(March 26, 2018 at 10:58 am)Mermaid Wrote:(March 25, 2018 at 10:56 pm)Minimalist Wrote: But, depending on the timing of the infection, you can get a dog who has adult worms which have not reached sexual maturity and thus not laid eggs. That was the situation we had with our second Korean dog, Jessica. They skipped the first two months of Heartguard and went right to the Immiticide. We had them double check with the microscope for microfilaria and they weren't there.... yet.How was she diagnosed? Antigen test? That test detects products of the female worm.
Yes, but. And the but comes in because of the previously mentioned Valley Fever issue which also uses an antigen test. After some weird test results - VF can be fatal - we started investigating the tests. Finding stuff like this does not do much to reassure us.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4336501/
Quote:False negative antigen tests in dogs infected with heartworm and placed on macrocyclic lactone preventives
Quote:Together, these data indicate that antigen tests may not be a reliable indicator of heartworm antigen status in D. immitis-infected dogs managed with SK; over half the dogs which converted to antigen negative were actually still antigen positive following treatment of serum to disrupt immune complexes.
I've seen studies where some vets only consider antigen tests 70% reliable. Troubling.
