title: Respiratory Pathology and Pathogens in Wild Urban Rats (Rattus norvegicus and Rattus rattus).
abstract: Norway (Rattus norvegicus) and black rats (Rattus rattus) are common peridomestic species, yet little is known about wild rat ecology, including their natural diseases. We describe gross and histological lesions in the respiratory tract of a sample of 711 wild urban rats. A subset was examined for 19 distinct categories of histological lesions in the respiratory tract. Testing for known respiratory pathogens included serology and polymerase chain reaction (PCR) of lung samples. Grossly evident lesions were rare (8/711; 1%). Upper respiratory tract inflammation was present in 93 of 107 (87%) rats and included rhinitis, submucosal and periglandular lymphoplasmacytic tracheitis, and/or tracheal intraluminal necrotic debris and was significantly associated (P < .05) with the presence of cilia-associated respiratory bacillus (CARB), Mycoplasma pulmonis, and increased body mass (odds ratio [OR] = 1.09; 95% confidence interval [CI] = 1.05-1.14 per 10 g). Within the lungs, peribronchiolar and/or perivascular lymphoplasmacytic cuffs were present in 152 of 199 rats (76%) and were also significantly associated (P ≤ .02) with CARB, M. pulmonis, and increased body mass (OR = 1.20; 95% CI = 1.14-1.27 per 10 g). Rats were frequently coinfected with M. pulmonis and CARB, and lesions associated with these pathogens were histologically indistinguishable. Pneumocystis sp was detected in 48 of 102 (47%) rats using PCR but was not significantly associated with lesions. This description of pathology in the respiratory system of wild rats demonstrates that respiratory disease is common. Although the impact of these lesions on individual and population health remains to be investigated, respiratory disease may be an important contributor to wild rat morbidity and mortality.
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada jamie.rothenburger@gmail.com.
authors.forename: J L
authors.initials: JL
authors.lastname: Rothenburger
authors.affiliation: Animal Health Centre, British Columbia Ministry of Agriculture, Abbotsford, British Columbia, Canada.
authors.forename: C G
authors.initials: CG
authors.lastname: Himsworth
authors.affiliation: Charles River, Wilmington, MA, USA.
authors.forename: C B
authors.initials: CB
authors.lastname: Clifford
authors.affiliation: Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Ellis
authors.affiliation: Department of Comparative Medicine, School of Medicine, University of Washington, Seattle, Washington, MA, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Treuting
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Canadian Wildlife Health Cooperative, National Headquarters, Saskatoon, Saskatchewan, Canada.
authors.forename: F A
authors.initials: FA
authors.lastname: Leighton
mesh_terms: D000818:Animals; D005260:Female; D008168:Lung / Q000382:microbiology / Q000473:pathology; D008171:Lung Diseases / Q000453:epidemiology / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D008297:Male; D009175:Mycoplasma Infections / Q000453:epidemiology / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D045803:Mycoplasma pulmonis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D009664:Norway / Q000453:epidemiology; D011010:Pneumocystis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D016720:Pneumocystis Infections / Q000453:epidemiology / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D051381:Rats; D012376:Rodent Diseases / Q000453:epidemiology* / Q000382:microbiology / Q000473:pathology
keywords: Mycoplasma pulmonis pathology; Pneumocystis; Rattus norvegicus; Rattus rattus; cilia-associated respiratory bacillus; lung; rats; respiratory diseases; wild