Collection of preputial material by scraping and aspiration for the diagnosis of Tritrichomonas foetus in bulls

Tritrichomonas Foetus as a Causative Agent of Tritrichomonosis in Different Animal Hosts

Tritrichomonas foetus is a protozoan parasite that has been traditionally identified as a cause of reproductive tract disease in cattle and gastrointestinal tract infection in cats. Moreover, T. foetus is also well known as a commensal of the nasal cavity, intestines, and stomach in swine. In this review we describe T. foetus as a pathogen dangerous to more than one animal host, diagnostic and taxonomic aspects of this infection, and the extent to which isolates from different hosts share genetic identity.

A retrospective epidemiological analysis of shared risk factors for bovine trichomoniasis and bovine genital campylobacteriosis in La Pampa province (Argentina)

The venereal diseases bovine trichomoniasis (BT) and bovine genital campylobacteriosis (BGC) cause economic losses in endemic areas like La Pampa province in Argentina, where beef cattle are usually managed extensively. The eradication of both diseases is a priority in Argentine. The aim of this case-control study was to identify shared and specific risk factors of both diseases from the data obtained from the Provincial Program for the Control and Eradication of BT and BGC in La Pampa (PCE). The study population included 5777 breeding beef herds tested for BT and BGC in 2013. The study comprised 3481 herds that were surveyed in situ by official PCE veterinarians, distributed as follows: 3159 negative herds (with no BT or BGC positive bulls), 121 BT case herds (with at least a BT positive bull), 170 BGC case herds (with at least a BGC positive bull) and 31 BT and BGC co-infected case herds (with at least a positive bull for each disease). Three multivariable analyses were performed in order to identify the risk factors using a logistic regression model. Results showed that the risk factors shared by both diseases were the number of bulls (OR for BT = 1.03, 95% CI: 1.02-1.04, p <  0.001; OR for BGC = 1.02, 95% CI: 1.01-1.03, p <  0.001; OR for BT and BGC co-infection = 1.02, 95% CI: 1.01-1.04, p =  0.003) and the presence in the previous year of each disease (OR for BT = 18.69, 95% CI: 11.82-29.57, p <  0.001; OR for BGC = 4.65, 95% CI: 3.18-6.81, p <  0.001; OR for BT and BGC co-infection = 39.18, 95% CI: 16.72-91.80, p <  0.001). Disease-specific risk factors were continuous breeding season for BT (OR = 1.59, 95% CI: 1.04-2.47, p =  0.034), and inadequate condition of the fences for BGC (OR = 1.51, 95% CI: 1.06-2.15, p =  0.022). An integrated approach to venereal disease management needs to consider the risk characteristics identified in this study. This could lead to reduce both diseases and improve the efficiency of BT and BGC control activities in La Pampa.

Novel genotype of Tritrichomonas foetus from cattle in Southern Africa

Bovine trichomonosis caused by Tritrichomonas foetus is a significant reproductive disease of cattle. Preputial samples were collected using sheath washing technique in bulls in Namibia. Thirty-six trichomonad cultures were characterized using the TaqMan-probe commercial real-time polymerase chain reaction (PCR) diagnostic assay (VetMAX™-Gold Trich Detection Kit) and CYBR real-time PCR assay based on TFR3/4 primers. Diagnostic real-time PCRs and DNA sequencing of the internal transcribed region confirmed presence of T. foetus in 35 out of 36 samples. Multilocus genotyping using cysteine proteases (CP1, CP2, CP4, CP5, CP6, CP7, CP8, CP9) and malate dehydrogenase (MDH1) gene sequences demonstrate that the T. foetus in Namibia are genetically distinct from those characterized elsewhere. We report the discovery of a novel genotype of T. foetus in Namibian cattle, distinct from other T. foetus genotypes in Europe, South and North America and Australia. We suggest recognition of a 'Southern African' genotype of T. foetus. Identification of the new genotype of T. foetus demonstrates the need for wider global sampling to fully understand the diversity and origin of T. foetus causing disease in cattle or cats.

Pooling of cultured samples and comparison of multistate laboratory workflows with the MagMAX sample preparation system and VetMAX quantitative polymerase chain reaction reagents for detection of Tritrichomonas foetus-colonized bulls

The objectives of the current study were 1) to compare sample preparation workflows and quantitative real-time polymerase chain reaction assays (qPCR) as currently used in veterinary diagnostic laboratories with a study protocol utilizing commercially available reagents for individual Tritrichomonas foetus testing, 2) to assess the accuracy of pooling cultured smegma samples followed by extraction and qPCR testing as used in the study laboratory, and 3) to assess the specificity of the currently used primers and probes by sequencing all positive and presumptive positive samples identified in the study laboratory in an attempt to capture any nucleotide variability between T. foetus isolates and to rule out false-positive results possibly due to Simplicimonas moskowitzi. Eight hundred three cultured smegma samples were collected from different regions of the United States with the collaboration of 5 veterinary testing laboratories. The samples were processed individually by the respective laboratories, and then sent to the study laboratory and retested using the study protocol. Comparison testing showed an overall agreement of 95.89% between the veterinary testing laboratories and the study laboratory. One hundred seventy-six positive or presumptive positive samples plus 625 negative qPCR samples were combined and retested using a pooling protocol. Pools consisted of 1 positive sample and 4 negative samples (1/5). These pools were processed using the same study laboratory protocols, and 96% of the positive samples were detected in these pools. Nested PCR followed by sequencing confirmed 175 of the 178 samples classified as positive or presumptive positive in the study laboratory as containing T. foetus-specific DNA.

Improved detection of Tritrichomonas foetus in bovine diagnostic specimens using a novel probe-based real time PCR assay

A Tritrichomonas foetus-specific 5' Taq nuclease assay using a 3' minor groove binder-DNA probe (TaqMan MGB) targeting conserved regions of the internal transcribed spacer-1 (ITS-1) was developed and compared to established diagnostic procedures. Specificity of the assay was evaluated using bovine venereal microflora and a range of related trichomonad species. Assay sensitivity was evaluated with log(10) dilutions of known numbers of cells, and compared to that for microscopy following culture (InPouch TF test kit) and the conventional TFR3-TFR4 PCR assay. The 5' Taq nuclease assay detected a single cell per assay from smegma or mucus which was 2500-fold or 250-fold more sensitive than microscopy following selective culture from smegma or mucus respectively, and 500-fold more sensitive than culture followed by conventional PCR assay. The sensitivity of the conventional PCR assay was comparable to the 5' Taq nuclease assay when testing purified DNA extracted from clinical specimens, whereas the 5' Taq nuclease assay sensitivity improved using crude cell lysates, which were not suitable as template for the conventional PCR assay. Urine was evaluated as a diagnostic specimen providing improved and equivalent levels of T. foetus detection in spiked urine by both microscopy following culture and direct 5' Taq nuclease detection, respectively, compared with smegma and mucus, however inconclusive results were obtained with urine samples from the field study. Diagnostic specimens (n=159) were collected from herds with culture positive animals and of the 14 animals positive by 5' Taq nuclease assay, 3 were confirmed by selective culture/microscopy detection (Fisher's exact test P<0.001). The 5' Taq nuclease assay described here demonstrated superior sensitivity to traditional culture/microscopy and offers advantages over the application of conventional PCR for the detection of T. foetus in clinical samples.

Evaluation of a PCR test for the diagnosis of Tritrichomonas foetus infection in bulls: effects of sample collection method, storage and transport medium on the test

The objectives of this study were to determine the detection limit of a PCR test for Tritrichomonas foetus, to investigate the effect of sampling method, guanidinium thiocyanate (GuSCN), and sample storage, and to confirm the accuracy of the test on field samples. Serial 10-fold dilutions of culture material were used to determine the detection limit. For the sample handling trial, five positive bulls were sampled by sheath washing and scraping on six occasions over a period of 18 days (n=29 samples) and eight control bulls were sampled three, four or six times (n=28 samples). Samples were cultured, while portions with and without GuSCN were subjected to DNA extraction within 6h, after 30 h and after 5 days at 4 degrees C. PCR and agarose gel electrophoresis was performed. A two-tailed chi-square test was used to test for differences between treatments. The PCR assay showed a specificity of 98%. Its sensitivity declined with storage time, from 90% at 6h to 31% at 5 days. Sampling method and GuSCN had no effect on test sensitivity. The detection limit of the assay was 100 organisms. Parallel testing of 193 field samples gave complete agreement between culture and PCR results.