Identification

 The ZIKA virus infection is determined by a virus transmitted by mosquitoes Aedes aegypti or Aedes albopictus that transmit other ailments such as Denga and Chikungunya fever. About 1 in 5 people infected with ZIKA virus are getting sick.  People infected with ZIKA virus usually have a mild fever, rash (allergic), joint pain and conjunctivitis. Other common symptoms include muscle aches and headaches. These symptoms typically take 2-7 days. The ZIKA virus was discovered in 21 Latin American countries. Epidemics were mostly recorded in Brazil, Colombia, Salvador, Panama and Republic of Cape Verde. The disease is usually mild with symptoms that lasts few days to a week.  The ZIKA virus usually remains in the blood of an infected person for a few days, but can be found in some people a longer period. Severe disease requiring hospitalization are less common. Deaths are rare.

The ZIKA virus can be transmitted by the pregnant female to fetus during pregnancy or at the time of birth. The infection of pregnant women with Zika virus during pregnancy may cause microcephaly, ocular defects, auditory defects, growth retardation and premature childbirth and spontaneous abortion.

In the diagnosis:

• In the acute period of disease:

            After the first 5 days of the disease can detect the virus from serum, saliva, urine, cerebrospinal fluid, amniotic fluid, sperm and breast milk by detecting viral RNA of the ZIKA virus. For the serum sample the blood is collected 5 days after the onset of symptoms, if viremia decreases and the RT-PCR test is negative that does not exclude the infection and should be performed and serological testing (detection of anti-ZIKA antibodies of IgM type). IgM anti-ZIKA antibodies are detectable from 4 days after the onset of the disease.

• During the convalescence of the disease:

   IgM anti-ZIKA antibodies usually persist 2-12 weeks. Due to the crossed serological reactivity between Flaviviruses, the detection tests of the circulating IgM antibodies cannot distinguish between the ZIKA infection and the Denga virus infection. In patients who have recently vaccinated against yellow fever or Japanese encephalitis or those who have been infected in the past with another flavivirus, the detection of IgM antibodies may not be sufficient to diagnose the infection with the ZIKA virus.

Antibody detection tests (serological tests) for ZIKA virus infection can also be performed on serum samples from asymptomatic pregnant women. The interpretation of serological tests is complex. Information on the performance of serological tests in asymptomatic persons is limited.

Testing of ZIKA virus through RT-PCR can be performed on amniotic fluid, but currently, it is not known how sensitive or specific this test is in congenital infection. It is also not known whether a positive result is predictive for a subsequent fetal anomaly, and if so, what percentage of children who are birthed after infection will have anomalies. For a birth with live fetus having evidence of infection with the maternal or fetal ZIKA virus, the following tests are recommended: testing of placental tissue and umbilical cord tissues for RNA-ZIKA; and testing of the umbilical cord serum for anti-Zika antibodies of IgM type. If a fetal loss occurs in a woman with a history of travel to a Zika transmission area with symptoms compatible with Zika disease during the journey or within 2 weeks of the journey or if there are findings of fetal microcephaly, tests have to be performed on the tissues of fetus, including umbilical cord and placenta.
In a pregnant woman with positive laboratory results for Zika virus infection in amniotic fluid or serum, a series of ultrasound exams should be considered to monitor fetal anatomy and growth every 3-4 weeks It is recommended to refer to a maternal-foetal specialist or to an infectious disease specialist with experience in pregnancy management.

Infectious Agent

The Zika virus is a member of the Flaviviridae family and is transmitted to humans through mosquitoes.  The same vector (mosquito) transmits other Flaviviruses (Denga, West Nile, Chikungunya and Japanese encephalitis), but produces a relatively mild disease in humans. In 2007, the virus caused a Zika epidemic on Yap island in Pacific. This was the first documented transmission outside of the traditional endemic areas of Africa and Asia, but Zika is considered an infectious disease emerging, with potential to spread in new areas/regions where the vector, the Aedes mosquito aegypti is present. There is no evidence of Zika virus transmission in Europe so far, and import cases are rare.

 

Incidence and prevalence

There are currently no mosquitoes of the species Aedes aegypti in Europe that can transmit the ZIKA virus. There are cases of import (people who have travelled to areas affected by Zika)

No local transmission reported. Countries with import cases: Switzerland, Italy, Great Britain, Netherlands, Portugal and Denmark.

The virus circulates in Africa, America, Asia and Pacific. Epidemics were mostly recorded in Brazil, Colombia, Salvador, Panama and the Republic of Cape Verde. According to the World Health Organisation (WHO), the virus is transmitted by blood, and the most effective method of prevention is to avoid areas where there are many mosquito, the use of substances against the bites of these insects and beds equipped with nets against mosquito.

In Brazil, the country most affected by Zika, 3,900 cases of microcephaly in newborns were detected. The WHO said that “there has not yet been established a case-effect link between infection with Zika during pregnancy and microcephaly in newborns”, but stressed that there is “circumstantial very worrying evidence” in this regard.

 

Source 

The main source is the infected blood transmitted through the bite of the mosquito Aedes aegypti or Aedes albopictus. The infection can be transmitted from people infected by sexual contact and maternofetal.

 

Method of transmission

According to the World Health Organisation (WHO), the virus is transmitted through the blood through the bite of an infected mosquito, and the most effective method of prevention is to avoid areas where there are many mosquito, the use of substances against bitesof these insects and beds equipped with nets against mosquito. So far there is no risk of transmitting the Zika virus from man to man through blood transfusions or organ transplantation.

Transmission by mosquito stings
-The Zika virus is transmitted to people primarily by the sting of an infected mosquito of the species Aedes aegypti, mosquito that can transmit viruses and Denga & Chikungunya (http://www.cdc.gov/chikungunya/index.html)
-These mosquitoes usually lay eggs near the water, on objects such as buckets, bowls, animal feed pots, flower pots and vases. Mosquitoes are aggressive and sting during the day, choosing the people, and living inside and outside close to people.
-infected mosquitoes, when they feed blood from a person already infected with the virus, can spread the virus to other people through stings.

Transmitting from mother to fetus
 -A mother already infected with the Zika virus near the time of birth can transmit to the newborn virus during delivery, but this is rare.
-It is possible that the Zika virus to be transmitted from the mother to the fetus during pregnancy. This mode of transmission is being investigated.

Transmitting through infected blood or sexual contact
-It has not been reported to date the spread of the virus through blood transfusions

-It has been proven to transmit the ZIKA virus through sexual contact, the virus resists in sperm up to 62 days after the onset of symptoms.

Risk groups

Pregnant women, women who want to conceive a child, persons with chronic or autoimmune diseases who travel to areas where there are mosquitoes Aedes aegypti or Aedes albopictus that transmit this infection through the bite. At risk are pregnant women who have unprotected sex with people infected with this virus. The virus circulates in Africa, America, Asia and Pacific. Epidemics were mostly recorded in Brazil, Colombia, Salvador, Panama and the Republic of Cape Verde.

Incubation period

The incubation period (period from exposure to symptoms) for Zika is not known accurately, but is likely from a few days to 12 days. About 80% of infections remain asymptomatic.

 

Infectiousness Period

            It’s not clearly established. The virus was detected in urine up to 3 weeks after the onset of the disease and in sperm up to 62 days.

 

Prophylaxis

Recommendations for travel in affected areas

When travelling to countries where the Zika virus or other viruses spread by mosquito, the following measures shall be taken:

• Wear long-sleeved shirts and long trousers.
  Stay in the air-conditioned places or use nets on window and doors to keep the mosquitoes out.
  Sleep in bed under a net for mosquito, whether you are abroad or outside and you are unable to protect yourself from the mosquito bites.
• Use substances registered by the Environmental Protection Agency that reject/combat insects and which have proven safe and effective, even for pregnant or breastfeeding women. (Always follow the instructions on the product label against insects. Apply the product against insects as instructed. Do not spray the product against mosquitoes on the skin under your clothes. )
• If you use sunscreen, it applies before you apply a product against insects
• If you have a baby or a child: Do not use insect products in children less than 2 months old. Dress the child in clothes that cover the arms and legs, or protect the crib, trolley and carrier for children with mosquito nets. Do not apply the product against insects to a child on the hands, eyes, mouth, or on the skin with cuts/wounds or irritated.
• Adults do not spray the product against insects on their hands and then apply it to a child’s face.

Vaccination

Since there is no vaccine, no prophylactic drugs to prevent infection with the Zika virus, the CDC recommends that all pregnant women consider postponing the journey to areas where the transmission of the Zika virus is underway . If a pregnant woman travels in an area with the transmission of Zika virus, she should be advised to strictly follow measures to avoid mosquito stings. Mosquitoes that spread the Zika virus sting both inside and outside, especially during the day, therefore it is important to ensure protection against mosquito throughout the day. Mosquito sting prevention strategies include wearing long-sleeved T-shirts and long trousers and the use of approved insecticides, to stay and to sleep in screened or air-conditioned rooms.

 

Birth to the woman infected with the ZIKA virus

            There are no recommendations.

Breastfeeding

There are no clear recommendations. So far, there are no children infected with the Zika virus through breastfeeding. Given the benefits of breastfeeding, mothers are encouraged to breastfeed even in areas where the Zika virus circulates.

Treatment

-There is no specific antiviral or vaccine treatment currently available.
-The best form of prevention is the protection against mosquito stings.

Treatment is generally supportive and symptomatic, may include rest, liquids and the use of analgesics and antipyretics. Although aspirin and other nonsteroidal anti-inflammatory drugs are not commonly used during pregnancy, these medicines should be especially avoided until the Deng can be excluded to reduce the risk of hemorrhaging.