The notion that fogging on roads and open spaces kills Aedes mosquitoes is a myth
Two major experts on dengue outbreak control -- World Health Organisation (WHO) official Dr BN Nagpal and Kolkata Municipal Corporation (KMC) Mayor Firhad Hakim -- on Monday confirmed that fogging drives against Aedes mosquitoes are largely ineffective.
Senior Entomologist of WHO Southeast Asia Region, Dr BN Nagpal further said the notion that fogging on roads and open spaces kills Aedes mosquitoes is a myth, as the particular species lives inside homes and under construction buildings.
He was addressing a special briefing at the office of the Directorate General of Health Services (DGHS).
“Aedes mosquitoes breed in clean water. Construction projects are big sources of Aedes mosquito larvae. Caution should be taken so that water does not stagnate in construction projects,” the Dr Nagpal said.
He recommended that the Dhaka city corporations should take action against firms for showing negligence in this regard, while residents should keep their houses clean and spray aerosol every afternoon.
“Number of dengue cases can be reduced by at least 40 percent by destroying the Aedes larvae breeding grounds in the under-construction buildings,” he said.
Dr Nagpal also mentioned that in Mumbai, construction firms are monitored by authorities and fines are handed down if mosquito breeding grounds are found in their project premises.
“The primary task is to identify the main source of Aedes mosquitoes. The species can lay eggs in very small amount of water (5mm or one spoonful of water) and the eggs can survive in adverse condition, even without water,” he said at the briefing.
Dr Nagpal further said the Aedes mosquitoes live under tables, beds, sofas and clothes kept on hangers.
“People’s participation is necessary in controlling Aedes mosquito and destroying their breeding grounds to prevent dengue. People should be directed to clean their homes for at least one hour every week,” he added.
He mentioned that Sri Lanka has succeeded in controlling dengue situation by involving people in anti-mosquito programme and Bangladesh can do it too in ten days.
Director General of the DGHS Prof Abul Kalam Azad and Director of the Institute of Epidemiology, Disease Control and Research (IEDCR) Meerjady Sabrina Flora were present at the press briefing.
‘Insecticides can no longer help’
Meanwhile, Kolkata Municipal Corporation (KMC) Mayor Firhad Hakim, who has experience on successfully combating the dengue menace, has echoed the same opinion.
He advised the Dhaka North City Corporation (DNCC) to collect data on the number of patients in every ward of the city and recommended that the collected data be used to identify and destroy Aedes mosquito breeding grounds in the capital.
The KMC mayor was speaking to DNCC Mayor Atiqul Islam through a video conference on Monday.
Firhad Hakim added that the collected data on the number of patients in each ward helped the KMC identify and destroy mosquito breeding grounds at the micro level. The Kolkata mayor also called for local politicians and public representatives to help raise awareness among the people.
Speaking at the same video conference, KMC deputy mayor Atin Ghosh warned DNCC that insecticides can no longer be any help in containing the dengue outbreak.
“Spraying insecticides will only cause mosquitoes to move to another location. A search and destroy operation must be launched in every ward of Dhaka to wipe out the Aedes mosquito population,” he told reporters.
More than 27,000 cases in Bangladesh
A total of 2,065 dengue patients have been admitted to different hospitals in the last 24 hours. The total number of dengue infected patients has crossed 27,000 across Bangladesh.
According to the DGHS data, a total of 27,437 dengue patients have been admitted to hospitals this year and 19,761 have returned home after recovery.
A total of 7,658 are still under treatment. Among them 4,962 dengue patients are admitted into 38 government and private hospitals in the capital Dhaka.
Meanwhile, 2,696 patients are admitted into different district hospitals outside Dhaka.
The DGHS data says 18 people have died of dengue fever so far this year. However, unofficial sources say the death toll is at least 60.
Outbreak in Singapore
The prevalence of dengue in Singapore has been higher this year. A total of 9,135 dengue cases have been reported so far, which is 5 times higher than the number in the previous year.
“The spike in dengue cases may be related to recent warm weather and an increase in the number of construction sites, with many new MRT stations and Changi Airport Terminal 5 under construction,” said Professor Tikki Pang, a visiting professor at the Lee Kuan Yew School of Public Policy.
“It may also be due to changes in mosquito behaviour or the emergence of a more virulent strain of dengue,” said the professor, who specialises in the subject of infectious diseases.