Saturday July 21, 2018

An international research team shows that carbohydrates may play a vital role in improving malaria vaccine

Malaria infects over 200 million people worldwide each year and kills around 650,000 people

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Malaria vaccine
Carbohydrates may improve malaria vaccine. Pixabay
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  • Carbohydrates on the surface of malaria parasites play an important role in their ability to infect mosquito Andy human hosts
  • The new research is aimed at improving malaria vaccine design
  • It’s hoped that a version of RTS, S with added carbohydrates will perform better than the current vaccine

New Delhi, September 18, 2017: Offering vital clues to improving malaria vaccine, an international research team has shown that carbohydrates on the surface of malaria parasites play a critical role in their ability to infect mosquito and human hosts.

The discovery, published in the journal Nature Communications, also suggests steps that may improve the only malaria vaccine approved to protect people against Plasmodium falciparum malaria — the most deadly form of the disease.

The team had shown that the malaria parasite “tags” its proteins with carbohydrates in order to stabilise and transport them and that this process was crucial to completing the parasite’s life cycle.

“Interfering with the parasite’s ability to attach these carbohydrates to its proteins hinders liver infection and transmission to the mosquito and weakens the parasite to the point that it cannot survive in the host,” said Justin Boddey from Walter and Eliza Hall Institute in Parkville, Victoria, Australia.

Malaria infects over 200 million people worldwide each year and kills around 650,000 people, predominantly pregnant women and children. Efforts to eradicate malaria require the development of new therapeutics, particularly an effective malaria vaccine.

Also readNearly 900,000 Nigerian Children Receive Anti-Malaria Vaccination: WHO Report

The first malaria vaccine approved for human use — RTS,S/AS01 — got the nod of the European regulators in July 2015 but has not been as successful as hoped with marginal efficacy that wanes over time.

The new research is aimed at improving malaria vaccine design.

“The protein used in the RTS, S vaccine mimics one of the proteins we’ve been studying on the surface of the malaria parasite that is readily recognised by the immune system,” Ethan Goddard-Borger from Walter and Eliza Hall Institute said.

“With this study, we’ve shown that the parasite protein is tagged with carbohydrates, making it slightly different to the vaccine, so the antibodies produced may not be optimal for recognising target parasites.”

“It may be that a version of RTS, S with added carbohydrates will perform better than the current vaccine,” he said, adding that there were many documented cases where attaching carbohydrates to a protein improved its efficacy as a vaccine. (IANS)

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Will Polio Workers Step Out of Their Comfort Zones to End Virus?

What's more, the border between Afghanistan and Pakistan stretches for more than 2,000 kilometers. Thousands of people who cross this very porous border can easily transmit the virus in both countries.

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Polio
Widespread unrest in Afghanistan has kept thousands of children from receiving polio vaccines this year. Conflict in northern Nigeria does the same. VOA

The move to end Polio started in 1985 with Rotary International. At that time, polio paralyzed hundreds of thousands of children every year. There is still no cure, but two scientists developed vaccines against the virus in the 1950’s.

Dr. Jonas Salk produced one with an inactivated virus that could protect against polio without spreading the disease. Later, Dr. Albert Sabin developed an oral vaccine with weakened strains of the virus.

In 1988, public and private groups joined the effort in the Global Polio Eradication Program. Members included governments, the World Health Organization, the United Nations Children’s Fund (UNICEF), Rotary International, the U.S. Centers for Disease Control and Prevention (CDC) and the Bill and Melinda Gates Foundation.

Since then, the number of polio cases has dropped by 99.9 percent. Last year, 22 children were crippled by this disease. The wild polio virus exists in only three countries: Pakistan, Afghanistan and Nigeria, but it’s still a global threat.

Dr. John Vertefeuille, from the CDC said, “This last mile is a complicated mile.” It’s not just because of conflict or terrorism. “It’s extreme remoteness. It’s very fragile health systems.” And in these remote conflict prone areas gaining access to children can be a major problem.

If polio exists anywhere, it can once again spread everywhere.

Polio
In many places the vaccinators are women because women can go into the homes, talk to other women and gain access to the children. Wikimedia

Vertefeuille and other experts discussed strategies to realize a polio-free world July 10 at the Center for Strategic and International Studies in Washington.

Widespread unrest in Afghanistan has kept thousands of children from receiving polio vaccines this year. Conflict in northern Nigeria does the same.

What’s more, the border between Afghanistan and Pakistan stretches for more than 2,000 kilometers. Thousands of people who cross this very porous border can easily transmit the virus in both countries.

While the funding and technical support has to come from large, private-public partnerships, immunization teams succeed best if they are local. Approaches have to take culture and customs into consideration.

In many places the vaccinators are women because women can go into the homes, talk to other women and gain access to the children.

Elsewhere, soldiers vaccinate children when they take over an area run by anti-government forces. Vaccination teams have to be prepared to move quickly when there is a lull in the fighting and to deliver multiple doses of vaccine in a short period of time.

Polio
Community volunteers are a great resource. Some get cell phones so they can alert health officials if a child becomes paralyzed. VOA

Surveillance is just as critical. To end polio, you have to know where the outbreaks are. Community volunteers are a great resource. Some get cell phones so they can alert health officials if a child becomes paralyzed.

Another challenge is getting children in migrant groups vaccinated. Vertefeuille says this is where technology helps. The CDC uses satellites to see where people have moved and what areas are abandoned. Clues are where structures have been repaired, where the grass grows on roads, indicating abandoned areas, and where it doesn’t, indicating where people are living.

Dr. Andrew Etsana from the International Federation of Red Cross and Red Crescent Societies said these groups present a particular challenge because “you have people moving with a virus and it is difficult to track them and vaccinate the vulnerable children in this mobile population.”

Another issue is the nature of viruses themselves. Viruses mutate. So far, the polio vaccines have been effective, but if not enough children get vaccinated, the virus can change, and perhaps make the vaccine less effective. That’s why every child needs to be vaccinated.

Outbreaks that can be avoided by vaccinating the whole population so that there are no gaps for the mutated virus to slip through.

International experts are working with local leaders to close this gap.

Another issue is complacency. Etsana said, “People are getting tired. The program has been going on. They thought it would have ended.”

Rotary has pledged to continue its support, other groups as well. International support and funding is critical to ending polio, but after three decades, many people have never seen polio. Etsana says he sees complacency creeping into all areas of the program. “The funders of the program are also getting tired. The fund is drying up and if the fund dries up and the job is not done, we’re going to have a major problem. We may have reinfection.”

Also Read-After Three Years Struggle, WHO Declares Somalia Polio Free

But, if people recognize the program’s value – it has united communities, established vaccine centers, created partnerships never before imagined – the world can not only end polio, but tackle other diseases as well. The polio program is widely credited with stopping the spread of Ebola in Nigeria while the disease ravaged other west African countries. (VOA)