Feline Heartworm Disease is a serious condition caused by the parasite Dirofilaria immitis, which primarily affects cats. The disease is transmitted through the bite of an infected mosquito, leading to the presence of heartworms in the cat's heart and lungs. Symptoms may include coughing, difficulty breathing, and lethargy, but some cats may show no signs at all. Diagnosis typically involves blood tests and imaging to detect the presence of heartworms. Treatment can be challenging and may require hospitalization. Preventive measures, such as monthly medications, are essential to protect cats from this potentially fatal disease.