Zika Attack

 

There has been a great deal of attention given to the Zika Virus lately.  Not because it's new, but rather because it's prevalent.  Zika virus is named after the Ugandan forest where it was first isolated in a rhesus monkey in 1947. The first human cases were detected in 1952 in Uganda and Tanzania. The virus subsequently spread across equatorial Africa and Asia, where it was associated with sporadic infections.

Zika virus infections were first detected in the Western hemisphere in February 2014 on Chile's Easter Island. Zika virus infections were subsequently detected in Brazil in May 2015.

Currently, there is an ongoing Zika virus outbreak in the Americas, the Caribbean, and the Pacific; the World Health Organization (WHO) has stated that the virus is spreading explosively and has declared Zika virus and its associated complications a public health emergency of international concern.

As of May 2016, countries with circulation of Zika virus include Aruba, Barbados, Belize, Bolivia, Bonaire, Brazil, Cape Verde, Colombia, Costa Rica, Cuba, Curacao, Dominica, Dominican Republic, Ecuador, El Salvador, Fiji, French Guiana, Grenada, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Jamaica, Kosrae (Federated States of Micronesia), Marshall Islands, Martinique, Mexico, New Caledonia, Nicaragua, Panama, Papua New Guinea, Paraguay, Peru, Saint Barthélemy, Saint Lucia, Saint Martin, Saint Maarten, Saint Vincent and the Grenadines, Samoa, Suriname, Tonga, Trinidad and Tobago, and Venezuela.

Zika virus infection has been detected in the United States territories of Puerto Rico, the US Virgin Islands, and American Samoa. Mosquito-borne transmission of Zika virus infection has not yet been reported in the continental United States, but cases of imported Zika infection have been reported in pregnant and non-pregnant travelers.

The primary mode of transmission is via mosquito bites. Zika virus is carried by the Aedes Aegypti mosquito, which lives in tropical regions; Aedes mosquitoes can also transmit dengue and chikungunya viruses.

Zika virus is an arthropod-borne flavivirus transmitted by mosquitoes. The virus is related to other flaviviruses including dengue virus, yellow fever virus, and West Nile virus. 

Symptoms

80% of people who contract the virus from a mosquito bite will not show symptoms according to the Center for Disease Control (CDC) preliminary estimates.  For those that do, the symptoms generally include joint pain, rash, fever, and in some cases conjunctivitis (aka "pink eye"), and less often may include headache and muscle pain.  The incubation period between mosquito bite and onset of clinical manifestations is typically 2 to 14 days. The illness is usually mild as described previously and symptoms resolve within two to seven days. Immunity to reinfection occurs following primary infection.  Severe disease requiring hospitalization is uncommon.

Consequences

Unfortunately, the presence of the mosquitoes with the Zika virus has been directly correlated with localized outbreaks of microcephaly.  Microcephaly is the birth defect where the head of the baby is significantly smaller than other babies born in the same area, unaffected by the virus. 

It is certainly not pleasant to contemplate since there's obviously less room for brain tissue and development.  Normally in the United States the risk of microcephaly is 0.02%-0.12%, caused by toxoplasmosis, rubella, or even cytomegalovirus.   Additionally, microcephaly can be caused by consuming alcohol or using certain drugs during pregnancy. The first case of Zika-related congenital microcephaly in the United States was reported in January 2016 in Hawaii, in a baby born to a woman who had resided in Brazil during her pregnancy. Babies affected by the Zika virus can experience hearing loss, vision problems, the inability to feed due to swallowing difficulties, seizures, problems with motor control, problems with the ability to balance, and consequently, developmental delay with tasks such as sitting, standing, and walking.  The effects are lifelong, and there is no standard treatment or cure.

Protect Yourself

The best strategy with the Zika Virus is not to contract the virus in the first place.  Avoiding travel to the affected areas is one obvious solution.  Preventing mosquito bites by wearing long sleeves and long pants, using

insect repellent, and staying indoors as feasible (with air conditioning, window/door screens, and/or mosquito nets to minimize contact between mosquitoes and people). However, if you must travel to an area that has the Zika virus then use a mosquito repellent with DEET or Picaridin, both of which are considered safe for pregnant or breastfeeding women.  Furthermore, even if you're not symptomatic, wait at least three months after you return before getting pregnant. 

While there have been no reported cases of female-to-male transmission so far, it does work in the other direction.  Unlike oocytes (women's pre-egg cells), men's semen contains factors which allow the virus to persist for several weeks post-infection.  There have been cases of sexual transmission, so utilize prophylactic measures to protect yourself from infection if your partner has travelled to an area that is endemic with the Zika virus. At least that way you don't have to put your entire life "on hold".  If you're already pregnant take plenty mosquito repellents and use them regularly.  Don't forget the ankles where these insects frequently attack.  In some locales it is even recommended to use mosquito netting over the bed to keep them at bay.

What is science doing?

As yet there is no vaccine for the Zika Virus but that work is already underway.  Once a new virus has been discovered, generally speaking it takes two decades to develop a vaccine.  Some viruses have already persisted for 80 years without a cure being developed.

However, the National Institutes of Health Vaccine Research Center in Bethesda, Maryland, where they successfully developed a vaccine for Ebola, H5N1, and West Nile are turning their resources to the fight.  Their ongoing successes with HIV make a strong case for their likelihood to succeed.

They're developing what are called DNA vaccines.  By using synthesized genetic information from the Zika Virus (instead of a live virus), they are priming the pump so to speak.  The body responds to the genetic trigger, preparing an immune response so that when the actual virus shows up it can be quickly destroyed.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases is optimistic that a DNA vaccine will be ready to begin testing by September of 2016.  Of course there are several levels of trials to go through with a new vaccine, so the earliest it could be expected is the year 2018.  That may seem like a long time, but in truth it is bordering on miraculous.

Their work on the West Nile Virus, which is transmitted by the same nasty little Aedes aegypti mosquito, simplifies a lot of the preliminary work.  This is especially so in light of the fact that both the West Nile Virus and the Zika Virus are members of the family of flaviviruses, so much of the groundwork has already been done.

Bharat Biotech, a company based in Hyderabad, India, is working on another solution.  There are two mosquito-borne infections that are prevalent in India called dengue and chikungunya.  They are carried by the same variety of mosquito that transmit Zika virus. Bharat Biotech owner Krishna Ella, began investigating Zika in 2014 before anyone else had become interested.  They are the first ones to have patented a Zika vaccine. 

Krishna Ella is developing two different models of Zika vaccine.  They're working from a DNA model similar to what the NIH is doing, but he is concerned that DNA vaccines sometimes do not stimulate a strong enough immune response. 

Ella's backup plan relies on working with a live Zika virus which has been deactivated so that it cannot replicate.  It can, however, still stimulate the strong immune response necessary from the body to protect against the actual virus when it arrives.

Other participants

Of course Bharat Biotech and the NIH are not alone in a rush to develop a vaccine.  Firms from all over the world including Japan's Takeda and France's Sanofi are hot on the trail. 

The Takeaway

The primary mode of transmission of Zika virus is via mosquito bites. Zika virus infection occurs in approximately 20 percent of patients and include acute onset of low-grade fever with maculopapular pruritic rash, arthralgia (notably small joints of hands and feet), or conjunctivitis (nonpurulent).  The best strategy with the Zika Virus is not to contract the virus in the first place.  Preventing mosquito bites by wearing long sleeves and long pants, using insect repellent, and staying indoors as feasible (with air conditioning, window/door screens, and/or mosquito nets to minimize contact between mosquitoes and people) is your backup strategy if you must travel to an area with Zika virus.