VOA常速英语:Climate, Brain Infection Linked in Uganda

Scientists say they have found the first major neurological condition linked to climate. A Ugandan study shows the amount of rainfall can affect the number of infants who develop a deadly brain infection. It’s estimated 100-thousand infants in sub-Saharan Africa get the infection every year.

It’s called Hydrocephalus -- a build-up of fluid that leads to a swelling of the brain and an enlarged head. Dr.  Steve Schiff, director of the Center for Neural Engineering at Penn State University, said that without treatment it can cause brain damage or death.

“Hydrocephalus is literally a medical word that means water on the brain. It is the most common reason that a child would need to have neurological surgery,” he said.

A small amount of fluid surrounding the brain is normal.

“We produce about a cup of fluid a day and it bathes and cushions our brains. And every drop we make has to be taken out of the head by the body. And there are tiny, little fluid channels that allow that to happen,” he said.

Unless, that is, something goes wrong.

Schiff said, “One of the reasons children get in trouble with this is that they have an infection and the inflammation plugs up the small channels that the fluid needs to exit through. Or they might have some bleeding at the time of birth and that blood can also plug up these channels. And then sometimes children are born with some channels that are not formed correctly.”

The blockages trigger an infection. Schiff says the most common treatment has been to insert a tube to drain fluid from the brain to the stomach. The body can then absorb and later eliminate it.  However, sometimes the tubes themselves can become blocked. If that happens, the child needs immediate medical care.

To prevent that, scientists, led by Harvard neurosurgery associate professor Benjamin Warf, developed a new technique. Using a scope to peer inside the head, doctors can make a very small opening to allow the fluid to drain without the use of a plastic tube. Schiff says it was a major advancement.

“This is very helpful in settings where a child might be very far removed to get to a hospital for any kind of emergency care,” he said.

However, he says treating or preventing the infection through a surgical technique is just part of the solution.

“We have two missions here,” he said, “First, we have to know what the organisms are. Because we have to make sure when we start treatment that that treatment is exactly the right antibiotic for the germs that are likely to be causing the infection. The second piece is, that long term, we need to know not only what the germs are, but we need to know how the infants got the organisms.”

Here is where medical and climate research came together. Ugandan hospital records of hydrocephalus were compared with rainy season satellite data collected by the U.S. National Oceanic and Atmospheric Administration or NOAA.

“In the hospital records we knew where the babies came from because their districts were all listed in the records. And when we looked at both the climate rainfall amounts for each month and the number of cases from each district for each month we saw very clearly that these babies were coming in larger numbers to the hospital when the rainfall was not too much, not too little, but just in the middle – just moist enough to affect the infants’ environment,” he said.

That’s when conditions are just right for bacterial growth that can lead to hydrocephalus.

Schiff said, “The complexities of the environment that infants are exposed to in Africa are unlike anything that we have had to deal with in the industrialized countries. And this is a major scientific and intellectual challenge that we have to do with our African colleagues in order to address what is indeed preventable.”

Schiff added that bacteria that cause hydrocephalus in one region may not be the same as in another region of Africa or Asia. So research needs to be tailored geographically to possibly find ways to disrupt the environmental mechanisms that trigger bacterial growth.