Comparison of the pathogenicity in rats of rat coronaviruses of different neutralization groups.
OBJECTIVE
Rat coronaviruses (RCVs) are common natural pathogens of rats that cause clinical illness, necrosis, and inflammation of respiratory, salivary, and lacrimal organs. The aim of the study was to determine whether antigenically different strains of RCV vary in their pathogenic potential in rats.


METHODS
Neutralization groups were identified by use of RCV strain-specific antisera. Sprague Dawley rats were inoculated oronasally with RCV-SDA, RCV-BCMM, or RCV-W. Histologic examination, immunohistochemical analysis, and reverse transcriptase-polymerase chain reaction analysis were performed on tissues from infected rats.


RESULTS
Clinical illness was not evident in any of the inoculated rats. The RCV-SDA strain caused mild lesions in the exorbital gland of one rat. The RCV-BCMM strain caused severe lesions in the Harderian and parotid glands and mild lesions in the exorbital glands, lungs, and nasal mucosa. The RCV-W strain caused severe lesions in the Harderian, exorbital, and parotid glands and mild lesions in the submandibular glands, lungs, and nasal mucosa. The RNA concentration was highest in the Harderian, parotid, and exorbital glands of RCV-BCMM- and RCV-W-infected rats at postinoculation day 7.


CONCLUSIONS
Although RCV-SDA, RCV-BCMM, and RCV-W caused different degrees and patterns of lesions, neutralization groups are not useful for predicting the pathogenic potential of a new RCV isolate.
Compton
S R
SR
Section of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut 06520-8016, USA.
Smith
A L
AL
Gaertner
D J
DJ
D000818:Animals; D000956:Antigens, Viral / Q000032:analysis; D018352:Coronavirus Infections / Q000662:veterinary* / Q000821:virology; D017941:Coronavirus, Rat / Q000145:classification / Q000235:genetics / Q000472:pathogenicity*; D006243:Harderian Gland / Q000821:virology; D008168:Lung / Q000382:microbiology; D009297:Nasal Mucosa / Q000821:virology; D010306:Parotid Gland / Q000821:virology; D012367:RNA, Viral / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012376:Rodent Diseases / Q000821:virology*; D013363:Submandibular Gland / Q000821:virology
D000956:Antigens, Viral; D012367:RNA, Viral