Effects of intranasal inoculation of porcine reproductive and respiratory syndrome virus, Bordetella bronchiseptica, or a combination of both organisms in pigs.
OBJECTIVE
To examine effects of co-infection with porcine reproductive and respiratory syndrome virus (PRRSV) and Bordetella bronchiseptica in pigs.


METHODS
Forty 3-week-old pigs. Procedure-30 pigs (10 pigs/group) were inoculated with PRRSV, B bronchiseptica, or both. Ten noninoculated pigs were control animals.


RESULTS
Clinical signs, febrile response, and decreased weight gain were most severe in the group inoculated with both organisms. The PRRSV was isolated from all pigs in both groups inoculated with virus. All pigs in both groups that received PRRSV had gross and microscopic lesions consistent with interstitial pneumonia. Bordetella bronchiseptica was cultured from all pigs in both groups inoculated with that bacterium. Colonization of anatomic sites by B bronchiseptica was comparable between both groups. Pigs in the group that received only B bronchiseptica lacked gross or microscopic lung lesions, and B bronchiseptica was not isolated from lung tissue. In the group inoculated with B bronchiseptica and PRRSV, 3 of 5 pigs 10 days after inoculation and 5 of 5 pigs 21 days after inoculation had gross and microscopic lesions consistent with bacterial bronchopneumonia, and B bronchiseptica was isolated from the lungs of 7 of those 10 pigs.


CONCLUSIONS
Clinical disease was exacerbated in co-infected pigs, including an increased febrile response, decreased weight gain, and B bronchiseptica-induced pneumonia. Bordetella bronchiseptica and PRRSV may circulate in a herd and cause subclinical infections. Therefore, co-infection with these organisms may cause clinical respiratory tract disease and leave pigs more susceptible to subsequent infection with opportunistic bacteria.
Brockmeier
S L
SL
Respiratory Diseases of Livestock Research Unit, National Animal Disease Center, USDA, Ames, IA 50010, USA.
Palmer
M V
MV
Bolin
S R
SR
D000372:Agglutination Tests / Q000662:veterinary; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D001831:Body Temperature; D001835:Body Weight; D001885:Bordetella Infections / Q000097:blood / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D016950:Bordetella bronchiseptica / Q000472:pathogenicity*; D018893:Bronchoalveolar Lavage / Q000662:veterinary; D001992:Bronchoalveolar Lavage Fluid / Q000821:virology; D015169:Colony Count, Microbial; D003371:Cough / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D008168:Lung / Q000382:microbiology / Q000473:pathology / Q000821:virology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000097:blood / Q000473:pathology* / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000472:pathogenicity*; D011897:Random Allocation; D013552:Swine; D014132:Trachea / Q000382:microbiology / Q000473:pathology / Q000821:virology; D014420:Turbinates / Q000382:microbiology / Q000473:pathology / Q000821:virology
D000907:Antibodies, Bacterial; D000914:Antibodies, Viral