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| Houston to combat West Nile from the air as virus spreads | Houston to combat West Nile from the air as virus spreads |
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| Houston will begin aerial spraying to combat West Nile on Wednesday night as the virus continues to ravage Texas and spreads in other parts of the US. | Houston will begin aerial spraying to combat West Nile on Wednesday night as the virus continues to ravage Texas and spreads in other parts of the US. |
| America's fourth-biggest city said it would scatter insecticide from planes over a 63,000-acre area northwest of downtown after two more deaths took the local total to three this year. | America's fourth-biggest city said it would scatter insecticide from planes over a 63,000-acre area northwest of downtown after two more deaths took the local total to three this year. |
| Texas is the epicenter of the country's worst West Nile outbreak of 2012, with the bulk of cases in the north. Dallas County, 240 miles north of Houston, has tracked 270 human infections, and the reported death toll in the Dallas-Fort Worth region is 18. Only two fatalities were recorded in Texas last year by the Texas department of state health services. | Texas is the epicenter of the country's worst West Nile outbreak of 2012, with the bulk of cases in the north. Dallas County, 240 miles north of Houston, has tracked 270 human infections, and the reported death toll in the Dallas-Fort Worth region is 18. Only two fatalities were recorded in Texas last year by the Texas department of state health services. |
| A warm winter and ample spring rainfall have been blamed for the sharp rise. About half of all infections in the US this year are in Texas, but according to the Centers for Disease Control, West Nile is present in 47 states. | A warm winter and ample spring rainfall have been blamed for the sharp rise. About half of all infections in the US this year are in Texas, but according to the Centers for Disease Control, West Nile is present in 47 states. |
| An elderly woman died from the disease in Fresno, California, Fresno County, officials said Tuesday. Six people have died in Louisiana this year. Texas, Mississippi, Louisiana, South Dakota and Oklahoma account for 75% of the cases. | An elderly woman died from the disease in Fresno, California, Fresno County, officials said Tuesday. Six people have died in Louisiana this year. Texas, Mississippi, Louisiana, South Dakota and Oklahoma account for 75% of the cases. |
| "We're in the midst of one of the largest West Nile outbreaks ever seen in the United States," Dr Lyle Petersen of the CDC told the Associated Press. | |
| The CDC on Wednesday released figures that showed 1,118 known human cases of West Nile, including 41 deaths – a rise of 425 cases in a week and the highest number ever recorded in the US at this time of year. The true numbers are likely to be higher, since cases emerge at local and state level before coming to the federal agency's attention. | The CDC on Wednesday released figures that showed 1,118 known human cases of West Nile, including 41 deaths – a rise of 425 cases in a week and the highest number ever recorded in the US at this time of year. The true numbers are likely to be higher, since cases emerge at local and state level before coming to the federal agency's attention. |
| Some areas of Dallas have been treated twice by aerial spraying since last week, and in total more than 360,000 acres were doused. "The initial result is showing is that aerial spraying is working, with no visible side effects. We believe it was the right tactic," Mayor Mike Rawlings told the Dallas Morning News. He declared a state of emergency last week. | Some areas of Dallas have been treated twice by aerial spraying since last week, and in total more than 360,000 acres were doused. "The initial result is showing is that aerial spraying is working, with no visible side effects. We believe it was the right tactic," Mayor Mike Rawlings told the Dallas Morning News. He declared a state of emergency last week. |
| CDC officials are analyzing data to determine how effectively the spray has reduced the mosquito population before Dallas decides whether to spray from the sky for a third time. Other cities in north Texas will use aerial spraying Wednesday night and Thursday but some have opted out. | CDC officials are analyzing data to determine how effectively the spray has reduced the mosquito population before Dallas decides whether to spray from the sky for a third time. Other cities in north Texas will use aerial spraying Wednesday night and Thursday but some have opted out. |
| While Houston has used the tactic each year since 2002, Dallas had not sprayed pesticide from planes since 1966, and many residents were opposed to the tactic, fearing that the risk from the poison is greater than the danger of contracting West Nile. | While Houston has used the tactic each year since 2002, Dallas had not sprayed pesticide from planes since 1966, and many residents were opposed to the tactic, fearing that the risk from the poison is greater than the danger of contracting West Nile. |
| The pesticide, Duet, is a combination of synthetic pyrethroids that is approved by the Environmental Protection Agency but is harmful to beneficial insects such as honey bees, and not risk-free for humans if mishandled. | The pesticide, Duet, is a combination of synthetic pyrethroids that is approved by the Environmental Protection Agency but is harmful to beneficial insects such as honey bees, and not risk-free for humans if mishandled. |
| EPA guidelines state: "Pyrethroids can be used for public health mosquito control programs without posing unreasonable risks to human health when applied according to the label. Pyrethroids are considered to pose slight risks of acute toxicity to humans, but at high doses, pyrethroids can affect the nervous system." | EPA guidelines state: "Pyrethroids can be used for public health mosquito control programs without posing unreasonable risks to human health when applied according to the label. Pyrethroids are considered to pose slight risks of acute toxicity to humans, but at high doses, pyrethroids can affect the nervous system." |
| Vanessa van Gilder, a Dallas resident and beekeeper, organized a petition against spraying that has attracted more than 2,000 signatures. "Truck spraying will continue … I find that very disturbing," she told the Guardian. | Vanessa van Gilder, a Dallas resident and beekeeper, organized a petition against spraying that has attracted more than 2,000 signatures. "Truck spraying will continue … I find that very disturbing," she told the Guardian. |
| "Adulticide with that non-targeted approach is not effective. Larvicide is the way to go – men on the ground with adulticide in hand spraying specific areas such as storm drains. At night, mosquitoes might not be out and can hide." She was skeptical about the Mayor's claims of success. "I've seen reports saying that mosquitoes are at the end of their natural life cycle and that's why some have died," she said. | "Adulticide with that non-targeted approach is not effective. Larvicide is the way to go – men on the ground with adulticide in hand spraying specific areas such as storm drains. At night, mosquitoes might not be out and can hide." She was skeptical about the Mayor's claims of success. "I've seen reports saying that mosquitoes are at the end of their natural life cycle and that's why some have died," she said. |
| West Nile was discovered in the US in 1999. It typically peaks between mid-August and early September and is thought to be transmitted when mosquitoes bite infected birds, then people. Most humans who are infected do not become unwell, but around one in five develop flu-like symptoms and fewer than 1% of victims may suffer neurological complications that can lead to brain damage and death. Older people and those with weakened immune systems are most at risk. | West Nile was discovered in the US in 1999. It typically peaks between mid-August and early September and is thought to be transmitted when mosquitoes bite infected birds, then people. Most humans who are infected do not become unwell, but around one in five develop flu-like symptoms and fewer than 1% of victims may suffer neurological complications that can lead to brain damage and death. Older people and those with weakened immune systems are most at risk. |
| Health experts advise taking precautions to reduce the chances of being bitten by mosquitoes, such as using repellent from dawn to dusk, wearing long sleeves and pants and draining standing water around properties. | Health experts advise taking precautions to reduce the chances of being bitten by mosquitoes, such as using repellent from dawn to dusk, wearing long sleeves and pants and draining standing water around properties. |
| Houston is employing Dibrom, also known as Naled, an organophosphate first registered in the US in 1959 that is also used on crops. It can cause severe health problems at extremely high dosages, but the EPA considers it safe for the general population when used correctly for mosquito control. Houston authorities recommend that anyone concerned about exposure stay indoors during aerial spraying, which is scheduled for 8.30pm local time. | |
| "In terms of a knockdown for mosquito populations [Naled] doesn't have any parallels," said Joe Conlon, technical advisor for the American Mosquito Control Association. He said that studies have shown the health risks of aerial spraying paled in comparison with the danger posed by West Nile. "The fact is it works, and that's why people do it," he said. | |
| Conlon added that the virus's impact this summer should be a wake-up call to the authorities and ordinary Americans after several relatively quiet years: "This will tell us that it's not going away and in the right conditions it'll present itself in a large scale outbreak." | |
| He believes it is inevitable that more mosquito-borne diseases will spread to the United States from other continents. "This is the first of many," he said. "Rift Valley fever, Chikungunya … the nastiest vector-borne diseases on the planet are an eight-hour plane ride away." |