Heat treatment prior to testing allows detection of antigen of Dirofilaria immitis in feline serum

Parasites & Vectors

Table 1 Results from testing feline serum samples collected 196 and 224 days after experimental infection with 100 third-stage larvae of Dirofilaria immitis(positive results in bold)

	Day 196				Day 224
Cat (number of worms recovered)	Antigen before heating (O. D.)	Antigen after heating (O. D.)	Antibody	Antigen/antibody ratio	Antigen before heating (O. D.)	Antigen after heating (O. D.)	Antibody	Antigen/antibody ratio
1 (0)*	0.157	0.666	0.529	1.259	0.059	0.604	0.396	1.525
2 (6)	0.070	0.587	1.301	0.451	0.099**	1.985	1.605	1.237
3 (1)	0.064	0.289	0.264	1.095	0.056	0.120**	0.509	0.236
4 (2)	0.055	0.081	0.578	0.140	0.060	0.068	0.528	0.129
5 (1)	0.060	0.146	1.111	0.131	0.074	1.921	1.329	1.445
6 (2)	0.050	0.191	0.374	0.511	0.057	0.579	1.387	0.417
Mean (2.0)	0.076	0.327	0.693	0.598	0.068	0.880	0.959	0.832
Number positive	1/6	5/6	6/6		1/6	5/6	6/6

*No adult worms recovered but severe pulmonary lesions identified on histologic examination of lung sections. **Antigen was detected by visual color change but did not exceed the manufacturer’s specified cutoff (negative control + 0.05) for positive on the spectrophotometric assay used (PetChek® Heartworm PF Antigen Test, IDEXX Laboratories, Inc).
Positive results in bold.

ISSN: 1756-3305