Sunday November 17, 2019

World Health Organization: “Historic Step” towards Polio-Free World

Global polio cases have been cut by more than 99% since 1988, but type 1 polio virus is still endemic in Pakistan and Afghanistan

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Afghan women wearing burqas from a polio immunization team walk together during a vaccination campaign in Kandahar, Oct. 15, 2019. Polio immunization is compulsory in Afghanistan, but distrust of vaccines is rife. VOA

The World Health Organization welcomed an “historic step” towards a polio-free world on Thursday as an expert panel certified that the second of three types of the crippling virus has been eradicated globally.

The announcement by the Global Commission for the Certification of Poliomyelitis Eradication means that only wild polio virus type 1 is still circulating, after type 2 was declared eradicated in 2015, and type 3 this week.

Global polio cases have been cut by more than 99% since 1988, but type 1 polio virus is still endemic in Pakistan and Afghanistan, where it has infected a total of 88 people this year. That is a resurgence from a record low global annual figure of 22 cases in 2017.

“The eradication of wild polio virus type 3 is a major milestone towards a polio-free world, but we cannot relax,” said Matshidiso Moeti, the WHO regional director for Africa.

World, Health, Historic
The announcement by the Global Commission for the Certification of Poliomyelitis Eradication means that only wild polio virus type 1 is still circulating, after type 2 was declared eradicated. Pixabay

Seth Berkley, chief executive of the GAVI vaccine alliance, said it was “a tremendous victory in the fight against polio.”

Polio invades the nervous system and can cause irreversible paralysis within hours. It cannot be cured, but infection can be prevented by vaccination – and a dramatic reduction in cases worldwide in recent decades has been due to intense national and regional immunization campaigns in babies and children.

In unvaccinated populations, however, polio viruses can re emerge and spread swiftly. Cases of vaccine-derived polio can also occur in places where immunity is low and sanitation is poor, as vaccinated people can excrete the virus, putting the unvaccinated at risk.

The Philippines last month said it was planning an emergency vaccination campaign after polio re-surfaced and caused the first two recorded polio cases there for 20 years.

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Moeti urged governments to be vigilant: “Countries must strengthen routine immunization to protect communities, ramp up routine surveillance so that we are able to detect even the slightest risk of polio re-emerging,” she said in a statement. (VOA)

Next Story

Immune Cells Become Active and Repair Brain While Sleep: Study

For the findings, researchers conducted the study on mice

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Study suggests that the enhanced remodeling of neural circuits and repair of lesions during Sleep may be mediated in part by the ability of microglia to dynamically interact with the Brain. Pixabay

Researchers have found that immune cells called microglia, which play an important role in reorganising the connections between nerve cells, fighting infections, and repairing damage, are also primarily active while we sleep.

Microglia serve as the brain’s first responders, patrolling the brain and spinal cord and springing into action to stamp out infections or gobble up debris from dead cell tissue.

“This research shows that the signals in our brain that modulate the sleep and awake state also act as a switch that turns the immune system off and on,” said study lead author Ania Majewska, Professor at University of Rochester in the US.

In previous studies, Majewska’s lab has shown how microglia interact with synapses, the juncture where the axons of one neuron connects and communicates with its neighbours.

The microglia help maintain the health and function of the synapses and prune connections between nerve cells when they are no longer necessary for brain function.

For the findings, researchers conducted the study on mice.

The current study points to the role of norepinephrine, a neurotransmitter that signals arousal and stress in the central nervous system.

This chemical is present in low levels in the brain while we sleep, but when production ramps up it arouses our nerve cells, causing us to wake up and become alert.

The study showed that norepinephrine also acts on a specific receptor, the beta2 adrenergic receptor, which is expressed at high levels in microglia.

When this chemical is present in the brain, the microglia slip into a sort of hibernation.

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Researchers have found that immune cells called microglia, which play an important role in reorganising the connections between nerve cells, fighting infections, and repairing damage, are also primarily active while we Sleep and affects Brain. Pixabay

The study, which employed an advanced imaging technology that allows researchers to observe activity in the living brain, showed that when mice were exposed to high levels of norepinephrine, the microglia became inactive and were unable to respond to local injuries and pulled back from their role in rewiring brain networks.

“This work suggests that the enhanced remodeling of neural circuits and repair of lesions during sleep may be mediated in part by the ability of microglia to dynamically interact with the brain,” said study first author Rianne Stowell.

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“Altogether, this research also shows that microglia are exquisitely sensitive to signals that modulate brain function and that microglial dynamics and functions are modulated by the behavioural state of the animal,” Stowell said.

The study was published in the journal Nature Neuroscience. (IANS)