On the frontline in the fight against dengue fever in Lahore, Pakistan’s second largest city, the authorities have a sharp eye for spare car tyres.
“When the police show up, we will throw all these tyres into the basement,” said Rohil Ayub, 18, who runs a downtown repair shop.
“The police fine us a lot, thousands of rupees every time,” he said.
Every few days, police inspectors fine anyone who leaves tyres outside - a nuisance, complain the owners of the hundreds of repair shops in the area but essential, health experts say, for combating dengue, a potentially fatal haemorrhagic fever without a vaccine.
In a four-month outbreak in 2011, the mosquito-borne virus infected 21,000 in Pakistan, 85 percent of them in Lahore, leading to 352 deaths.
At the time, a range of rapidly deployed measures, including using smartphone technology, fumigation and the tracing of larvae breeding grounds, were set in motion by the provincial government to help prevent a worse crisis and keep deaths in the hundreds.
“No one expected this kind of political commitment,” said Qutbuddin Kakar, who oversees programmes to combat malaria and dengue in Pakistan for the World Health Organization (WHO). “In this part of the world, at least, we had not seen this kind of response before.”
The anticipated 1,000-plus deaths did not occur, and since then, dengue fever cases have dropped - 200 in the province (Punjab) last year, without any reported deaths.
So, what was done right, and what do the authorities need to do to make sure solutions are long-term?
The tactics developed to prevent another dengue outbreak were first developed in 2011: information campaigns, data-sharing, and destroying mosquito larvae sites.
Hundreds of government entomologists regularly visit cemeteries, public parks, and gardens, testing for aedes mosquitoes and larvae in any sources of water.
The results they collect are processed on site by specially-designed Android based applications on their smartphones, and uploaded to a centralized dengue prevention centre.
There, analysts match the entomological data with reports from hospitals showing where dengue patients are being treated. Based on the findings, a team is sent to fumigate areas where aedes mosquitos seem to be breeding and infecting people, or to identify and remove sources of standing water.
The key season for infections comes with monsoon rains, when the aedes aegyptus and aedes albopictus mosquitoes, which can carry the virus, begin to appear.
Chronology of an outbreak
In August 2011 heavy monsoon rain dumped 13 inches in a week, leaving parts of Lahore with large bodies of standing water, and raising immediate concerns about disease.
By mid-October, the provincial government in Punjab reported that more than 11,000 dengue cases were recorded.
“It was an exponential increase in number, and it really frightened the government,” said Faran Naru, a consultant hired by the provincial government to tackle the problem. “And the issue was resonating in the media... so it created a panic in the public which had to be contained.”
Most people infected with dengue recovered on their own, said Naru, but once media outlets began reporting on the extent of the outbreak, thousands showed up at hospitals and laboratories to get tested.
An initial team of 70 entomologists conducted 12,000 spot-checks to track where aedes mosquitos were present. By mid-October, this data had been mapped, along with the locations of 11,000 reported dengue patients.
The results surprised the scientists. The worst affected areas were some of the wealthiest neighbourhoods of Lahore: Model Town, Race Course, Mozang, and Gulberg.
“I saw that in Model Town there is a big park, and in Race Course there are two of Lahore's biggest parks… and I believe lots of breeding was happening there and mosquitoes were leaving from there and infecting people,” said Naru.
The mosquitoes need fresh water to lay their eggs, and the large puddles in Lahore's biggest public parks proved to be ideal homes.
Another hotspot was the Mozang neighbourhood, home to one of Pakistan's largest graveyards. The 150-acre area was found to be a major breeding ground for mosquitos. Gravediggers had dug large pits to hold water, which they used to soften the dirt when digging.
“It's fresh water,” said Naur, “from the tap, and there were 70 pits, and all of those were infected, full of larvae.”
Back in the hospital, dengue patients were separated into special areas for treatment. The home of each dengue patient was fumigated, along with 12 surrounding houses, three in each direction.
Sanitation workers unclogged sewers and drains in an effort to clear areas of rainwater; and parks, gardens, and cemeteries were also sprayed. Thousands of Mosquitofish and Garden Carp - fish species known to attack mosquito larvae - were also released into ponds and ditch canals.
Within a few weeks, entomologists detected far fewer aedes mosquitoes, and the prevalence of dengue cases rapidly decreased.
A public awareness campaign also helped - with city residents encouraged to use mosquito repellent and bednets, and schoolchildren instructed to wear long-sleeved clothing, despite the monsoon heat.
There have only been two cases of dengue fever reported in the province so far this year, suggesting the anti-dengue measures have had an impact.
But the disease tends to come in 2-4 year cycles, and public health officials worry that if the lessons learned from the 2011 outbreak are not institutionalized, future governments might not handle subsequent outbreaks as well.
In March, an interim government took over in Pakistan to oversee national and provincial elections.
“We must see if the government is able to plan long-term for dengue. This was just a short-term response,” said Kakar from WHO. He says the teams of entomologists and fumigators, and funding resources devoted to surveillance and data transmission, need to continue to work every season.
He also says Pakistan could devote the same kinds of resources to other mosquito-carried diseases like malaria.
Pakistan sees more than 300,000 cases of malaria every year according to WHO, a figure that would inevitably drop with a successful long-term anti-mosquito campaign.
“So far,” he said, “a negligible amount is spent on malaria eradication in Pakistan. We should expect that all vector-borne diseases - malaria, dengue... should be brought together under one programme.”
Kakar says malaria is mostly restricted to rural parts of Pakistan, where healthcare facilities are so bad that it is difficult to even get an accurate count of how many people are dying from the disease.
He said if the government provided good sources of water, in both cities and rural areas, he would expect a major impact on mosquitoes, whether they carry malaria or dengue.