Monitoring Babesia bovis infections in cattle by using PCR-based tests

• Published in: Journal of Clinical Microbiology 1996-11, Vol.34 (11), p.2748-2755
• Main Authors: Calder, J.A.M. (New York City Department of Health, New York, NY.), Reddy, G.R, Chieves, L, Courtney, C.H, Littell, R, Livengood, J.R, Norval, R.A.I, Smith, C, Dame, J.B
• Format: Article
• Language: English
• Subjects: Animals; Babesia bovis - genetics; Babesia bovis - isolation & purification; Babesiosis - diagnosis; Babesiosis - parasitology; Base Sequence; Biological and medical sciences; Carrier State - diagnosis; Carrier State - parasitology; Carrier State - veterinary; Cattle; Cattle Diseases - diagnosis; Cattle Diseases - parasitology; Complement Fixation Tests - statistics & numerical data; DNA Primers - genetics; DNA, Protozoan - blood; DNA, Protozoan - genetics; Evaluation Studies as Topic; Experimental protozoal diseases and models; Infectious diseases; Male; Medical sciences; Molecular Sequence Data; Parasitemia - diagnosis; Parasitemia - parasitology; Parasitemia - veterinary; Parasitic diseases; PCR; Polymerase Chain Reaction - methods; Polymerase Chain Reaction - statistics & numerical data; Protozoal diseases; SECUENCIA NUCLEOTIDICA; Sensitivity and Specificity; SEQUENCE NUCLEOTIDIQUE; Time Factors
• ISSN: 0095-1137; 1098-660X
• DOI: 10.1128/jcm.34.11.2748-2755.1996

The sensitivity and specificity of PCR tests based on the small-subunit rRNA gene sequence of Babesia bovis were compared in a blind study of experimentally infected cattle with the corresponding parameters of the complement fixation (CF) test currently used in the United States to screen for bovine babesiosis. Cattle were experimentally infected with a single inoculum of a cloned laboratory strain of B. bovis. Blood samples were collected and tested over a period covering from the day of infection to 10 months postinfection. The level of parasitemia (percent infected erythrocytes) present in each sample was estimated from test results and was plotted as a function of time postinfection. These data are the first describing the course of infection by methods capable of detecting parasitemias in the range of 10(-7)%, which frequently occur in the carrier state. Parasitemias in the samples tested strongly influenced the sensitivity and negative predictive value of the PCR-based tests which varied with time postinfection. The average sensitivities of the three PCR-based tests for B. bovis ranged from 58 to 70% for a single determination, while the sensitivity of the CF test was only 6%. Both PCR-based and CF tests for B. bovis had high specificity values ranging from 96 to 100%