The Zika virus is a flavivirus, which is mosquito-borne. It is related to the dengue virus. In 1947, the virus was extracted from the rhesus monkey in Uganda’s Zika forest. In the same forest, the virus was extracted from the mosquito known as Aedes africanus in 1948. In 1954, the Zika virus was detected in human found in Nigeria. The Zika virus is known to have been initially identified in the region of the South Pacific, after an unexpected outbreak in Micronesia’s Yap Island (2007).
How the Zika Virus is Transmitted
The bite of Aedes mosquitoes primarily transmits the Zika virus to humans. This species of mosquito thrive in urban areas. They are usually active during late afternoons and early mornings. There are some evidence suggesting that the virus can also be transferred to humans by means of blood transfusion, sexual intercourse, and perinatal transmission. Yet, these modes of transmission are rare. Take note that the Zika virus incubates at a length of between two and seven days.
The Differences among the Zika Mosquito, Dengue Mosquito, and the Chikunguya Mosquito
The Zika virus is transmitted by an infected female Aedes albopictus and Aedes aegypti mosquito. These species of mosquitoes lay their eggs near and in stagnant water in animal dishes, vases, buckets, flower pots, and bowls. The females love to bite people outdoors and indoors, near crowds. This is known to aggressively bite people during the day. These mosquitoes are infected by feeding on people who are infected with Zika. Other subspecies of Aedes mosquitoes that transmit Zika are:
- Aedes hensilli thrives in plastic containers, metal drums, tree holes, coconut shells, canoes, and tins.
- Aedes polynesiensis live and breed in crab holes, tree holes, and coconut shells.
The Dengue virus is transmitted by the Aedes aegypti mosquito. Like the Zika mosquito, the female Dengue mosquitoes are the ones that bite. They usually lay their eggs in containers with stagnant water and in plants near your home. They bite both animals and humans. The Aedes aegypti thrives the entire year in subtropical and tropical climates.
The Aedes aegypti is described as a mosquito with markings the shape of a lyre. It also has banded legs. They usually travel indoors to bite humans. They can use simple and small household materials and local habitats as nesting grounds. The females usually lay their eggs in the daytime. Expect dengue mosquito eggs in stagnant water with organic materials such as algae and decaying leaves. They prefer dark containers with wide openings.
The Chikunguya mosquito transmits the virus through the female Aedes albopictus and Aedes aegypti. As you already know, these two species also transmit the Zika and the Dengue viruses. They bite during the day, but their peak biting hours may also be in the late afternoon and early morning. Take note that both species bite both indoors and outdoors. The Aedes aegypti usually feeds indoors.
Symptoms of Zika
According to the Center for Disease Control or CDC, most people who are infected by the Zika virus usually have no idea that they have already been infected. The reason behind this is because they do not exhibit the symptoms at all. The known symptoms of Zika virus are red eyes (conjunctivitis), fever, joint pain, and rashes. Others may experience headaches and muscle pain. The Zika virus’ incubation period is not established. It is estimated that the virus incubates for a few days to about a week.
If you develop conjunctivitis, fever, joint pain, or rashes within a couple of weeks after your travel from a place where Zika cases have been reported, and you know you are pregnant, see your attending physician immediately. Tell your doctor where you have traveled.
Remember that the Zika virus stays in the bloodstream of an infected person for at least a week. The positive thing about this infection is that once you have been infected, you will be immune against future Zika infections.
Diagnosis of Zika Virus
As you know, Zika symptoms are similar to the symptoms of Chikunguya and dengue. This is because these diseases are also transmitted by the species of mosquito that spreads Zika. It is very helpful if you tell your doctor where and when you have traveled. Blood tests may be ordered to diagnose Zika and rule out dengue or chikunguya.
Here are some diagnostic methods to detect the Zika virus:
- Viral nucleic acid detection
- Serological testing (enzyme-linked immunosorbent assays and immunofluorescence assays pinpoint the anti-Zika IgG and IgM antibodies.
- Virus isolation (research purposes)
- Detection of the nucleic acid via reverse transcriptase-polymerase chain reaction (targets the non-structural protein 5 genomic region)
***The urine or saliva samples should be collected during the first 3 – 5 days after the onset of symptoms. The serum samples should be collected during the first 1-3 days. When the samples are collected right, they are suitable for Zika testing.
Microcephaly: Adverse Effect of Zika
The most concerning thing about the Zika virus is its adverse effect—microcephaly. Microcephaly is a known birth defect. It is manifested by the infant’s unexpectedly small head. The small size of the baby’s head indicates that the brain has not developed properly. This is so because during pregnancy, the mother contracted the Zika virus. It is also possible that the infant’s brain has stopped developing after his or her birth. Microcephaly may occur by itself or with other birth defects as well.
Babies diagnosed with microcephaly suffer from many problems. These issues depend on the gravity of their microcephaly. Here are some of the problems associated with microcephaly:
- Developmental delays (walking, speech, standing, and sitting)
- Balance and movement problems
- Significant decrease in the ability to function and learn
- Problems in vision
- Loss of hearing
- Difficulty in feeding
Aside from the Zika virus, microcephaly may be caused by the following during development in the womb:
- Infected by cytomegalovirus, rubella or toxoplasmosis during pregnancy
- Extreme malnutrition
- Blockage of the flow of blood to the baby’s brain while still in the womb
- Baby’s exposure to toxic chemicals, alcohol, or drugs while still in the womb
While the mother is still pregnant, she is subjected to an ultrasound scan. This should be performed in the late 2nd trimester or in the early 3rd trimester of the pregnancy. After birth, the healthcare provider usually measures the circumference of the infant’s head during the standard physical examination. The measurement obtained is them compared to the standard head circumference of babies with the same age and sex.
Measuring the newborn’s head should be measured, at least 24 hours after birth. This is to make sure that the compression of the head during delivery has already been resolved. If the baby is suspected to have microcephaly, the attending physician could subject the baby to more tests, so that the diagnosis can be confirmed. These tests include an MRI scan or a CT scan. These tests can give vital information about the baby’s brain, so that the doctors can determine of the baby had a type of infection while she was still in the womb.
Take note that microcephaly is a condition that the baby has to suffer for a very long time. So far, no treatment or cure exists for it. Treatment options vary because the treatments depend on how severe the microcephaly is. In mild microcephaly, babies do not experience other neurological problems—just the smallness of their heads. Even so, they still need to have regular health check-ups so that their development could be monitored.
Treatment for Zika Infection
The Zika virus still has no vaccine or cure. The healthcare providers merely target the symptoms. Below are some of the things you can do to help relieve the manifesting symptoms of Zika:
- Drink plenty of fluid to help prevent dehydration
- Make sure you have plenty of bed rest
- Never take NSAIDs (non-steroidal anti-inflammatory drugs) and aspirin, until dengue is ruled out. Taking NSAIDs and aspirin. These medications can increase your risk of bleeding out.
- To reduce pain and fever, take paracetamol or acetaminophen (Tylenol)
If you already have Zika in your system, see to it that you keep away from mosquito bites during the first week. This is to keep uninfected mosquitoes and people from being infected.
Part of the Zika treatment is to control and prevent the breeding of Aedes species of mosquitoes. Contact between humans and mosquitoes can also be achieved by:
- Using insect screens, repellents, and other such effective barriers
- Getting rid of stagnant water located in living environments (This eradicates the number of adult mosquitoes in communities, at risk for Zika).
Transmission of Zika
Below are some of the common pathways of Zika transmission:
A woman, who is pregnant and infected by the Zika virus at the same time, may pass the virus to her fetus during her pregnancy. It is a given that Zika is a cause of severe brain defects in fetuses. One of these defects is known as microcephaly. The Zika virus can also be transmitted from the infected mother to her child during birth. Presently, there are still no cases of Zika infections in infants who breastfeed from infected mothers. Mothers are actually encourages to breastfeed in places where Zika cases have been reported.
2.Blood transfusion transmission
There are no confirmed Zika transmissions through blood transfusion yet, as of February 1, 2016 in the US. In Brazil, multiple reports of this type of transmission have been reports. The said reports are still being studied. When the French Polynesian outbreak happened, 2.8% of the listed blood donors turned out to be Zika positive. Previous outbreaks showed that the blood donors were Zika positive.
It is true that the Zika virus can be transmitted by a man to his partners in bed. The man who has Zika virus symptoms can spread the virus before the symptoms appear and after they resolve. There is one reported case wherein the virus was transmitted three days before the manifestation of symptoms. It is known that the Zika virus is present longer in semen than in the bloodstream.
Control and Prevention of Zika
A known risk factor for the Zika infection is the proximity of the human living environment to the vector mosquito’s breeding areas. An effective method of control and prevention is to reduce the breeding of the mosquitoes through the modification and removal of their nesting sites. The contact between mosquitoes and people should also be prevented. This can be accomplished through the following:
- Eliminate the containers, which are filled with stagnant water
- Reduce the number of natural mosquito nesting grounds in the area
- Using barriers to prevent mosquitoes from biting people (insecticide vaporizers, mosquito nets, mosquito coils, long pieces of clothing, repellents, closed windows and doors, insect screens)
- Using WHO recommended insecticides and larvicides
People who travel in high risk areas should wear long sleeved, light colored clothing, using repellents, and installing screens or nets in their rooms when they sleep.
The Response of the WHO
Below is the response of the World Health Organization toward Zika:
- Providing guidance and support to various countries, so that they could manage outbreaks and cases effectively
- Giving support to countries in improving their surveillance
- Helping people train on diagnosis, vector control, and clinical management, even through several WHO Collaborating Centers
- Publishing effective guidelines in controlling the vectors
- Motivating different countries in maintaining and developing the capacity to confirm and detect Zika cases, implement strategies for social communication to decrease the number of mosquitoes, and manage Zika patients,
Zika may be a simple, mild infection, but it can bring about microcephaly, which is a terrible fate for all infants and mothers. Prevention is always better than cure. Talk to your doctor and be aware of Zika before you even travel to affected countries. It would help significantly if you choose not to go to those areas at all. If you really need to travel to an affected country, bring more than enough protection against mosquitoes. Even if you have a mosquito net, slather on some mosquito lotion and spray insecticide around the room and around your bed.