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Entries in Transmission (2)

Thursday
Jun142012

Breast Milk Blocks HIV Transmission in Mice, Study Finds

George Doyle/Thinkstock(CHAPEL HILL, N.C.) -- Women with HIV are often told by health care providers to refrain from breastfeeding for fear their breast milk will transmit the virus to their infants. But a new study released Thursday in the journal PLoS Pathogens suggests breast milk may kill the virus and protect against its transmission.

The study was done on mice, adding to the growing confusion as to whether it’s ever safe for women with HIV to breastfeed.

Researchers at the University of North Carolina School of Medicine fed mice whose immune systems had been engineered to mimic those of humans breast milk from healthy human donors that had been injected with HIV.

The researcher found that the virus could not be transmitted to the mice through the breast milk, and that the virus died when it entered the breast milk.

“We reinforced the belief, and we have solid data that milk is not a vehicle for transmission but may offer protection,” said Victor Garcia, a professor of medicine at the University of North Carolina, and a co-author of the study. “Milk should not be withheld from children.”

More than 15 percent of new HIV infections occur in children, according to the World Health Organization. If untreated, only 65 percent of HIV-infected children will live to see their first birthdays, and fewer than half will make it to the age of 2, WHO estimates.

For years, HIV experts have linked the virus in babies to breastfeeding. But most infants who are breastfed by HIV-infected mothers, even for long periods of time, do not become infected.

WHO recommends that infected mothers in some countries breastfeed their infants, and that both mother and infant take antiretroviral medication to avoid HIV transmission.

“One of the big breakthroughs of having this model is to look at what is affecting transmission,” said Garcia. “If milk isn’t it, then how is it being transmitted?”

Garcia said one way to answer that question might be to learn what it is in breast milk that kills the HIV and study whether it can be used to protect against other forms of transmission.

But the findings don’t mean that infected mothers should breastfeed their children without taking antiretroviral medications just yet, Garcia said. Future studies will look at milk from infected donors to see if the outcome will be the same, he said.

“Milk itself has an inhibitory effect,” said Garcia. “But from what we know so far, it seems like there won’t be a big difference.”

Copyright 2012 ABC News Radio

Wednesday
Jun152011

Is 'Risk Zone' Reduction Key to Understanding Disease Spread?

Digital Vision/Thinkstock(CANBERRA, Australia) -- The great increase in plane travel in the past 60 years has increased the spread of infectious diseases around the world.  A great example is the 2009 H1N1 flu pandemic.  How likely an infection will spread on a plane is dependent on many factors, including the type of virus, the length of the flight and how much passengers and crew move around.  Usually, the infectious “risk zone” for the flu is about two rows of seats on either side of the infected passenger.  But a new study from the Department of Health and Ageing in Australia suggests that the risk zone may be smaller than previously thought.
 
The authors analyzed the transmission of the H1N1 flu from surveys and infection records of passengers on two international flights to Australia in 2009.  

Turns out that people seated in the two-row area around an passenger known to have had flu symptoms before the flight were only at a 3.6 percent greater risk of catching the infection.  However, when the authors looked at passengers seated in a smaller area around the infected person -- two seats in front, two seats behind and two seats on either side -- they found that those passengers were at 7.7 percent greater risk of catching the flu.  

Therefore, reducing the area of the “risk zone” could improve the efficiency of tracing disease spread and identifying potentially exposed patients without compromising the effectiveness of public health interventions.

Copyright 2011 ABC News Radio







ABC News Radio