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- Written by: Lake County News reports
Summer is mosquito season, and a new study gives insight into why repellents work on mosquitoes.
Spray yourself with DEET, and you’ll repel mosquitoes, but why? It’s not because DEET jams their sense of smell; it’s because they dislike the smell of the chemical repellent intensely, researchers at the University of California, Davis have discovered in groundbreaking research published Monday.
“We found that mosquitoes can smell DEET and they stay away from it,” said noted chemical ecologist Walter Leal, professor of entomology at UC Davis. “DEET doesn’t mask the smell of the host or jam the insect’s senses. Mosquitoes don’t like it because it smells bad to them.”
The study's conclusions about how the repellent works is especially important in a time when West Nile Virus has reached California. The disease has so far affected 92 people in 13 California counties this summer, according to the state's West Nile Virus Web site.
DEET’s mode of action or how it works has puzzled scientists for more than 50 years.
The chemical insect repellent, developed by scientists at the U.S. Department of Agriculture and patented by the U.S. Army in 1946, is considered the “gold standard” of insect repellents worldwide. Worldwide, more than 200 million use DEET to ward off vectorborne diseases.
Scientists long surmised that DEET masks the smell of the host, or jams or corrupts the insect’s senses, interfering with its ability to locate a host. Mosquitoes and other blood-feeding insects find their hosts by body heat, skin odors, carbon dioxide (breath) or visual stimuli. Females need a blood meal to develop their eggs.
Entomologist James “Jim” Miller of Michigan State University praised the work as correcting “long-standing erroneous dogma.”
"For decades we were told that DEET warded off mosquito bites because it blocked insect response to lactic acid from the host – the key stimulus for blood-feeding,” said Miller. “Dr. Leal and co-workers escaped the key stimulus over-simplification to show that mosquito responses – like our own – result from a balancing of various positive and negative factors, all impinging on a tiny brain more capable than most people think of sophisticated decision-making.”
He said the work also shows that a recent study on DEET published in the flagship journal, Science, “apparently was flat-out wrong,” Miller said.
“One of the great attributes of science is that, over time, it is self-correcting,” he added.
Leal said previous findings of other scientists showed a “false positive” resulting from the experimental design.
The UC Davis work, “Mosquitoes Smell and Avoid the Insect repellent DEET,” is published in the Aug. 18 edition of the Proceedings of the National Academy of Sciences.
Mosquitoes detect DEET and other smells with their antennae. Leal and researcher Zain Syed discovered the exact neurons on the antennae that detect DEET, which are located beside other neurons that sense a chemical, 1-octen-3-ol, known to attract mosquitoes.
“I was so delighted when I first encountered the neuron that detects DEET, a synthetic compound,” said Syed. “I couldn’t believe my eyes because it goes against conventional wisdom so I repeated the experiment over and over until we discussed the findings in the lab.”
The UC Davis investigators set up odorless sugar-feeding stations, some containing DEET, and found that DEET actively repelled them. The mosquitoes they used were Culex quinquefasciatus, also known as the Southern house mosquito. The mosquito transmits West Nile virus, St. Louis encephalitis, and lymphatic filariasis, a disease caused by threadlike parasitic worms.
“Despite the fact DEET is the industry standard mosquito repellent, relatively little is known about how it actually works,” said UC Davis research entomologist William Reisen. “Previous studies have suggested a 'masking' or 'binding' with host emanations. Understanding the mode of action is especially important because DEET is used as the standard against which all other tentative replacement repellents are compared.”
What the study means to consumers
Dr. Jamesina Scott, district manager and research director for Lake County Vector Control, said there are several effective mosquito repellents on the market now – DEET, picaridin, oil of lemon eucalyptus, and IR-3535 – and understanding how DEET works to repel mosquitoes will help researchers to identify other compounds that work similarly to repel mosquitoes.
The Centers for Disease Control Web site (www.cdc.gov/ncidod/dvbid/westnile/RepellentUpdates.htm) has information for consumers about those four repellents, Scott said.
“For consumers, the critical point is that DEET is an effective mosquito repellent,” Scott said. “How DEET works is not as important to the consumer as the fact that it works well and that using a repellent reduces the risk of mosquito bites and mosquito-borne illness.”
The important things that consumers should know, according to Scott, are that:
They should use a mosquito repellent when they are outside, especially at dusk or dawn when mosquitoes are most active;
They should look for mosquito repellents containing DEET, picaridin, oil of lemon eucalyptus or IR3535
They should always follow the label directions when using a mosquito repellent.
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- Written by: Elizabeth Larson
It's another twist in the most unusual case of Renato Hughes Jr., who turned 24 on Friday and was acquitted earlier this month in a homicide trial for which he was tried for the deaths of friends Christian Foster and Rashad Williams.
The two men were shot by Clearlake Park homeowner Shannon Edmonds, into whose home Foster, Williams and Hughes had allegedly broken in search of marijuana on Dec. 7, 2005. That resulted in Hughes' trial under the provocative act doctrine, because he was taking part in a crime that could result in a lethal response.
The trial was moved to Martinez in Contra Costa County after a judge granted a change of venue late last year.
On Aug. 8 the 12-woman jury found Hughes not guilty of the two homicide counts, robbery and attempted murder, with the jury hanging on assault causing great bodily injury three days later, as Lake County News has reported.
Hughes was convicted of burglary and assault with a firearm.
On Friday morning, Judge Barbara Zuniga summoned back to her Martinez courtroom District Attorney Jon Hopkins and defense attorney Stuart Hanlon.
Hopkins said there is a new judicial rule, passed in 2007, that sends a trial granted a change of venue back to the transferring court for sentencing. It's the first time he's run across it.
"No one has heard of it," Hanlon added Friday.
Hopkins said Zuniga remembered it and called them back to discuss it.
The rule is so new that there's not much legal history on it, said Hopkins.
But Zuniga felt her choice was clear – that the case will return to Lake County, where hearings will be held about where the sentencing should take place, Hopkins said.
"The idea behind it is the community in which the crime occurred is the court with the most interest in the post-conviction proceedings," Hopkins explained.
A hearing is scheduled for 9 a.m. Thursday, Aug. 28, in Judge Arthur Mann's courtroom, to decide if the sentencing will stay in Lake County or return to Martinez, he said.
Hopkins said the discussion will involve balancing Hughes' interest between having his sentencing conducted by the judge who heard the case and the community's interest in arriving at a decision.
Hanlon, who had filed three change of venue motions before succeeding in having the trial moved, said Friday he's happy to see it come back to Lake County for sentencing.
"I think we're probably better off with sentencing before Judge Mann," said Hanlon.
That's because he believes Zuniga – though she was very fair – probably thinks Hughes is guilty.
Sentencing had been scheduled for Sept. 9 in Martinez. Hopkins said that hearing was vacated, although Hanlon added that Hughes hadn't waived his time. That means sentencing could take place in Lake County on that date.
Hopkins, however, said the Lake County Probation Department will be hard-pressed to finish its sentencing recommendations by Sept. 9, especially if they're currently unsure of where the sentencing might be held.
Hanlon said he's hoping for a sentence where Hughes can get out of jail soon. He's been held in jail since December of 2005.
The burglary and assault with a firearm charge could bring an upper term of eight years in prison, with the burglary counted as a strike, according to Hopkins.
With credit for time served plus 50 percent, Hughes should have credit for four years and may spend very little time, if any in prison, due to sentencing guidelines that require the judge to sentence to the middle term unless there are extraordinary circumstances, as Lake County News has reported.
Even with those convictions, and with the uncertainty of the possible sentence, Hanlon said, "I think we've already won the case."
E-mail Elizabeth Larson at
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- Written by: Lake County News reports
Efren Herrera, 57, of Pomona was arrested for the warrant during a routine traffic stop just after 1 p.m. on Soda Bay Road near the Jack in the Box, Capt. James Bauman of the Lake County Sheriff's Office reported Friday.
Bauman said Herrera was the driver during the stop; when his driver's license status was checked the misdemeanor warrant was discovered.
The $25,000 bench warrant, said Bauman, was issued by Orange County for misdemeanor contempt of court violations.
Bauman said Herrera was booked into the Lake County Jail, with jail records indicating bail was set at $25,000. He was bailed out a little over an hour after he was booked, Bauman added.
Herrera is in Lake County this weekend for the annual Pepsi Celebrity Golf Shootout at Buckingham Golf and Country Club.
He was a place kicker in the National Football League from 1974 to 1982, during which time he played for three years with the Dallas Cowboys and was a member of one of their Super Bowl-winning teams. Herrera also kicked for the Seattle Seahawks.
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- Details
- Written by: Elizabeth Larson
Board President Helen Locke and Vice President Mike Anisman both submitted resignation letters to General Manager Darin McCosker on Thursday, which Locke and Anisman confirmed to Lake County News.
Both resignations will become effective on Sept. 5, the outgoing board members said.
Locke said the delay until Sept. 5 is in order to give the district two weeks to establish a new signature authority for specific documents and contracts the board president is required to sign.
Anisman did not detail his reasons for leaving, although he had been considering his options in light of last Saturday's heated rate hike meeting. He had left that meeting in the wake of what he considered to be verbal abuse by ratepayers.
Later in that meeting, community member Mike Benjamin began circulating a petition for a notice of intent to file a recall action against Anisman and another board member, Pat Shaver.
Shaver tendered her resignation on Monday, as Lake County News has reported.
At Wednesday's regular board meeting, Benjamin served Anisman with his intent to pursue the recall which, had Anisman not resigned, could have cost the district several thousand dollars for a special election.
Locke, who had indicated earlier this week that she wanted to keep working with the board, said it was not "any one thing" that led to her decision to step down.
She did some soul searching and came to the decision, which has left her with mixed feelings of guilt and relief.
Anisman, Locke and board member Frank Toney were elected to the board last November. Earlier this year, the board appointed McCosker as general manager to succeed Ellen Pearson, who stepped down to the auditor/secretary role. In March the board terminated Pearson.
It was in March or April that the board discovered its financial problems, said Locke.
Those issues included thousands of dollars in bills that hadn't been paid or had been paid late, resulting in late fees; Internal Revenue Service penalties; next to nothing left of the district's reserves, which 10 years ago had totaled $1.3 million, as Lake County News has reported.
"I have lain awake at night, every night, worrying about how we were going to pay our bills," said Locke.
The district this spring suggested a 39.4-percent hike of both sewer and water rates, which has garnered 427 protest letters and resulted in the board's once-empty meetings now drawing standing-room-only attendance.
Since the original rate hike proposal, McCosker has suggested two new options for raising rates – one amount to 25 percent, the other 10 percent.
The board on Wednesday voted to hire an auditing firm and moved meeting times to the third Thursday of each month at 7 p.m. to allow for more public participation.
But just when the board will next be able to meet is so far unclear.
The only remaining board members are Toney and Harry Chase. In order to make an appointment to replace the other board members, the district has to publish the seats' availability, take applications and meet to make a selection, which it can't do without a quorum. McCosker said Wednesday an empty seat must be filled in 60 days.
Locke said how the board moves forward will be a complicated matter.
"I don't think it's going to get much better for a while," she said.
E-mail Elizabeth Larson at
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