Diagnostic Accuracy of Methods for Detecting Anaplasma Marginale Infection in Lactating Dairy Cattle of Puerto Rico

Abstract

Abstract. Bovine anaplasmosis (BA) is a hemoparasitic disease of great importance in cattle within the tropical and subtropical regions of the world. Control programs for BA require accurate diagnostic assays but validation can be challenging because the true disease status of all animals is frequently not known with certainty. The objective of this study was to estimate the accuracy of assays for detection of Anaplasma marginale infection in lactating dairy cattle of Puerto Rico using Bayesian methods without a perfect reference test. There were 2,331 cattle with complete diagnostic results sampled from 79 herds, and the prevalence of BA was estimated as 22% (95% probability interval [PI]: 19-25%). The sensitivity (Se) and specificity (Sp) of a major surface protein 5 competitive enzyme-linked immunosorbent assay (MSP-5 cELISA) were estimated as 99% (95% PI: 96-100%) and 89% (95% PI: 87-92%), respectively. The Se and Sp of a quantitative polymerase chain reaction (qPCR) were 67% (95% PI: 60-74%) and 99% (95% PI: 99-100%). The Se and Sp of a card agglutination test were 34% (95% PI: 29-39%) and 99% (95% PI: 99-100%). Area under the receiveroperating characteristic curve for the MSP-5 cELISA was 0.748 (95% PI: 0.71-0.79). The MSP-5 cELISA appears to be the test of choice for screening cattle for subclinical BA based on the high estimated Se, rapidity of results, relative low cost, and ease of standardization.

Sensitivity and specificity of a hand-held milk electrical conductivity meter compared to the California mastitis test for mastitis in dairy cattle

“…Area under the estimated ROC curve (AUC) was calculated by the trapezoid approximation method (Munem and Foulis, 1984). More information concerning latent class models based on ordinal classifications can be found elsewhere (Fosgate et al, 2007;Fosgate et al, 2010).…”

Correlations among Anaplasma marginale parasitemia and markers of oxidative stress in crossbred calves

“…The agro-ecological and geoclimatic conditions of India are highly favorable for growth and multiplication of ticks that act as natural vectors of anaplasmosis (Minjauw and Mcleod 2003). Anaplasmosis causes significant magnitude of economic losses due to low weight gain, reduction in milk production, abortion, and cost of treatments (Fosgate et al 2010). A. marginale infects mature erythrocytes by an endocytic process and exit by exocytosis from infected erythrocytes to attack other fresh erythrocytes.…”

Improved diagnostic performance of a commercialAnaplasmaantibody competitive enzyme-linked immunosorbent assay using recombinant major surface protein 5–glutathioneS-transferase fusion protein as antigen

“…34 A comparative study reported that PCR has a low sensitivity of 67% due to variable parasitemia levels in chronically infected animals. 10 In addition, PCR methods need significant effort to prevent false-positive results, which affect the diagnostic specificity of the assay. 32 A recombinant major surface protein 5 (rMSP5)-based cELISA has proven useful for serological detection of Anaplasma-infected animals in previous studies.…”

“…Such assays have been used to detect carrier cattle and include complement fixation (CF), 13 card agglutination, 13,21 indirect enzyme-linked immunosorbent assay (ELISA), 8 dot ELISA, 22 competitive ELISA (cELISA), 19 and indirect fluorescent antibody test (IFAT). 13,29 Most of these assays have diagnostic specificities higher than 96% 2,3,10,[22][23][24][25]29 ; however, the diagnostic sensitivities vary greatly. 10,34 Complement fixation test has a very high specificity, but reports of sensitivity range from 20% 4 to 70%.…”

“…13,29 Most of these assays have diagnostic specificities higher than 96% 2,3,10,[22][23][24][25]29 ; however, the diagnostic sensitivities vary greatly. 10,34 Complement fixation test has a very high specificity, but reports of sensitivity range from 20% 4 to 70%. 13 The CF test is no longer considered reliable for disease certification of individual animals due to low sensitivity.…”