As the virus spreads, governments and business look to nets, fumigators, insect repellents and genetically modified mosquitoes to combat it
Like avian flu and ebola, Zika seems to have sprung from nowhere. Now affecting more than 3m people in 33 countries, it is linked to microcephaly, a birth defect where a baby’s head is smaller than normal, and, more recently, to the neurological disorder Guillain-Barré syndrome.
The virus was discovered in 1947 by Scottish scientist Alexander John Haddow, who found it in the blood of the rhesus monkey living in Uganda’s Zika forest. It is spread primarily by the Aedes aegypti species of mosquito, although it can be transmitted during sex and from mother to baby during pregnancy. Zika remained virtually unknown until 2012, when Haddow’s grandson Andrew, a medical entomologist, analysed an outbreak on the Micronesian island of Yap, and warned that it might spread.
As there is no cure for Zika – and experts say it may take years to develop a vaccine – the focus has been on containment. Mosquito nets are the first line of defence. Procuring them is now cheaper and easier, thanks to a consortium including the Department for International Development (DFID) and the Global Fund to Fight Aids, TB and Malaria (GFATM). In 2014 they won the CIPS Supply Management Award for the best contribution to the reputation of the procurement profession after simplifying the tender process for mosquito nets and providing better value. Carrying out the world’s largest tender for these items, the consortium saved around £86.1m, providing 190m bed nets and protecting 400m people across 30 African and Asian countries.
In El Salvador in Central America, where there have been 7,000 suspected cases of Zika, fumigation machines known as ‘motobombas’ move from house to house, deployed by men in jumpsuits, masks and hard hats. The fact that the health ministry has urged women not to get pregnant until 2018 does suggest the government is struggling to cope with the virus. Street traders are doing brisk business selling $5 mosquito nets and a $3 anti-Zika electric mosquito zapper. One device – the OFF! Clip-on, which releases a vapour form of insecticide via a battery-operated fan – has been found in US tests to paralyse and/or kill mosquitoes within a 0.3m radius.
The most significant development in the campaign to contain Zika is probably the breeding of a genetically modified strain of the Aedes mosquito by British biotech company Oxitec. Last year Brazil’s National Biosafety Technical Commission gave the firm a licence to release the mutant mosquito anywhere in the country.
A single modified gene kills the offspring of the mutant male Aedes. The males are released into the wild, mate with females and once the eggs hatch into larvae they die. In April 2015, several million GM-mosquitoes were released into the district of Piracicaba, in Sao Paulo state, and by the end of the year the numbers of Aedes had fallen by 82%. The GM mosquitoes do not perpetuate themselves – they die within four days of being released. Oxitec is planning to produce them locally, enabling it to protect the entire district.
Although largely confined to Central and South America, Zika’s global notoriety has spurred Tata Motors, India’s largest car manufacturer, to rebrand their newest model. Showcasing their new hatchback, the Zica (short for ‘zippy car’) at a motor show in Delhi, Tata announced that the car would be renamed before its commercial release to avoid any association with the deadly virus.
For American environmentalist Bill McKibben, the real significance of this outbreak is that it suggests climate change, creating a warmer, wetter world that suits mosquitoes, may pave the way for more such viruses. “Zika provides a glimpse of a future we should do everything possible to avoid,” he said. “This is a terrifying reminder of why the fight for a stable physical planet is the fight of our time.”