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LAST_UPDATEThu, 23 Nov 2017 7pm

Zika Virus: How It Spreads And Why Malaysians Should Be Prepared

FilePic: GettyImagesFilePic: GettyImages

ZIKA, which the World Health Organization says is "spreading explosively" across the Americas, is transmitted by the same mosquitoes that also carry other tropical viruses such as dengue and yellow fever.

However it is the recently discovered potential link to brain defects in infants as well as a rare syndrome that can lead to paralysis that have raised the alarm among health officials worldwide.

"When you have the Aedes mosquito (in your country), all it requires is the virus (to spread the disease),” said Health Minister Dr S. Subramaniam earlier this month. As all Malaysians know only too well, we have an abundance of Aedes mosquitoes in the country.

What are the chances of Zika virus finding its way into our country?

From Dr Subramaniam’s observation, it is dangerously high.

"Unfortunately in this region, Malaysia, Singapore, Thailand, Indonesia, Philippines, we all have the (Aedes) mosquito. There are challenges because the (Aedes) mosquito is there,” said Dr Subramaniam in a statement to Bernama earlier this month. “Secondly, people are asymptomatic. Thirdly, there's no drug to treat the disease.”

Earlier this month, the World Health Organization has declared the Zika virus an international public health emergency, estimating that as many as four million people could be infected by the end of the year.

Malaysian and Singaporean health officials have also warned of a high risk of spreading if the virus is introduced there. There has been  a lot of publicity lately about Zika but how much does the average Malaysian really know to protect themselves?

We broke down the Zika health scare into easily digestible pieces of information that you need to know in order to prevent yourself from becoming infected as well as basic facts like how you can and cannot get the virus.

What Is The Situation In Malaysia?

Pic: BernamaPic: BernamaThere are no reported Zika cases in Malaysia, but the Ministry of Health has warned that preventive measures should be taken to keep the Zika virus at bay, after the World Health Organization declared it an international public health emergency.

293 patients in Malaysia who were tested for dengue and Zika after showing symptoms of dengue, were declared clear of both diseases on Wednesday (Feb 3), according to health officials, Bernama reports.

Both mosquito-borne viruses have similar symptoms, and the Aedes mosquito, which is the carrier for the dengue virus, also spreads the Zika virus. Responding to this, Malaysia’s Health Minister Dr S. Subramaniam has warned that dengue-prevalent Malaysia offered a conducive environment for the spread of the disease.

“In countries where the (Aedes) mosquito is not there, even if the virus reaches (there) it will not spread because the vector is not there," Dr Subramaniam had noted that this unfortunately is not the case in Malaysia where the Aedes mosquito is endemic.

Malaysian authorities have issued guidelines for people to protect themselves against the Zika virus, advising Malaysians, particularly pregnant women, to postpone travel to 24 countries in Central and South America, where the Zika virus had been detected.

The risk is heightened by the fact that Zika cases have been reported in neighbouring countries.

According to media reports, Zika is not new in Thailand, which had its first confirmed case in 2012, and no more than five cases annually since then.

Indonesia, which has reported a domestic case of the Zika virus, has requested the International Atomic Energy Agency help it control its mosquito population, Reuters reported.

Basic Facts About The Virus

FilePic: AFPFilePic: AFP

The Zika virus is a mosquito-transmitted infection related to dengue, yellow fever and West Nile virus. Although it was discovered in the Zika forest in Uganda in 1947 and is common in Africa and Asia, it did not begin spreading widely in the Western Hemisphere until last May, when an outbreak occurred in Brazil.

The infection often causes no symptoms and leads to no lasting harm in most cases except for the recently discovered link to its effect on women who become infected while pregnant and those who develop a temporary form of paralysis after exposure to the Zika virus.

Where did it come from? First isolated in 1947 and described in a paper in 1952, Zika has long been known to occur in Africa and Southeast Asia—but until a decade ago, fewer than 15 cases had been described in the scientific literature.

In 2007, the virus caused a big outbreak on Yap, an island group in the Western Pacific that is part of the Federated States of Micronesia; since then, it went on a major tour of other Pacific Islands before it landed in Brazil, and from there spreading rapidly to South America, Central America, Mexico, and the Caribbean.

Since April 2015, a large, ongoing outbreak of Zika virus that began in Brazil has spread to much of South and Central America and the Caribbean.

In January 2016, the CDC issued a level 2 travel alert for people traveling to regions and certain countries where Zika virus transmission is ongoing.

What Are The Basic Symptoms?

The most common symptoms of Zika are fever, rash, joint pain, or red eyes. Only 1 in 5 people infected with Zika virus become ill. Other common symptoms include muscle pain and headache. The incubation period (the time from exposure to symptoms) for Zika virus disease is not known, but is likely to be a few days to a week.

The illness is usually mild with symptoms lasting for several days to a week. People usually don’t get sick enough to go to the hospital, and they very rarely die of Zika as it usually remains in the blood of an infected person for about a week but it can be found longer in some people.

Besides, medical studies have revealed that the symptoms of Zika are similar to those of dengue and chikungunya, diseases spread through the same mosquitoes that transmit Zika.

How Is The Virus Transmitted?

Vector

The Zika virus is transmitted by daytime-active mosquitoes as its vector. It is primarily transmitted by Aedes aegypti, but has been isolated from a number of arboreal mosquito species in the Aedes genus, such as A. africanus, A. apicoargenteus, A. furcifer, A. hensilli, A. luteocephalus and A. vittatus with an extrinsic incubation period in mosquitoes of about 10 days.

However, the true extent of the vectors is still unknown. The Zika virus has been detected in many more species of Aedes, along with Anopheles coustani, Mansonia uniformis, and Culex perfuscus, although this alone does not incriminate them as a vector.

Transmission by A. albopictus, the tiger mosquito, was reported from a 2007 urban outbreak in Gabon, Africa. There is concern for local infections in urban areas of European countries infested by A. albopictus mosquitoes too because the first two cases of laboratory confirmed Zika virus infections imported into Italy were reported from travelers already carrying the virus returning from French Polynesia.

Sexual

In 2014, Zika virus capable of reproducing itself was found in the semen of a man at least two weeks (and possibly up to 10 weeks) after he fell ill with Zika fever.

The other report is of a United States biologist who had been bitten many times while studying mosquitoes in Senegal. Six days after returning home in August 2008, he fell ill with symptoms of Zika fever but not before having unprotected intercourse with his wife, who had not been outside the US in 2008. She subsequently developed symptoms of Zika fever, and Zika antibodies in both the biologist's and his wife's blood confirmed the diagnosis.

It is still unknown whether women can transmit the virus to their sexual partners. As of February 2016, the CDC recommended that men who reside in or have traveled to an area of active Zika virus transmission who have a pregnant partner should abstain from sexual activity or consistently and correctly use condoms during sex for the duration of the pregnancy.

During Pregnancy

In 2015, Zika virus RNA (ribonucleic acid) was detected in the amniotic fluid of two pregnant women whose fetuses had microcephaly, indicating that the virus had crossed the placenta and could have caused a mother-to-child infection.

Last Friday, the CDC in the USA updated its health care provider guidelines for pregnant women and women of reproductive age. The new recommendations include offering testing to pregnant women without Zika fever symptoms who have returned from areas with ongoing Zika virus transmission in the last 2–12 weeks; and for pregnant women without Zika symptoms living in such areas, they recommend testing at the beginning of prenatal care and follow-up testing in the fifth month of pregnancy.

What Are The Affected Countries?

As of end of last month, according to the Pan American Health Organization, the affected countries include Brazil, Colombia, El Salvador, French Guiana, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Saint Martin, Suriname and Venezuela, as well as Puerto Rico.

On early of February, the CDC added eight more countries to the list namely, Barbados, Bolivia, Ecuador, Guadeloupe, Saint Martin, Guyana, Cape Verde, and Samoa.

And last week, the agency also added the U.S Virgin Islands and Dominican Republic to the list.

Pic: CDCPic: CDC

Who Is At Risk?

Ask yourself these three questions, if you think you may have been exposed to the Zika virus: (i) Are you pregnant? (ii) Are you a woman who is thinking about getting pregnant? (iii) Are you a man who is going to have unprotected sex with a woman who is pregnant or may become pregnant?

If your answer to all of these questions is "no," there is arguably no reason for you to get tested. Remember, only 20% people who contract the virus will even develop any symptoms, and those who do will experience only mild and short-lived discomfort.

If you answered "yes" to any of these questions, however, you should contact your doctor about being tested for Zika. He or she can order blood tests to look for Zika or other similar viral diseases, such as dengue or chikungunya. A blood test performed in a clinical setting is the only way to be definitively diagnosed.

How To Reduce Risk Of Becoming Infected?

According to the CDC's guidance, "Zika virus can be spread from a pregnant woman to her unborn baby. There have been reports of a serious birth defect of the brain called microcephaly and other poor pregnancy outcomes in babies of mothers who were infected with Zika virus while pregnant. Knowledge of the link between Zika and these outcomes is evolving, but until more is known, CDC recommends special precautions for the following groups:

"Women who are pregnant (in any trimester): Consider postponing travel to any area where Zika virus transmission is ongoing. If you must travel to one of these areas, talk to your doctor first and strictly follow steps to prevent mosquito bites during your trip.

"Women who are trying to become pregnant: Before you travel, talk to your doctor about your plans to become pregnant and the risk of Zika virus infection. Strictly follow steps to prevent mosquito bites during your trip. Specific areas where Zika virus transmission is ongoing are often difficult to determine and are likely to change over time."

USA is connected by land to the areas where Zika is spreading rapidly and American health officials cannot overemphasize the risk it poses to their citizens, putting together general preventive measures which are also applicable to anyone thinking of travelling to affected regions.

The CDC has listed basic tips for travelers to prevent getting bitten by mosquitoes which you can refer to here 

Is There Any Specific Treatment For Zika?

Although a blood test can be used to diagnose a Zika virus infection, there is no current treatment for the disease. People who get sick can take medicines such as acetaminophen to reduce the fever and pain associated with the infection. Here’s some ways one can do to treat the symptoms:

- Get plenty of rest.

- Drink fluids to prevent dehydration.

- Take medicine such as acetaminophen (Tylenol®) to relieve fever and pain.

- Do not take aspirin and other non-steroidal anti-inflammatory drugs.

- If you are taking medicine for another medical condition, talk to your healthcare provider before taking additional medication.

If you have Zika, prevent mosquito bites for the first week of your illness.

- During the first week of infection, Zika virus can be found in the blood and passed from an infected person to a mosquito through mosquito bites.

- An infected mosquito can then spread the virus to other people.

Can We Expect A Vaccine In The Near Future?

Several groups have begun to make ‘candidate Zika vaccines’, a process that will take at least several months. Most of these vaccine approaches are piggybacking on existing vaccines. For example, many vaccines are made by stitching proteins from a pathogen’s surface into a harmless virus or vector; that is now being tried with Zika using those same vectors. Once a candidate vaccine is made, it will have to be tested in animals before humans.FiilePic: CorbisFiilePic: Corbis

Work has begun in the USA towards developing a vaccine for the Zika virus, according to Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. The researchers at the Vaccine Research Center have extensive experience from working with vaccines for other viruses such as West Nile virus, chikungunya virus, and dengue fever, scientific journal Life Science reported yesterday.

Nikos Vasilakis of the Center for Biodefense and Emerging Infectious Diseases in Texas, USA had predicted that it may take two years to develop a vaccine, but 10 to 12 years may be needed before an effective Zika virus vaccine is approved by regulators for public use, in an interview on BBC News earlier this month.

However, an Indian company, Bharat Biotech International, reported last week (early February) that it was working on vaccines for the Zika virus. The company is working on two approaches to a vaccine: "recombinant", involving genetic engineering, and "inactivated", where the virus is incapable of reproducing itself but can still trigger an immune response. The company announced animal trials of the inactivated version would commence in late February.

On the local front, the most practical approach to adopt is to eradicate the breeding of Aedes mosquitoes as much as possible. Government and non-government agencies have also been told to implement preventive measures to eradicate its breeding grounds.

The United Nations nuclear agency has also suggested using exposing laboratory-bred male Aedes mosquitoes to nuclear radiation to make their sperm sterile before releasing them into the wild to mate as another way to reduce the spread of Aedes mosquitoes.

 
-mD