Fogging will not be effective and help the authorities take the dengue situation under control as Aaedes mosquitoes, which are responsible for the ongoing dengue outbreak, bear special bio-ecological characteristics, according to a WHO expert.
The authorities concerned are struggling to take the crisis under control, as they are yet to kill the existing mosquitoes and stop their breeding.
The two Dhaka city corporations are also struggling to import new insecticides, after it was revealed that the insecticides currently used for fogging was ineffective against Aedes mosquito.
BN Nagpal, senior entomologist of WHO Southeast Asia region, yesterday said fogging on the sides of the streets and roads would not help much as Aedes take rest in the darkest part of a house. Aedes also travels less and the fog would rarely reach them.
In 100ml fog, 95% is oil or diesel and rest 5ml is insecticides, and that would make very low impact on Aedes, he said. “It’s better to use [mosquito repelling] aerosol at home and temephos [larvicide] in any water container to killing the existing mosquitoes and stop their breeding.”
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His remarks came at a media orientation on dengue awareness and prevention organized by the Disease Control division of Directorate General of Health Services (DGHS).
“It’s [Aedes] a smart urban area based mosquito species. It does not rest on walls. It rests under the tables, beds, sofas, curtains, hanging clothes and dark places,” he said, suggesting spraying of mosquito repelling aerosol in these places.
Fact about aedes • Two species – Aedes aegypti ( in Urban) and Aedes albopictus (in Rural) • Aegypti causes 99% of dengue • Aedes is a hydrophilic insect that loves higher humidity • Aedes remains in resting place (dark corners) during days • Aedes need human blood to develop eggs, so female aedes only bites • Aedes bites in every alternate days • A day biter with peak biting hours after sunrise and two hrs before sunset • A female lays 60-100 eggs in initial oviposition but in different places • Aedes travel less • 2 ml water or in a small water bottle-cap is enough for breeding • Larvae can survive for one year without water • Adult Aedes mosquitoes does not rest on the wall • 40% of dengue breeding take place at construction sites |
He also emphasized on the detecting and destroying the mosquito breeding spots. “2ml water in any pot or even a bottle cap is enough for Aedes breeding. The eggs can survive for one year and hatch rapidly as soon as it comes into contact with water.
According to Dr Nagpal, if people take action properly, dengue can be brought under control just in 10 days.
He said the best way to quickly stop the disease from spreading was cleaning ones homes and community on a regular basis. “We need to give the proper message to the community, because this disease cannot be controlled without mobilizing the community.”
Dengue patients outside Dhaka increasing
At least five dengue patients, including a pregnant woman, died in Dhaka, Khulna and Madaripur yesterday, while the number of patients in 24 hours crossed 2,000 for the first time this year.
According to DGHS data, at least 2,065 patients — 1,159 in Dhaka city and 906 in other divisions — were identified between Sunday and 8am on Monday.
What to do • Clean each and every corner of the house • Clean your whole house once a week • Spray aerosol at each corner of the house after sunrise and before sunset • For larvicide, WHO suggests using Temephos 1 gram in 10 litres of water • Put netting cloth on the mouth of rainwater pipes • Always keep drinking glasses or buckets upside down • Regular cleaning at all types of establishments • Take legislative action to destroy Aedes breeding spots in construction sites • Cleaning vehicle dumping areas in police stations |
Between January 1 and yesterday, 27,437 people were identified as dengue patients, and 18 of them have died, according to DGHS.
The unofficial death toll, however, stood around 60 people across the nation until yesterday.
Aedes in rural areas
BN Nagpal yesterday also said that Aedes Aegypti was mainly responsible for the recent dengue outbreak.
Among the two species, Aegypti causes 99% of the dengue spread while Aedes Albopictus, which is mostly a rural mosquito, causes less than 1%.
Responding to a question, he however said that the recent increase in the number of dengue patients around Bangladesh might also suggest that Aedes Aegypti may have reached the rural areas too.
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Speaking at yesterday’s program, DGHS Director General Abul Kalam Azad expressed fear that dengue cases outside Dhaka might rise further during Eid-ul-Azha.
Every hospital at the district and upazila level has been allocated Tk10 lakh and Tk2 lakh, respectively, for procuring dengue testing kits and treatment of dengue patients, he added.
The hospital authorities can spend the money without DGHS approval, but they must not waste the funds, Azad added.
The DGHS chief also asked all doctors and nurses to remain dedicated to their job and comply with the recent government order that cancelled the Eid holidays of all officials and employees of the Health Ministry and related directorates and departments, to tackle the crisis.
He urged all to consult doctors before going for the NS1 test for dengue identification to avoid waste of resources and money.