Author Archives: bigbadvirus

Since this emergency committee on Zika virus first met on 1 February, substantial new clinical and epidemiological research has strengthened the association between Zika infection and the occurrence of fetal malformations and neurological disorders.

In addition, the geographical distribution of the disease is wider. The risk group is broader. And the modes of transmission now include sexual intercourse as well as mosquito bites.

Local transmission has now been reported in 31 countries and territories in Latin America and the Caribbean.

In this region, cases of dengue, which is carried by the same mosquito species as Zika, typically increase during the rainy season, which lasts from January to May. We can expect to see more cases and further geographical spread.

Imported cases of Zika have been reported from every region in the world.

Concerning the link with fetal malformations, the virus has been detected in amniotic fluid. Evidence shows it can cross the placental barrier and infect the fetus. We can now conclude that Zika virus is neurotropic, preferentially affecting tissues in the brain and brain stem of the developing fetus.

Zika has been detected in the blood, brain tissue, and cerebrospinal fluid of foetuses following miscarriage, stillbirth, or termination of pregnancy.

Microcephaly is now only one of several documented birth abnormalities associated with Zika infection during pregnancy. Grave outcomes include fetal death, placental insufficiency, fetal growth retardation, and injury to the central nervous system.

To date, microcephaly has been documented in only two countries: French Polynesia and Brazil. However, intense surveillance for fetal abnormalities is currently under way in countries, like Colombia, where the outbreaks started later than in Brazil.

Nine countries are now reporting an increased incidence of Guillain-Barré syndrome or laboratory confirmation of a Zika virus infection among GBS cases. A retrospective case-control study of GBS associated with Zika in French Polynesia recorded no deaths, but the disease progressed rapidly and a large percentage of patients required admission to an intensive care unit for as long as 51 days.

Growing evidence of a link with GBS expands the group at risk of complications well beyond women of child-bearing age. GBS has been detected in children and adolescents but is more common in older adults and slightly more common in men. The anticipated need for expanded intensive care adds a further burden on health systems.

Reports and investigations from several countries strongly suggest that sexual transmission of the virus is more common than previously assumed.

All of this news is alarming.

Women who are pregnant in affected countries or travel to these countries are understandably deeply worried.

I convened this second meeting of the Emergency Committee to gather expert advice on the strength and significance of these new research results. We also asked the experts whether the findings warrant changes in WHO recommendations to countries.

The Committee underscored the increasing strength of evidence showing a likely association between Zika infection and fetal malformations and neurological disorders.

At the same time, the experts pinpointed the types of studies needed to establish a causal relationship, but stressed their view that strong public health actions should not wait for definitive scientific proof.

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Study results from Zika virus infected immune deficient mice treated with BioCryst's BCX4430 will be presented at a World Health Organization (WHO) conference. The primary goal of the study was to assess the effect of BCX4430 treatment on survival through Day 28 in immune-deficient mice infected with the Zika virus. BCX4430 was administered by intramuscular (I.M.) injection twice a day beginning prior to virus challenge and continuing for eight days. In the standard dose BCX4430 group, 7 of 8 mice survived through Day 28. In the low dose BCX4430 group (n=8), and in control groups administered vehicle placebo (n=8) or ribavirin at two dose levels (n=16), no animals survived to Day 28.
This study was conducted at Utah State University, under the ongoing Animal Models of Infectious Disease Program at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. BCX4430 is a broad spectrum antiviral that is being tested in a Phase 1 clinical safety and pharmacology study in healthy subjects. BCX4430 has demonstrated survival benefits in nonclinical studies against a variety of serious pathogens, including Ebola, Marburg, and Yellow Fever viruses. Since September 2013, NIAID has supported BioCryst in developing BCX4430 as a therapeutic for Ebola and Marburg viruses under Contract No. HHSN272201300017C.
BCX4430 is an RNA dependent-RNA polymerase inhibitor that has demonstrated broad-spectrum activity in vitro against more than 20 RNA viruses in nine different families, including filoviruses, togaviruses, bunyaviruses, arenaviruses, paramyxoviruses, coronaviruses and flaviviruses. BioCryst is developing BCX4430 in collaboration with NIAID and the Biomedical Advanced Research and Development Authority (BARDA), following the Animal Rule regulatory pathway.
BioCryst Pharmaceuticals designs, optimizes and develops novel small molecule drugs that block key enzymes involved in rare diseases. BioCryst's ongoing development programs include oral plasma kallikrein inhibitors for hereditary angioedema, avoralstat, BCX7353 and other second generation compounds, and BCX4430, a broad spectrum viral RNA polymerase inhibitor. For more information, please visit the Company's website at www.BioCryst.com.

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Light
Light at the End of the Tunnel

Thomas Masterson, MD, Editor, MedicalNewsService.com

When the Zika epidemic was young, there was controversy.  The world did not associate Zika with microcephaly, and was reluctant to rush to judgement.  Fingers were pointed in many directions.  Two recent reports have changed the landscape of doubt and uncertainty.  The first is a work at Johns Hopkins and Florida State

demonstrating that the Zika Virus specifically targets Human Cortical Stem Cells.  The second is a study of pregnant Brazilian women with rashes in Brazil.  In rash study, when the rash came from Zika, 29% of the pregnancies had serious issues and when rash didn't come from Zika, there were no issues in this report.

Controversy and conspiracy is always more interesting than reasoned logic, but the time has come to step away from the noise and embrace what researchers are discovering.  eZikaVirus.com is dropping it's list of controversial microcephaly theories links.

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Brasilia, Brazil
Brasilia, Brazil

The FDA has new guidelines for blood donation. No donation for six months after that trip to Zika endemic areas -- see list at the end of the article.  Donors should be considered ineligible if they were diagnosed with Zika virus infection, were in an area with active Zika virus transmission, or had sex with a male with either of those risk factors, within the past six months. Donors of umbilical cord blood, placenta, or other gestational tissues should be considered ineligible if they have had any of the above risk factors at any point during their pregnancy.
A deferral period of six months was chosen because of the limited data available on the length of time the virus can persist in all tissues. Zika virus has been detected in tissues and body fluids after the virus is no longer detectable in the blood stream, and has been detected in semen possibly up to 10 weeks after the onset of symptoms. Given the uncertainty, six months was determined to provide the appropriate level of caution.

CDC Travel Advisory on Zika Virus. Level 2 Countries:
Pacific Islands: American Samoa, Marshall Islands, Samoa, Tonga
Caribbean: Aruba, Barbados, Bonaire, Curaçao, The Dominican Republic, Guadeloupe, Haiti, Jamaica, Martinique,The Commonwealth of Puerto Rico, a U.S. territory, Saint Martin, Trinidad and Tobago, U.S. Virgin Islands
North America: Mexico
South America: Bolivia, Brazil,Colombia, Ecuador, French Guiana, Guyana, Paraguay, Suriname, Venezuela
Central America: Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama
Africa: Cape de Verde

Thomas Masterson, MD, Editor, MedicalNewsService.com

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Zika Virus
6,300 pregnant women with Zika Virus in Columbia

Patricia Brasil and colleagues report widespread fetal abnormalities in the March 4 New England Journal of Medicine. They had enrolled 88 pregnant women who had a rash and then looked for Zika.  Of the recruited patients, 82 percent test positive for the Zika virus.  Of the women who had ultrasounds, 29 percent of the Zika infected patient had evidence of birth defects.  None of the of patients without Zika had birth defects.  The Zika-related birth defects included fetal deaths, growth restriction, microcephaly, and other central nervous system abnormalities.

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Johns Hopkins researchers led by Drs. Guo-Li Ming and Hongjun Song and Florida State researcher Dr. Hengli Tang have found that the Zika virus infects human cortical neural progenitor stem cells. 90 percent of their stem cells were infected and produced more virus. This is in contrast to pleuripotent stem cells which were not infected. Furthermore, the genes needed to fight viruses had still not been switched on, which is highly unusual. Many of the infected cells died, and others showed disrupted expression of genes that control cell division, indicating that new cells could not be made effectively. The researchers hope this is the first step towards finding a treatment for the Zika virus. This work reinforces the finding of Garcez and colleagues who found that the Zika virus targets neural tissue.

In many ways, the Zika virus is illustrating the Web speed of research today.  We are months after WHO and the CDC declaring Zika to be an emergency, and researchers are able to go to the lab and share reports with us and each other at unprecedented rapidity.

Thomas Masterson, MD, Editor, MedicalNewsService.com

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Jean Michel Mansuy and colleagues in a recent Lancet article describe persistent Zika virus in the semen of a traveler returning to France. The traveler had returned from a trip to French Guyana and Brazil. He had become ill two days after returning home. Blood tests revealed Zika virus infection. The traveler recovered in a few days. When his blood, urine and semen were tested two weeks later, enormous quatities of the virus were found in the semen. The viral load of semen was 100,000 times that of his blood or urine. With only one of five Zika infected persons showing signs of infection and the persistent virus in semen, Zika continuous to show itself as a danger even when the traveler looks and feels fine. In other words, women who are pregnant or may become pregnant need to avoid Zika mosquito bites and avoid unprotected sexual activity with men who been in contact with Zika mosquitos.

Thomas Masterson, MD, Editor, MedicalNewsService.com

 

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Thomas Masterson, MD, Editor, MedicalNewsService.com

French Polynesia
French Polynesia

The Lancet reports a study of Guillain-Barré syndrome in French Polynesia. The Pacific outbreak preceded our South American outbreak by a year. The Zika virus was present from October 2013 to April 2014, and there was corresponding increase in Guillain-Barré syndrome which causes paralysis. Dr, Cau-Lormeau and his associates evaluated 42 patients who had been paralyzed and found that all of them had antibodies against the Zika Virus. They looked at residents who had been well during this time and found that 56% of the healthy Polynesians had anti Zika antibodies. Indeed, most of the patients with Guillain-Barré had been ill the week before their paralysis suggesting that this was onset of Zika virus infection. Further supporting the relationship between virus and paralysis was the absence other common antibodies seen in non-Zika Guillain-Barré. The association of the Zika virus with the paralytic syndrome is striking. Equally striking is how widespread the virus became.  Over ½ of randomly selected Polynesians had anti-Zika antibodies.

Guillain-Barré Syndrome outbreak associated with Zika virus infection in French Polynesia: a case-control study

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Dr. Tom Frieden, Director CDC
Dr. Tom Frieden, Director CDC

Many people exposed to Zika virus will have only mild symptoms - such as fever, rash, joint pain, and red eyes or conjunctivitis - that will last no more than a week. In past outbreaks, about four out of five people infected with Zika appear not to have had symptoms at all, although we do not know if that is the pattern in this outbreak. Increasing evidence suggests that Zika virus infection may be associated with more serious health outcomes. In October 2015, Brazilian authorities recognized a concerning increase in microcephaly, which has occurred in close sequence to Brazil’s outbreak of Zika virus. Microcephaly is a usually rare, serious condition where a baby’s head is smaller than expected based on age and sex. Microcephaly is not a diagnosis in and of itself, but a sign that the brain did not develop as it should in the womb. Babies with microcephaly can have a range of problems, including seizures, developmental delay, feeding problems and hearing loss. In some cases these problems can be fatal.

Laboratory tests at CDC strongly suggest a link between Zika virus infection during pregnancy and microcephaly. We do not fully understand the nature of this relationship, or if there are important cofactors. We also do not know what, if any, other outcomes might be associated with Zika infection during pregnancy among infants who do not have microcephaly. Microcephaly in infants can be devastating to the affected families, and this ongoing outbreak is concerning to everyone, especially for pregnant women, and their families who may travel to or live in the infected areas. The association between Zika virus and microcephaly is unexpected. A new infectious cause of fetal malformations has not been identified in decades. Zika virus spread in the Americas and its effect on pregnancy are developments that we are working with partners to better understand.

Our key priority at this point is to reduce the risk to pregnant women of Zika virus infection. Given the potential risks associated with maternal Zika infection, prevention is key for this response, with a parallel approach of acting based on what we know now and, at the same time, discovering more so that we can better prevent adverse health outcomes in the future. That’s why, during the same week we identified Zika in brain tissue specimens from affected infants, we issued a warning to advise pregnant women not to travel to affected areas. That’s why we are working intensively with the Commonwealth of Puerto Rico and other areas to get support to women who are or who may become pregnant and do what we can to reduce the threat of Zika there. And that’s why we are engaging in studies with international partners so that we can more fully understand the magnitude of risk and the range of outcomes associated with Zika virus infection during pregnancy.

Health authorities in Brazil and elsewhere have also reported an increase in suspected cases of Guillain-Barré syndrome, a rare neurologic disorder in which a person's own immune system damages nerve cells, leading to nerve damage or paralysis that lasts for several weeks or several months. Most people fully recover, but it can take a few months or even years to do so. Some people with Guillain-Barré syndrome have permanent damage and, in rare cases, people have died. It is difficult to determine if any particular pathogen “caused” or “triggered” Guillain-Barré syndrome. Currently, we do not know if Zika virus infection causes Guillain-Barré syndrome. However, the development of Guillain-Barré syndrome is a recognized after-effect of a variety of different infections. CDC is currently collaborating with public health officials in Brazil to investigate whether there is any causal link between Zika infection and Guillain-Barré syndrome.

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Dr. Anthony Fauci
Dr. Anthony Fauci

Zika virus is a flavivirus. These viruses typically are transmitted by mosquitoes and often have the ability to spread quickly to new geographic locations because of the widespread prevalence of these vectors. Other well-known flaviviruses include dengue virus and yellow fever virus; like Zika virus they are transmitted by Aedes mosquitoes. Zika virus was discovered in monkeys in Uganda in 1947 and is now endemic to Africa and Southeast Asia. During the past decade it has emerged in other areas of the world, including Oceania, the Caribbean, and Central and South America, where countries, notably Brazil, are currently experiencing unprecedented Zika transmission.

Infections caused by Zika virus are usually asymptomatic. About 20 percent of infected individuals experience clinical symptoms such as fever, rash, joint pain, and conjunctivitis (red eyes). Symptoms of Zika virus infection in humans are typically mild and brief, with very low hospitalization and fatality rates. The recent outbreak of Zika virus disease in Brazil has coincided with a reported increase in the number of infants born with microcephaly, a birth defect characterized by an abnormally small head resulting from an underdeveloped and/or damaged brain. In addition, increases in suspected cases of Guillain-Barré syndrome (GBS), a rare, acute, immune-mediated peripheral nerve disease that leads to weakness, sometimes paralysis, and infrequently, respiratory failure and death, have been noted in Brazil and other countries in the Americas.

Further research is needed to better understand the effect of Zika virus infection on the body, particularly during pregnancy; to investigate the potential relationship between Zika infection and congenital abnormalities including microcephaly, as well as to explore the potential relationship between Zika infection and GBS; and to develop better diagnostics, vaccines and treatments, and new methods of vector control. Currently, no vaccines or specific therapeutics are available to prevent or treat Zika virus disease. Improved diagnostic tests also are needed because Zika virus infection causes non-specific symptoms or no symptoms at all and can be difficult to distinguish by antibody screening tests from other mosquito-borne infections such as dengue, malaria, and chikungunya. Moreover, current antibody screening tests can be falsely positive or inconclusive if the individual was previously infected with related viruses such as dengue, which is prevalent in South America and the Caribbean. Therefore, a positive result with the antibody screening test requires an additional test to confirm the diagnosis.

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