1. Jason Soderberg and Sam Rawson

2.  Phylum: Nematoda  Class: Secernentea  Sub-class: Spiruria  Order: Spirurida  Family: Dirofilaria immitis

3. World-wide but very common in mild to warm climates (where mosquitoes thrive)

4.  Definitive Host:  Dogs, coyotes, wolves, cats  Others that can be infected: humans, beavers, and horses  Intermediate Host:  Mosquito (Anopheles, Aedes, Mansonia and Culex spp)

5.  Adult:  Females 230-310mm long by 0.35mm  Male 120-190mm long by.300mm  Microfilariae  307-322µm by 6.8µm (no egg)  Larva  4 molts total

7.  Mosquito introduces L3 filarial larvae into skin of DH  L3 molts into L4 and then again into adult form  (in the subcutaneous tissue, takes 1-3 days)  Adults reside in pulmonary arteries and right ventricle of the heart  Adults can live for 5-10 years

8.  In the heart the female is capable of producing microfilariae (pre-larval stage)  Microfilariae are then pumped into the peripheral blood  Mosquito ingests microfilariae during blood meal  Microfilariae migrate to the mosquito’s midgut and develop into L1 and molt until L3

9.  In humans larvae generally move through the right ventricle to the lungs  They often then lodge in small-caliber vessels causing infarcts and typical “coin lesions” visible on radiographs  Forms a granuloma in lung and might resemble lung cancer on an x-ray (requiring biopsy)

10.  Based on severity of infection, age of infection, and host’s immune response  Early stages- host may appear asymptomatic  Mild to moderate disease may include chronic cough, dyspnea, and exercise intolerance  Disease progression: congestive heart failure

11.  Death may occur during cardiac hypertrophy  Due to microfilarial thrombi  Pulmonary vessels may become thickened and tortuous  Cardiac output may be reduced  Caval syndrome has been reported  Worms found in the post cava and right atrium causing interference of tricuspid valve ▪ leads to hemolytic anemia and right heart failure  Rarely systemic circulation or infection of the eye, CNS, or peritoneal cavity

12.  Blood tests:  Antigen tests  ID of microfilariae on wet blood smear  ID of heart enlargement on radiographs

13.  Injections of melarsomine dihydrochloride into lumbar muscles  1 injection  After 4 weeks, 2 more injections (24hrs apart)  Exercise must be limited for a month after each injection  Decreases the chance of pulmonary complications  Prophylactic dose of Ivermectin will eliminate microfilariae

14.  Test dog once a year for heartworms (blood test)  Heartgard preventative given once a month (contains ivermectin)

15.  What are the definitive and intermediate hosts?  Where is Dirofilaria immitis most commonly found?  How much damage can it cause in humans?  What disease does it cause?

16.  http://www.vet.uga.edu/vpp/clerk/Lobeck/ind ex.php http://www.vet.uga.edu/vpp/clerk/Lobeck/ind ex.php  http://www.capcvet.org/capc- recommendations/canine-heartworm http://www.capcvet.org/capc- recommendations/canine-heartworm  http://bioweb.uwlax.edu/bio203/s2007/eddy_ greg/habitat.htm http://bioweb.uwlax.edu/bio203/s2007/eddy_ greg/habitat.htm