The Zika virus is now even in Ireland, brought by a couple who returned from Colombia, South America two weeks ago. What is the Zika virus, and how could it affect the world?
Zika Virus Origins
Zika was first identified in the Zika forest in Uganda 1947. Due to the mildness of symptoms, the virus was a scientific curiosity until the Brazilian outbreak in 2015.
There are two identified genetic strains of the Zika virus; African and Asian. The Asian strain is now coursing through the Americas. In 2014 there was an outbreak in French Polynesia.
Zika virus sufferers may experience symptoms such as a rash, sore eyes, severe headache and a fever. The Zika virus is carried by the Aedes aegypti mosquito, which lives in the tropics and sub-tropics of the western hemisphere. Female mosquitoes pick up the virus by biting an infected individual and then spread it by biting another person.
Little is known about the Zika virus. No one knows why there have been no outbreaks of microcephaly in either Africa or Asia. There is no evidence of human immunity in those locations, but it is possible that the virus may have mutated to cause these more serious side effects in Brazil.
Zika Virus: Current Distribution
At present, Zika virus is concentrated in the tropical parts of Brazil, with currently 1.5 million infections. The WHO describes the Zika virus as spreading explosively across the Americas. The UN predicts 3-4 million cases within the next 12 months.
Humans living outside Asia and Africa have no immunity to Zika, so the spread of Zika to the US is inevitable. Temperate countries like the UK will not have problems with a disease-bearing mosquito, which will soon die in a northern climate.
The more common culex mosquito, with ranges outside of Aedes, could now harbour the virus. The Asian tiger mosquito, Aedes albopictus, widespread in southeast US and southern Europe may now harbour the virus. This larger availability of carriers makes the problem worse. It will take several years to develop a vaccine, which could leave the world with a serious public health emergency.
The WHO prediction includes an epidemic of birth defects, such as a significant rise in microcephaly. Since October 2015, 4,000 cases of microcephaly were recorded in Brazil. Normally 160 cases are expected in a Brazilian population of 200 million.
Zika and Associated Illness
Viral specialists in the Brazilian Department of Health now link the Zika infection with a rare illness called Guillain-Barre Syndrome, an autoimmune disease that cripples the nervous system, rendering the victim paralysed and struggling to breathe. Northeast Brazil has recorded hundreds of such cases.
Pregnant women are advised to avoid travelling to 24 countries in Central and South America. Should Zika spread north to Central America, Mexico and the US, the advice to women and families, to avoid becoming pregnant, will apply. Sexual transmission of the zika virus may occur, however this is highly unlikely to aid widespread transmission.
Eradicate the Mosquito?
The spread of Ebola was, paradoxically, hindered by the disease’s severity, with most victims too ill to travel and spread the plague. Zika, however, appears relatively harmless, so those infected move around and spread the disease.
Dr. Olivia Judson, a British evolutionary biologist, suggests eradicating the mosquito altogether, confirming that the world could survive without this species . Mosquitoes kill and debilitate millions of people with dengue, yellow fever and malaria – but it’s possible to reduce their population. For example, Genetically Modified (GM) male mosquitoes father offspring that die before they reach adulthood. Releasing GM mosquitoes can reduce populations by more than 90%.
The alternative of human misery, disease, and death remains.