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→Clinical Signs
===Clinical Signs===
===Clinical Signs===
The onste of disease due to ''Dirofilaria immitis'' is insidious, and clinical sign are related either to a high parasite burden, or to an allergic response to the parasite<sup>2</sup>. Signs often only manifest during exercise, and so patients with a sedentary lifestyle may never show overt disease.
The onset of disease due to ''Dirofilaria immitis'' is insidious, and clinical signs are related either to a high parasite burden, or to an allergic response to the parasite<sup>2</sup>. Signs often only manifest during exercise, and so patients with a sedentary lifestyle may never show overt disease. Affected dogs most often show coughing, and dyspnoea/tachypnoea, exercise intolerance, loss of condition and syncope may also be seen. In severe cases the pulmonary vessels may rupture, leading to haemoptysis. If right-sided congestive heart failure ensues, signs can incluse jugular disension, ascites, marked exercise intolerance and hepatomegaly, possibly with a systolic murmur audible on cardiac auscultation.
In dogs, infection should be identified by serologic testing prior to the onset of clinical signs; however, it should be kept in mind that HW antigenemia and microfilaremia do not appear until ~5 and 6.5 mo postinfection, respectively. When dogs are not administered a preventative and are not appropriately tested, clinical signs such as coughing, exercise intolerance, unthriftiness, dyspnea, cyanosis, hemoptysis, syncope, epistaxis, and ascites (right-sided CHF) are likely to develop. The frequency and severity of clinical signs correlate to lung pathology and level of patient activity. Signs are often not observed in sedentary dogs, even though the worm burden may be relatively high. Infected dogs experiencing a dramatic increase in activity, such as during hunting seasons, may develop overt clinical signs. Canine HW disease can be classified by physical examination, thoracic radiographs, urinalysis, and PCV.
Caval syndrome represents a severe form of heartworm
Caval syndrome represents a severe form of heartworm
disease both in dogs and cats. This is characterised
disease both in dogs and cats. This is characterised
frequently, disseminated intrav ascular coagulaktion1.
frequently, disseminated intrav ascular coagulaktion1.
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Although the majority of infected cats are asymptomatic,
cases of sudden death without any premonitory
clinical signs have been reported. Sometimes, the sudden
death is preceded by an acute respiratory crisis, probably
due to a parasitic embolism and obstruction of a major
pulmonary artery. When present, clinical signs of heartworm
disease in cats are generally vague and non-specific.
These may include anorexia, lethargy, coughing, vomiting,
dyspnoea, syncope and collapse. In some cases, the respiratory
signs are very similar to those generally observed in
feline asthma.
nfected cats may be asymptomatic or exhibit intermittent coughing, dyspnea, vomiting, lethargy, anorexia, or weight loss. The symptoms often resemble those of feline asthma. In general, signs are most prevalent during periods when worms die, including when young adult worms arrive in the lungs. Antigen tests in cats are negative during the early eosinophilic pneumonitis syndrome, although antibody tests may be positive. Subsequently, clinical signs often resolve and may not reappear for months. Cats harboring mature worms may exhibit intermittent vomiting, lethargy, coughing, or episodic dyspnea. HW death can lead to acute respiratory distress and shock, which may be fatal and appears to be the consequence of pulmonary thrombosis.
nfected cats may be asymptomatic or exhibit intermittent coughing, dyspnea, vomiting, lethargy, anorexia, or weight loss. The symptoms often resemble those of feline asthma. In general, signs are most prevalent during periods when worms die, including when young adult worms arrive in the lungs. Antigen tests in cats are negative during the early eosinophilic pneumonitis syndrome, although antibody tests may be positive. Subsequently, clinical signs often resolve and may not reappear for months. Cats harboring mature worms may exhibit intermittent vomiting, lethargy, coughing, or episodic dyspnea. HW death can lead to acute respiratory distress and shock, which may be fatal and appears to be the consequence of pulmonary thrombosis.