BOGOTA, Feb 19 (Thomson Reuters Foundation) - The
mosquito-borne Zika virus spreading through the Americas, linked
to severe birth defects in Brazil, will not be controlled over
the long-term unless governments improve poor living conditions
in the region's sprawling slums, experts say.
Across Latin America, poor neighbourhoods crammed with
shacks built with bricks, scrap metal and wood, often surrounded
by rubbish and without access to running water, are a common
feature of the urban landscape.
Such an environment has fuelled the spread of the Zika
epidemic and other diseases carried by the Aedes aegypti
mosquito, such as dengue and chinkungunya, and poor communities
living in slums often bear the brunt, experts say.
"People living in crowded circumstances, a lack of piped
water, and poor sanitation have given rise to the perfect set of
conditions for the transmission of mosquito-borne viruses like
Zika," said Amy Y. Vittor, assistant professor in medicine at
the University of Florida's Emerging Pathogens Institute.
"The lack of decent living conditions, which gives rise to
not only epidemics such as Zika and dengue but also childhood
diarrheal diseases, must be addressed," she told the Thomson
Reuters Foundation in a phone interview.
Around 113 million people across Latin America - or nearly
one in five people - live in slums, partly a result of mass
migration from rural to urban areas from the 1950s onwards as
people moved to the city in search of jobs.
Such rapid urbanisation has often happened without proper
urban planning, allowing slums to expand without basic
infrastructure and services.
Many slum dwellers store water in buckets and collect rain
water in root-top tanks, and water also collects in discarded
tyres, making ideal breeding grounds for mosquitoes.
"You have a lot of places where water can be stored and
where mosquitoes can lay their eggs, making people living in
slums vulnerable," said Ana Carla Pecego, an infectious disease
specialist in Rio de Janeiro.
The Zika virus has spread to more than 30 countries and
territories, with Brazil the worst hit by the outbreak, followed
Much remains unknown about Zika, including whether the virus
actually causes microcephaly, a condition marked by abnormally
small head size that can result in developmental problems.
Brazil is investigating the potential link between Zika
infections and more than 4,000 suspected cases of microcephaly.
The World Health Organization (WHO) said on Friday there was
an increasing accumulation of evidence of an association between
the Zika virus and microcephaly, a neurological disorder in
babies, but it could take 4-6 months to prove.
The WHO declared the outbreak an international health
emergency on Feb. 1, citing a "strongly suspected" relationship
between the Zika virus and infection in pregnancy and
The WHO says the Aedes aegypti mosquito has shown "a
remarkable ability to adapt to changing environments," including
rapid unplanned urbanisation.
DISEASE OF THE POOR
Current efforts are focused on protecting people, especially
pregnant women, from bites and eradicating the mosquito breeding
sites in affected areas.
For the poor living in densely populated slum areas it is
harder to avoid getting bitten, some experts say.
"When you have a lot of people living together in one small
place it makes is easier for the Zika virus to spread and for
mosquitoes to bite many people in a small space," Pecego said.
People living in affluent neighbourhoods have access to
running water and can protect themselves better by using insect
repellent, pesticide-treated mosquito nets, screens on windows
and air conditioning - options not often available to slum
During heavy rainfall, slums often flood because of
non-existent and or blocked drains, leaving puddles of stagnant
water outside people's homes where mosquitoes can breed.
In Colombia, an El Nino-related drought has meant more
people have resorted to storing water. In Cali, Colombia's third
city, rationing of tap water due to drought has prompted
residents to store more in containers.
In neighouring Brazil, tens of thousands of health workers
are going door-to-door to eradicate mosquito breeding sites in
homes, along with a massive insecticide-spraying operation to
stem the Zika outbreak.
Pecego said previous dengue outbreaks have shown that such
methods can control the number of cases only for "a brief period
to time" and that the disease flares up again.
"To control the Zika virus over the long-term we have to
invest in sanitation and health education, not throw garbage in
the streets and rivers and cut out the necessity for people to
store water," she said.
(Reporting by Anastasia Moloney, editing by Ros Russell.;
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