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[IP] Diabetics may be more susceptible to flu
NEW YORK, Aug 05 - Diabetics may be particularly susceptible to some
strains of the flu, according to a study in the August issue of the Journal of
People with diabetes tend to get sicker, are more likely to develop pneumonia,
and run a higher risk of dying once they are infected with the influenza virus,
previous studies have shown.
To determine whether having diabetes increases a person's odds of getting
infected to begin with, the study's authors ran a number of tests on healthy
The authors first inoculated the mice with a common strain of influenza virus,
waited a day, and then checked the extent to which the virus had proliferated
the animals' lungs. After 24 hours, the diabetic mice had 10 times as much
their lungs as the healthy mice, "indicating a deficiency in some aspect of
immunity,'' report the authors, a team of researchers headed by Dr. Patrick C.
Reading of the University of Melbourne in Australia.
Viral levels were highest in the lungs of the diabetic mice that had the
highest levels of glucose in their blood at the time they were inoculated,
Reading and colleagues found.
But when the researchers gave the diabetic mice insulin - to lower their blood
glucose levels - then inoculated them with the virus, waited 3 days and
measured viral proliferation, they found the animals had no more virus in their
lungs than healthy mice.
The researchers found similar results when they inoculated healthy and diabetic
mice with a second strain of influenza virus. Once again, the diabetic animals
had higher levels of the virus in their lungs than the healthy mice.
But Reading and colleagues found no difference in extent of viral proliferation
in the lungs of healthy and diabetic mice when they inoculated the animals with
a third strain of the virus. Unlike the other two strains, this strain is
resistant to a class of immune system proteins called collectins, Reading and
This finding is significant, because previous research suggests that glucose
can bind to and interfere with the activity of a collectin called lung
surfactant protein D (SP-D), the researchers write. Consequently, diabetics may
be more susceptible to SP-D responsive strains of the influenza virus because
the high glucose levels in their blood inactivate SP-D.
"The results of the present study suggest that susceptibility to influenza
virus infection itself may also be higher for diabetic than for nondiabetic
individuals, due to compromise of their collectin-mediated host defenses,''
Reading and colleagues conclude.
SOURCE: Journal of Virology 1998;72:6884-6887.
Insulin-Pumpers website http://www.bizsystems.com/Diabetes/