News Feature | February 22, 2016

Zika Virus Enabled By Shoddy Water, Sewer Systems

Sara Jerome

By Sara Jerome


Shoddy water and sewer infrastructure is abetting the spread of the Zika virus, which has exploded throughout Latin America in the past year and is now documented in 20 nations.

The virus is largely spread by mosquitos. Related to dengue, yellow fever, and West Nile, it has a foothold in urban areas where decrepit water and sewer systems provide a comfortable breeding ground for mosquitoes.

“The mosquito lays its eggs in containers of water, of a sort that are especially common in the huge slums of Latin American cities. With unreliable access to piped water, people there store water in rooftop cisterns, buckets and the like. Old tires and other debris can also become mosquito habitat,” The New York Times reported.

“Water storage near homes is commonplace in areas where Zika has spread rapidly, like the cities of Recife and Salvador in northeastern Brazil, and where dengue experienced a surge in 2015, like São Paulo, Brazil’s largest state,” the report said.

Why is this virus so threatening?

“The main fear is that it may cause birth defects if pregnant women contract it. A few cases of sexual transmission have been documented, and the new guidelines were issued to prevent that,” The New York Times reported.

“The possibility that the Zika virus causes microcephaly [in babies] — unusually small heads and often damaged brains — emerged only in October, when doctors in northern Brazil noticed a surge in babies with the condition,” the Times reported.

Claims have emerged that pesticides, not Zika, are to blame for the rise in birth defects, but scientists and public officials, including U.S. health authorities, debunked that argument this week, according to USA Today. Nevertheless, “Brazil’s southernmost state halted the use of a mosquito larvicide that an Argentine doctors’ group warns could be behind the recent surge of babies born with microcephaly,” The Wall Street Journal reported.

Research has shown that “productive” mosquito breeding sites are often related to shoddy water and sewer systems. Clara Ocampo, a scientist at the independent research organization CIDEIM, recently investigated this link.

“In one pilot project in the Colombian city of Buga, Ocampo’s team determined which catch basins — boxes that catch debris before it can enter the sewer system — provided the best areas for mosquitoes to reproduce. When researchers applied insecticide to just those boxes, Buga reported fewer cases of dengue compared with nearby cities for several months,” STAT, a medical news site, reported.

Brazil is redoubling its effort to fend off mosquitoes, according to the Associated Press.

“Brazil's health minister says the country will mobilize 220,000 troops to battle the mosquito blamed for spreading a virus suspected of causing birth defects, but he also was quoted Tuesday as saying the battle already is being lost,” the report said. “[Health Minister] Marcelo Castro said that Brazil's armed forces would go door to door to help in mosquito eradication efforts ahead of the country's Carnival celebrations.”

Scientists say the Zika epidemic should be considered a “warning” about the effects of climate change. That’s because “global warming is likely to increase the range and speed the life cycle of the particular mosquitoes carrying these viruses, encouraging their spread deeper into temperate countries like the United States” in the coming decades, the Times reported.

Image credit: "virus," AJC © 2012, used under an Attribution 2.0 Generic license: