Dengue fever: Pakistan’s recurring nightmare

The monsoon rains have historically brought mixed fortunes to Pakistan. While they help spur the cultivation of crops, changing demographics and population distribution have given rise to recurring catastrophes the rains leave in their wake. As Pakistan suffers from another cycle of floods in both rural and urban areas, recent weeks have seen the explosion of a dengue fever epidemic in central Punjab. In the past two weeks alone, more than 6,000 cases have been reported, with the majority occurring in Lahore. At least 40 deaths  have now also been reported. The extent of the epidemic is such that schools in Punjab have been closed for the last ten days.

Dengue fever is a mosquito-borne viral infection. While most cases present with non-specific symptoms such as fever and muscle aches, in about 1 percent of cases, the disease progresses to a more dangerous condition called "dengue hemorrhagic fever." In this condition, the normal human clotting process becomes deranged, resulting in spontaneous bleeding in patients, leading in some cases to death. In the appropriate context, dengue can be diagnosed without the help of any advanced laboratory tests. However, treatment options are limited only to supportive measures, such as providing anti-fever and pain medication, as well as using transfusions to combat platelet deficiency, though no "cure" or vaccine exists.

Dengue fever epidemics have become a cyclical nightmare in Pakistan over the last several years. The infection was quite rare in South Asia before the turn of the century, but starting in the last decade, dengue epidemics have become a regular occurrence, usually peaking in September and October. As the population in Pakistan grows or people move around in search of economic opportunity or safety from militant violence, settling in many places into overcrowded urban slums on the outskirts of cities like Lahore.

These slums are hotbeds of contamination, given that the proliferation of these ramshackle neighborhoods outpaces that of adequate infrastructure development. With hygienic practices already poor, they grow worse in such settings, where public sanitation is often subpar. The best measure to prevent dengue can be by halting the reproduction of mosquitoes or preventing mosquito bites. Mosquitoes reproduce in stagnant water, and unless widespread measures are taken to drain such collections or fumigate mosquito-prone areas, the insects continue to proliferate, helping spread infections.

The current armed conflict in Pakistan has also been a key driver of disease. The plains of Punjab provide a home to millions of internally displaced refugees who have moved away from the war-torn northeastern and tribal regions, bringing with them an increase in disease. Furthermore, war itself is known to be one of the most potent fomenters of infectious disease: Studies have shown that "complex emergencies" can cause a several-fold increase in infection rates.

But aside from these direct environmental factors fueling the spread of dengue, another potential cause of the infection’s appearance might well be climate change. Like most other infections spread by an intermediary organisms (like mosquitoes), dengue transmission increases with atmospheric temperature and humidity, since higher temperatures and moisture optimize mosquito breeding.

Complicating this problem further is emerging evidence that Pakistan’s mosquitoes are developing resistance to insecticide that is used to eliminate them.

Unfortunately, many of the factors contributing to dengue outbreaks, from poor hygiene and sanitation to climate change, are risk factors common to most infectious diseases. If no major changes occur, Pakistanis could be exposed to a host of epidemics, such as measles, pneumonia, and cholera.

One important reform would be to empower public health specialists to develop overarching strategies to reduce factors leading to transmission. However, the medical community in Pakistan is focused on other things, with young doctors in Punjab on strike for long periods of time this year protesting low wages. Given that there is such resentment among trainees, who form the backbone of the clinical work force, it is likely that these protests are also adversely affecting the response to the current epidemic, as there are fewer doctors available to try and stem the crisis.

Since neither cure nor vaccine exists for dengue fever, prevention is the only option to control the human and economic cost of the epidemic. While the local media has criticized the government’s response, one has to consider that they are over whelmed by several public health crises spanning the length and breadth of the country simultaneously, such as the widespread floods, ongoing polio transmission and rampant malnutrition. Nevertheless, improving hygiene and sanitation, in addition to helping better-manage public infrastructure development and population growth, remain the only long term solutions for preventing dengue, and other infections, from breaking out.

Haider Warraich, MD, is a research fellow at Harvard Medical School. He is a graduate of the Aga Khan University in Karachi, Pakistan, and the author of the novel, Auras of the Jinn.