Do you wonder why you are sneezing and wheezing so? If dust and ozone are in the air you are breathing – or trying to breathe – it is likely that you may be beset with an overabundance of those achoos and gasping noises. It doesn’t much matter where the dust comes from. In the current forecasts, those fine particulates are blowing in all the way from Africa. (That’s a bit hard to believe, isn’t it?) Sure enough, the dust is coming to Harris County on the wind. As to the ozone, it is a home-grown irritant and the less wind blowing on these hot and sunny days of summer, the thicker the ozone will be, so to speak. It seems like there is no winning for losing – more wind means more dust and less wind means more ozone. Here is what the Texas Commission on Environmental Quality (TCEQ) believes that our air will be like around here over the next several days:
African dust with “Moderate” fine particulate levels should continue over most of the state except the El Paso area. The dust levels may diminish for about half a day as one dust cloud leaves and the next approaches. Winds may be light enough for ozone to reach “Moderate” or possibly higher levels in the El Paso area in the afternoon and early evening. “
African dust with “Moderate” fine particulate levels should continue over most of the state. Winds may be light enough for ozone to reach “Moderate” or possibly higher levels on the north and northeast side of the Houston area and “Moderate” levels on the north side of the Dallas-Fort Worth metro area and in the El Paso area in the afternoon and early evening.”
Winds may be light enough for ozone to reach “Unhealthy for Sensitive Groups” on the southeast and east side of the Houston area and “Moderate” or possibly higher levels on the northeast and north side of the Dallas-Fort Worth metro area, in parts of Northeast Texas, and in the Beaumont-Port Arthur area in the afternoon and early evening. African dust with “Moderate” fine particulate levels should continue over most of the state.”
St. Louis Encephalitis and West Nile Virus in Harris County
St. Louis Encephalitis (SLE) and West Nile (WN) virus infections are mosquito-borne diseases that affect warm-blooded animals and are transmitted from one to another by mosquitoes. Both are now well entrenched in Harris County and in other areas of Texas.
The City of Houston’s Department of Health and Environmental Services (HDHES) performs testing for these infections in humans suspected of being infected by these viruses.
Testing of blood from stray dogs is also done. As well, mosquitoes themselves are tested for presence of these viruses. Over an approximately 13-year-long period of such testing, slightly more than 33 mosquito “pools” tested virus-positive for SLE.
In 2002, 260,138 mosquitoes of the type that ordinarily spreads the viruses were collected and assayed for virus presence. Almost 1,000 mosquitoes tested positive for SLE virus. A significant number of mosquitoes tested positive for the WN virus, but not as many as tested positive for SLE virus.
Wild birds serve as important intermediaries for the maintenance and spread of the virus pool, particularly the birds, blue jays and shrikes.
There are several major means of controlling SLE and WN virus diseases in the human and animal populations of Harris County and elsewhere. Periodic broadcast spraying of city and town habitation areas beginning in late springtime is one much-used method of control. Draining of stagnant water from ditches and soil depressions is used to cut down on mosquito breeding, as is encouragement of residents to empty water catchers on their properties in which mosquitoes can multiply. The use of appropriate clothing and of mosquito repellants is also suggested.
Prevention of these diseases in humans is very much a matter of curtailing the presence of mosquitoes that spread the viruses. Largely cutting down their breeding does this, and that cutting-down is mainly a matter of control of the environments in which they would multiply.