Friday December 14, 2018

Anti-dengue Antibody Drug May Neutralize Zika Virus

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Test for Zika more than once during pregnancy: Study
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Washington, Sep 26: An anti-dengue antibody-based drug could potentially protect a mother and her foetus from the deadly Zika virus as well, suggests new research.

In experiments with mice, the researchers found that an antibody that protects against dengue virus is also effective against Zika.

“We found that this antibody not only neutralises the dengue virus but, in mice, protects both adults and foetuses from Zika disease,” said Michael Diamond, Professor at Washington University School of Medicine in St. Louis, and senior author of the study published in the journal Nature Immunology.

Antibodies remain in the bloodstream for weeks, so one or a few doses of an antibody-based drug given over the course of a woman’s pregnancy potentially could protect her foetus from Zika, with the added benefit of protecting her from both Zika and dengue disease, the researchers said.

Dengue causes high fever, severe headaches, and joint and muscle pain in children and adults but does not directly harm foetuses.

Since dengue and Zika are related viruses, the researchers reasoned that an antibody that prevents dengue disease may do the same for Zika.

In collaboration with Gavin Screaton of Imperial College London, who had generated a panel of human anti-dengue antibodies years before, the scientists infected nonpregnant adult mice with Zika virus and then administered one of the anti-dengue antibodies one, three or five days after infection.

For comparison, another group of mice was infected with Zika virus and then given a placebo.

Within three weeks of infection, more than 80 per cent of the untreated mice had died, whereas all of the mice that received the anti-dengue antibody within three days of infection were still alive, and 40 per cent of those that received the antibody five days after infection survived.

To find out whether the antibody also could protect foetuses from infection, the researchers infected female mice on the sixth day of their pregnancies with Zika virus and then administered a dose of antibody or a placebo one or three days later.

On the 13th day of gestation, the amount of Zika’s genetic material were significantly lower in the placentas and in the foetal heads from the pregnant mice that were treated one day after infection, compared with mice that received the placebo.

However, administering the antibody three days after infection was less effective, the findings showed.

These findings suggest that for the antibody to effectively protect foetuses from Zika infection, it must be administered soon after infection.

Such a goal may be unrealistic clinically because women rarely know when they get infected.

However, giving women the antibody as soon as they know they are pregnant could provide them with a ready-made defence against the virus should they encounter it.

“We mutated the antibody so that it could not cause antibody enhancement of dengue infection, and it was still protective,” said Diamond.

“So now we have a version of the antibody that would be therapeutic against both viruses and safe for use in a dengue-endemic area because it is unable to worsen disease,” Diamond added.(IANS)

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Fetal Microcephaly Not Found In The Zika Virus Strain Of Rajasthan

In India, the first outbreak was reported in Ahmedabad in the beginning of 2017

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Nurses set up a mosquito tent over a hospital bed, as part of a precautionary protocol for patients who are infected by Zika at Farrer Park Hospital in Singapore Sept. 2, 2016 (VOA)

Zika virus strains linked to fetal microcephaly were not found in Rajasthan, the Union Health Ministry said on Saturday.

Microcephaly is a birth defect in which babies are born with extremely small heads.

“Advanced molecular studies of zika virus strains, carried out through Next Generation Sequencing suggest that the known mutations linked to fetal microcephaly and high transmissibility of zika virus in aedes mosquitoes are not present in the current zika virus strain that has affected Rajasthan,” a statement by the Ministry said.

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Aedes aegypti mosquitos, potential carriers of the Zika virus, are photographed in a laboratory at the University of El Salvador, in San Salvador, Feb. 3, 2016. Researchers have found that during the height of the viral epidemic the incidence of the paralytic illness Guillain-Barre was 100 times the number of cases usually seen.(VOA)

It said the Indian Council of Medical Research-National Institute of Virology (ICMR-NIV) had sequenced five zika virus strains collected at different time points of the Jaipur outbreak, which has affected 135 persons.

However, the government is maintaining high vigil of the possibility of adverse pregnancy outcomes in women exposed to zika virus as the strain may mutate in future or some other unknown host factors may play a role in microcephaly and other birth defects.

The Ministry said the situation is being reviewed on a daily basis.

Around 2,000 samples were tested for zika virus, of which 159 positive cases have been confirmed.

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FILE – A worker of the Ministry of Public Health and Population fumigates in the street against mosquito breeding to prevent diseases such as malaria, dengue and Zika in Port-au-Prince, Haiti, Feb. 15, 2016. VOA

“Adequate numbers of testing kits have been provided to the Viral Research and Diagnostic Laboratories,” the statement said.

Rajasthan government has been supplied with Information, Education and Communication (IEC) material to create awareness about zika virus disease and its prevention strategies.

All pregnant mothers in the area are being monitored through National Health Mission (NHM). Extensive surveillance and vector control measures are being taken up in the area as per protocol by the state government.

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FILE – A mother holds her son who is 4-months old and born with microcephaly, in Olinda, near Recife, Brazil, Feb. 11, 2016. Researcher Carlos Pardo says that during the height of the Zika outbreak the magnitude of the paralytic disease Guillain-Barre was similar to that of microcephaly but went underreported. (VOA)

Zika virus disease is an emerging disease currently being reported by 86 countries worldwide. Symptoms of zika virus disease are similar to other viral infections such as dengue, and include fever, skin rashes, conjunctivitis, muscle and joint pain, malaise, and headache.

Also Read: Indian Supreme Court Allows Only Green Firecrackers

In India, the first outbreak was reported in Ahmedabad in the beginning of 2017 and the second in July 2017 from Krishnagiri district in Tamil Nadu.

It is no longer a Public Health Emergency of International Concern vide World Health Organization’s notification issued on November 18, 2016. (IANS)