CDC updates its guidance for prevention of sexually transmitted Zika infection

The Center for Disease Control (CDC) recently issued an interim update to its guidance for Preconception Counseling and Prevention of Sexual Transmission of Zika Virus for Men with Possible Zika Virus Exposure. The recommendations were published in the weekly Morbidity and Mortality Weekly Report (MMWR).

Zika infection in pregnancy may cause multiple abnormalities including congenital Zika syndrome which includes– severe anencephaly, decreased brain tissue, macular scarring and focal pigmentary retinal mottling, clubfoot or arthrogryposis, and hypertonia restricting body movement soon after birth.

Zika infection is transmitted primarily through the bite of infected Aedes aegypti mosquito or through unprotected sex with an infected partner. Since 2015, 52 confirmed cases of sexual transmitted Zika infection have been known in the US. In most of the cases, the transmission occurred from infected men to women, although some instances of men to men and women to men transmission are also known.

The recent CDC update is for men with a possible Zika exposure who are planning a pregnancy with their partners or who want to prevent the sexual transmission of Zika anytime.

CDC now recommends that men with Zika exposure should wait for a minimum of 3 months after the onset of Zika Symptoms (symptomatic) or after Zika exposure(asymptomatic) before they plan a pregnancy with their partners.

If the couple is not planning a pregnancy, they should use condoms or abstain from sex for three months to prevent the sexual transmission of infection. 

Recommendations for men with possible Zika virus exposure whose partner is pregnant remains unchanged, they are advised to consistently and correctly use condoms during sex or abstain from sex for the duration of the pregnancy.

MMWR report

CongenitalZika Syndrome & Other Birth Defects

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Should universal serological screening for Toxoplasmosis be recommended during pregnancy?

Toxoplama gondii is ubiquitous in nature and infects animals and human alike. In immunocompetent host the infection is typically asymptomatic; however, in congenital settings, toxoplasmosis causes a range of manifestations in the fetus and newborn including but not limited to prematurity, IUGR, microcephaly, seizures, myocarditis, and life-long neurological and ophthalmologic sequelae.

The global incidence of congenital toxoplasmosis has been estimated to be 190,100 cases annually which corresponds to a burden of 1.20 million disability-adjusted life years. Yet only a few countries in the world have policies about universal serologic screening during gestation, followed by treatment of women who seroconvert. France is one of such countries where routine serologic screening is performed monthly during pregnancy. 

Surprisingly, In USA, serological screening is not universally recommended, although some obstetric practices do the screening. The current issue of American Journal of Obstetrics and Gynecology reports the results of first RCT Toxogest (ClinicalTrials.gov Identifier: NCT01189448) compare the efficacy and tolerance of pyrimethamine + sulfadiazine(PS) vs spiramycin to reduce placental transmission with an accompanying editorial about the systematic screening of toxoplasmosis during pregnancy.

Since placebo-controlled RCT was not possible, the trial compared the potential of spiramycin vs. PS to treat congenital toxoplasmosis in 150 women who have seroconverted during their second trimester of gestation or later.

Unfortunately, the trial was terminated early because of insufficient participants and problems with funds, but there were fewer transmission and no fetal cerebral toxoplasmosis lesions in the PS group, prompting to perform further research on prevention of congenital toxoplasmosis.

However, there is a lot to learn from results of Toxogest trial write Jose G. Montoya from Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA in the accompanying editorial.

Based on results of study and literature review so far, the author advises systematic screening for toxoplasmosis in every pregnant woman where Toxoplasma infection is known to occur because of devastating consequences of congenital toxoplasmosis. Further, congenital toxoplasmosis is preventable and treatable in utero.

If a woman tests positive or seroconverts during pregnancy, the question is not about to treat or not to treat, but what to treat with. The author proposed a simple algorithm for serological screening and follow up of pregnant women who were identified to be at risk for seroconversion during gestation (negative for Toxoplasma immunoglobulin G and M).  

If Toxoplasma IgM/IgG remains negative along with normal fetal ultrasound till term, no further treatment is needed. If the patient seroconverts and tests positive for IgM/IgG, follow the following algorithm.

At 18 weeks of pregnancy, do amniotic fluid PCR in patients on Spiramycin or pyrimethamine +sulfadiazine(PS) and follow the algorithm.

Algorithm  after amniotic fluid PCR in Spiramycin group

Algorithm  after amniotic fluid PCR in pyrimethamine +sulfadiazine(PS) group

The author concludes, “It is time to not leave anymore pregnant women who silently seroconvert for toxoplasmosis during gestation in the equivalence of a placebo arm.”

Abstract

Editorial full text

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Novel emerging infectious diseases in pregnancy

Last two decades have seen epidemics of several infectious diseases which were previously not so prevalent worldwide. Pregnant mothers are especially prone to many infections because of anatomical and physiological changes that accompany pregnancy. The immune tolerance to semiallogenic fetus is because of down regulation of immunity, which puts the pregnant women at high risk of other infectious diseases reports a paper published in May 2017 issue of Journal Obstetrics and Gynecology.

The world has seen epidemics of four major and other minor emerging infectious diseases in the last two decades such as severe acute respiratory syndrome, the 2009 H1N1 pandemic influenza, Ebola virus, and, most recently, the Zika virus. Each of this infection has unique implications in pregnant women that are distinctly different from general population.

Each of this infectious disease has different clinical course, complications and future implications when occurring in pregnant women and requires special technique and skills and coordination at national and international levels to contain the outbreak, some basic principles are common to all for diagnosing and limiting the spread of these diseases.

A number of epidemiological factors have contributed towards emergence and widespread occurrence of these infection in pregnant women like global travel, development of microbial resistance and barriers towards vaccinations in pregnant women in-spite of increasing evidence of distinct benefits to mother and fetus.

Although the general principles of disease containment are common to all, some disease specific measures for treatment and prevention of individual infections in pregnancy are:

SARS: During the severe acute respiratory syndrome (SARS) outbreak by coronavirus in 2003, standard non-pharmaceutical measures were applied, and global containment was achieved in 5 months.

Influenza: All pregnant women should get influenza vaccine every year as soon as it is available and should not wait for the unpredictable influenza season to start. It is safe in all the trimester. The rapid influenza tests currently available has low sensitivity resulting in many false negative results. Hence, to err on the side of safety it is always recommended to prescribe oseltamivir as precaution and is recommended both by Centers for Disease Control and Prevention (CDC) and the American College of Obstetricians and Gynecologists.

Ebola virus: Women are always at high risk for contracting Ebola during an epidemic as they are the primary caregivers to other infectious family members. Women who are pregnant with the virus during acute Ebola epidemic usually transmit virus to the fetus, leading to intrauterine fetal death, stillbirth, or neonatal death. Ebola virus is also excreted in breast milk.

They also transmit the virus to healthcare providers and caregivers during labor or abortion. Standard precaution including the use of personal protective equipment (PPE) during labor and delivery for protection against blood and body fluids should be used along with rigorous hand hygiene, appropriate waste, sharps and laundry management and cleaning and decontamination.

WHO states that women who get pregnant after having being recovered from Ebola infection are not infectious but standard precautions and use of PPE should be implemented all the time during handling such patients. 

Zika virus: Zika virus is a flavivirus that has potential for sexual and vector born transmission by Aedes (Stegomyia) species of mosquitoes. It was declared as a public health emergency by the World Health Organization from 2016. A pregnant woman is susceptible to Zika virus in all three trimesters. Maternal Zika infection is associated with a range of adverse neonatal complications, most important of which is microcephaly. Peripartum transmission is also known to occur.

In absence of antiviral vaccine, CDC recommends that all pregnant women should postpone their travel to Zika infected areas and those who are in such areas should avoid mosquito bite especially during the day.

Pregnant women with laboratory-confirmed Zika virus infection can be offered amniocentesis to test for Zika virus RNA by RT-PCR after 15 weeks of gestation.

Deliveries of mothers with positive Zika infection should take place at specialized center.   

No specific antiviral treatment is available.

Abstract

Expert Discussion

WHO guide to Ebola disease in pregnancy

Media courtesy: InfectiousDiseaseAdvisor and Coherent news.

A secret weapon against Zika and other mosquito born disease.

Zika Virus disease is a nationally notifiable condition in US. As of June 2017, there were 1,997 pregnant women with laboratory evidence of Zika.

There were 8 pregnancy losses and 88 infants born with Microcephaly in US, with the worldwide estimate being 2,300.

Zika is spread mostly by the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus), although sexual transmission has also been documented.

Although, Zika virus no longer constitutes an international public health emergency but according to WHO ‘Zika is here to stay.’

"Although Zika's spread has waned, it still holds the potential for an explosive epidemic. If it were to reemerge in the Americas or jump to another part of the world, it would significantly threaten a new generation of children born with disabilities such as microcephaly." said Lawrence Gostin, a global health law expert from Georgetown University.

In this Ted Talk Molecular biologist Nina Fedoroff takes us around the world to understand Zika's origins and how it spread, proposing a controversial way to stop the virus -- and other deadly diseases -- by preventing infected mosquitoes from multiplying.

No evidence of congenital anomalies with Zika infection in third trimester.

The first outbreak of Zika virus occurred in South America occurred in Brazil in May 2015 subsequently in October Columbia confirmed 156 cases of Zika in 13 municipalities.[1]  Neurological abnormalities and other adverse pregnancy outcomes are associated with Zika infection in first and second trimester of pregnancy.

A recent surveillance report from the Colombian Instituto Nacional de Salud (INS) suggested that Zika infection in the last trimester of pregnancy does not cause any structural fetal defect. The report of this study was published in recent online edition of New England Journal of Medicine.[2]

A total of 65,726 cases of ZVD were reported in Colombia during the study period from August 9, 2015, through April 2, 2016. Out of these 2485 (4%) were found positive on RT-PCR assay. Zika infection was widespread in Colombia with 11,944 pregnant women affected, of which 1484 (12%) were confirmed on RT-PCR assay.

Out of 11,944 infected pregnant women, INS had complete data on for a subgroup of 1850 women correlating gestational age and the onset of symptoms of Zika infection. Out of these 1850 women, 616 women got infection in third trimester and in nearly 89-90% of these women no congenital anomalies were detected at birth.

The remaining women were infected in first and second trimester, so they still had ongoing pregnancy when the cut-off date of the study was reached. 

The number of cases reported in the study does not show the true magnitude of the Zika infection as the surveillance system does not include asymptomatic women or those women who do not go to healthcare provider.

The authors stressed the importance of healthcare providers in educating the patients about the vector and sexual mode of transmission of the Zika infection.

The INS and CDC jointly are implementing intensified surveillance in places with Zika infections to determine the full spectrum of disease in mother and infants in relation to gestational age at infection. 

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[1] http://www.who.int/emergencies/zika-virus/history/en/

[2] http://www.nejm.org/doi/full/10.1056/NEJMoa1604037#t=article

First baby born with ZIKA related microcephaly in Continental US

Tuesday saw the birth of first baby born with Zika related microcephaly at the  Hackensack University Medical Center, New Jersey. This is the second known case of a baby born with Zika-related birth defects in the United States. The first baby was born in Hawaii.

The mother is from Honduras and travelled to US to her relatives in hope of better medical care. Doctors in US believe that she contracted the disease probably in second trimester when she had fever and rash, which are symptoms of viral infection.

Her OBGYN  in Honduras suspected that she  had a baby with IUGR  and coordinated with CDC to send the samples for testing. As expected the results came back positive.

A last trimester ultrasound  revealed that baby had abnormalities including severe microcephaly, calcification of the brain, bowel problems and restricted growth.

Baby was delivered by emergency C-section and also suspected to suffer from other problems.

Honduras is one of half a dozen Latin American and Caribbean countries where abortion is not legal with no exceptions, not even to save a woman’s life, according to reproductive rights advocacy groups.

 As of May 12, 2016, the two Zika virus infection surveillance systems are monitoring 157 pregnant women in the U.S. states and 122 pregnant women in the U.S. territories with laboratory evidence of possible Zika virus infection.  That is a total of 279 pregnant women in U.S. states and territories who are followed closely as a part of national registry.

Till date almost 600 cases of Zika have been diagnosed in the US, but all sufferers have travelled to an infected country and none of them got infected in US.

According to the World Health Organization (WHO), women planning to become pregnant should wait at least eight weeks before trying to conceive if they or their partner live in or are returning from Zika virus hotspots.

The case comes at a time when Congress has yet to approve new funding to fight the virus, despite months of White House pressure. Congressional Republicans have rejected the White House’s request for $1.9 billion in new funds. 

References:

http://www.cdc.gov/media/releases/2016/s0520-pregnant-women-zika.html

http://www.cdc.gov/zika/hc-providers/registry.html

CDC Confirms the link between Zika infection and microcephaly.

Zika has been linked to microcephaly since Brazil reported a sudden increase in number of infants born with microcephaly in September 2015, but causation was not established. CDC today made an important announcement after careful review of all the possible evidence that Zika virus is a cause of microcephaly and other severe fetal brain defects.

The study is published online in the New England Journal of  Medicine today.

“This study marks a turning point in the Zika outbreak.  It is now clear that the virus causes microcephaly.  We are also launching further studies to determine whether children who have microcephaly born to mothers infected by the Zika virus is the tip of the iceberg of what we could see in damaging effects on the brain and other developmental problems,” said Tom Frieden, M.D., M.P.H., director of the CDC. “We’ve now confirmed what mounting evidence has suggested, affirming our early guidance to pregnant women and their partners to take steps to avoid Zika infection and to health care professionals who are talking to patients every day. We are working to do everything possible to protect the American public.”

The investigators examined the causality evidence in light of Shepard’s criterias, which is set of rules that must be satisfied before labeling  an agent being ‘ teratogenic’  and causing  congenital malformations. According to the Shepard’s criterias, causality is established when either criteria 1, 3, and 4 (rare exposure–rare defect approach) or criteria 1, 2, and 3 (epidemiologic approach) are fulfilled.

So, the relationship between Zika infection and microcephaly was termed casual under the rare exposure–rare defect approach as criteria 1, 3 and 4 were fulfilled:

1. Proven exposure must occur at a critical time during prenatal exposure: The microcephaly and other anomalies occur when the exposure occurs during first trimester or early second trimester. 
2. Careful delineation of clinical cases with the finding of a specific defect or syndrome: Infants with Zika infection do have a typical pattern which includes severe microcephaly, intracranial calcifications, and other brain anomalies, sometimes accompanied by eye findings, redundant scalp skin, arthrogryposis, and clubfoot which led the scientist to coin a term “Congenital Zika Syndrome.”
3. Rare exposure and a rare defect: This criterion was met because microcephaly is a rare defect with an incidence of 6 infants per 10,000 liveborn infants in the United States and infection in travelers who spent a limited amount of time in Brazil with active infection, constitute rare exposure for the patients.

Also supportive of causation is lack of alternative explanation for sudden increase in microcephaly cases in Brazil, French Polynesia and Colombia.

But, proving the causation is not enough in the fight against Zika infection. Many key questions are yet to be answered that have important implications.

CDC's director, Tom Frieden, MD said “We are launching further studies to determine whether children who have microcephaly born to mothers infected by the Zika virus is the tip of the iceberg of what we could see in damaging effects on the brain and other developmental problems," in a statement.

In addition to this researchers are also interested in knowing relative and absolute risk of infection and malformation. At present 1% to 29% of babies are born with microcephaly of all the mothers infected with the virus. They are also looking at other factors that modify the risk and severity of infections, such as gestational week at infection, additional morbidities and co-viral infection like Dengue fever.

CDC has not changed the travel warning or guidelines related to Zika infection after this publication.

Mark S. DeFrancesco, MD, MBA, President of the American College of Obstetricians and Gynecologists (ACOG), released the following statement regarding the U.S. Centers for Disease and Control and Prevention (CDC) paper addressing Zika virus “The message of the CDC paper underscores the importance of ongoing research into this outbreak. We once again encourage Congress to act swiftly to pass emergency funding to enhance our public health preparedness and enable America’s researchers to lead the charge in the development of a vaccine or treatment for this virus. Ongoing support for Zika virus research will protect American families and, indeed, families around the world."

References:

http://www.nejm.org/doi/full/10.1056/NEJMsr1604338?query=featured_home&

http://www.acog.org/About-ACOG/News-Room/Statements/2016/ACOG-Statement-on-the-CDC-Update-on-Zika-Virus

http://www.cdc.gov/media/releases/2016/s0413-zika-microcephaly.html

Maternal ZIKA virus infection linked to fetal and placental malformations, apart from Microcephaly.

The World Health Organization has declared the Zika virus an international public health emergency, with a prediction of about four million people being infected at the end of the year.

WHO has issued a travel warning for pregnant women advising them not to travel to areas with continuing outbreaks of Zika virus due to the potential risk of birth defects.

Sexual transmission appears to be more common than previously thought of. "Pregnant women whose sexual partners live in or travel to areas with Zika virus outbreaks should ensure safe sexual practices or abstain from sex for the duration of their pregnancy," the WHO said, based on advice from its Emergency Committee of independent experts.

According to a preliminary report of case series  from Rio de Janeiro, Brazil, published online March 4 issue of the New England Journal of Medicine, ZIKA is also linked to fetal death, placental insufficiency, IUGR and Nervous system malformation.

Dr. Patrícia Brasil, MD, the principal investigator of the study  “our findings provide further support for a link between maternal ZIKV infection and fetal and placental abnormalities that is not unlike that of other viruses that are known to cause congenital infections characterized by intrauterine growth restriction and placental insufficiency.”

In September, 2015 researchers in Brazil identified dengue like fever, which was later identified as ZIKV. In the same month the ZIKV was linked to microcepahy, cases in Brazil rocketed to 3,500 from 147, the average for the same time last year (2014).

The link was first detected when Brazilian health authorities found traces of the Zika virus in a deceased infant born with microcephaly or in amniotic fluid of mothers delivering microcephalic infants.

In the present study, the researchers enrolled pregnant women of any gestation, who presented with a rash that had developed within the previous 5 days. Out of 88 women, 72 (82%) women tested positive ZIKV in blood and/or urine by reverse-transcriptase polymerase chain reaction assays. The researchers followed the women prospectively with clinical examinations and serial ultrasound. All the study participants were generally healthy with no h/o congenital malformations.

Clinically the women presented with a macular or maculopapular rash, pruritus (94%) arthalgia (65%), conjuntival redness (58%). Fever was not a significant symptom with only one third of women reporting it.

All the ZIKV negative as well as positive women had ultrasound. USG showed abnormalities in 12 of ZIKV positive women while those women who are negative showed normal USG.  Sonographically detected abnormalities include:

• intrauterine growth restriction, with or without accompanying microcephaly(5)
• cerebral calcification (4)
• CNS alterations (n = 2)
• Oligohydramnios and anhydramnios (2)
• Abnormal arterial flow in the cerebral or umbilical arteries(4)
• additional malformations, including agenesis of the vermis, Blake’s pouch cyst, and potentially a club foot, in addition to cerebral calcifications, intrauterine growth restriction, and microcephaly(1)

Abnormalities were present in fetuses of women irrespective of there gestational age at ZIKV infection, although those women infected in first trimester show signs of insult during embryogenesis. CNS abnormalities seen in fetuses infected as late as 27 weeks.

Six live births and two still births occurred during the follow up and confirmed the Sonography findings.

The authors suggest that “many aspects of ZIKV infection are similar to those of rubella, particularly rash, arthralgias, pruritus, and lymphadenopathy in the mother without high fever.” But, it is worrisome that there is no population immunity for ZIKV as compared to rubella U.S. pandemic of 1959–1965, when only 17.5% of women of childbearing age lacked rubella antibodies.

In summary the study findings provide support to the hypothesis of link between maternal ZIKV infection and fetal and placental abnormalities. The women infected with ZIKV should be followed up closely with serial ultrasonography to evaluate for signs of placental insufficiency, given the risks of fetal death and intrauterine growth restriction.

References:

http://www.who.int/mediacentre/news/statements/2016/zika-ec/en

http://www.nejm.org/doi/full/10.1056/NEJMoa1602412?query=featured_home#t=articleDiscussion

 

All about Zika virus infection.

Zika Virus was first isolated from rhesus monkeys  in Zika forest in Uganda in 1947, but was barely in news till now as it did not cause outbreak in humans.

The Zika virus is a flavivirus, part of the same family as yellow fever, West Nile, chikungunya and dengue. But unlike some of those viruses, there is no vaccine to prevent Zika or medicine to treat the infection.

The incubation period of Zika virus disease is not clear, but is likely to be a few days. The symptoms are similar to other arbovirus infections such as dengue, and include fever, skin rashes, conjunctivitis, muscle and joint pain, malaise, and headache. These symptoms are usually mild and last for 2-7 days. But, majority of patients with this infection have no or very little symptoms, causing it very difficult to track. They can, however, still transmit the disease if they are bitten by a mosquito that then bites someone else.

Transmission

The Vector for Zika is  Aedes mosquitoes (which usually bite during the morning and late afternoon/evening hours. On Tuesday CDC reported the first sexually transmitted case of Zika virus in Dallas, Texas.  Previously, there have been only two documented cases linking Zika to sex and isolated cases of spread through blood transfusion.

In addition, the CDC says there have been documented cases of virus transmission during labor( vertical transmission ) , blood transfusion, and laboratory exposure. While Zika has been found in breast milk, it's not yet confirmed it can be passed to the baby through nursing.

Diagnosis

According to CDC- During the first week of illness, Zika virus disease can often be diagnosed by performing reverse transcriptase-polymerase chain reaction (RT-PCR) on serum. Serology assays can also be used to detect Zika virus-specific IgM and neutralizing antibodies, which typically develop toward the end of the first week of illness. Plaque-reduction neutralization testing (PRNT) can be performed to measure virus-specific neutralizing antibodies to confirm primary flavivirus infections and differentiate from other viral illnesses.

World Health Organization Director-General Margaret Chan declared the current outbreak as  a public health emergency on February 1, 2016, with 24 countries involved from South and Central America and the Caribbean involved in the outbreak.

Courtesy: Vox.com

Zika is commanding attention worldwide because of connection between the virus and microcephaly.

According to CDC, in the past four months, microcephaly cases in Brazil rocketed to 3,500 from 147, the average for the same time last year (2014).  About 46 babies have died due to birth defects.

The link was first detected when Brazilian health authorities found traces of the Zika virus in a deceased infant born with microcephaly or in amniotic fluid of mothers delivering microcephalic infants.

The first confirmed cases of ZIKV infection in Brazil were reported in May 2015.

Transmission of the virus in Brazil is likely to have started several months before because the disease is new and mild, and could have been unrecognised or misdiagnosed, as dengue and chikungunya epidemics were ongoing.

Microcephaly caused due to any infection is usually caused by transplacental infections occurring early in pregnancy and is only detected during the second half of pregnancy or after birth.

The observed six months delay between the recognition of the transmission of ZIKV in May 2015, and the detection of an increase in microcephaly in November 2015, is therefore compatible with a temporal association between the two events.

Currently there is only ecological evidence of an association between the two events, due to sudden epidemic of microcephalic babies born and clustered around a specific time period. Researchers are still working to confirm the link — could it be something else that's causing the microcephaly?

On 13 January 2016, the Brazil Ministry of Health reported the detection of Zika virus genome, through the RT-PCR technique in four cases of congenital malformation in the state of Rio Grande do Norte. The cases correspond to two miscarriages and two full-term newborns (37 and 42 weeks respectively) who died in the first 24 hours of life. Tissue samples from both newborns were also positive for Zika virus by immunohistochemistry

Obstetrical providers should obtain a travel history from all pregnant women and use recent travel history to guide decisions about testing.  Testing is not indicated for pregnant women without a travel history to an area with Zika virus transmission.

Courtesy: Vox.com

Diagnosis in pregnant patients.

Zika virus RT-PCR can also be performed on amniotic fluid.  Other testing that can performed includes the following: 1) histopathologic examination and immunohistochemical staining of the placenta and umbilical cord, 2) Zika virus testing of frozen placental tissue and cord tissue, and 3) IgM and neutralizing antibody testing of cord blood.

Amniocentesis should be offered to pregnant women with recent travel to an area with Zika virus transmission, reporting 2 or more symptoms within two weeks of travel and a positive or inconclusive maternal serum test.  For pregnant women with recent travel to an area with Zika virus transmission and ultrasound findings of microcephaly or intracranial calcifications, amniocentesis may also be considered.

A positive Zika virus RT-PCR result from amniotic fluid would be suggestive of intrauterine infection.  This information would be useful for pregnant women and their healthcare providers to assist in determining clinical management (e.g., antepartum testing, delivery planning).  A negative Zika virus RT-PCR result from amniotic fluid may prompt a work up for other causes of microcephaly (e.g., other infections, genetic disorders).

There is currently no cure for the Zika virus. A number of institutions are scrambling to develop a vaccine, but it could take up to five years, as health experts called for new incentives for drug companies.

Meanwhile, American women who are pregnant have been advised to stay out of countries where the Zika virus is circulating. The CDC recommends consulting your doctor before your trip and following steps to prevent mosquito bites during the trip.

References:

http://www.cdc.gov/zika/index.html

http://www.who.int/csr/don/29-january-2016-zika-usa/en/

http://www.paho.org/hq/index.php?%20option=com_topics&view=article&id=427&Itemid=41484&lang=en

Microcephaly in Brazil potentially linked to the Zika virus epidemic says European Center for Disease Control (ECDC).

photo by CDC PHIL, Aedes Mosquito

 

New European Center for Disease Control ( ECDC) risk assessment is currently evaluating a possible link between the observed increase of congenital microcephaly in Brazil and Zika virus (ZIKV) infection.

Until recent months Zika virus was not widely associated with microcephaly.

According to CDC, in the past four months, microcephaly cases in Brazil rocketed to 3,500 from 147, the average for the same time last year (2014).  About 46 babies have died due to birth defects.

The link was first detected when Brazilian health authorities found traces of the Zika virus in a deceased infant born with microcephaly or in amniotic fluid of mothers delivering microcephalic infants.

The first confirmed cases of ZIKV infection in Brazil were reported in May 2015.

Transmission of the virus in Brazil is likely to have started several months before because the disease is new and mild, and could have been unrecognised or misdiagnosed, as dengue and chikungunya epidemics were ongoing.

Microcephaly caused due to any infection is usually caused by transplacental infections occurring early in pregnancy and is only detected during the second half of pregnancy or after birth.

The observed six months delay between the recognition of the transmission of ZIKV in May 2015, and the detection of an increase in microcephaly in November 2015, is therefore compatible with a temporal association between the two events.

Currently there is only ecological evidence of an association between the two events, due to sudden epidemic of microcephalic babies born and clustered around a specific time period.

A possible causative association cannot be ruled out but further investigations and studies are needed to understand the association and the possible role of other factors, states the ECDC risk assessment.

In November the Brazilian Ministry of Health declared a public health emergency in relation to an unusual increase in the number of children born with microcephaly in 2015.

In addition to Brazil's findings, French Polynesian health authorities have also reported an unusual increase in autoimmune and central nervous system malformations in babies born during a Zika virus outbreak on the islands from 2014 to 2015. (73 cases, 42 of them being Guillain-Barré Syndrome, in a population of about 270 000). 

CDC map illustrates areas affected or possibly affected by the spread of Zika virus

Zika virus disease is a mosquito-borne viral disease caused by Zika virus (ZIKV), a flavivirus from the Flaviviridae family and is primarily transmitted through the bite of infected Aedes mosquitoes.

The virus was first identified in 1947 in the Zika forest in Uganda in the rhesus Macaque population and have two main lineages, the African lineage and the Asian lineage.

Prenatal or perinatal complications of ZIKV infections have not been described in the literature. There is some evidence that perinatal transmission can occur, most probably transplacental or during the delivery of a viraemic mother. However, materno-foetal transmission has been demonstrated for several other Flaviviruses (dengue, West Nile fever).

Some other Flavivirus infections are known to have the potential to cause premature birth, congenital defects and microcephaly.

The most common symptoms of Zika virus disease are fever, rash, joint pain, and conjunctivitis (red eyes). The illness is usually mild with symptoms lasting from several days to a week.

Meanwhile, Brazilian officials are also reporting neurologic complications in other Zika virus patients, primarily Guillain-Barre syndrome, which has also been seen in French Polynesian patients who had suspected infections. "Although neither even establishes a causal relation with Zika virus, the hypothesis cannot be ruled out," says a health official in Brazil.

In conclusion, a causative association between microcephaly in newborns and ZIKV infection during pregnancy is plausible, but not enough evidence is available yet to confirm or refute it. Many studies are needed before a definite conclusion can be reached.

There is no vaccine to prevent infection or medicine to treat Zika virus.

Meanwhile, CDC issues a travel advisory to pregnant women  to consider postponing travel to areas where Zika virus transmission is ongoing.

References:

http://www.cidrap.umn.edu/news-perspective/2015/12/paho-issues-zika-virus-alert

http://www.cdc.gov/zika/pregnancy/question-answers.html

http://www.cdc.gov/zika/fs-posters/index.html

http://www.health.govt.nz/our-work/diseases-and-conditions/zika-virus

http://ecdc.europa.eu/en/healthtopics/zika_virus_infection/Pages/index.aspx

http://www.cdc.gov/zika/resources/index.html

http://www.cdc.gov/zika/hc-providers/index.html

http://www.cdc.gov/media/releases/2016/s0315-zika-virus-travel.html

http://ecdc.europa.eu/en/publications/Publications/zika-microcephaly-Brazil-rapid-risk-assessment-Nov-2015.pdf

http://www.cnn.com/2016/01/17/health/hawaii-zika-baby-microcephaly/