Dengue Alert!
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Careful in daytime, that's when they attack
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Sunday September 11, 4:17 PM
Current fogging practices ineffective in killing the Aedes mosquitoes
SINGAPORE: In the war against dengue, current fogging practices may be ineffective in killing the Aedes mosquitoes.
The World Health Organization (WHO) has advised that fogging at dawn is most effective.
But according to the Singapore Pest Management Association, most fogging here is carried out after 10am or in the afternoons when most Singaporeans are at work and away from their homes.
Mosquitoes may be killed when they come into contact with the fogging fumes but fogging done during these times is not very effective for several reasons.
One, ambient temperature is higher in the day and hot air causes the fumes to dissipate faster.
Two, more air drafts in the day carry the fumes away from intended target areas.
"You can actually fog anytime during the day because the Aedes mosquitoes are active during the day time and they bite throughout the day. But of course, peak biting is during dawn and dusk. So, it is more beneficial to fog during these periods because you have a bigger abundance of mosquitoes around," explained Christina Liew, a medical entomologist at the National Environment Agency (NEA).
So is fogging as it is currently done just a smokescreen?
"The end user insists that fogging be done because he is being harassed by mosquitoes. So when he sees that there is lots of smoke going on, he is happy that something is being done. The pest company knows it is ineffective doing it. I have heard stories. Some just add kerosene to water so that when you fog, you still get white smoke coming out. In fact, it's all for show, " said G. Surajan, president of Singapore Pest Management Association.
Responding to Channel NewsAsia's query, NEA says it does not know of any pest control companies which have been adding kerosene to water. And it will take action against any who has done so.
So why don't pest companies carry out fogging at dawn or dusk?
They say cost is an issue. Pest companies have to pay their workers one and a half times more in overtime pay if fogging is done outside the standard nine to five work day.
And most town councils, private condominiums and construction companies will only award fogging contracts to the lowest bidder.
There is another reason why fogging is done when the sun is high - pest management companies say Singaporeans complain of noise pollution from fogging at dawn.
Biologists have also warned that fogging, if conducted at sub-lethal dosages, will cause mosquitoes to develop resistance to the pesticides used.
But it is not known if all fogging carried out here is at the appropriate lethal dosages.
(source: Yahoo Singapore News) -
The insects, bacteria, and all other microorganisms are getting stronger and more resilient, whilst we're getting less immune and our arsenal of antibiotics and other defence mechanisms used against them are getting less and less effective.
Grim...
Bleak...
This past week alone, FOUR dengue patients have passed through the area I'm in charge of. That's A LOT!! -
No immunity because of our too successful clean up campaign
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Yeah, I read that this was what the docs say, then what's the point about lack of immunity about?Originally posted by Rhonda:If someone has caught dengue before, subsequent occurences of dengue in the same person may become more deadly because instead of dengue, the person may end up having Dengue Hemorrhagic Fever, which can be fatal.
Yesterday's Sunday Times reported 3 reasons for the rise in dengue:
1. Fumigation is ineffective (DDT is not used as it's banned in S'pore)
2. New strains brought in by foreign workers
3. Lack of immunity due to successful wipe out of dengue in the 70s (?).
#3 seems to imply if you get dengue once, then you get immunity? Contradiction?
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You'll get immunity to the same strain, I guess. But if you are unlucky enough to catch dengue for subsequent times, the danger of it being the deadly Dengue Hemorrhagic Fever is higher.Originally posted by zozo:Yeah, I read that this was what the docs say, then what's the point about lack of immunity about?
Yesterday's Sunday Times reported 3 reasons for the rise in dengue:
1. Fumigation is ineffective (DDT is not used as it's banned in S'pore)
2. New strains brought in by foreign workers
3. Lack of immunity due to successful wipe out of dengue in the 70s (?).
#3 seems to imply if you get dengue once, then you get immunity? Contradiction?
It's kinda like if you catch flu, you'll be immune to the particular strain, but it doesn't mean you'll never catch flu again ever, because there are too many different strains of flu and new ones are coming up every year. -
Oh, one more thing about immunity... it's a double-edged sword!
It's true that immunity helps keep us healthy and prevents us from succumbing to illnesses. BUT, that very same ability to keep ourselves immune can actually backfire because White Blood Cells have been known to 'attack' friendly cells in the body too! It's kinda like the immune system gone berserk!
Under this category, you have SLE (Systemic Lupus Erythematosus), where the white blood cells in the body hold a 'rebellion' and attack the body.
This protective mechanism gone rogue can also be seen in organ transplant patients. That's why they have to take drugs to suppress the immune system so that the body doesn't attack its new organ. -
there are now 4 types of dengue virus.
we are used to only 1 and 2.
3 and 4 were brought in by foreigners.
young people are more inclined to catch it. -
Opp..Originally posted by dragg:there are now 4 types of dengue virus.
we are used to only 1 and 2.
3 and 4 were brought in by foreigners.
young people are more inclined to catch it.
SG normally gets Type 3 and 4... -
Just on TV, overnight, there's been an increase of 190 new dengue patients!!
Apparently, although construction sites are frequently blamed, it's actually homes that are the #1 culprit in flouting rules and thus, helping to breed mosquitoes.
Everyone, play your part in ensuring that you're not a mosquito breeder! -
Can let them breedOriginally posted by Rhonda:Just on TV, overnight, there's been an increase of 190 new dengue patients!!
Apparently, although construction sites are frequently blamed, it's actually homes that are the #1 culprit in flouting rules and thus, helping to breed mosquitoes.
Everyone, play your part in ensuring that you're not a mosquito breeder!
Then sabo, drain off water and scrub with soap... -
Has hit abv 100 cases a day...
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How many deaths have officially been attributed to the current Dengue outbreak?Originally posted by sbst275:Has hit abv 100 cases a day...
MG -
8 for this year.
another 100 odd cases yesterday. -
Yup! The Aedes mosquito is actually day-biting, so if you kena bitten at night, it's not the Aedes!Originally posted by sbst275:Careful in daytime, that's when they attack
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i thought so too. but recently i read from the papers that some bite in the night too.Originally posted by Rhonda:Yup! The Aedes mosquito is actually day-biting, so if you kena bitten at night, it's not the Aedes!
so who is right?