Calls to public health hotlines can predict dengue fever outbreaks two or three weeks earlier than local hospitals can confirm them, according to a new study from Pakistan.
The study looked at 300,000 calls to a health hotline in Lahore over two years. By asking callers to describe their symptoms and give their addresses, operators were able to pinpoint which districts in the city were having dengue outbreaks.
Getting that information quickly was important because mosquito-control teams could be quickly dispatched to the right neighborhoods instead of arriving late or working at random in Lahore, a city of more than 10 million people, said Lakshminarayanan Subramanian, a computer science professor at New York University and one of the authors of the study, which was published this month in the journal Science Advances.
The idea works a bit like Google Flu Trends, which tries to spot influenza outbreaks early by identifying clusters of people searching for flu symptoms or flu remedies. But in poor countries like Pakistan, few people have internet access while many have cellphones, Subramanian said.
In Lahore, mosquito-borne diseases surge each September as the first monsoons create pools of water in which mosquitoes breed. The hotline was created after a large 2011 dengue outbreak swamped local hospitals.
Residents are encouraged to call and describe their symptoms so they can be told whether to see a doctor and which hospitals have room.
They can also complain about uncollected garbage or old tires, where mosquitoes breed, or ask that mosquito-control teams visit their neighborhoods. The teams spray houses, put larvicide in water sources or even drop tilapia minnows, which eat mosquito larvae, into pools of water.