale-up releases of GM mosquitoes in dengue-endemic Brazil should be halted whilst the implications of these poor results are thoroughly considered” said Dr Wallace. “Authorities in other places where releases have been planned, such as Florida and Panama, should also stop and think again”.
For further information contact:
Dr Helen Wallace: 01298-24300 (office); 07903-311584 (mobile).
Notes for Editors:
(1) Harris et al. (2012) Successful suppression of a field mosquito population by sustained release of engineered male mosquitoes. Correspondence to Nature Biotechnology.
(2) “The only consistent project-related criticism from the community related to nuisance from the large numbers of males in each individual release in the first part of Period 3. In response we promptly reduced these numbers and moved the release points further from habitations. We also partly substituted with pupal releases, from which adults emerge over a period of time. Following these changes, no further adverse comments were received”. Supplementary material to (1).
(3) Reeves RG et al. (2012) Scientific Standards and the Regulation of Genetically Modified Insects.
Lehane MJ, ed. PLoS Neglected Tropical Diseases, 6(1), p.e1502.
(4) Oxitec’s Genetically Modified Mosquitoes: Ongoing Concerns. GeneWatch UK briefing. August 2012. On: http://www.genewatch.org/uploads/f03c6d66a9b354535738483c1c3d49e4/Oxitec_unansweredQs_fin.pdf
New toxic strain of H5N1 bird flu spreading fast in Vietnam
September 9, 2012 – VIETNAM – A new highly-toxic strain of the potentially deadly bird flu virus has appeared in Vietnam and is spreading fast, according to state media reports. The strain appeared to be a mutation of the H5N1 virus which swept through the country’s poultry flocks last year, forcing mass culls of birds in affected areas, according to agriculture officials. The new virus “is quickly spreading and this is the big concern of the government”, Deputy Minister of Agriculture and Rural Development Diep Kinh Tan said, according to a Thursday report in the VietnamNet online newspaper. Experts cited in the report said the new virus appeared in July and had spread through Vietnam’s northern and central regions in August. Outbreaks have been detected in six provinces so far and some 180,000 birds have been culled, the Animal Health department said. The Central Veterinary Diagnosis Centre said the virus appeared similar to the standard strains of bird flu but was more toxic. The centre will test how much protection existing vaccines for humans offer, the report said. Some experts suggested that the new strain resulted from widespread smuggling of poultry from China into the northern parts of Vietnam. According to the World Health Organization, Vietnam has recorded one of the highest numbers of fatalities from bird flu in Southeast Asia, with at least 59 deaths since 2003. The avian influenza virus has killed more than 330 people around the world, and scientists fear it could mutate into a form readily transmissible between humans, with the potential to cause millions of deaths.
West Nile in Hidalgo
(AP) – 3 days ago
GOMA, Congo (AP) — Local authorities in eastern Congo say that the population lack of information on Ebola and the traditional practice of washing corpses before funerals are helping the epidemic to spread.
Fifteen people have died in the current outbreak, which started in mid-August. It started in the village of Isiro and has now spread to Viadana. Medical experts say increased education is needed to encourage people to use extreme caution when washing the bodies of Ebola victims before burial. The disease is spread by contamination from body fluids, including sweat.
Although this is the ninth Ebola epidemic in Congo, it is the first one in the Haut-Uélé territory, in northeastern Congo. Ebola has no cure and is deadly in 40 percent to 90 percent of cases. The disease causes severe internal bleeding.
British Columbia to require flu vaccines for ALL healthcare workers
Friday, September 07, 2012 by: Jonathan Benson, staff writer
(NaturalNews) The Canadian province of British Columbia has become the first in that nation to mandate that all healthcare workers get vaccinated yearly for influenza, or else be forced to wear face masks every time they work, according to CBC News. Despite the fact that flu vaccines have never even been proven to work, B.C. health authorities have decided that healthcare workers should not be allowed any freedom of health choice in the matter, at least not without having to comply by humiliating consequences as a result.
There are so many reasons why this latest affront to health freedom is both mindless and absurd. As we pointed out back in 2009, flu masks do not even effectively prevent the spread of influenza, which makes the mandate that unvaccinated healthcare workers wear them to protect patients patently ridiculous (http://www.naturalnews.com/026160_preparedness_flu_swine.html). Numerous studies have also shown that flu shots are wholly ineffective at preventing flu infection, despite all the government hype. (http://www.naturalnews.com)
But since only about 40 percent of B.C. healthcare workers get vaccinated every year — this percentage has been steadily dropping year after year — health authorities are apparently deeply worried that their flu vaccine scam is quickly losing credibility. So the only way to effectively stop this, in their own estimate, is to basically force healthcare workers to get their annual flu shots, or else be summoned to look silly wearing “scarlet letter” face masks that serve no legitimate purpose.
This is the same tactic that many healthcare authorities in the U.S. adopted during the great “swine flu” hoax of 2009. Even though federal officials openly admitted that the N95 face masks being encouraged during this so-called “pandemic” were not foolproof by any means (http://www.latimes.com), hospitals across the country began enacting draconian policies that required unvaccinated healthcare workers to wear them at all times while working.
Yosemite hantavirus warning extends worldwide
UPDATE, 6:35 p.m. Sept. 6: A third Yosemite visitor has died from rodent-borne hantavirus disease, which has infected eight travelers who stayed at least one night in the California national park between June 10 and late August, Reuters reports. The park has also extended its alert to 12,000 more former visitors, warning them of possible exposure to the rare but deadly virus.
U.S. officials have warned travelers from 39 other countries, most in the European Union, that those who stayed in certain Yosemite National Park tent cabins earlier this summer may have been exposed to a rare but deadly mouse-borne hantavirus, a park service epidemiologist told Reuters Tuesday.
Of the 10,000 people the federal Centers for Disease Control estimate could be at risk of contracting hantavirus pulmonary syndrome from their stays in Yosemite between June 10 and Aug. 24, some 2,500 live outside the USA, said Dr. David Wong.
Six cases of the rodent-borne disease have been linked to Yosemite, and two men, from northern California and Pennsylvania, have died. Park officials traced four of the cases to 91 “signature tent cabins” in Curry Village, one of Yosemite’s most popular campgrounds. They said a design flaw allowed mice to nest between the double walls of the insulated cabins. Another approximately 400 canvas-walled tent cabins in Curry Village remain open.
Britain’s Health Protection Agency said in a statement Monday that officials were “providing health advice and information … about the ongoing situation in the U.S.” to about 100 people believed to have traveled to the national park between June 10 and Aug. 24.
Yosemite officials have sent e-mails and letters to 3,100 people who reserved any of the 91 signature tent cabins during that time frame, urging them or anyone in their party to seek immediate medical attention if they start to show the initial flu-like symptoms of the disease, Associated Press reports.
Through 2011, the CDC had identified a total of 587 cases in 34 states. Of those cases, 556 occurred in or after 1993, when an outbreak in the “Four Corners” area of the Southwest killed at least 26 people. About three-quarters of the victims live in rural areas, and 36% of reported cases have resulted in death.
Spread through urine, droppings or saliva of infected rodents, primarily deer mice, hantavirus takes between one and six weeks before causing symptoms in humans, officials say. The disease is generally transmitted when people come in contact with an enclosed area that has been infested by mice, and most infections are caused by breathing small particles of mouse urine or droppings that have been stirred up into the air.
If the virus is contracted, says Yosemite’s website, symptoms include fever, headache, and muscle ache, and the disease progresses rapidly to severe difficulty in breathing and, in some cases, death.
News of the outbreak has rattled recent visitors, notes the Los Angeles Times. Rangers have fielded thousands of calls from concerned travelers, the park is answering questions on its Facebook page and a spokeswoman with the park’s lodging concessionaire Delaware North told the Times the company had a 20% cancellation rate for a usually sold-out Labor Day weekend.
Nearly 4 million people visit Yosemite each year, and about 70% of those congregate in Yosemite Valley, where Curry Village is located.
West Virginia Hantavirus Death Linked To Yosemite Outbreak
CHARLESTON, W.Va. (AP) — A West Virginian is the third person to die so far from a rodent-borne illness linked to some tent cabins at Yosemite National Park that has now stricken eight people in all, health officials said Thursday.
Five people are ill from the outbreak reported last week by park officials, who said up to 10,000 guests could have been exposed to hantavirus pulmonary syndrome from sleeping in the cabins since June 10.
More infections could be reported. Alerts from the U.S. Centers for Disease Control and Prevention sent to public health agencies, doctors and hospitals have turned up other suspected cases that have not yet been confirmed. This week the European CDC and the World Health Organization issued global alerts for travelers to any country to avoid exposure to rodents.
Dr. Rahul Gupta, director of the Kanawha-Charleston Health Department, declined to release details of the West Virginia victim at a news conference.
Gupta said the victim had visited the park since June but declined to be more specific, citing the family’s wish to grieve in private.
The other deaths occurred in California and Pennsylvania. Those that were sickened also were from California and the National Park Service said Wednesday they were either improving or recovering.
Seven of the cases involved guests at the insulated “Signature” cabins in the park’s historic Curry Village section. The California Department of Public Health said the other case involved someone who stayed in several High Sierra Camps in a different area of Yosemite in July.
Yosemite officials said the cabins have been closed and the park is reaching out to overnight guests who have stayed in the cabins.
Gupta declined to elaborate on whether anyone was traveling with the Kanawha County victim, although he said his department knew of no other cases of hantavirus.
“The time has lapsed in a way that it should not be a concern,” Gupta said.
Health officials say the disease isn’t spread from person to person. There is no cure for the virus, which can affect people of any age. The disease is carried in the feces, urine and saliva of deer mice and other rodents and carried on airborne particles and dust.
People can be infected by inhaling the virus or by handling infected rodents. Infected people usually have flu-like symptoms including fever, shortness of breath, chills and muscle and body aches. The illness can take six weeks to incubate before rapid acute respiratory and organ failure.
Anyone exhibiting the symptoms must be hospitalized. More than 36 percent of people who contract the rare illness will die from it.
Health officials said there have been 602 hantavirus cases nationally since the virus was first identified in 1993. The Yosemite cases are unique because they occurred in clusters, while previous cases have been individual exposures.
Park concessionaire Delaware North Co. had sent letters and emails to nearly 3,000 people who reserved the cabins between June and August, warning them that they might have been exposed. Because the rooms can hold up to four people, up to 7,000 more visitors might have been exposed, a park spokesman has said.
Yosemite’s hantavirus hotline has received thousands of calls about the outbreak.
“We want to make sure that visitors have clear information about this rare virus and understand the importance of early medical care,” Yosemite Superintendent Don Neubacher said Wednesday. “We continue to work closely with state and national public health officials, and we urge visitors who may have been exposed to hantavirus to seek medical attention at the first sign of symptoms.”
More than 60 hantavirus cases have been diagnosed in California since 1993. In West Virginia, the densest population of carrier mice are found in higher elevations. Gupta said only three cases of hantavirus have been documented in the state since 1981.
In 2004, a Virginia Tech graduate student who was conducting field studies of small mammals in Elkins died after contracting the disease.
“People do not need to freak out,” Gupta said. “This is not a common disease.”
West Nile virus hits San Antonio
Mosquitoes may seem harmless, nothing more than a nuisance to most, but because they feed on the blood of vertebrates, like humans, they can transmit harmful diseases. The evening news has been reporting the presence of the West Nile virus, a virus spread by mosquitoes, in Texas for the last few months, with the majority of the cases concentrated in the Dallas area. However, San Antonio is not immune to the effects of this disease; the virus has infected three people in Bexar County and caused the death of one of those victims just last week.
The Centers for Disease Control and Prevention first detected and reported the presence of the West Nile Virus in the United States in 1999. Since then, the virus has infected more than 30,000 people causing serious life-altering disease in some. The virus has been reported in 48 states and caused 65 deaths.
Although you should take precautions during the warm months when mosquitoes thrive, there is no need to panic at the site of every mosquito. The CDC reports that 80 percent of people who get bit by an infected mosquito will never show any symptoms of the virus. The other 20 percent develop mild symptoms including fever, headache, body aches, nausea, vomiting, skin rash and swollen lymph glands. These symptoms typically last a few days to several weeks. Only approximately 1 in every 150 cases of West Nile virus will develop severe symptoms including high fever, stiff neck, stupor, disorientation, tremors, convulsions, vision loss, numbness and even paralysis. These symptoms can last for several weeks and may cause permanent neurological damage or death.
Those over the age of 50 are at the greatest risk of developing severe West Nile illness. In fact, The San Antonio Express News reports the gentleman who died from the virus was a 77-year old retired military man. The City of San Antonio and military personnel have enacted mosquito elimination plans, but to keep you and your family safe from infection take the following precautions:
- Remove any standing water from around your home, such as in flower pots, buckets and barrels.
- Change pet water and bird bath water at least once a week to prevent mosquito larvae from hatching.
- Keep doors and windows closed or make sure the screens are intact.
- Wear protective clothing including long sleeves and pants, especially during dusk and dawn when mosquitoes are most active.
- Wear mosquito repellent that contains an EPA-registered active ingredient like DEET.
About the Author: