Dirofilaria infection

2. Infects – dogs, cats, foxes, wolves, rarely horse & human
Transmitted by-mosquito bite
transmission in warmer months
Zoonotic potential
Aetiology
D.Immitis
D.repens

5. PATHOGENES
 Microfilaria are ingested by mosquitoes
 Development takes place in their body cavity
 Infective larvae enter sub cutis & muscle through bite
 Later they enter the veins &reach right ventricle
 Resulting in incompetence of tricuspid valve

6. Chronic disease
More commonly affected
than cats
Clinical picture very
typical
Predictable disease
Acute symptoms
Sometime chronic
disease
No typical symptoms
Unpredictable disease

7. CLINICAL SIGNS
Early Infection Little or no abnormal clinical
indicators observed
Mild Disease Cough
Moderate Disease Cough,
irregular lung sounds,
anaemia,proteinuria
Severe Disease Cough, exercise intolerance,
dyspnea, irregular lung sounds,
hepatomegaly, syncope, ascites,
defective heart sounds, loss of life

8. MACROSCOPIC FEATURES
 Chronic venous congestion of liver, spleen, lungs
 Ascites
 Pulmonary vessels thickened & tortuous
 Hypertrophy of right ventricle & arteries
Thrombosis Proliferative endarteritis

9.  coin lesions
 Human dirofilariasis-nodules in lungs
 Caval syndrome
Sudden rising of pulmonary pressure (thromboembolism)
HW displacement from PA to right ventricle
3 main symptoms :
•Dyspnoea
•Cardiac murmur
•Haemoglobinuria

10. MICROSCOPIC FEATURES
 Parasite causes endothelial damage of PA
 Dead worms form emboli & pulmonary infarctions
 Worms in pulmonary artery cause fibrosis of intima
 If microfilaria dies-small foci of granulomatous
inflammation occurs

11. Alveoli
HW infection
Proliferative endarteritis in a dog death for
thromboembolism

12. DIAGNOSIS
• Demonstration of microfilaria in peripheral blood
• ELISA
• Indirect IFA
• Radiography
• Echocardiography
• Electrocardiography
• Laboratory tests
• PCR based tests
• Specific agglutination &immune chromatography
tests

13. Treatment
 Cage rest before treatment
 Anti inflammatory doses of corticosteroid
 Anti thrombic drugs
 Melarsomine dihydrochloride-I/M
 Ivermectin-prevent further infection
 Surgery-in case of caval syndrome
 Mosquito bed net
 Milbemycin, Oxime-remove microfilaria from circulation