New Delhi: Ever thought that dwindling count of frogs from water bodies can be a cause of manifold-increase in mosquito population and subsequent rise in vector borne diseases? Yes, say environmentalists.

The untimely demise of the iconic filmmaker Yash Chopra due to dengue came as a rude shock to the country.

Also in the national capital, a new variety of dengue- causing mosquito - Asian Tiger - has been spotted which is believed to be resistant to traditional forms of control mechanism.

According to municipal officials, aedes albopictus or Asian tiger mosquito breeds in the open as against yellow fever-causing aedes aegypti mosquito, which also causes dengue and breeds inside homes.

Environmentalists attribute the reasons for the increase in vector-borne diseases to ecological imbalance and global warming besides increasing human population and their food habits.

Naturalist Raza H Tehsin says there is an urgent need to introduce and increase the population of weed fish in water bodies and wetlands and also curbing the illegal export of frog legs.

"Frogs are almost wiped out from our subcontinent. Frogs are the major predators of mosquito larvae. In every wetland flowing or stagnant there was abundance of frogs, surviving largely on mosquito eggs and larvae," Udaipur-based Raza told PTI.

He says that while frogs from water bodies have dwindled, mosquito population has increased manifold.

According to Raza`s daughter and Udaipur`s Wildlife Warden Arefa, decline in the population of small fish is also responsible for population of mosquitoes going up.

"In almost all the water bodies and wetlands of India there were numerous small fish. The number of weed fish species found in different water bodies has not yet been surveyed and ascertained," she says.

Besides, many exotic fish are introduced in the water bodies for commercial purposes.

"There is no study to see how this affects the ecosystem of our water bodies. Some of the introduced fish are voracious carnivores, like tilapia and magoor, which feed on small fish."

She says many small species of fish, which are not only predators for vector larvae but also a very important link in the food chain, have depleted.

"The fingerlings of these carnivore weed fish too are predators of larvae. With their dwindling numbers malaria, dengue, chikungunya and other vector-borne diseases are increasing all over India," claims Arefa.

Interestingly, an international team of scientists, educators, policymakers and naturalists dedicated to protecting the world`s amphibian species have started a campaign called `Save the Frogs`. On April 28, the group organised the 4th Annual `Save The Frogs Day`. In India, the main event was organised in Guwahati in Assam.

In Delhi, over 1,200 cases of dengue have been reported so far. Two children have so far succumbed to dengue in the city ever since the disease began spreading early last month.

In 2011, a total of 857 cases were reported in Delhi and five deaths took place while in 2010, a total of 5,682 dengue cases and eight people died.

Meanwhile, the Delhi government has decided to launch an SMS campaign to educate people about preventive measures required to be taken to contain the spread of dengue.

PTI