Sunday November 17, 2019

World Health Organization Says First Local Case of Polio Found in Zambia Since 1995

The U.N. health agency said there is no established link between the Zambia case and the ongoing Congo outbreak

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World, Health, Polio
FILE - A Congolese child is given a polio vaccination at a relief camp near Gisenyi, Rwanda, Jan. 25 , 2002. The WHO says Zambia has reported its first local case of polio since 1995 in a 2-year-old boy paralysed by a virus derived from the vaccine. VOA

The World Health Organization says Zambia has reported its first local case of polio since 1995, in a 2-year-old boy paralyzed by a virus derived from the vaccine.

In a report this week, WHO said the case was detected on the border with Congo, which has reported 37 cases of polio traced to the vaccine this year. The U.N. health agency said there is no established link between the Zambia case and the ongoing Congo outbreak but said increased surveillance and vaccination efforts are needed, warning that “there is a potential for international spread.”

In rare cases, the live virus in oral polio vaccine can mutate into a form capable of sparking new outbreaks.

Nine African countries are currently battling polio epidemics linked to the vaccine as WHO and partners struggle to keep their efforts to eradicate polio on track. Elsewhere, cases have been reported in China, Myanmar and the Philippines.

World, Health, Polio
In a report this week, WHO said the case was detected on the border with Congo, which has reported 37 cases of polio traced to the vaccine this year. Pixabay

On Thursday, WHO and partners are expected to announce they have rid the world of type 3 polio virus.

There are three types of polio viruses. Type 2 was eliminated years ago. That now leaves only type 1. But that refers only to polio viruses in the wild. Type 2 viruses continue to cause problems since they are still contained in the oral polio vaccine and occasionally evolve into new strains responsible for some vaccine-derived outbreaks.

The global effort to eradicate polio was launched in 1988 and originally aimed to wipe out the potentially fatal disease by 2000. While cases have dropped dramatically, the virus remains stubbornly entrenched in parts of Pakistan and neighboring Afghanistan. This year there have been 72 cases of polio in Pakistan after only eight in 2018.

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In meeting notes from an expert polio oversight board in September, WHO’s Michel Zaffran said the status of eradication was “of great concern,” noting the Taliban’s ban on house-to-house vaccination in Afghanistan. Officials described the program in Pakistan as a “failing trajectory.” (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.

Sleep
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)