The Zika virus: All you need to know about the latest global health scare and how it could affect India

The Zika virus — the latest health scare to grip the planet — came to prominence in 2015 when pregnant Brazilian women infected with the virus gave birth to babies with abnormally small heads that are normally associated with incomplete brain development (also called microcephaly). While the virus, at present, is being detected primarily in Latin America, it appears India may not be as safe as hoped. According to India Today, India has been free of this virus for over 60 years, and that traces of Zika were last seen in 1952-53.

A representational image of the Aedes aegypti mosquito. AP

A representational image of the Aedes aegypti mosquito. AP

However, Hindustan Times reported that the Union health ministry is procuring testing kits to detect the virus, which is spread by the bite of the Aedes aegypti mosquito — the same vector that spreads dengue and chicken guinea. "The government is also writing to the Centers for Disease Control and Prevention (CDC) to know more about the infection and prepare accordingly,” the report quoted a senior official from the Zoonosis unit of the Union health ministry as saying. Furthermore, the report added that the ministry is putting together protocols to track the 'sudden rise' of birth defects across the country.

With Brazil emerging as the epicentre of the Zika crisis, the 2016 Rio Olympics are turning into a source of some concern. The Times of India quoted physician Dr Pratit Samdani who said that considering the fact that people "travel across countries a lot" — particularly those planning summer holidays with the Rio Olympics in mind — it would not be too surprising "if we suddenly got a case of Zika in India".

But it's not all doom and gloom for Indians. After all, there's a chance that we're already have an immunity (cross-reactive immunity, to be precise) and we just didn't know it.

The Indian Express quoted Dr Lalit Dar, professor of microbiology at Aiims as saying “When the proteins of the virus are similar, so are the antibodies that develop against them. Since Indians are exposed to all four strains of dengue circulating in the atmosphere since birth, the body develops antibodies against them. Since Zika virus is similar in composition, these antibodies may be cross reactive with the Zika virus.”

What do we know about the virus?

First in Africa: Aedes aegypti is a small, dark, hot-weather mosquito with white markings and banded legs. Scientists believe the species originated in Africa, but came to the Americas on slave ships. It's continued to spread through shipping and airplanes. Now it's found through much of the world, including the southern United States.

Once yellow fever mosquito: Early in the 20th century, scientists showed it was the engine behind devastating yellow fever outbreaks. It became known as the yellow fever mosquito, although that name has been used less often since a successful vaccine was developed against yellow fever. Since then, it's also been identified as a carrier for other tropical illnesses such as dengue fever, chikungunya and Zika fever. Scientists are investigating whether other types of mosquitoes are spreading Zika in Latin America and the Caribbean, too.

A city-dweller: Aedes aegypti is the primary spreader of Zika and some other tropical diseases, largely because of its unusually cozy relationship with people. While other species thrive in more rural areas, or at least in parks and gardens, this is a domesticated species - sort of a housecat mosquito - accustomed to living in apartment buildings and city centers. It prefers biting people to animals and likes to feed indoors, during daylight hours. Also, it is a hardy bug that can be particularly challenging to get rid of.

Killed off, but it came back: In the early 20th century, many countries developed programs to destroy all Aedes aegypti mosquitoes through spraying chemicals and other measures. By 1970, it was eradicated from much of South America — including Brazil. But many mosquito-control programs were cut back. Reasons included budget cuts, and concerns about the use of some insecticides, and the yellow fever vaccine made the mosquito's elimination less critical. The species roared back. It played a key role in the reemergence of dengue fever in Latin America and the Caribbean, and the recent spread of chikungunya and Zika virus.

Going for blood: Female mosquitoes drink human blood for nutrients used in making eggs. After a female bites an infected person, it can spread the virus through its saliva to its next human victim. Some scientists think Zika may have arrived in Brazil in 2014, carried by visitors attending World Cup soccer games. Perhaps one or more infected visitors were bitten by mosquitoes and started the chain reaction, said Jeffrey Powell, a Yale University mosquito expert who works in Brazil.

Gleyse Kelly da Silva, 27, holds her daughter Maria Giovanna, who was born with microcephaly, outside their house in Recife, Brazil. AP

Gleyse Kelly da Silva, 27, holds her daughter Maria Giovanna, who was born with microcephaly, outside their house in Recife, Brazil. AP

How has Zika affected Latin America and the Caribbean so far?

Brazil: The mosquito-spread Zika virus appeared in Brazil last year and officials say hundreds of thousands of people apparently have been infected. Authorities soon saw what appears to be a sharp jump in cases of microcephaly — children born with unusually small heads — and investigators are scrambling to determine if the two are linked. Officials said Wednesday they've found 4,180 suspected cases of microcephaly since late October, though only 270 of those so far have been confirmed.


Colombia: Over 16,419 confirmed or suspected cases of Zika, including 1090 pregnant women. Of the total, only 798 have been confirmed by blood tests. President Juan Manuel Santos said the virus could hit as many as 600,000 people this year. Health authorities say one case of microcephaly and 12 cases of Guillain-Barre syndrome are suspected to be linked to Zika.

Venezuela: Officials decline to issue guidelines about Zika or release epidemiological data, but have confirmed the virus is in Venezuela. Non-governmental organizations say that the country saw more than 400,000 unusual cases of acute fever in the second half of 2015 that may have been Zika. The country has not seen microcephaly or Guillan-Barre with suspected links to Zika.

Caribbean nations: The Caribbean island nations have had a couple of hundred suspected cases of Zika, the majority of them in Puerto Rico and the Dominican Republic. There have been at least 19 laboratory-confirmed cases in Puerto Rico and at least 10 in the neighboring Dominican Republic. The majority of those in the U.S. territory are believed to be locally contracted. Haiti has reported at least five confirmed cases and the U.S. Virgin Islands at least one. Regional officials so far have not reported any suspected microcephaly or Guillain-Barre cases linked to Zika.

Ecuador: 33 reported Zika cases, 17 of them confirmed by laboratory tests. No cases of microcephaly or Guillain-Barre suspected of being linked to Zika.

Bolivia: Four confirmed cases of Zika, including three who caught it in Brazil and one locally infected pregnant woman

El Salvador: 2,474 suspected cases of Zika, 122 of which were pregnant women.

Honduras: At least 1,000 cases reported since mid-December, including two people with Guillain-Barre syndrome possibly linked to Zika.

Guatemala: 68 confirmed cases of Zika.

Mexico: 18 confirmed cases of locally acquired Zika; no cases of microcephaly or Guillain-Barre suspected of being linked to Zika.

Panama: 42 cases of Zika, including one pregnant woman. No cases of microcephaly or Guillain-Barre suspected of being linked to Zika.

Costa Rica: One case, acquired in Colombia.

Nicaragua: Two cases.

You can find out more about the Zika virus here.

With inputs from AP

Updated Date: Jan 29, 2016 09:43 AM

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