Dengue fever, also known as Breakbone disease seems to be spreading in many tropical countries and a specific variety of mosquito (A.aegypti) is known to be the carrier of the virus that causes the disease. Hemorrhagic fever, bleeding, depletion of blood platelets, drastic lowering of blood pressure are some of the symptoms manifested in affected persons. In some cases Dengue fever can become fatal and so far no vaccine has been developed to immunize people from this scourge. Mosquito is one of the biggest menaces mankind faces and practically there is no way this creature can be eliminated from the environment, especially in tropical regions of the world. Mosquitoes breed in stagnant waters laying their eggs which hatch in no time spawning new ones that swell the the population. Many known pesticides are some what less effective in killing these mosquitoes. Interestingly there are four types of Dengue virus variations and though small bites can confer some immunity against one type that does not guarantee the same from fresh infection if other viruses are transmitted by later biting episodes. Best approach would be to "nip the source in the bud" through destruction of the larvae which is much easier than killing the adult predators. Biological control is being attempted using natural agents that can "sterilize" the mosquitoes preventing proliferation. According to a recent report clove oil is an effective larvaecide which can be easily tried in every home vulnerable to Dengue epidemic. Here is an insight into this new development.
In fact, removing breeding sites around the house is a routine that most Brazilians have grown accustomed to, with televised public announcements constantly reminding them of the chore. However, if some stagnant water is unavoidable, those looking to keep Aedes aegypti at bay can turn to another ally in nature. Recently, the Instituto de Nacional de Pesquisas da Amazônia, an Amazon-based research center, discovered that a substance called Eugenol, which is found in clove (Syzygium aromaticum), can kill the larva of the dengue mosquito in 24 hours. The formula is undergoing patenting, but it's simple and can be prepared at home by blending 60 clove buds and a cup of water. No sieving is required and the solution can be kept in a fridge for up to one year. In terms of dosage, three drops suffice for a 15-cm vase (popular targets for dengue mosquitoes) or other types of containers that retain water. The blend will remain effective for about 14 days.The researchers highlight that the clove solution is no substitute for other preventive measures, but it can drastically reduce reproduction of the mosquito. Like the Wolbachia bacteria method and the genetic modification of the mosquitoes, the clove-based remedy is harmless to the environment. Most importantly, it is readily available.
Though the report is encouraging, one has to look into the practical aspect in translating this technique on a wider scale. It is alright that small volume of stagnant water can be made larvae free for two weeks but what is causing the real problem is the availability of public water bodies, cesspools. sewage treatment areas, etc for these creatures to breed and flourish. If clove is really effective why not evolve formulations based on extracts rich in Eugenol, the active principle responsible for the kill effect, for preemptive spraying programs under governmental agencies in countries where they are prolific? There was a time when government agencies used to have regular pesticide spraying programs which could bring about some control of mosquito population responsible for transmitting several diseases like Malaria, Filariasis etc but such control measures are more conspicuous by their absence these days. It is time this practice is revived and mosquito control measures are reformulated and made more intensive and extensive to give protection to the helpless citizens in the country who are vulnerable to diseases caused by these winged messengers of misery.