BABIES whose mothers have both HIV and malaria are more at risk from malaria
than if their mother had malaria alone. HIV seems to weaken the protection
against malaria that mothers would otherwise transfer to their children.
午夜福利1000集合 researchers warn that the interaction between these two major threats
to health will complicate efforts to fight both diseases in sub-Saharan Africa.
鈥淢others, when they become pregnant, suddenly get horribly susceptible to
malaria. It鈥檚 a very big question as to why,鈥� says Ora Lee Branch of the
parasitic diseases division at the Centers for Disease Control and Prevention
(CDC) in Atlanta, Georgia. And new evidence suggests that HIV reduces the
protective antibodies against malaria that a mother passes to her baby.
Branch and her colleagues studied HIV and malaria in 209 mothers and their
infants at the Nyanza Provincial General Hospital in Kisumu, Kenya. They looked
at the number of malaria parasites in the placenta, because pregnant women with
small numbers of parasites in their bloodstream can sometimes have many more
lurking in placental tissues. They also measured levels of the maternal
antibodies against malaria that normally pass into the fetal bloodstream and
then linger for months after the baby鈥檚 birth, protecting the infant while its
own immune system matures.
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Women with HIV had lower levels of antibodies against malaria. 鈥淭hey have
less antibody, and the little bit they have isn鈥檛 getting across the placenta,鈥�
says Branch.
To find out why the placenta seems so affected by HIV, Venkatachalam
Udhayakumar, also of the CDC , and his colleagues took blood cells from the
placentas of both HIV-positive and HIV-negative women. They wanted to see how
well these cells could produce immune system signals when confronted with
foreign agents such as malaria parasites.
They found that the cells from HIV-positive women produced smaller
amounts of the signalling chemical called interferon, which is thought to help
protect the placenta against malarial infection.
Branch鈥檚 group is now investigating whether children born to HIV-infected
women with malaria die more frequently from malaria than children born to women
with malaria alone. A study a few years ago suggested that infants whose mothers
have both HIV and malaria are more than four times as likely to die early as
those whose mothers only had malaria.
鈥淭here are a lot of important public health implications,鈥� says Udhayakumar.
Infants of mothers infected with HIV and malaria may need to be given
anti-malaria drugs. Branch points out that a lot of attention has been paid to
preventing babies acquiring HIV at birth. Now public health officials have to
consider that those children may still be at increased risk even if they escape
the virus. 鈥淛ust giving the mother AZT and letting her go is not enough,鈥� says
Branch.
