CURE IMMINENT: Malaysians should not be overly alamred over the discovery of the Den-5 dengue virus because it isn’t the culprit of the current virus of the current dengue epidemic, “nor is it likely to cause any major problems anytime soon”. Meanwhile. a vaccine for the other four serotypes of the virus is imminent, virologist Prof Emeritus Datuk Dr. Lam Sai Kit, a high impact research consultant at Universiti Malaya, tells Tan Choe Choe.
Question: Malaysia intends to step up the use of a biological agent to fight the dengue epidemic as a staggering 2,000 cases of the viral infection are being reported each week. The agent, Bacillus thuringiensis israelensis, or BTi, is a bacterium found naturally in soil and has been used worldwide to combat mosquitoes and black flies since 1982. The health minister said this was the first time BTi was being used on a large scale against a dengue epidemic. How effective will BTi be in combating dengue?
Answer: There are several measures that have been used for the control of dengue mosquito vectors. Fogging with insecticide is effective against the adults, while using Abate for larvicide is also good. Combining insecticide with BTi was considered by the Ministry of Health (MoH) a long time ago and I am surprised that this is only now being considered — perhaps there were some logistical problems with it earlier on. But there’s a problem with the use of BTi or Toxorhynchites splendens (a species of mosquito) larvae to destroy Aedes larvae — you have to make sure they land in the same breeding container or site. This is not easy to achieve as the breeding sites are all over the place, so its significance for widespread application is doubtful.
Question: So, you view this as a desperate measure?
Answer: Well, I view it as an additional measure. Whether it’ll be effective, time will tell. But I have my doubts. I think all these are fire-fighting methods. In the end, some may work, while some may not be sustainable in the long term.
Question: There was a lot of talk about using GM (genetically modified) mosquitoes to mate with female Aedes mosquitoes to ensure the eggs do not turn into larvae. What is your opinion on this? Answer: This is a non-starter as far as I am concerned. It is an interesting piece of science but I doubt it can be applied as a control measure on a wider scale. There are many issues which work against its use. — For one, there’s public perception.
GM mosquitoes, like anything labelled GM, has a stigma to it and will find it hard for the community to accept. Also, the flight range of mosquitoes is short, so one has to release millions of mosquitoes at frequent intervals at multiple sites. It will definitely cost the government a lot of money. It is difficult to sustain such control measures even if it works.
Question: It was reported that there’s a fifth dengue variant in the country, the Den-5 virus, and that it has been discovered in the blood sample of a man from Padawan, Kuching. However, deputy director-general of health (public health) Datuk Dr Lokman Hakim Sulaiman has dismissed the existence of the Den-5 virus. Is Den-5 a new threat to Malaysians?
Answer: I think we must not be alarmist and think the Den-5 will be a new threat to the country. Being a sylvatic strain (simian strain), it is unlikely to cause any major problems anytime soon. For example, the Sylvatic Den-2 strains have been reported in only very few cases, even in Africa, after many years. Apparently, these types of dengue viruses do not seem to spread readily or cause diseases once introduced into the human cycle. It is a well-known fact that dengue viruses have a zoonotic cycle in the jungle. This was documented in the early 1960s in Malaysia by the Hooper Foundation, University of California, when monkeys hoisted up in cages in forest canopies got infected and viruses were
Read more @: Stay calm, wait for the dengue vaccine: Virologist – General – New Straits Times http://www.nst.com.my/nation/general/stay-calm-wait-for-the-dengue-vaccine-virologist-1.485053#ixzz2tW64JwMf