Zika: the globalisation of disease

The zika virus was discovered in a Uganda forest in 1947. During the next 60 years it was occasionally found in west and central Africa and south-east Asia. No serious illness seemed to result and it was largely ignored. The first sign it was spreading was a major outbreak in the western Pacific Yap Islands in 2007. An estimated 73% of the population was infected, with some reporting headaches, rash and fever. In a population of only 11,000, serious but rare results of infection did not show.

Nevertheless, a study of that outbreak, published in the highly respected New England Journal of Medicine (2009), concluded: "The emergence of zika virus (ZIKV) outside of its previously known geographic range should prompt awareness of the potential for ZIKV to spread to other Pacific islands and the Americas. Because the virus has spread outside Africa and Asia, ZIKV should be considered an emerging pathogen [capable of causing disease]".

Similar viruses, such as West Nile fever, had also been thought to be harmless, until found to cause serious illness after spreading beyond their normal geographic area. During the next outbreak in 2013, 3,000 miles away in French Polynesia, the first case of a paralysing illness, Guillain-Barré syndrome, was reported in an adult seven days after zika infection. This rare condition seems to have increased 20-fold in zika-affected areas, affecting younger adults more than normal.

Alarm bells should have been ringing in 2009. Research into zika – its transmission, possible consequences, prevention, tests and treatment – should have been ramped up. The findings should have been sent for urgent action to governments in countries at risk. Tragically, this did not happen. Research is only now being pushed ahead – like sending for the fire brigade after a forest fire has raged for weeks.

Zika probably entered Brazil in 2014, possibly during the football World Cup. The first confirmed infection was in March 2015. It has since spread to 30 countries in south and central America, reaching the Caribbean (not including returning infected travellers). An estimated 1.5 million have been infected in Brazil alone, where there has been a sharp increase of microcephaly – babies born with arrested brain development and small skulls. It is possible other (as yet unknown) factors interact with zika to cause microcephaly. Other viral infections are the most likely culprits.

The failure to prevent this terrible outbreak has similarities with west Africa’s 2013-15 ebola pandemic. A virus known and largely ignored for years is carried from its isolated habitat to urban centres, and then spreads like wildfire. Unlike ebola, passing directly from person to person, zika is carried by mosquito from one infected person to another. Sexual transmission may also occur. Poor, overcrowded shantytowns (favelas) around Latin American cities are ideal for mosquitoes to breed – in stagnant water, uncovered water tanks and rubbish – and feed (on humans).

Most people catching zika have few or no symptoms. The foetus is at highest risk, early pregnancy being the most dangerous time. There could be more miscarriages taking place. Between 130 and 170 cases of microcephaly a year usually occur in Brazil. In the first nine months of 2015 this roughly doubled. From October 2015 to the end of January 2016, over 3,800 cases were reported. Worst affected is the north east, a particularly poor region. One hospital in Recife went from an average of five cases a year to 300 in six months.

The spike in cases began roughly nine months after mid-summer, when mosquito activity is highest. New cases in the worst affected areas are now falling but another spike could occur later this year. It is not clear exactly how an infected baby is affected until it grows – 10% have few problems. Others are severely disabled, physically and mentally, with impaired hearing and vision, and fits. Some are too badly affected to survive.

Early and intensive medical care is needed to give affected babies their best chance to develop. Most will need care for life. This tragedy has similarities with the thalidomide scandal of the late 1950s. Ten thousand babies were born with missing or undeveloped limbs after pregnant women were encouraged to take the supposedly safe drug for ‘morning sickness’ – despite the manufacturer not having tested it in pregnancy. But unlike thalidomide, which was mostly taken in western Europe, there are no pharmaceutical companies to sue for zika damages and there is less health and social care available, especially to poor families.

Five Latin American governments have advised women not to get pregnant for periods between six months and two years. This is completely unrealistic – 56% of pregnancies in the region are unplanned. Many pregnancies, especially of teenagers, result from sexual violence and abuse. Contraception needs to be free and readily available. Women most in need, in poor housing and rural areas, are least likely to have access to reproductive health services.

Understandably, there is now great anxiety among pregnant women in affected areas. They need good antenatal care. Scans can identify microcephaly 20-24 weeks into pregnancy, but not always. Abortion is illegal in most Latin American countries, in some with no exceptions. The Catholic church still has influence over social policy. Nevertheless, an estimated 4.4 million abortions took place in 2008, most unsafe or illegal. Women need rapid access to tests for zika infection and a choice of safe legal abortion if infected during pregnancy, without waiting for a scan.

The most urgent task to prevent zika is eradication of the mosquito Aedes aegypti. "It loves urban life and has spread across the entire tropical belt of the planet, and of course that belt is expanding as global warming takes effect", said Jeremy Farrar, head of the Wellcome Trust. Used tyres, non-biodegradable containers, plastic bags and wrappers are ideal places for mosquitoes to lay eggs. With a little rain they soon hatch. A. aegypti flies less than 200 metres so clearing rubbish and stagnant water around homes and public places is effective. But more and more people live in cities, rubbish accumulating around them. Mosquitoes thrive when public services like refuse collection, piped water and sewage disposal do not exist or break down.

"From the 1950s through the 1970s", writes professor Michael T Osterholm, "there was a major initiative to eradicate Aedes aegypti from the Americas by public health organisations, non-profits and national governments. It almost succeeded. In part, that was because eliminating these mosquitoes’ breeding sites was much simpler before the spread of plastic and rubber waste. But governments and non-profit agencies decided too early that the job had been done, and dismantled these programmes to save money. Now the mosquito is back". (New York Times, 29 January)

Parts of Brazil’s water industry are privatised. Sabesp, supplying São Paulo, is part privatised paying US$83 million dividends to shareholders early in 2015. Soon afterwards a major drought hit this city of 20 million people, along with Rio de Janeiro and other coastal cities. Studies link this to the destruction of 40% of Amazon rainforest. Intermittent water supply encourages storage in tanks and containers that can become mosquito breeding grounds. Inadequate sewage disposal means even Olympic outdoor water sport sites are heavily polluted. Corruption and economic crisis, with China buying fewer commodities from Latin America, magnify failures to invest in public services and infrastructure.

Although A. aegypti is spreading zika in Latin America, the virus may adapt to other mosquito species, further increasing its range. A. albopictus arrived in the USA in the 1980s and has now spread to 30 states, including the eastern coast up to New York. It has also spread to Europe and can tolerate temperatures below freezing. International trade in used tyres and lucky bamboo (a houseplant) have helped it on its way. Travellers and goods criss-cross the world, taking insects and viruses with them.

Other viruses are spread by both these mosquito species, such as the three causing dengue fever. This has increased worldwide 30 times in the last 50 years, with 2.3 million cases in 2013 occurring in the countries now affected by zika. Although usually a mild infection, there were 37,000 severe illnesses and 1,300 deaths. Symptoms can quickly worsen so free and rapid access to good healthcare facilities is essential. A third virus, chikungunya, also appeared in the Caribbean in 2013, spreading throughout the Americas within two years with almost two million cases reported. Rarely fatal, it often leads to painful joints, sometimes becoming long-term.

According to the World Health Organisation in 2012: "For dengue prevention and control there is very little international advocacy or successful funding efforts. Whereas some research organisations are successfully raising funds for focused research work, almost no money is available for international control efforts. This funding gap affects all areas where international response could help, such as outbreak preparedness and response, development of training material, organisation of training courses and support of research networks". Only two countries greatly reduced the spread of dengue by 2011, with anti-Aedes laws and sustained action: Singapore (small and relatively wealthy) and Cuba (still able to plan public health programmes).

Mosquito resistance to insecticides will spread. There have been calls for DDT to be used again. This insecticide was banned over 40 years ago (except for malaria control) as it accumulates at the top of the food chain, including in human breast milk, and is linked to cancer in animals. Vaccines could help prevent zika, dengue and other viruses. Vaccination programmes have successfully tackled deafness and other problems resulting from rubella (German measles) during pregnancy. Tick-born encephalitis vaccination covers 85% in Austria and 81% in the Sverdlovsk district of Russia and is 98% successful.

However, vaccines can also cause problems. Yellow fever vaccine’s manufacturing process has hardly changed since 1945 and contains a substantial amount of chicken protein that can cause allergic reactions. Other rare but serious complications can occur. About 80% of global vaccine sales come from five multinational corporations. Vaccines are expensive to produce and deliver. They are often required only once in a lifetime – rarely more than five times. Tropical diseases mostly hit people too poor to pay for vaccines. In short, therefore, vaccine research gets low priority because profits are low.

The best-selling vaccine in the USA generates about $1 billion a year, compared to over $8 billion for each of the top three selling drugs: treating rheumatoid arthritis, major psychosis and hepatitis C – illnesses needing daily treatment for many years. In 2004 one cholesterol-lowering drug made more money than the worldwide sale of all vaccines. Now that zika is threatening an epidemic in the USA though – creating a new market – research into a vaccine has accelerated. The global pharmaceutical industry needs to be brought into public ownership, so its massive resources can be democratically planned to meet the needs of people everywhere. Under capitalism, however, the industry’s main aim is to maximise profits.

Zika will eventually be controlled by vaccination or preventive measures, but is unlikely to disappear. The numbers of babies born with microcephaly will grow. They will need lifelong care and treatment, unavailable at present to most of the families affected. Zika will not be the last infection to suddenly invade across national boundaries, threatening the health and lives of millions. Capitalism, with its inequality, inability to provide basic public health and hygiene, environmental destruction and global traffic, has made the whole world vulnerable. Billions of dollars are squandered on so-called defence (of the interests of the super-rich), while the rest of us are left defenceless against these real threats.

Jon Dale