Tilapia fish is Pakistan’s frontline fighter against dengue

LAHORE: On one side of the battle are the countless swarms of mosquitoes that thrive in Pakistan’s steamy summer months. On the other, vast quantities of hungry fish conscripted into a fight against a deadly virus that is reaching epidemic proportions.

Authorities battling the dengue menace claim to have turned the tide against the mosquitoes with the help of 1.6 million fish released this year into pools, puddles, fountains and any other potential insect breeding places. Punjab has waged an all-out campaign against dengue — a potentially lethal disease spread by mosquito bites — since a major outbreak in 2011 infected tens of thousands and killed more than 300 people.

Software designers were tasked to make smartphone apps to track outbreaks, the government cracked down hard on anyone who left old tyres in areas where they could collect rainwater, and areas of stagnant water were doused with tons of noxious chemicals. But it’s the release of huge numbers of fish, even into water that soon evaporates, that many credit with helping to beat back the disease.

A typical target the Punjab’s fish team is an acre of murky water that forms every year in a depression squeezed between a flyover and brick factory in an unlovely outskirt of Lahore.

It is one of the hundreds of glorified puddles that fill during the monsoon season that are of little interest to anyone. Every few months a team led by a white bearded technician in an lab coat return to the pool, test the water and then release up to a thousand voracious tilapia fish from giant plastic bags partially inflated with oxygen. Immediately on their release the surface of the water ripples with fish rising to gobble insects and the larvae that would otherwise quickly mature into mosquitoes.

The effect has been dramatic with just over 100 cases reported in Punjab this year, compared with 20,000 in 2011. Officials say it has also curbed other pests, not just the Aedes mosquito that car ries dengue.