This is Mabel. She is a sweet, lovable, 2 year old pit bull mix who was adopted from the local humane society. Mabel is also heartworm positive.
When Mabel was adopted she was heartworm negative, but six months later it was discovered she had heartworms. How is this possible? The current heartworm antigen tests only detect adult heartworms. It can take up to 6 months for microfilaria or baby heartworms to migrate from the mosquito bite to the heart and mature into adults. Therefore, there is a small window where a dog can test negative for heartworms, but still have microfilaria.
Mabel is heartworm positive. What do we do now? Mabel was placed on monthly heartworm prevention to kill any microfilaria. She was also placed on Doxycycline, an antibiotic used to kill a bacteria called Wolbachia that is associated with heartworms and can cause complications with heartworm treatment. Once completing this treatment, Mabel was given 3 injections of Immiticide over the course of a month. Immiticide is an injectable substance that kills adult heartworms. This injection is painful and Mabel was given opioid injections and anti-inflammatory medication. Over the next 4-6 weeks Mabel will need to be confined and kept calm.
Excessive exertion or strenuous exercise can cause sudden disruption of the adult heartworms. This disruption can cause pulmonary thromboembolism and death. Mabel will be retested in 4 months to ensure that all adult heartworms have been killed.