Zika Virus

Zika Virus

What is the Zika virus?

Pronounced ‘Zee-ka’, the Zika virus is a mosquito-borne Flavivirus (viral infection belonging to a genus of viruses in the family Flaviviridae). The virus is known to occur in tropical and subtropical areas worldwide, with the vast majority of infected individuals experiencing mild fever, rash, headache, conjunctivitis, muscle pain and general malaise.

The virus was first identified in monkeys in Zika Valley (forest), Uganda in 1947 when yellow fever was being monitored. The virus was later discovered in humans in the early 1950s in Uganda and the United Republic of Tanzania. Between the 1960s and 1980s, small outbreaks had been recorded in other parts of Africa, Southeast Asia, the Pacific islands and the Americas, the majority of which appeared symptomatically mild.

It was in 2007 when the first large outbreak in humans occurred on the Island of Yap (Federated States of Micronesia in the South Pacific). The Zika virus became instantly known in worldwide mainstream media between July and October 2015 when an association between the infection and microcephaly (a potentially fatal congenital condition whereby a baby is born with a smaller than normal head and abnormal brain development), and Guillain-Barré syndrome (a rare neurological disorder in which the body’s immune system attacks the nerves) was reported in Brazil. The outbreak of the virus was classified as an epidemic (widespread occurrence).

As a mosquito-borne virus, Zika is transmitted by the Aedes mosquito (Aedes aegypti), the same species that carries dengue fever, yellow fever and the chikungunya virus.

Illustration showing a viral infection in the blood.

How is the Zika virus transmitted?

The virus is primarily transmitted via an infected Aedes mosquito, found throughout the globe. For this mode of transmission to occur in humans, a mosquito will need to bite an individual infected with Zika virus and then bite another. The virus then enters the newly bitten person’s bloodstream, causing an infection.

Increased cases have prompted studies in to how the virus is transmitted, especially since not all modes of apparent transmission appear to have involved the bite of a mosquito. Studies have noted that the virus is capable of being transmitted through exposure to the bodily fluids such as blood, urine, saliva, fluids of the eye and semen of infected people. Some cases of exposure have been reported following sexual contact and blood transfusions.

This has raised the alarm for women, especially those in their reproductive years or who are carrying an unborn child. Zika virus can be passed from a pregnant woman to her developing baby, resulting in birth defects. As a result, the Centers for Disease Control (CDC) have issued warnings to pregnant women who may travel to areas most affected by the virus, and would therefore be most vulnerable to the irreversible effects of an infection.

As it is now known that the Zika virus is capable of being transmitted through blood exposure, blood donations are all screened before any transfusion takes place. This is so as to reduce the risk of transmitting the virus, especially in areas where there are virtually no active outbreaks. Thus, ensuring that the virus does not spread further.

The FDA (Food and Drug Administration) has recommended that the public be mindful of making blood donations for at least four weeks if:

  • A person has a history of Zika virus infection.
  • A person has experienced symptoms known to be associated with the Zika virus within 2 weeks of travel (especially if the destination is an area where the virus is most prevalent – see below for details).
  • A person has travelled to or lived in an area where active outbreaks or virus transmission is known to have occurred.
  • A person has had sexual contact with an individual who has been diagnosed and / or treated for a Zika virus infection, or whom has travelled or lived in an area where the virus is most prevalent (especially in the past 3 months).

Signs and symptoms of a Zika infection

Young woman feeling unwell.The majority of infections don’t typically display many symptoms at all. Those that do experience symptoms of an infection (an estimated 1 in 5 infections) will experience mild ailments (not requiring hospitalisation), such as:

  • A fever
  • A skin rash
  • Conjunctivitis (redness in the whites of the eyes / pinkeye)
  • Joint and / or muscle pain
  • Headache
  • General malaise

Individuals who do experience these flu-like symptoms of an infection typically do so within 3 to 14 days following exposure (normally a bite from an infected mosquito). Symptoms do not generally linger for very long either and clear within a few days or up to a week. Most will make a full recovery without known medical complications.

Anyone who experiences these symptoms, and especially a pregnant woman (at any stage of her pregnancy), after having been potentially exposed to the virus (having visited or lived in an area prevalent with infection outbreaks, or another potentially infected person) must seek medical treatment as soon as possible. All pregnant women must be tested for the Zika virus (or any others that are similar and transmitted by the same mosquito) if exposure is suspected.

Zika virus infographic elements - prevention, transmission, vaccine, symptoms, microcephaly, protection measures.

Who is most at risk?

Areas where the Zika virus is most prevalent are:

  • Africa: Angola, Guinea-Bissau, Benin, Burkina-Faso, Burundi, Cameroon, Congo (Congo-Brazzaville), Democratic Republic of the Congo (Congo-Kinshasa), Central African Republic, Chad, Côte d’Ivoire, Equatorial Guinea, Ghana, Gabon, Gambia, Guinea, Kenya, Liberia, Mali, Niger, Nigeria, Rwanda, Sierra Leone, Senegal, Sudan (and South Sudan), Tanzania, Togo, and Uganda.
  • Asia: Singapore, Bangladesh, Burma (Myanmar), Brunei, Cambodia, India, Indonesia, Laos, Malaysia, Maldives, Pakistan, Philippines, Timor-Leste (East Timor), Thailand and Vietnam.
  • The Pacific Islands: Fiji, Marshall Islands, Micronesia, Papua New Guinea, Palau, Samoa, Solomon Islands, and Tonga.
  • Federated States of Micronesia: Kosrae.
  • Atlantic Ocean islands: Cape Verde.
  • The Caribbean: Aruba, Turks and Caicos Islands, Anguilla, Dominican Republic, Haiti, Antigua and Barbuda, the Commonwealth of Puerto Rico, The Bahamas, Barbados, Saint Vincent and the Grenadines, British Virgin Islands, Bonaire, Curaçao, Cuba, Dominica, Grenada, Jamaica, Saba, Saint Kitts and Nevis, Saint Martin, Sint Maarten, Saint Lucia, Montserrat, Cayman Islands, Sint Eustatius, Trinidad and Tobago, and the US Virgin Islands.
  • North America: Mexico (Federal Republic).
  • South America: Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Suriname, and Venezuela.
  • Central America: Belize, El Salvador, Costa Rica, Guatemala, Nicaragua, Honduras and Panama.

Zika virus warning for pregnant women.

Risk factors as issued by the CDC to take note of include:

  • High-risk areas: Those that live in or travel to high-exposure areas, especially in the Pacific, islands near West Africa, and in Central, South and North America. The virus-carrying mosquito exists everywhere in the world, but outbreaks with the highest rates of transmissions have thus far been most prevalent in tropical and subtropical areas.
  • Sexual contact: Not the primary means of transmission, but isolated cases have been reported whereby infection can be spread from person to person via sexual contact. Precautionary methods, such as correct condom use or even abstinence (especially during pregnancy), have been highly recommended for those who either live in or have travelled in higher risk areas.
  • Pregnant travellers and couples wishing to conceive: Women in the first and early second trimesters of their pregnancy are at particular risk if frequenting areas with frequent outbreaks or high transmission rates. Pregnant women or those wishing to conceive have been warned not to take the chance – the CDC has recommended that women wait at least 2 months before trying to conceive, and men, at least 6 months (the virus can remain in semen and vaginal fluids for months even if symptoms were not present during an active infection) following possible exposure. Safe sex practice is also advisable for both men and women for 6 months, even if not trying to conceive, following possible exposure to the virus in a risk area that has been travelled to. Studies are investigating the reasons why it appears that the virus can linger in bodily fluids, and most especially semen, even after symptoms of the infection have cleared. For this reason, those with multiple sex partners may be at risk of infection if precautions are not effectively taken.
  • Blood transfusions: Multiple cases of transmission in this capacity have thus far been documented in Brazil, and are part of ongoing research. The virus has also been reported to have been detected in blood donors as well. Thus, donations are now screened for the virus before transfusions are performed in many countries around the world.

Diagnosing Zika virus

With the majority of infected individuals not presenting symptoms of the Zika virus, detecting a local spread has proved challenging. When symptoms are present, it can take up to two weeks to show up in the body. Medical professionals can now test for signs of the virus in the body, and based on that make a diagnosis. Investigations of outbreaks can take several weeks when they occur too.

If symptoms are present and a person suspects a Zika virus infection, it is strongly advisable to consult a medical doctor (normally a general practitioner or GP) as soon as possible. Symptoms may be mild and flu-like, but if there is reason to suspect an infection, such as signs appearing following recent travel to a high-risk area or a mosquito bite, a doctor will wish to assess the nature of ailments and potentially test for the virus.

A doctor will conduct a medical overview of a person’s overall health history, as well as any recent travels around the world. A doctor may also ask specific questions regarding a sexual partner (where relevant) and whether they have recently travelled (where have they visited and on what dates). A doctor will ask about possible exposure to mosquitoes and if any bites have occurred recently.

A doctor will likely suggest a test for the Zika virus if he or she suspects possible exposure. Tests may also rule out other infections of a similar nature, also carried by the same mosquito.

Zika virus testing (blood sample).

What tests are used for a Zika virus diagnosis?

Currently, there are two available tests for diagnosing the Zika virus using blood and urine samples. A blood sample will be taken intravenously (through a vein in the arm) using a needle and syringe and sent to the laboratory for analysis. The sample will be assessed for the presence of antibodies (proteins) in the bloodstream (which are normally produced by the body’s immune system as a defence mechanism to fend off the presence of an infection).

A urine sample will be requested in a cup provided and sent to a laboratory for analysis. Signs of viral infection will be assessed and a diagnosis of which virus is present in the body made – Zika, dengue fever, yellow fever or chikungunya.

If Zika virus is suspected, it is important to test and diagnose an infection, even once symptoms begin to clear. Blood and urine tests can detect the presence of the Zika virus, irrespective of the transmission mode (mosquito bite, sexual transmission or other).

Analysis will look at the genetic code of the virus (during an active infection). Tests are not effective once the body has completely cleared the infection.

If a woman is pregnant, a doctor will likely recommend testing between 2 and 12 weeks following possible virus exposure. A doctor may also recommend an ultrasound scan during a woman’s pregnancy to detect any abnormalities of the brain, and specifically microcephaly. Ultrasounds may be recommended every 3 or 4 weeks thereafter to monitor the baby. A doctor may also suggest an amniocentesis test which involves extracting a sample of amniotic fluid (the clear, yellow-ish fluid surrounding a developing foetus during pregnancy, contained in the amniotic sac) using a needle which is inserted into a pregnant woman’s uterus.

Zika virus treatment

Treating a Zika virus infection

Currently, there is no specific antiviral treatment plan for Zika virus infections, nor has a vaccine yet been developed. Doctors thus typically treat the set of active virus symptoms presented during consultation and testing. As the symptoms are typically flu-like in nature, doctors will recommend the following:

  • Plenty of rest
  • Plenty of fluid-intake (water, broths and juices will help to prevent dehydration)
  • The taking of over-the-counter medications, such as acetaminophen or ibuprofen to reduce fever, aches and pains

Treatment recommendations will take into consideration any other medications and supplements (including herbal products) already being taken, so as to avoid adverse drug interactions. If it is determined during the initial consultation that aspirin or NSAIDS (non-steroidal anti-inflammatory medications) were used to treat symptoms before a specific viral infection was diagnosed, a doctor will have requested immediate discontinuation. Until dengue fever is ruled out, none of these medication types will be safe to take as they can lead to internal bleeding (haemorrhage).

Symptoms of Zika virus should clear within a week (approximately 7 days).

Treatment tips when caring for another with a Zika virus infection

Exposure to the virus through bodily fluids can place someone caring for an infected person at risk. Although few, cases of this means of transmission have been documented.

Things a person can do to minimise risk of exposure include:

  • Avoiding direct skin contact: Take extra care not to touch bodily fluids (such as blood) or surfaces where these fluids have come into contact. Wear gloves where possible to avoid doing so.
  • Handwashing: Each and every time an infected person is handled during care, gloves should be worn where possible and hands should be washed with soap and water. Handwashing is advised before and after physical contact with an infected person.
  • Home hygiene: The environment an infected individual is staying in must be cleaned daily using household cleaning agents and disinfectants, paying special attention to surfaces that have come into contact with bodily fluids.
  • Clothing: Worn clothing should be washed daily using laundry detergent, especially if exposed to the bodily fluids of an infected individual.

What types of complications are associated with the Zika virus?

Zika virus doesn’t appear to cause too many physical complications in most cases. Where the virus has caused great concern is in the following instances:

1. Microcephaly

Exposure to the Zika virus during pregnancy has presented the most cause for concern due to the high risk of microcephaly – a birth defect in which a baby’s head and brain (if severe) are insufficiently developed (smaller than normal). If a baby’s brain does not develop at an appropriate rate during a woman’s pregnancy, neither does the size of the head. A baby’s head grows because of the development of the brain. Sometimes, the brain simply stops growing following birth or is compromised during pregnancy due to infections such as Zika, or even rubella (German Measles) contracted during any trimester.

Microcephaly is considered an isolated condition, which means that it typically does not occur in combination with any other major birth defects.

A baby born with this defect can experience an array of problems throughout their lifetime. These will depend on the severity of the under-developed brain and head and can include:

  • Developmental delays – walking, standing, sitting and speech
  • Intellectual disability and learning difficulties
  • Problems with feeding and swallowing
  • Difficulties with balance and movement
  • Vision impairment
  • Hearing loss
  • Seizures

Illustration showing the size of a baby's head: normal versus microcephaly

Severe instances of this birth defect typically result in more of the aforementioned symptoms occurring than milder cases, or more difficulties with a handful of them. The condition is potentially life-threatening for a baby in its more severe form, but all babies born with this defect require regular medical check-ups, as well as monitoring of overall growth and development throughout their lives.

Microcephaly may either be diagnosed during a woman’s pregnancy or once the baby is born. During pregnancy, an ultrasound scan can be done during the latter half of the second trimester or early on during the third trimester.

Once a baby is born, a doctor will assess the circumference of the head during a physical exam (measuring the distance around a baby’s head). The measurement is then compared to the population standard according to age and sex. A circumference measurement that is smaller (less than 2 standard deviations) than the average of other babies of the same age and sex and is determined as less than the third percentile (the value below which a percentage of average observations fall) will likely be diagnosed as microcephaly.

Head circumference measurements are best taken during the first day of a baby’s life. A more accurate measurement can then be compared with the standard chart which is based on those taken before the end of an initial 24-hour period. The sooner a measurement is taken, the better.

A doctor may recommend testing to confirm a diagnosis. This can involve an MRI (magnetic resonance imaging) which is capable of producing detailed visuals of a baby’s brain / head structure. These visuals will provide a doctor with critical information in order to make an accurate diagnosis and also determine if a baby was indeed affected by an infection in the mother’s body during pregnancy. Scans will also be helpful for determining any other abnormalities which will require medical care.

One of the main reasons pregnancy precautions have been urged by the CDC is because of the irreversible damage of this birth defect. There is no cure for microcephaly, nor is there a standard treatment plan. Treatment options vary on a case-by-case basis and depend on the needs of the child according to the severity level of the condition.

Mild cases may only require routine check-ups where growth and development will also be monitored. Severe cases will need the aid of developmental services from the early stages of life, with multidiscipline areas of expertise. These will include speech, physical and occupational therapy sessions to teach, improve and provide optimum quality of life when it comes to both the intellectual and physical challenges a child with this condition will face. If a baby or child experiences seizures, medication may be required for treatment to control the potentially life-threatening experiences of this symptom.

The link of this condition to Zika virus is still being researched but is a significant one following the birth of more than 2 100 babies in Brazil (in early 2015) showing signs of the condition and other birth defects, all associated with infected mothers. The CDC feels that the evidence in this regard is substantial enough to show that the virus is directly linked to the outcome (birth defects).

Researchers have thus far, been able to determine that women who contracted the virus during the earlier stages of their pregnancy, while the organs of the baby are still forming, appeared to result in the most severe cases.

2. Congenital Zika Syndrome

A pattern of congenital defects due to a Zika virus infection at any stage of a woman’s pregnancy can also be diagnosed as congenital Zika syndrome. There are 5 main features of this series of defects, which are rarely seen with any other pregnancy associated infections:

  • A partial collapse of the skull (also characterised as severe microcephaly)
  • Reduced brain tissue with calcium deposits (resulting in a specific pattern of brain damage)
  • Excess muscle tone which restricts body movement shortly after a baby is born
  • Clubfoot or other joint problems causing a limited range of motion
  • Problems at the back of the eye

A baby may not be born with microcephaly following a Zika virus infection, but instead experience slow head growth later on (post-birth). This is often referred to as postnatal microcephaly. To date, it is not entirely understood what the full range of health-related complications are as a result of an infection with the Zika virus. Chances of defects are certainly high, but not all babies may be born with visible concerns. Studies of the virus and the transmission effects continue on an ongoing basis.

It is thought that a woman who is not pregnant and infected with the virus should not be high-risk for birth defects in a future pregnancy. The virus clears from the body fairly quickly and is not likely to have any future impact on potential pregnancies down the line. The theory regarding similar viral infections is that once the Zika virus has cleared, a person should be protected for any others in future.

What is currently known regarding birth defects (as an outcome of Zika infected pregnancies)?

  • The virus causes brain abnormalities with or without microcephaly: congenital microcephaly, cerebral atrophy, intracranial calcifications, abnormal cortical formation, collapsed skull, prominent occipital bone, overlapping sutures, scalp rugae, intraventricular haemorrhage in utero, cerebellar abnormalities etc.
  • Infection can result in neural tube defects and other brain malformations: spina bifida, encephalocele, anencephaly, and holoprosencephaly
  • The virus can also cause structural eye abnormalities: cataracts, intraocular calcifications, microphthalmia, coloboma, chorioretinal atrophy and scarring, gross pigmentary mottling and retinal haemorrhage, optic nerve atrophy and various other optic nerve abnormalities.
  • Zika may also be directly linked to central nervous system dysfunction: congenital hip dysplasia, club foot, arthrogryposis, congenital deafness and hearing abnormalities.

Research with regards to birth defects in particular is ongoing. Teams are currently assessing the links between infected women and the resulting health complications in young infants. Assessments are looking at direct causal links not influenced by any other potential factors. Research is being continuously documented with comprehensive monitoring records and laboratory evidence in Zika pregnancy and infant registries. This is used to update recommendations regarding clinical care, as well as plan for more effective support for pregnant women and improve prevention methods when it comes to infections during pregnancy.

How will a baby affected by birth defects be cared for?

A new-born with birth defects following a Zika infection in the mother will likely experience a series of tests post-birth before being discharged from hospital. A baby will not only have head circumference measurements taken but also have their weight, length, skin, neck, heart, lungs, abdomen, muscles, bones, genital, as well as overall responsiveness or alertness checked and examined. Testing will also involve a neurological exam to assess brain function, especially responses to the environment, hearing, vision, reflexes (sucking and swallowing) and overall movement. A baby’s ability to grab things will also be checked.

Other tests involve:

  • An ophthalmology exam (eyes)
  • Head ultrasound
  • Hearing test (auditory brainstem response / ABR)
  • Blood and urine samples for laboratory testing (to assess possible infection with the Zika virus, as well as liver and kidney, and thyroid function)

Tests will be recommended multiple times, especially during a baby’s first year of life. Any abnormalities will be addressed with a treatment plan and potentially specialist care. Specialists can include a neurologist (brain, spinal cord and nerves), ophthalmologist (eyes), endocrinologist (hormones and glands), orthopaedist (musculoskeletal – bones and muscles), pulmonologist (lungs), ENT (ear, nose and throat), physical therapist (physical rehabilitation), as well as a nutritionist, speech or occupational therapist, lactation specialist and gastroenterologist (gastrointestinal tract and liver).

A new parent will need to take an active role in coordinating medical care for a baby with birth defects, ensuring that all involved effectively address and take the best possible care of a child with developmental and physical problems. Early intervention is best, so parents are advised not to put off medical care for their new-born. Medical health insurance providers can assist with costs involved in the care for a child with abnormalities and birth defects.

3. Guillain-Barré Syndrome (GBS)

A rare condition, GBS occurs when a person’s own immune system begins attacking nerve cells in the body (instead of invading organisms only), causing damage to muscles and even paralysis. Damage caused by this unnatural action prevents the body’s nerves from being able to transmit signals to the brain.

It is not common, but isolated reports have been noted with strong ties between the development of the condition following a Zika virus infection. Studies are still being conducted to better understand the nature of this association.

What is known about the condition (unrelated to the Zika virus) is that it typically occurs within days or weeks following an infection of the respiratory or digestive tract.

Initially tingling sensations and weakness begin in the legs, toes, ankles and feet (or wrists), before spreading to the trunk of the body (upper body) and arms. This then results in problems with walking, where an individual may have difficulties climbing stairs or become unsteady while moving about.

Muscle weakness can sometimes affect those that control breathing too, as well as cause difficulties with eye or facial movements in general (such as speaking, swallowing and chewing).

Other symptoms and complications of the condition include:

  • Pain (achy or cramp-like) which may worsen at night
  • Bladder and bowel control or function difficulties
  • A rapid heart rate
  • Blood pressure problems (low or high)

Guillain-Barré Syndrome can be tricky to diagnose during initial stages as many symptoms mirror other neurological conditions. The most significant symptoms experienced typically arise within a period of 2 to 4 weeks, after which they plateau.

Diagnosis is typically achieved following a thorough medical evaluation which will involve a physical examination, spinal tap (lumbar puncture), electromyography or a nerve conduction study (whereby electrodes are taped to the skin and a small shock is passed through the nerves to assess the signal speed).

To date, there is no cure for GBS, but two treatment options are available depending on the severity of the condition. These are a plasma exchange (plasmapheresis treatment which removed part of a person’s plasma and is separated from blood cells, which are then placed back into the body) and immunoglobulin therapy (using healthy antibodies from blood donors and administered intravenously in an effort to block damaging antibodies). Treatment will also involve medication for pain relief and to prevent blood clots, as well as physical therapy.

The outlook is not as severe as that for birth defects as treatment can result in vast physical improvements in at least 6 months or up to a year following diagnosis. Some cases, however, never make a full recovery.

The Zika virus link first arose in Brazil and French Polynesia when outbreaks of infections and the condition occurred around the same time. Research teams are looking into gaining more insight regarding this link.

Are there other possible health condition links?

Zika virus infections have possible links with the following conditions and are currently being researched further:

  • Acute disseminated encephalomyelitis (ADEM) – an autoimmune disorder characterised by a sudden widespread attack of inflammation in the brain and spinal cord.
  • Meningoencephalitis – swelling in the brain and surrounding tissues.
  • Severe thrombocytopenia – abnormally low levels of platelets or thrombocytes in the blood which can lead to internal bleeding.
  • Miscarriage or stillbirth

As of yet, there have been no reported risks concerning breastfeeding mothers transmitting to virus to young infants.

Zika virus prevention

1. Mosquito bite prevention

The Aedes mosquito (Aedes aegypti), that carries the virus and causes the majority of transmission infections is of primary concern when it comes to prevention.

Mosquitoes and their habits cannot be controlled. The best thing populations around the world can do is better understand the mosquito and take preventative measures within their control to avoid bites as much as possible.

The Aedes aegypti females typically bite human beings. Male mosquitoes do not have a need to bite and thus are not responsible for the spread of various diseases. The females require nutrients found in human blood in order to produce eggs. The mosquito becomes infected with the Zika virus when they have bitten a person with an active infection. The mosquito may bite multiple individuals during their lifetime, making the spread of infections a difficult problem to get under control, especially since transmission requires a single bite at a time.

Once a female mosquito has been infected with a virus, an incubation period occurs. This is normally between 8 and 12 days whereby the virus infects the mid-gut of the mosquito before spreading to their salivary glands. The next feeding (bite) transmits the disease.

The Aedes aegypti mosquitoes are one of the most widespread of the species, occurring almost anywhere in the world. This too, makes controlling transmission difficult when it comes to disease transmission, particularly because chemical-based methods have become ineffective. The situation in this regard is a double-edged sword - mosquitoes appear resistant to insecticides (resistance is also passed from generation to generation) and the chemicals used have damaging effects to the natural environment (many insecticides used have a poor environmental safety track record). The result is that the Zika virus, along with other mosquito-borne diseases is not under sufficient control and an alarming number of infections continues to grow, especially in areas where outbreaks are more prevalent.

A mosquito is also capable of flying a total of 400 metres during their lifetime. Mosquitoes may reproduce in higher numbers, but they do not cover much distance during their lifetime. The rapid spread of infection is then also greatly influenced by the movements of humans, who can easily transmit disease between communities and even countries.

The female mosquito appears to favour daytime biting (before sunset), which means that when humans are most active, so are the aedes aegypti. This coupled with the way in which humans live presents another problem. Mosquitoes also prefer breeding in doors, making them less susceptible to climatic changes which will affect their lifespan. Humans live in such a way which thus provides mosquitoes with ideal breeding grounds. Pools of stagnant water are one example. (Did you know that a mosquito can breed in a small capful of water?). Larvae thrive in small, wet areas and can be found anywhere – discarded tyres, potted plants, cups or vases. Mosquito eggs can also survive for up to 6 months without being in any water at all. Cool, shaded places are also thriving breeding grounds, making the home an ideal spot for mosquitoes to breed – cupboards and cabinets, wardrobes and laundry baskets, or beneath furniture.

A mosquito’s reproductive cycle is another reason gaining control of this species is a challenging one. Mosquitoes are described as ‘an invasive species’. A female will lay her eggs in several different locations approximately 3 days after biting (or feeding). The reason mosquitoes are described as invasive is because of the number of eggs a female is capable of laying at one time. As many as 100 eggs per ‘blood feed’ can be laid. A female will lay approximately 5 batches of eggs during the course of her lifetime (between 1 and 2 weeks). This makes the species capable of expanding at a rapid rate, easily extending their presence geographically, and effectively creating new areas of risk when it comes to f disease transmission.

Zika virus warning for travel (high risk areas).Understanding the nature of a mosquito’s life can help to better avoid being bitten by taking proactive measures to protect against a potential infection. Repellents (containing DEET, IR3535, picaridin, lemon eucalyptus oil or 2undecanone) can be effective with use throughout the day, especially since these mosquitoes are more active during the daytime.

Protection by means of long-sleeved shirts and long trousers can also significantly reduce risk of bites, when indoors and outdoors. Screens in the home may also help when placed on doors, entranceways and windows. Air conditioning and bed nets may also be used to keep mosquitoes at bay. Any areas where there is standing water can also be emptied to reduce the chances of mosquito larvae hatching close by.

2. Travel

The CDC has issued strong advisements when it comes to general travel, and especially for women at any stage during pregnancy. The general population has been urged to be vigilant when it comes to travel, especially when frequenting areas known to be experiencing outbreaks of the Zika virus. The general public is also urged to keep up to date with the latest information regarding outbreaks and transmission occurrences.

A map of these provided by the CDC can be found here. 

Due to the nature of irreversible birth defects known to occur as a direct result of an infection, women in particular must be vigilant regarding travel. Those who are pregnant have been warned not to travel to areas with the most prevalent cases of the virus. Women intending to fall pregnant (and their male partners) should also take precaution with regards to future travel plans and take steps to keep their risk rate at an absolute minimum.

3. Transmission control

Where transmission occurs by any means other than a mosquito bite, precautions can be taken to lower the risk of transmission. The CDC has strongly recommended that all pregnant women either abstain from sexual contact during pregnancy or take extra care in using a condom correctly if either she or her partner has lived in or travelled to an area known for Zika infections.

As of yet, there is no vaccine for the Zika virus.

Should insect repellents be used on children as a preventative measure?

No repellents should ever be used on children under the age of 2. Products which contain para-menthane or lemon eucalyptus are also not advisable for use on children under the age of 3. If using repellents around a child, care must be taken not to make contact with a child’s eyes, mouth, hands, area of skin which is irritated, inflamed or cut.

The best preventative measures for a young child include:

  • Dressing a young child in clothing that covers the body and limbs.
  • Using mosquito nets to cover, cribs (cots), strollers or baby carriers.
  • Parents can apply insect repellent on their children older than three by spraying onto their own hands and then lightly applying. Care must be taken to avoid contact with a child’s eyes and mouth.

Is it safe for children to travel to Zika-risk areas?

Travel guidelines as stipulated by the CDC applies to all, adults and children or infants.

What is currently being done by the CDC?

Data collection is currently being focussed around surveillance of population-based birth defects (so as to identify the full spectrum of potential complications associated with Zika virus infections), and reviewing all medical records (active case findings).

Surveillance data has proved useful in better understanding Zika virus disease patterns (to track the frequency and severity of congenital defects and associated complications), various known risk factors, identify types of defect patterns, and determine the overall effects infection has on communities and populations around the world. Using the data, authorities can better inform prevention methods and assist in connecting affected families with relevant healthcare and social services.

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