How old is Trixie? Has she had all her shots?
Puppies are most vulnerable to parvo. They get immunities from nursing which interfere with vaccinations if they are started to soon.
In one study of a cross section of different puppies the age at which they were able to respond to a vaccine and develop protection covered a wide period of time. At six weeks of age, 25% of the puppies could be immunized. At 9 weeks of age, 40% of the puppies were able to respond to the vaccine. The number increased to 60% by 16 weeks, and by 18 weeks of age, 95% of the puppies could be immunized. Parvovirus: Serious Diarrhea in Puppies & Dogs
If Trixie is older, fully vaccinated at the proper age and you take reasonable precautions to keep her away from infected areas, you should be okay.