Clinical risk scores versus simple integrated clinical judgment in patients with suspected acute coronary syndromes

Background

The clinical utility of clinical risk scores in patients presenting with suspected acute coronary syndromes to the emergency department (ED) is uncertain.

Purpose

We aimed to directly compare the performance of three established clinical risk scores to simple integrated clinical judgment (ICJ) of the treating ED physician.

Methods

Thirty day major adverse cardiac events (MACE) including all-cause death, life-threatening arrhythmia, cardiogenic shock, acute myocardial infarction (AMI, including the index event), and unstable angina requiring urgent coronary revascularization were centrally adjudicated by two independent cardiologists in patients presenting to the emergency department (ED) with acute chest discomfort in an international multicenter study (12 centres in 5 European countries). ICJ for the likelihood that an ACS is the cause of acute chest discomfort was quantified by the treating ED physician using a visual analogue scale at 90 minutes after patient's presentation to the ED. At this time, the ED physician had obtained the patient history, physical examination including vital signs, the 12-lead electrocardiogram at presentation, and the first local (hs)-cTn measurement. We directly compared the prognostic performance of the HEART-score, the GRACE-score, and the T-MACS decision aid to simple integrated clinical judgment (ICJ) of the treating ED physician. We also assessed the safety for rule-out of MACE at 30-days.

Results

Among 4551 eligible patients, 1110/4551 patients (24.4%) had at least one MACE within 30 days. Prognostic accuracy as quantified by the area under the receiver-operating characteristics curve was 0.85 (95% CI, 0.84–0.87) for the HEART-score, 0.85 (95% CI, 0.84–0.87) for the GRACE-score, 0.79 (95% CI, 0.77–0.80) for the TIMI decision aid, and 0.87 (95% CI, 0.85–0.88) for ICJ (Figure). The HEART-score identified 1893/4551 (41.6%) patients as low-risk with an NPV of 96.0% (95% CI, 95.0–96.8), the GRACE score identified 1542/4551 (33.9%) patients as low-risk with an NPV of 97.0% (95% CI, 96.0–97.7), the TIMI score identified 2157/4551 (47.4%) patients as low-risk with an NPV of 93.1% (95% CI, 91.9–94.1), and simple ICJ identified 1743/4551 (38.3%) patients as low-risk with an NPV of 95.6% (95% CI, 94.5–96.5).

Conclusion

The simple ICJ of the treating physician performed well for the prediction of 30-day MACE and might be an alternative to the well-validated HEART-score, GRACE-score, and T-MACS decision aid.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The study was supported by research grants from the the Swiss Heart Foundation and the University of Basel.

Performance of high-sensitivity cardiac troponin T versus I for the early diagnosis of myocardial infarction

Background

Clinical practice guidelines assume that both cardiac troponin (cTn) T and cTnI concentrations reflect identical pathophysiological processes and are equally effective in the detection of myocardial injury. However, there are differences between cTnT and cTnI that have been reported.

Purpose

The aim of this study was to directly compare the diagnostic performance of high-sensitivity cardiac troponin (hs-cTn) T versus hs-cTnI for the early diagnosis of acute myocardial infarction (MI).

Methods

In a prospective multicentre study, diagnostic and prognostic accuracies of hs-cTnT and I were analyzed in consecutive patients presenting to the emergency department with acute chest pain. The final diagnosis was adjudicated by two independent cardiologists using all information pertaining to the individual patient according to the fourth universal definition of MI. Adjudication of the final diagnoses was performed twice: once using serial measurements of hs-cTnT and once using hs-cTnI. Furthermore, the clinical performance of hs-cTnT/I when embedded in the European Society of Cardiology (ESC) 0/1h-algorithm was assessed.

Results

Among 5087 consecutive patients (median [Interquartile range, IQR] age 61 [49.0, 74.0] years, 33.2% female), 951 (18.7%) and 901 patients (17.7%) had an adjudicated final diagnosis of non-ST-segment elevation myocardial infarction (NSTEMI) when using serial measurements of hs-cTnT and hs-cTnI for adjudication, respectively. Diagnostic accuracy was very high for both hs-cTnT and hs-cTnI and comparable when using hs-cTnT for adjudication (hs-cTnT: area under the curve [AUC] 0.93 [95% CI 0.92–0.94] versus hs-cTnI AUC 0.93 [95% CI 0.92–0.94]; p=0.891). However, when using serial measurements of hs-cTnI for adjudication, diagnostic accuracy was significantly higher for hs-cTnI (AUC 0.93 [95% CI 0.92–0.94] versus AUC 0.94 [95% CI 0.94–0.95], p<0.001; Figure 1). This was confirmed in subgroup analyses including early presenter (≤3h), patients with renal failure, known coronary artery disease and elderly (≥70 years). However, both assays performed excellent with very high safety for rule-out and high accuracy for rule-in MI when embedded in the ESC 0/1h-algorithm. Prognostic accuracies for 730-day all-cause mortality and cardiovascular death were significantly higher for hs-cTnT compared to hs-cTnI (Figure 2).

Conclusions

While there seem to be differences between hs-cTnT and hs-cTnI in their diagnostic and prognostic performance, clinical relevance needs to be further evaluated since both assays performed excellent when embedded in their respective early triage algorithms.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swiss National Foundation, Swiss Heart Foundation

Association of accompanying dyspnea with diagnoses and outcome of patients presenting with suspected acute coronary syndromes

Background

The presence of accompanying dyspnea is routinely assessed and common in chest pain patients with suspected acute coronary syndromes (ACS), but its impact on differential diagnoses, diagnostic work-up and outcome is incompletely understood.

Purpose

To determine the association of accompanying dyspnea with diagnoses, diagnostic work-up, and outcome of patients presenting with suspected ACS to the emergency department (ED).

Methods

We prospectively enrolled unselected patients presenting to the ED with chest pain as the main symptom suggestive of ACS in an international multicenter study. Final diagnoses were adjudicated by two independent cardiologists using all information including cardiac imaging. Patients were stratified by the presence or absence of self-reported dyspnea. The primary diagnostic endpoint was the differential diagnosis. The secondary diagnostic endpoint was the performance of high-sensitivity cardiac troponin (hs-cTn) and the European Society of Cardiology (ESC) 0/1h-algorithms for the diagnosis of myocardial infarction (MI). The primary prognostic endpoint was all-cause mortality at two years.

Results

Among 6045 patients, 2892/6045 (48%) had accompanying dyspnea. Final diagnoses in patients with versus without dyspnea were different (overall p<0.001), but prevalence of ACS was comparable (MI 22.4% vs. 21.9%, p=0.602, unstable angina 8.7% vs. 7.9%, p=0.291). In contrast, patients with dyspnea more often had cardiac, non-coronary disease (15.3% vs. 10.2%, p<0.001). Diagnostic accuracy of high-sensitivity cardiac troponin (hs-cTn)T/I concentrations at presentation for the diagnosis of MI was high and not affected by the presence of dyspnea (area under the curve 0.89–0.91 in both groups). The ESC 0/1h-algorithms performed excellent in both groups with negative predictive values >99.4%. The presence of dyspnea was associated with all-cause death at two years (hazard ratio [HR] 2.487 [95% CI, 2.001–3.091, p<0.001) and remained an independent predictor after adjustment for covariates at baseline (HR 1.813 [95% CI, 1.453–2.261, p=0.001]). Overall mortality rates were higher in patients with dyspnea at two years (9.0% vs. 3.7%, p<0.001).

Conclusion

Accompanying dyspnea was not associated with a higher prevalence of ACS but with cardiac, non-coronary disease such as heart failure. While the safety of the diagnostic work-up was not affected, accompanying dyspnea was associated with and an independent predictor for two-year all-cause mortality.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Swiss Heart Foundation, University of Basel.

0/1h-algorithm using a new high-sensitivity cardiac troponin I assay for early diagnosis of myocardial infarction

Background

The clinical performance of the novel high-sensitivity cardiac troponin I EXL (hs-cTnI-EXL) assay is unknown so far.

Purpose

We aimed to validate the clinical performance of the hs-cTnI-EXL assay and to derive and validate an hs-cTnI-EXL-specific 0/1h-algorithm for the early diagnosis of myocardial infarction (MI).

Methods

This multicenter study included patients presenting to the emergency department with symptoms suggestive of myocardial infarction. Central adjudication of final diagnoses was performed by two independent cardiologists using all clinical information including cardiac imaging twice: first, using serial hs-cTnI-Architect (primary analysis) and second, using serial hs-cTnT-Elecsys (secondary analysis) concentrations in addition to those clinically used (hs)-cTn. Hs-cTnI-EXL was measured at presentation and at 1h. The primary objective was to directly compare diagnostic accuracy quantified by the area under the receiver-operating-characteristic curve (AUC) of hs-cTnI-EXL, hs-cTnI-Architect and hs-cTnT-Elecsys. Secondary objectives included the derivation and validation of an hs-cTnI- EXL-specific 0/1h-algorithm.

Results

MI was the adjudicated final diagnosis in 204/1454 (14%) patients. At presentation, the AUC for hs-cTnI-EXL was 0.94 (95% CI, 0.93–0.96), being comparable to hs-cTnI-Architect (0.95; 95% CI, 0.93–0.96) and hs-cTnT-Elecsys (0.93; 95% CI, 0.91–0.95; Figure 1). In the derivation cohort (n=813), an optimal hs-cTnI-EXL-0/1h-algorithm was rule-out of MI with <9ng/L if onset of chest pain >3h or <9ng/L & 0h-1h-change <5ng/L, and rule-in with ≥160ng/L or 0h-1h-change ≥100ng/L. In the validation cohort (n=345), this hs-cTnI-EXL-0/1h-algorithm also performed well: rule-out in 56% of patients, negative predictive value 99.5% (95% CI, 97.1–99.9), sensitivity 97.8% (95% CI, 88.7–99.6), rule-in in 9% of patients, positive predictive value 83.3% (95% CI, 66.4–92.7), specificity 98.3% (95% CI, 96.1–99.3; Figure 2). Secondary analyses confirmed the findings using adjudication including serial measurements of hs-cTnT-Elecsys.

Conclusions

Hs-cTnI-EXL has comparable diagnostic performance to the currently best-validated hs-cTnT/I assays.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swiss National Foundation, Swiss Heart Foundation

Clinical risk scores and integrated clinical judgment in patients with suspected acute coronary syndrome

Background

Clinical risk scores are recommended for formal risk stratification in patients presenting with suspected acute coronary syndrome (ACS). It is unknown, whether these scores still provide additional value in the era of high-sensitivity cardiac troponin (hs-cTn) compared to simple integrated clinical judgment.

Purpose

To evaluate the diagnostic and prognostic performance of integrated clinical judgment compared to clinical risk scores.

Methods

We prospectively enrolled patients presenting to the emergency department with symptoms suggestive of ACS such as acute chest discomfort. The primary prognostic endpoint was the composite of 30-day major adverse cardiac events (MACE) including all-cause death, life-threatening arrhythmia, cardiogenic shock, acute myocardial infarction (AMI, including the index event), and urgent coronary revascularization and was adjudicated by two independent cardiologists. The performance of five well-established formal risk scores (T-MACS, HEART, GRACE, TIMI, and EDACS) for the prediction of 30-day MACE was directly compared with simple integrated clinical judgment for the ACS likelihood by the treating ED physician. Integrated clinical judgment was quantified using a visual analogue scale at 90 minutes after patient's presentation to the ED. The primary diagnostic endpoint was index AMI.

Results

Among 2031 patients, 417/2031 patients (20.5%) had at least one MACE within 30 days. Prognostic accuracy for 30-day MACE quantified by the area under the receiver-operating characteristics curve (AUC) was 0.87 (95% CI 0.85–0.89) for T-MACS, 0.87 (95% CI 0.85–0.89) for HEART, 0.84 (95% CI 0.82–0.86) for GRACE, 0.81 (95% CI 0.79–0.83) for TIMI, 0.75 (95% CI 0.73–0.78) for EDACS, versus 0.89 (95% CI 0.87–0.91) for simple integrated clinical judgment (p<0.01 versus GRACE, TIMI, and EDACS; Figure 1). Similarly, diagnostic accuracy was 0.92 (95% CI 0.90–0.94) for T-MACS, 0.89 (95% CI 0.87–0.90) for HEART, 0.88 (95% CI 0.86–0.89) for GRACE, 0.80 (95% CI 0.78–0.82) for TIMI, 0.74 (95% CI 0.72–0.77) for EDACS, versus 0.89 (95% CI 0.88–0.91) for simple integrated clinical judgment (p<0.01 versus GRACE, TIMI, and EDACS).

Conclusion

None of the formal clinical risk scores outperformed simple integrated clinical judgment for ACS in the prediction of 30-day MACE or the diagnosis of AMI. Therefore, in the era of hs-cTn testing as part of integrated clinical judgment, clinical risk scores seem to no longer provide incremental value.

Figure 1. Diagnostic accuracy for MACE at 30-days

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Swiss National Science Foundation, Swiss Heart Foundation

Validation of the FAINT risk score in a large prospective international multicenter study

Background

Risk stratification of older patients presenting to the Emergency Department (ED) with syncope remains an unmet clinical need. The FAINT Score was derived in a large American cohort in an attempt to predict 30-day serious cardiac outcomes in patients >60y.o. While a FAINT score of 0 showed high sensitivity to exclude death and serious outcomes at 30 days in the derivation cohort, it remains unvalidated.

Methods

We validated the FAINT score (History of heart failure, history of arrhythmia, initial ECG result abnormal, elevate NT-proBNP, elevated hs-troponin T) in a large prospective international multicenter study recruiting patients 40 years presenting to the ED with syncope within the last 12 hours in eight countries on three continents. Main outcome measure was 30-day serious cardiac events or mortality. We assessed the performance and calibration of the FAINT score for validation and compared it to the OESIL score (Age >64y, cardiovascular disease history, syncope without prodromes, abnormal ECG).

Results

1885 patients were eligible for this validation analysis. 169 (8.9%) patients experienced 30-day serious adverse events.

A FAINT score of 0 was present for 378 patients (20% of the cohort) and allowed for a sensitivity of 0.97 to rule out adverse events and death at 30-days. A FAINT score of 0 or 1 was present for 626 patients (33% of the cohort) and allowed for a sensitivity of 0.92.

The area under the receiver operating characteristic curve (AUC) for the FAINT score was 0.75 (95%, Confidence Interval (CI) 0.72–0.79), which was comparable to the performance of N-terminal pro-B-type natriuretic peptide (NT-proBNP) or high-sensitivity Troponin T (hs-cTnT) alone, which are two biomarkers used in the FAINT score. The score did not outperform the OESIL score.

A calibration curve showed that the score was extremely well calibrated for low-risk patients.

Conclusion

This is the first validation of the FAINT score in a large international syncope cohort. The safety of a FAINT score of 0 or 1 was good and comparable to the results obtained in the derivation cohort. While the score is suitable to highlight low-risk patients and calibrates well in an external cohort, its discrimination for higher risk patients is not better than biomarkers alone or an older, less complex risk score.

Figure 1. Area under the Receiver Operating Curve (ROC) for the FAINT score and for NT-proBNP and hs-cTnT as continuous markers as well as for the OESIL score. CI = Confidence Interval.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): University Hospital Basel, Switzerland

Possible introduction of Leishmania tropica to urban areas determined by epidemiological and clinical profiles of patients with cutaneous leishmaniasis in Casablanca (Morocco)

Leishmaniases are a group of infectious diseases caused by protozoan Leishmania parasites and are transmitted by the bites of infected phlebotomine sandflies. The heterogeneity of these diseases is influenced by both parasitic properties and host factors. Cutaneous leishmaniasis (CL) is a major public health problem in Morocco, where the geographical expansion of CL (particularly CL caused by Leishmania tropica), the heterogeneous appearance of lesions and the difficulty in diagnosing CL contribute to late diagnosis of CL and delayed treatment of patients. Therefore, the main objective of this study was to describe the epidemiological and clinical profiles of patients with CL diagnosed in Casablanca (Morocco), which is a non-endemic area for CL. A cross-sectional study was conducted between 2010 and 2016, during which epidemiological and clinical data were collected from patients that met the inclusion criteria through an information sheet. Then, samples were obtained from each patient for parasitological and molecular diagnosis, and only patients with positive polymerase chain reaction and genotyping results were included in the study. Overall, 106 cases of CL were genotyped, of which 61 (57.5%) were caused by L. tropica, 38 (35.9%) by L. major and 7 (6.6%) by L. infantum. While all age groups were affected, CL cases wherein L. tropica was the causative agent were most frequently diagnosed in children aged 0–9 years (p = 0.005), whereas those caused by L. major were more frequently diagnosed in elderly patients (p = 0.004). Multivariate logistic regression analysis showed that two clinical variables were significantly associated with CL caused by L. tropica: lesion size (p = 0.002) and occurrence of lesion on the face (p = 0.005). Furthermore, the results of our survey highlighted the association of Leishmania infection when travelling to endemic areas. The high number of endemic foci where patients with CL were infected with L. tropica illustrated the tendency of this form to spread and generate epidemics, exposing young people to a greater degree to the disease. The epidemic status of CL caused by L. tropica in Morocco and the increased movement of the population from rural to urban areas indicate a possible introduction of this species to urban areas.

Concomitant visceral and localized cutaneous leishmaniasis in two Moroccan infants

Background

Leishmaniases are vector-borne diseases caused by the protozoa of the Leishmania genus. The clinical spectrum of these diseases extends from benign dermal lesions to visceral forms. In the Mediterranean region, zoonotic visceral leishmaniasis (ZVL) is caused by L. infantum. If untreated within two years, the disease usually leads to death. In Morocco, ZVL is endemic in the north, with a hundred cases notified each year, mostly in children aged below five years. Here, we report on two clinical observations in infants presenting unusual concomitant VL and cutaneous leishmaniasis (CL) in Morocco.

Case presentation

In this case study, we report on two infants aged nine and 12 months old. They both have a history of febrile splenomegaly, anemia, and pallor of mucous membranes. Visceral leishmaniasis was confirmed by parasitological diagnosis (positive bone marrow smear and screening of anti-L. infantum antibodies). However, the clinical examination also showed cutaneous lesions that suggested the presence of CL. This was reinforced by the patients having a history of living or traveling to endemic foci. Thus, direct examination, culture, and PCR-RFLP (ITS1-Hae 3) were carried out on the patients’ dermal exudates. In one of the infants, CL was associated with L. infantum, while in the other it was associated with L. tropica. The infants were treated as according to the recommendations of the Ministry of Health. Both patients were cured in two months; defervescence, reduction of splenomegaly, and healing of cutaneous lesions were all observed.

Conclusions

These singular patients illustrate the clinical polymorphism of CL and the necessity of updating the differential diagnosis of leukemia-like syndromes, including VL, in children living in or travelling to known endemic areas. These observations suggest a change in the Mediterranean VL phenotype that may be associated with CL.

Electronic supplementary material

The online version of this article (10.1186/s40249-018-0413-8) contains supplementary material, which is available to authorized users.

Molecular diagnosis of Pseudoterranova decipiens s.s in human, France

Background

Anisakis and Pseudoterranova are the main genera involved in human infections caused by nematodes of the Anisakidae family. Species identification is complicated due to the lack of differential morphological characteristics at the larval stage, thus requiring molecular differentiation. Pseudoterranova larvae ingested through raw fish are spontaneously eliminated in most cases, but mechanical removal by means of endoscopy might be required. To date, only very few cases of Pseudoterranova infection have been reported in France.

Case presentation

A 19-year-old woman from Northeastern France detected, while brushing her teeth, a larva exiting through her mouth. The patient who presented with headache, diarrhea, and abdominal cramps reported having eaten baked cod. The worm was a fourth-stage larva with a size of 22 × 0.9 mm, and molecular biology identified it as Pseudoterranova decipiens sensu stricto (s. s.). In a second P. decipiens infection case, occurring a few months later, a worm exited through the patient’s nose after she had eaten raw sea bream.

Conclusion

These two cases demonstrate that Pseudoterranova infection is not uncommon among French patients. Therefore, molecular techniques should be more widely applied for a better characterization of anisakidosis epidemiology in France.

Molecular diagnosis of cutaneous leishmaniasis and identification of the causative Leishmania species in Morocco by using three PCR-based assays

Background

The diagnosis of cutaneous leishmaniasis (CL) might be difficult, in particular in endemic areas where different species of Leishmania can cause lesions of very similar appearance and where other skin diseases with similar clinical symptoms occur. Even today, the parasitological diagnosis of CL remains the gold standard and it is based on the direct identification of amastigotes in microscopy smears and/or culture of promastigotes from infected tissues. Although these techniques are highly specific, they are not sensitive enough. The objective of this study is to contribute to improving the diagnosis of CL and the identification of Leishmania species in Morocco by comparing three PCR-based assays applied directly on dermal samples.

Methods

A total of 58 patients presenting with cutaneous lesions suggestive of CL were sampled for parasitological diagnosis by direct examination (DE), culture in NNN medium, two kinetoplast DNA (kDNA) PCRs (Lmj4/Uni21 and 13A/13B primers) and one rRNA gene internal transcribed spacer 1 (ITS1) PCR (LITSR/L5.8S primers). The techniques were statistically analyzed and compared.

Results

According to our consensus positive, 44 out of 58 samples were true positives. The 13A/13B-PCR and ITS1-PCR showed the highest sensitivities (100%). Parasite microscopy and culture detected 43% and 29% of the true positives, respectively, while culture and microscopy together improved sensitivity to 52%. PCRs 13A/13B and ITS1 were associated to four and one false positives, respectively, while the other assays were 100% specific. Furthermore, the ITS1-PCR-RFLP assay clearly identified the Leishmania species for all the true positives (44/44), whereas Lmj4/Uni21-PCR identified 35/44 samples. The comparison between the Leishmania molecular characterizations and the expected species according to the national data from the Ministry of Health indicate 7 discrepant results.

Conclusions

The PCR-based assays tested on our samples increased the speed and sensitivity of the diagnosis of CL compared to the conventional techniques. Furthermore, we showed that we can not base the species identification on the national data from the Ministry of Health. Finally, we suggest the use of PCR-ITS1-RFLP for diagnosis and simultaneous identification of the species in the Moroccan epidemiological context, but also in similar areas of the Mediterranean Basin.

Isoenzymatic polymorphism of Leishmania infantum in southern Spain

Over a period of more than 10 years we have isolated and classified 161 Leishmania strains from cases of human visceral, cutaneous and mucosal leishmaniasis in immunocompetent subjects, from cases of visceral leishmaniasis in immunocompromised individuals with HIV, from dogs with leishmaniasis (visceral and cutaneous), from Rattus rattus and from sandflies. The strains were all L. infantum, the only species endemic in Spain, and corresponded to 20 different zymodemes. We describe the life cycle of these zymodemes for which, in most cases, we only partially know the hosts involved. We also discuss possible reasons for the greater polymorphism of L. infantum in southern Spain.

Diagnosis of infections with Leishmania infantum using PCR-ELISA

On the basis of partial amplification of a cloned fragment of kDNA of Leishmania infantum which is specific for this species, we developed a PCR-ELISA technique which avoids the problems associated with classical diagnostic techniques. This technique was tested on 33 L. infantum strains from 19 different zymodemes, which were recognized equally. It was also used on human and canine clinical samples. PCR-ELISA has a higher sensitivity than the other techniques used (IFAT, parasite cultures, optical microscopy of stained samples) and permits detection of a minimum of 0.1 promastigotes or 1 fg of genomic DNA. PCR-ELISA can be used to diagnose human cutaneous leishmaniasis using material obtained by scraping the lesion margin, and human visceral leishmaniasis in HIV(+) individuals and canine leishmaniasis with peripheral blood samples. The presence of L. infantum in dogs with low antibody titres with IFAT technique (20 and 40) was demonstrated indicating that seroprevalence data from epidemiological studies underestimate the true rates of infection.

Theileria annulata: genetic characterization of Spanish isolates by isoenzyme electrophoresis and random amplified polymorphic DNA

Isoenzyme electrophoresis and RAPD techniques were used to study the genetic polymorphism of different Spanish isolates of Theileria annulata in the schizont and piroplasm stages. Enzyme activity attributable to the parasite was detected in only 5 of the 13 loci studied with isoenzyme electrophoresis. Of these, differences between the cell lines studied were found only in the loci GPI, ICD, and FH. Only 6 of the 11 primers used in the RAPD generated reproducible genomic DNA fingerprints. None of the amplification products generated using primers ILO 509, ILO 525, ILO 872, and ILO 875 hybridized with DNA of the bovine cell line not infected by T. annulata, BL20, indicating that this technique can be used with either piroplasm DNA or DNA from parasite schizonts after first passing it through DEAE cellulose columns. The results obtained with both characterization techniques demonstrate a moderate degree of polymorphism among the Spanish isolates of this protozoan.