VietNamNet Bridge – Closing door and burning lemongrass extract oil is how the family of 22-year-old Thao Hien tries to prevent the seasonal dengue fever outbreak using natural products. 

With the rapid spread of dengue fever, anti-mosquito services and special products have sprung up everywhere, especially in Ha Noi and HCM City. — Photo zing.vn

Hien’s fear has increased since her neighbourhood on Thuy Khue Street near West Lake was declared one of the capital’s dengue fever outbreak hotspots, with five residents infected. Symptoms typically include a fever, headache, muscle and joint pains and a rash.

Unlike Hien, other families choose chemical sprays to kill the virus-bearing mosquitos. Khanh Huyen of Giang Vo Ward told Viet Nam News that her father had her house sprayed several days ago, however, mosquitos keep appearing. 

With the rapid spread of dengue fever, anti-mosquito services and special products have sprung up everywhere, especially in Ha Noi and HCM City. 

However, the quality and safety of many of these chemicals and products are unknown. 

“I spent about VND2 million (nearly US$100) on anti-mosquito chemicals to spray all over a three–storey house. I prefer to buy chemicals myself rather than rely on medical staff for the safety of our children,” Ta Tien Hung, a resident of Ha Noi’s Nam Tu Liem District, told Tien Phong (Vanguard) newspaper. 

According to him, there are still mosquito larvae in his house even after it was sprayed by the district’s medical staff. Hung is just one of thousands of the captial’s citizens worried about the rapid spread of dengue fever. 

A survey by Tien Phong newspaper mapped the variety of anti-mosquito chemicals sold in Ha Noi. Duat, a shop owner on Minh Khai Street, said anti-mosquito chemicals were the hottest products he was selling. 

Prices range from VND15,000 (65 cents) for one litre of the made-in-Germany Fendona 10SC to VND1.5 million ($65) for one litre of Britain-made Permethrin 50EC. The cost of a spayring service is VND300,000 (nearly $15) a day. Those products bring him a daily profit of about VND10 million ($500).

Another chemical shop on De La Thanh Street offers a three-month guarantee for its products. However, its owner told Tien Phong that the schedule of spraying was all booked. “You should choose a chemical and pay in advance. Three days later, our staff will spray for you,” he said.  

50 ways to kill mosquitos

Many parents have also bought anti-mosquito products for their children, such as pins or bracelets imported from Korea and Japan and advertised as repelling mosquitoes. However, the products’ effectiveness has not been confirmed. 

Results of Googling “anti-mosquito spraying” show several advertisements of imported and toxic-free chemicals effective up to six months. 

Children are said to be the most vulnerable group to dengue fever. On online forums, mothers circulate anti-mosquito tips, including citrus or lemongrass extract. 

“I used many types of repellents for my kid, but they did not have any significant effect. Then I heard that melaleuca oil can prevent mosquitos, I tried. It works! Therefore, since my kid was two years old, I have only used melaleuca oil as an anti-mosquito product and always bring it along when travelling,” a mother nicknamed Burin2312 wrote on webtretho.com, a website for parents to share experiences in caring for babies.

Electronics showrooms have also grasped the chance by introducing anti-mosquito air conditioners or mosquito-zapping UV lights. The market is flooded with several types of gadgets, from anti-mosquito bracelets at VND8,000 (35 cents) to a combo of 60 stickers at VND65,000 ($3), or incense sticks at VND 60,000 ($2.5). Social networks and mobile phones are flooded with such ads in recent days.

Expert warnings

“There are many kinds of mosquito repellents advertised and sold in the market. However, people should be alert about products for use in urban areas and those for agricultural purposes,” said Ha Tan Dung, Head of the Insect and Parasite Department under the Ha Noi Preventive Health Centre.

He also warned that many companies take advantage of fever prevention to conduct spraying services, which could result in drug resistance and make it impossible to control dengue fever.

Hoang Minh Nam, a lecturer at the Faculty of Chemistry under the HCM City University of Technology, said that spraying chemicals was only temporary prevention. “People need to avoid using those repellents for a long time to prevent negative impacts on their health,” he said.

“Chemical-based mosquito repellents usually contain Tetramethrin, D-Phenothrin or Permethrin which are nerve inhibitors. Sniffing those substances may cause headache, dizziness or hypertension,” he added. 

Dr. Nguyen Tri Dung, Director of HCM City’s Preventive Health Centre, recommended to frequently kill mosquito larvae, empty stangnant water containers and sanitise the environment to prevent dengue fever effectively. “People should be careful with those anti-mosquito product advertisements because of their impact on your health,” he emphasised. 

VNS