[The tropical disease, though life-threatening
for a tiny fraction of those infected, can be extremely painful. Growing
numbers of Western tourists are returning from warm-weather vacations with the
disease, which has reached the shores of the United States and Europe. Last
month, health officials in Miami announced a case of locally acquired dengue
infection. ]
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Enrico Fabian for The New York Times
A man at the Yamuna River, an ideal breeding ground for mosquitoes. Filthy standing
water abounds in New Delhi. More Photos »
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India has become the focal point for a
mosquito-borne plague that is sweeping the globe. Reported in just a handful of
countries in the 1950s, dengue (pronounced DEN-gay) is now endemic in half the
world’s nations.
“The global dengue problem is far worse than
most people know, and it keeps getting worse,” said Dr. Raman Velayudhan, the
World Health Organization’s lead dengue coordinator.
The tropical disease, though life-threatening
for a tiny fraction of those infected, can be extremely painful. Growing
numbers of Western tourists are returning from warm-weather vacations with the
disease, which has reached the shores of the United States and Europe. Last
month, health officials in Miami announced a case of locally acquired dengue
infection.
Here in India’s capital, where areas of
standing water contribute to the epidemic’s growth, hospitals are overrun and
feverish patients are sharing beds and languishing in hallways. At Kalawati
Saran Hospital, a pediatric facility, a large crowd of relatives lay on mats
and blankets under the shade of a huge banyan tree outside the hospital
entrance recently.
Among them was Neelam, who said her two
grandchildren were deathly ill inside. Eight-year-old Sneha got the disease
first, followed by Tanya, 7, she said. The girls’ parents treated them at home
but then Sneha’s temperature rose to 104 degrees, a rash spread across her legs
and shoulders, and her pain grew unbearable.
“Sneha has been given five liters of blood,”
said Neelam, who has one name. “It is terrible.”
Officials say that 30,002 people in India had
been sickened with dengue fever through October, a 59 percent jump from the
18,860 recorded for all of 2011. But the real number of Indians who get dengue
fever annually is in the millions, several experts said.
“I’d conservatively estimate that there are
37 million dengue infections occurring every year in India, and maybe 227,500
hospitalizations,” said Dr. Scott Halstead, a tropical disease expert focused
on dengue research.
A senior Indian government health official,
who agreed to speak about the matter only on the condition of anonymity,
acknowledged that official figures represent a mere sliver of dengue’s actual
toll. The government only counts cases of dengue that come from public
hospitals and that have been confirmed by laboratories, the official said. Such
a census, “which was deliberated at the highest levels,” is a small subset that
is nonetheless informative and comparable from one year to the next, he said.
“There is no denying that the actual number
of cases would be much, much higher,” the official said. “Our interest has not
been to arrive at an exact figure.”
The problem with that policy, said Dr. Manish
Kakkar, a specialist at the Public Health Foundation of India, is that India’s
“massive underreporting of cases” has contributed to the disease’s spread.
Experts from around the world said that India’s failure to construct an
adequate dengue surveillance system has impeded awareness of the illness’s vast
reach, discouraged efforts to clean up the sources of the disease and slowed
the search for a vaccine.
“When you look at the number of reported
cases India has, it’s a joke,” said Dr. Harold S. Margolis, chief of the dengue
branch at the Centers for Disease Control and Prevention in Atlanta.
Neighboring Sri Lanka, for instance, reported
nearly three times as many dengue cases as India through August, according to
the World Health Organization, even though India’s population is 60 times
larger.
Part of India’s problem is that some
officials view reports of dengue infections as politically damaging. In
September, Mamata Banerjee, the chief minister of West Bengal, dismissed
reports of an increasing number of dengue-related deaths, saying doctors were
misdiagnosing. “So everyone is earning a bad name,” she said at a news
conference.
A central piece of evidence for those who
contend that India suffers hundreds of times more dengue cases than the
government acknowledges is a recent and as yet unpublished study of dengue infections in West Bengal
that found about the same presence of dengue as in Thailand, where almost every
child is infected by dengue at least once before adulthood.
“I would say that anybody over the age of 20
in India has been infected with dengue,” said Dr. Timothy Endy, chief of
infectious disease at Upstate Medical University in Syracuse.
For those who arrive in India as adults, “you
have a reasonable expectation of getting dengue after a few months,” said Dr.
Joseph M. Vinetz, a professor at the University of California at San Diego. “If
you stay for a longer period, it’s a certainty.”
The reason that such an extensive epidemic
can hide in plain sight is that as many as 80 percent of dengue infections
cause only mild symptoms of fatigue, said Anthony S. Fauci, director of the
National Institute of Allergy and Infectious Diseases. For many, the disease is
experienced as “maybe just a fever that
someone shrugs off.”
But the remaining 20 percent may be affected
by more serious flulike symptoms, with high fever, vomiting,
searing pain behind the eyes, skin rash, and muscle and joint aches that can be
so intense that the illness has been dubbed “breakbone fever.”
The acute part of the illness generally
passes within two weeks, but symptoms of fatigue and depression can linger for
months. In about 1 percent of cases, dengue advances to a life-threatening
cascade of immune responses known as hemorrhagic or shock dengue.
This potentially mortal condition generally
happens only after a second dengue infection. There are four strains of the
dengue virus, and infection with a second strain can fool the immune system,
allowing the virus to replicate. When the body finally realizes its mistake, it
floods the system with so many immune attackers that they are poisonous. Such
patients must be provided intravenous fluids and round-the-clock care to avoid
death.
Twenty years ago, just one of every 50
tourists who returned from the tropics with fever was infected by dengue; now,
it is one in six, said Dr. Velayudhan, the W.H.O. official. The Portuguese
archipelago of Madeira is in the midst of an epidemic.
On Oct. 9, Puerto Rico’s Health Department
declared a dengue epidemic after at least six people died and nearly 5,000
people were sickened.
The great danger of having hundreds of
millions of people in India with undiagnosed and unacknowledged primary
infections is that a sudden shift in the circulating dengue strain could cause
a widespread increase in life-threatening illnesses.
“We have been fortunate so far,” said Dr.
Kakkar of the Indian public health group. “But if, God forbid, we come across
that situation we probably need far better health-care management and inpatient
care facilities.”
Trucks spewing pesticides
against mosquitoes are now a regular presence in New Delhi neighborhoods, but
rapid and disorderly urbanization — a hallmark of India’s development —
increases the risks of dengue proliferation, so few believe the government here
can do much to halt its spread.
The best hope for relief is a vaccine, but a
recent trial of the most advanced vaccine candidate largely failed.
“I think we’re looking at 10 to 12 years
before we see an effective vaccine, and that’s if we’re lucky,” Dr. Halstead
said. “In the meantime, we’re in trouble.”
Hari Kumar contributed reporting.
