Mosquitos

GM Mosquito Progeny Not Dying in Brazil: Study

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The biotech Oxitec had released the genetically engineered insects with the hope that they would breed with wild populations and produce offspring that die young. But that’s not always happening.

Sep 17, 2019
KERRY GRENS

1.1K

Update (September 18): Scientific Reports has issued an editor’s note, stating that “the conclusions of this paper are subject to criticisms that are being considered by editors.” In a statement sent to The Scientist, Oxitec says it takes issues with a number of conclusions the authors made in their report. Among them, “The authors infer that Oxitec’s self-limiting genes persist in the environment. Yet as confirmed by their own data, multiple other scientific studies and regulatory filings, this is not the case. Oxitec’s self-limiting genes do not establish or spread in the environment.” The journal’s note states that it will issue another response once the issues are resolved.

ABOVE: © ISTOCK.COM, KWANGMOOZAA

Afield experiment in Brazil that deployed genetically modified mosquitoes to control wild populations of the pest may be having unintended consequences. According to a genetic analysis of mosquitoes in the area, it appears the engineered stock has bred with wild mosquitoes and created viable, hybrid insects, scientists reported in Scientific Reports last week (September 10).

“The claim was that genes from the release strain would not get into the general population because offspring would die,” coauthor Jeffrey Powell, a professor of ecology and evolutionary biology at Yale University, says in a press release. “That obviously was not what happened.”

The biotech company Oxitec began releasing hundreds of thousands of genetically engineered mosquitoes in the city of Jacobina between 2013 and 2015. The idea is that genetically modified (GM) males would mate with wildtype females and pass on a gene that kills their offspring before they themselves can breed, ultimately knocking down Jacobina’s mosquito populations.

The study’s authors, who are not affiliated with Oxitec, began sampling mosquitoes in Jacobina before, during, and after the deployment of the GM insects. They created a genetic panel that distinguished the wildtype mosquitoes from the introduced ones and found that insects analyzed more than two years after the releases stopped were progeny of both wildtype and mutant, or OX513A, lineages. “The degree of introgression is not trivial,” the authors write in their report. “Depending on sample and criterion used to define unambiguous introgression, from about 10% to 60% of all individuals have some OX513A genome.”

Oxitec takes issue with Powell’s study. The company tells Gizmodo it is “currently in the process of working with the Nature Research publishers to remove or substantially correct this article, which was found to contain numerous false, speculative and unsubstantiated claims and statements about Oxitec’s mosquito technology.”

The company has reported positive results as far as reducing mosquito populations—and potentially mosquito-borne diseases—in its field sites.

Texas and Florida have considered using Oxitec’s GM mosquitoes to control populations in their states. On September 11, the Environmental Protection Agency posted a request for public comment on Oxitec’s application to release engineered insects in the Florida Keys. If approved, it would be the first deployment of the animals in the US.

Kerry Grens is a senior editor and the news director of The Scientist. Email her at kgrens@the-scientist.com.

Ohio Vector-borne Disease Update 07/12/2019

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As of 07/11/19, 5,389 of 5,642 pooled mosquito samples (170,866 Culex spp. total) have been tested and 7 samples were positive for West Nile virus (WNV) from Franklin (5), Ross (1) and Summit (1) counties. Below is a graph of the minimum infection rate (MIR) in Culex spp. mosquitoes collected in Ohio. As you can see, the MIR is below where it was at this time last year. No human cases have been reported so far.

While WNV activity in Ohio is currently low, in the past week, several suspected cases of La Crosse virus disease have been reported. Although these cases are pending confirmatory testing, this suggests La Crosse virus activity is ongoing in Ohio. Please ensure you continue with your community and public education efforts focusing on personal protection to avoid mosquito bites and source reduction to prevent mosquito breeding.

For more information, see the current Ohio vector-borne surveillance update at www.odh.ohio.gov/vectorupdate.

NOTE: Since Internet Explorer is no longer being supported, ODH’s new webpage is best viewed in other browsers (e.g. Microsoft Edge, Google Chrome, Firefox, etc.).

Please do not hesitate to contact the Zoonotic Disease Program (614-752-1029, option 1) if you have any questions.

Ohio Vectorborne Disease Surveillance Update

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The Ohio Department of Health (ODH) Zoonotic Disease Program, in partnership with ODH Laboratory, local public health partners and sanitary district partners, collects and tests mosquitoes and ticks from many communities in Ohio as part of statewide vectorborne disease surveillance.  This surveillance also includes monitoring for human and veterinary cases as well.

Collections of mosquitoes are identified and tested at ODH Laboratory, while ticks are identified by ODH entomologists.  Results from mosquito and tick identification and testing are shared with our partners who use the information to guide public health interventions.

We will monitor for mosquito infections and tick findings throughout the summer and fall and will report positive results and summary statistics on this website, updated each Friday at noon.  Please download the attached document for a more detailed summary of mosquito and tick surveillance in Ohio.

2019 Numbers At-A-Glance

As of July 3, 2019

West Nile virus

Infographic: West Nile virus surveillance statistics

La Crosse/Unspecified California encephalitis virus

Infographic: La Crosse/unspecified California encephalitis virus surveillance statistics

Travel-associated mosquito-borne diseases

Infographic: Travel-associated mosquito-borne disease surveillance statistics

* Ohioans traveling to areas where local transmission is occurring should be aware of the ongoing situation and make every effort to avoid mosquito bites.  Additional information can be found from the Centers for Disease Control and Prevention (CDC)’s Travelers’ Health and Pan-American Health Organization websites.

West Nile Virus: Case Update

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As of 8/20,2018, ODH is reporting 5 human West Nile virus (WNV) cases, including 1 fatality, and 2 asymptomatic WNV viremic blood donors in Ohio.  Additionally, ODH received a report today from the Ohio Department of Agriculture of an equine case in an unvaccinated horse.  WNV activity in mosquitoes continues to rise and we have now seen indications of virus activity in 52 Ohio counties so far this year.

The graph below shows where we are this year with infection rates in mosquitoes compared to 2012, a high WNV activity year (red dotted line), and 2016, a relatively normal WNV activity year (green dashed line):

In addition to WNV, ODH is also reporting 6 LAC cases and 2 unspecified California virus cases.  The rainfall we’ve had this summer has continuously filled tree holes and containers with water, creating ideal conditions for tree hole mosquitoes (vectors of LAC virus) to breed. For more information about arbovirus cases and surveillance data, see the current Ohio arbovirus surveillance update at http://www.odh.ohio.gov/arboupdate, updated earlier today.

There are quite a few weeks left in this  mosquito season and cases can occur into October, so it is very important to continue your community and public education efforts focusing on personal protection and source reduction. Also, please call the Zoonotic Disease Program (ZDP) at (614) 752-1029 if you have any questions.

West Nile Virus Activity Continues to Increase

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West Nile virus activity continues to increase and the statewide mosquito infection rate as of week 27 (week of July 4) is trending with infection rates we saw in 2012, our last epidemic year when we recorded 122 human cases.  No human cases have been reported this year yet; however, 2 asymptomatic viremic blood donors were reported this past week, so there is evidence human infections have occurred. If you haven’t already, please be sure to increase your community and public education efforts focusing on personal protection and source reduction.

Here is a graph that shows where we are this year as of week 27 with infection rates in mosquitoes compared to 2012, an epidemic WNV year (blue line), and 2016, a relatively average WNV year (orange line):

For more information, see the current Ohio arbovirus surveillance update at http://www.odh.ohio.gov/arboupdate.  The data on this website was last updated on 7/16/18 and will be updated each Monday thru mosquito season. Please call the Zoonotic Disease Program (ZDP) at (614) 752-1029 if you have any questions.

Minimum Infection Rate: West Nile Virus

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West Nile virus activity has been increasing, and it has now been detected in mosquitoes in 14 counties as of noon on 7/9/18.  Of the 4,832 pooled mosquito samples (141,835 mosquitoes total) tested so far, 110 samples have tested positive from Athens (1), Delaware (1), Franklin (43), Hamilton (1), Hancock (1), Licking (4), Lucas (25), Portage (12), Richland (3), Ross (1), Stark (1), Summit (15), Tuscarawas (1) and Wood (1) counties.  This is up from 26 positive samples reported in the last message.  No human cases have been reported so far.

Here is a graph that shows where we are this year as of week 25 with infection rates in mosquitoes compared to 2012, a high WNV activity year (blue line), and 2016, a relatively low WNV activity year (orange line):

 

For more information, see the current Ohio arbovirus surveillance update at http://www.odh.ohio.gov/arboupdate.  The data on this website was last updated on 7/9/18 and will be updated each Monday thru mosquito season.

Ohio Arbovirus Surveillance Updates

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Beginning this year, the Ohio arbovirus surveillance update can be found on the ODH website at http://www.odh.ohio.gov/arboupdate .  The table will be updated each Monday through mosquito season.

Ohio Mosquito-borne Disease SurveillanceFight the Bite! Avoid, Plan, Stop
June 18, 2018

Mosquito season is here.  The Ohio Department of Health (ODH) Zoonotic Disease Program, in partnership with ODH Laboratory, local public health partners and sanitary district partners, collects and tests mosquitoes from many communities in Ohio as part of statewide mosquito-borne disease surveillance.  This surveillance also includes monitoring for human and veterinary cases as well.

Full Update:   http://www.odh.ohio.gov/arboupdate