240 
PULMONARY MODELS 
Figure 4. — Pulmonary artery from a cat infected with 
T. cati for 74 weeks. An endarteritis and a marked 
thickening of the tunica media. H and E stain ; x 160. 
Group III, T. canis. The lesions in the pul- 
monary arteries were similar to those induced 
by T. cati except endarteritis and periarteritis 
were more severe. The pulmonary arteries were 
very thickened by 6 to 8 weeks PI (Figure 5). 
MHPA was induced in 11 of the 14 cats exposed 
to T. canis. In the 11 cats with MHPA there 
were parasitic granulomas in the lungs and 
other organs which indicated the cats had be- 
come infected. In 3 cats there was no evidence 
of parasitic granulomas in the lungs or other 
tissues, which suggests that the parasite did not 
migrate. In these cats, the pulmonary arteries 
were normal. T. canis, unlike T. cati, induced 
numerous parasitic granulomas in the lungs 
and other tissues. 
Group IV, Ascaris suum. MHPA was induced 
in 10 of 12 cats infected with A. suum. The le- 
sions were much milder than T. cati and T. 
canis. In two cats there was no evidence that 
the larvae had migrated, and the pulmonary ar- 
teries were normal. 
Group V, T. leonina. All cats infected with T. 
leonina had normal pulmonary arteries. There 
was no evidence of parasitic migration in any 
of the lungs, and MHPA was not observed. This 
parasite is restricted to the gastrointestinal 
tract and does not migrate through the lungs. 
Group VI, Controls. Four of the 31 control 
Figure 5. — Pulmonary arteries from a cat infected 
with Toxocara canis for 8 weeks. Thickened pulmon- 
ary arteries and periarteritis. H and E stain; X 160. 
