Five years ago the Indian subcontinent experienced its first epidemic of dengue fever, with more than 5,000 people in India and more than 2,000 in Pakistan hospitalized (M. A. Rai and H. Khan J. Clin. Virol. 38, 269–270; 2007). Pakistan is now in the middle of a dengue resurgence: more than 15,000 cases have been recorded in Lahore alone. This is potentially disastrous for the country's health-care system, which is already on its knees.

Mortality is much higher this time. There have also been reports in Pakistan of resistance to agrochemicals evolving in dengue mosquitoes (H. A. Khan et al. Parasite Vectors 4, 146; 2011), calling into question the current massive fumigation drive. Last year's record floods have aggravated the situation.

Dengue experts have been flown in from Sri Lanka, Indonesia and the World Health Organization, but they may be too late. Prior planning and policy formulation by Pakistan's health-care authorities are key to the prevention of future dengue outbreaks.