Temporal patterns of diagnostic results in serial samples from cattle with advanced paratuberculosis infections.
As part of investigating diagnostic strategies for Mycobacterium avium subsp. paratuberculosis (Map), serial results from polymerase chain reaction (PCR) on extraintestinal tissues (blood, milk, and liver) were compared with those from more conventional detection methods including serum enzyme-linked immunosorbent assay (ELISA), fecal culture, and fecal PCR. Three cows previously identified as being subclinically infected with Map were selected for the study. Blood, milk, and feces were collected daily and liver biopsies were obtained weekly for a 30-day period. Unexpectedly, a substantial daily variation in serum ELISA sample to positive (S/P) ratios was observed in all 3 cows. In contrast, fecal culture results were consistently positive. However, whereas fecal culture colony counts were consistently high for 2 cows throughout the study, colony counts from the third cow varied from day to day. Diagnostic sensitivity of PCR for fecal, blood, milk, and liver samples in these advanced subclinically infected cows was 87%, 40%, 96%, and 93%, respectively.
Barrington
George M
GM
Department of Veterinary Clinical Sciences, Washington State University, Pullman, WA 99164, USA.
Gay
John M
JM
Eriks
Inge S
IS
Davis
William C
WC
Evermann
James F
JF
Emerson
Carlene
C
O'Rourke
Jennifer L
JL
Hamilton
Mary J
MJ
Bradway
Daniel S
DS
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology*; D015169:Colony Count, Microbial; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000382:microbiology; D005260:Female; D008099:Liver / Q000382:microbiology; D008892:Milk / Q000382:microbiology; D016927:Mycobacterium avium subsp. paratuberculosis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D010283:Paratuberculosis / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013997:Time Factors