Table 2.

Major parasitic infections, associated lesions, and demographic characteristics associated with increased odds of having the parasite among a sample of wild urban Norway rats (Rattus norvegicus) trapped in Vancouver, British Columbia, Canada.

System	Location	Organism	Associated lesion	n/N*	Demographic characteristics†	Ref.
Digestive	Upper GI tract‡	Eucoleus spp.	Mucosal hyperkeratosis, hyperplasia, inflammation	164/399 (41)	Heavy body mass & sexual maturity	85
Hepatic	Liver	Capillaria hepatica	Multifocal granulomatous hepatitis and fibrosis	242/672 (36)	Sexual maturity	83
Integumentary	Ears, nose, distal limbs, tail	Notoedres muris	Proliferative and crusting dermatitis	2/672 (0.3)	NA	1
Urinary	Urinary bladder§	Trichosomoides crassicauda	Variable, mild submucosal lymphoplasmacytic inflammation	59/194 (30)	Female sex & heavy body mass	—¦

NA = not available; Ref. = reference to previous studies of a subsample of rats in the current study. We found no evidence of Angiostrongylus cantonensis, Echinococcus multilocularis, Sarcocystis spp., Toxoplasma gondii, or Trichinella spiralis infection in any of the rats.

^*Rats were positive if there was at least one characteristic egg and/or adult cross-section in the sections examined. The number of rats examined for each lesion varies because not all tissues were available for each individual rat because of sampling error, tissue artifacts, and/or autolysis. Numbers in parentheses are prevalences.

^†Demographic characteristic(s) associated with increased odds of having the parasite as determined by multivariable logistic regression modeling with a random effect for city block to control for clustering.

^‡Adults and/or eggs were present in upper gastrointestinal tract including tongue, oropharynx, esophagus, and/or non-glandular stomach.

^§Adults and/or eggs were also rarely present within the renal pelvis.

^¦There are no previous studies of these parasites in this population of rats.