West Nile epidemic 'worst in history' as virus infects 1,118 in America and leaves 41 dead

By Leon Watson and Daily Mail Reporter

America is in the midst of its biggest ever outbreak of West Nile virus, with four times the usual number of cases reported for this time of year.

Nearly 1,120 people have already contracted the mosquito-borne illness, up from fewer than 300 by mid-August in an ordinary year, and 41 people have died.

Medical experts believe the mild winter and very hot summer boosted the number of mosquitoes around, helping to spread the virus.

State of emergency: The Culex quinquefasciatus mosquito is associated with transmission of the West Nile virus

But it's still too early to say how bad epidemic will end up because most West Nile infections are reported in August and September.

'We're in the midst of one of the largest West Nile outbreaks ever seen in the United States,' said Dr Lyle Petersen, of the Centers for Disease Control and Prevention.
Never before have so many cases been called in this early in the year and the number of patients are accelerating, with about 400 of them being struck down in just the last week.

Panic: 76-year-old William Mueller's death has sparked fears the virus epidemic may be spreading 

Almost half of the cases so far reported have come from Texas, mainly around the Dallas area.

Twenty-one people have died in the state this year, which is more than all other years combined. Four of the Texas deaths were reported on Tuesday.

Officials don't know why Texas is seeing so many cases, but it's alarming.
Last week, they started aerial spraying for mosquitoes in Dallas County. 

But it's too soon to measure the effect — it takes between three and 14 days for people to develop symptoms after being infected by a mosquito.

But infections were not restricted to Texas, with residents in 37 other states have also been struck down.

Mosquitoes pick up West Nile from birds they bite and then pass it on to people.
As well as weather conditions spurring on mosquito breeding, CDC officials are also looking into the possibility that the virus mutated, Petersen said. But so far they have no evidence of this.

The latest person to succomb to the disease was 76-year-old William Mueller from Illinois who died on Saturday, two weeks after being hospitalised.

Serving as president of Lombard Village, Mueller was described by his family as 'an amazing dad, husband and grandpa'.

'It is not clear why we are seeing more activity than in recent years,' Marc Fischer of the CDC told CNN. 

'Regardless of the reasons for the increase, people should be aware of the West Nile virus activity in their area and take action to protect themselves and their family.'

Preparing for action: An aircraft carrying insecticide is loaded with fuel before taking off to spray parts of Dallas County as part of the battle against the spread of the West Nile virus

Battle: An aircraft sprays insecticide over part of Dallas County 

There is no medication to treat West Nile virus, symptoms of which include fever, headache, body aches, joint pains, vomiting, diarrhea or rash.

No vaccinations exist, either.

The Majority of cases have been recorded in Texas, Mississippi and Oklahoma.
In Dallas panic has deepened since a judge declared the epidemic to be a public health emergency.

An aerial assault was launched on the blood-sucking insect population for the first time in 45 years in a bid to combat the spread.

Aircraft loaded with insecticide have sprayed parts of the north east of Dallas County, after the virus killed 10 people and left at least 230 more ill.

Although commonplace in other major cities, the efforts have provoked a debate in the Dallas area between health officials trying to reduce the risk of disease and residents concerned about the dangers posed by the chemical cloud drifting down from above them. 

New strain?: Officials are looking into the possibility that the virus mutated but so far they have no evidence of this

'I cannot have any more deaths on my conscience because we did not take action,' Dallas mayor Mike Rawlings said.
 
Aerial spraying is also being used elsewhere, including in neighborhoods in New York City and Sacramento, California, to combat the spread of West Nile virus.

Cases of West Nile Virus have also been reported in the Chicago area, with officials spraying the nearby town of Skokie with insecticide.

Two people have been taken ill with the virus in Skokie, while the Chicago suburb of Lake County has reported its first case.

Nearly half of all West Nile cases in the United States so far this year are in Texas, however, according to the Centers for Disease Control and Prevention. 

If the trend continues, 2012 will be the worst West Nile year in the southern state's history.

Dallas mayor Mike Rawlings, pictured with his wife Micky, has declared a state of emergency in his city

Parts of north Dallas are being sprayed with insecticide to combat the spread of the virus

A gravid trap (left), in a field near Spruce High School in Dallas, is part of the mosquito control efforts by the Dallas County Mosquito Lab. First Lieutenant Carol Calix (right) examines a mosquito through a microscope at the U.S. Army Center for Health Promotion and Preventive Medicine-North in Maryland (File picture) 

Byron Chism, mosquito technician at Dallas County Mosquito Lab, holds a trap while collecting mosquitoes

Covering up: Jenny Wegley is seen wading into waist-deep water to guide protective tarps over koi ponds at the Dallas Arboretum

Ponds' protection: The arboretum had crews out working to cover about 8,000 square feet of ponds with tarps to protect the aquatic ecosystems from insecticide that will be sprayed over the city from aircraft

The hot, dry weather has created ideal conditions for some species of mosquito.
The heat speeds up their life cycle, which accelerates the virus's replication process.
And during a drought, standing water can quickly turn stagnant when it's not flushed away by rain or runoff. 

Both the mayor and Dallas County Judge Clay Jenkins have declared a state of emergency and voiced their support for the use of aircraft to battle the virus. 

Yet even with the threat of infection, the spraying has sparked widespread opposition from people who fear the chemicals could be harmful. 

Because of the severity of the outbreak, the Texas Health Department is stepping in to oversee the effort and to pay for it. 

Research: Mosquito technician Daryl Beckwith looks through the mosquitos as local, state and federal officials are set to meet to discuss options for responding to the growing number of West Nile virus cases

Prevention: The mosquitoes seen in a laboratory will help researchers fight the disease's spread 

Sorting: These dead mosquitoes await sorting at the Dallas County mosquito lab

'This year is totally different from the experience Texas has had in the past,' state Health Commissioner Dr. David Lakey said. 'If it's nuisance mosquitoes, we ask the city or county to pay part of that.

But in the midst of this disease outbreak, it's easier for us to go ahead and do it.'
A national spraying company called Clarke was set to deploy two to five Beechcraft King Air twin-engine planes for three hours of spraying. 

Close eye: Mosquito tech Spencer Lockwood is seen sorting the mosquitoes beneath a microscope at the Dallas County mosquito lab

Critics have questioned whether the approach is scientifically proven to reduce West Nile cases.

But at least one study in California concluded that the odds of infection are about six times lower in treated areas than in those that are untreated. 

Still, some residents fear the chemicals could harm their children, pets and useful insects such as honeybees and ladybugs. 

Plans: Dallas Mayor Mike Rawlings talks about aerial spraying to curb the spread of West Nile virus while standing before one of the Beechcraft aircraft being used to administer the insecticide

Target areas: A map of Dallas County highlights the areas that were planned to be sprayed by air on Thursday night

Chemical released from the planes, synthetic pyrethroid, mimics a naturally occurring substance found in chrysanthemums. 

The Environmental Protection Agency has said that pyrethroids do not pose a significant risk to wildlife or the environment, though no pesticide is 100 percent safe.
About eight-tenths of an ounce of chemical is applied per acre.

The insecticide's common name is Duet Dual-Action Adulticide. 

Dr David Lakey, commissioner with the Texas Department of State Health Services, speaks to area media about the spraying of mosquitoes in Dallas County

OUT OF AFRICA: SPREAD OF WNV

 

 
West Nile Virus (WNV) is found in both temperate and tropical regions, having been first identified in the West Nile region of Uganda in 1937.

It mainly infects birds and horses, and human infection is almost always transmitted through the bite of an infected mosquito.

Symptoms include fever, headache, excessive sweating), weakness,  drowsiness and, pain in the joints. Stronger strains of the virus can inuce nausea, vomiting and diarrhoea.
The most dangerous form can lead to unconsciousness, sometimes approaching near-coma, and death.

Up to 80 per cent of human infections do not show any symptoms.

WNV emerged as a distinct virus around 1,000 years ago, developing into two distinct forms. One has been transmitted in Africa and around the world, while the other has been confined to Africa - although it has been recently detected in horses Europe.

The label says it's toxic to fish and other types of aquatic life, and it contains distilled petroleum. 

Kelly Nash, who lives in Dallas and works for an environmental consulting firm, has questioned the move.

'One ounce an acre doesn't sound like much, but we will spray at least 2,000 gallons all over the city,' Nash said.

'A 2,000-gallon oil spill would be significant.

'I'm concerned that we're breeding resistant mosquitoes that next time will have Dengue fever or something worse.'

Harris County, which includes humid, mosquito-filled Houston, has used aerial spraying once a year since 2002, the year the virus was first detected in Texas. 

The county uses ground spraying first and moves to aerial spraying as the virus spreads. 

 'We can't be everywhere at all times,' Mosquito Control Director Dr. Rudy Bueno said.
'Aerial treatment is a way to supplement what we do on the ground.'
Most people infected with West Nile virus won't get sick, but about one in 150 people will develop the severe form of the illness.
Symptoms include headache, high fever, neck stiffness, disorientation, coma, tremors, convulsions, muscle weakness and paralysis.
Jordan Conner, 14, spent eight days in intensive care with the most severe form of West Nile virus.
Her mother, Ebonie Conner of Arlington, said she doesn't approve of aerial spraying and wishes local leaders would do more to educate the community.
'We've been desensitized to West Nile virus,' Mrs Conner said.
'It's been ingrained in us that it affects older people and infants.
'I think they need to pass out insect repellent, mention it in back-to-school drives.'

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