OFFICIAL NASA HEADQUARTERS PRESS RELEASE


Michael Braukus
Headquarters, Washington, D.C.                          
                          July 26, 1994
(Phone:  202/358-1979)

Diane Farrar 
Ames Research Center, Mountain View, Calif.
(Phone:  415/604-9000)


RELEASE:  94-123

NASA USES SATELLITE DATA TO DETECT LYME DISEASE RISK

     Scientists at NASA's Ames Research Center,
Mountain View, Calif., and the New York Medical College
(NYMC) in Valhalla, N.Y., are using satellite remote
sensing and computer technology to predict the risk of
Lyme disease transmission.

     "We have successfully used satellite imagery to
identify specific types of suburban areas in
Westchester County, New York, where the risk of
exposure to  Lyme disease is high," said Sheri Dister,
a research scientist.  Dister, with  Byron Wood and
Louisa Beck, all employees of Johnson Controls World
Service, Inc., collaborate on the project at Ames.

     The NASA team, with Dr. Durland Fish of NYMC and
Westchester County Health Department investigators,
combined Landsat imagery and Geographic Information 
System (GIS) technology, which uses layers of maps to
display spatial  relationships to map landcover for all
of Westchester County to identify  types and placement
of landscape elements associated with Lyme disease
risk.
 
     They found that the higher the proportion of
vegetated residential area next to woods within a
municipality, the higher the transmission risk.  It has 
been reported that 69 percent of the deer tick bites in
Westchester County  are acquired by people near their
homes.

     Lyme disease is transmitted to humans by infected
deer ticks.  It is now the most commonly reported
vector-borne (transmitted by a variety of insects and 
ticks) disease in the United States.  When untreated,
it can result in  debilitating arthritis, and
neurological and cardiac disorders.
 
     "Knowing where the risk of Lyme disease occurs is
the first step in  prevention -- whether behavioral,
spraying for ticks, or vaccination," Fish  said.

     "This new method of getting information has given
us a complete picture of the high risk areas throughout
the county, without sending teams of people  into the
field," he said.  Westchester County covers more than
450 square  miles.

     The preliminary study used rates of Lyme disease
antibodies in the blood of domestic dogs as a measure
of exposure risk.  Dogs exposed to tick bites  produce
specific antibodies to Lyme disease.  The dogs'
infection rate can  indicate the risk of Lyme disease
transmission in these areas.
  
     NYMC scientists analyzed the percentage of sampled
dogs testing positive for Lyme disease in each
municipality of Westchester County.  Antibody rates 
increased, they found, from south to north as the
character of the  countryside changed from urban to
rural.

     The Ames scientists used Landsat data to
characterize this urban-to-rural transition in terms of
different types of residential areas and vegetation
important for ticks and their hosts.

     Overlaying the canine data onto the landscape map
showed a significant correlation between the canine
exposure rate and the proportion of vegetated 
residential areas located next to woods.  Residential
areas not adjacent to  woods did not show this same
pattern, indicating the importance of the  surrounding
landscape in mapping residential risk of Lyme disease.
 
     "We found that remote sensing and GIS technologies
can be used to map  landscape elements for large areas
and relate them to Lyme disease risk.  We  are now
looking at residence-level field data in relation to
the satellite  data to see if we can find a similar
pattern at this finer scale," Dister  said.

     The team is working to develop a predictive model
that can be applied to other regions of the Northeast
similar to Westchester County.

     Earlier this year, the U.S. Centers for Disease
Control issued a report that suggested using innovative
tools for surveillance of emerging and re-emerging 
infectious diseases in the U.S. 

     "This particular innovative approach shows the
significant contribution NASA can make in the
surveillance and prediction of emerging diseases," said
Dr.  Joan Vernikos, director of NASA's Life and
Biomedical Sciences and  Applications Division at NASA
Headquarters, Washington, D.C.  The division,  through
its Global Monitoring and Disease Prediction Program,
supports the  use of remote sensing and GIS
technologies in public health applications. 

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