Neospora spp. Seroprevalence and Risk Factors for Seropositivity in Apparently Healthy Horses and Pregnant Mares.

Equine Neospora infection has been linked to neurological disorders and infertility in horses. This study looked into the risk factors for infection and the exposure to Neospora spp. in horses. The study was performed in two independent populations in Israel. The first consisted of apparently healthy horses, and the second consisted of mares examined during pregnancy and after parturition. Sera samples collected from horses and mares were tested for Neospora exposure by the indirect fluorescent antibody test (IFAT). The study revealed seroprevalence of 24% in apparently healthy horses and 66.4% and 48.6% in mares during gestation and after parturition, respectively. Among the investigated risk factors, older age (p = 0.026) and housing in both stalls and paddocks (p = 0.033) in apparently healthy horses, and Arabian breeds (p = 0.005) in pregnant mares, were found to be significantly associated with Neospora spp. seropositivity in univariable, but not multivariable, statistical analysis. This study revealed high exposure of equines to Neospora parasites, especially mares. Horse farm management, in combination with active surveillance, including serological testing and follow up, could help reduce the spread of the parasite among horses in endemic areas.

Detection of Neospora caninum Infection in Aborted Equine Fetuses in Israel.

In horses, Neospora caninum and Neospora hughesi have been associated with fetal loss, and neurological disease, respectively. This study investigated the role of Neospora spp. infection in equine abortion in Israel. The presence of anti-Neospora spp. antibodies was evaluated in 31 aborting mares by indirect fluorescent antibody test (IFAT) and the presence of parasite DNA in their aborted fetuses was evaluated by polymerase chain reaction (PCR), using two target loci (ITS1 and Nc5). The seroprevalence found in aborting mares was 70.9% and the prevalence by DNA detection in the aborted fetuses was 41.9%. Transplacental transmission from positive mares to their fetuses was 45.4% (10/22), while 33.3% (3/9) of fetuses of seronegative mares also tested positive for Neospora. The use of two PCR targets improved the sensitivity of parasite detection, and positive samples were identified by sequence analyses as N. caninum. These finding suggest that N. caninum could be a significant cause of abortion in horses, and that transplacental transmission in horses is an important way of transmission of N.caninum. The results presented here demonstrated the necessity to use several tests concurrently, including serological and molecular assays in order to confirm the involvement of Neospora in mare abortions.

Transplacental Transmission of Theileria equi Is Not a Common Cause of Abortions and Infection of Foals in Israel.

Although the main route of transmission of Theileria equi is through tick feeding, transplacental transmission is also possible and may lead to abortion, or to the birth of a sick or carrier foal. The aim of this study was to evaluate the role of T. equi as a cause of abortions in Israel and the risk of foals being infected at a young age. Eight aborting mares were serologically evaluated for exposure to T. equi via the immunofluorescence antibody test (IFAT) and their aborted fetuses were evaluated using PCR and qPCR. In addition, five mares and their foals (aged 4-6 months) from a highly endemic farm were tested for T. equi infection using IFAT, PCR and qPCR. Five of the eight aborting mares were seropositive for T. equi; however, none of the aborted fetuses was infected. All five mares from the endemic farm were subclinically infected with T. equi. Of their five foals, one was infected, with relatively high parasitemia and different parasite genotype than its dam's, suggesting another source of infection. The results of this study suggest that transplacental transmission of T. equi is not common and does not appear to be a prominent cause of abortion in chronically infected mares.

Atrial fibrillation at mid-term after bioprosthetic aortic valve replacement ­ implications for anti-thrombotic therapy.

BACKGROUND: Little is known about mid-term (3-month) postoperative atrial fibrillation (MT-POAF) in patients treated with bioprosthetic aortic valve replacement (BAVR). The aim of this study was to describe the natural history, identify the predictors and investigate the potential consequences in terms of anti-thrombotic therapy. METHODS AND RESULTS: During a longitudinal, prospective study, 219 patients were treated with BAVR early (7 days) and at mid-term postoperatively (30 and 90 days). POAF was monitored and risk factors were identified on logistic regression analysis. History of previous AF (OR, 3.08; 95% CI: 1.35-6.98), early POAF (OR, 5.93; 95% CI: 2.96-11.8), and BMI (per 5 kg/m(2): OR, 1.46; 95% CI: 1.03-2.09), were independent predictors for MT-POAF whereas sex, age and Euroscore were not. Results were identical when restricted to the 176 patients free from preoperative AF. In this subgroup, 36 patients (20.4%) had MT-POAF; 33 out of 174 (18.7%) would have required anticoagulation (CHA2DS2VASc score ≥ 1). Conversely, patients with BMI <27.7 and sinus rhythm at early follow-up had a very low risk of MT-POAF (OR, 0.16; 95% CI: 0.06-0.42). CONCLUSIONS: There was a higher than expected occurrence of MT-POAF in patients treated with BAVR, particularly in overweight patients with early POAF. This raises the question of implementing an anti-thrombotic therapy in these patients at higher risk of delayed atrial arrhythmia.

Aortic event rate in the Marfan population: a cohort study.

BACKGROUND: Optimal management, including timing of surgery, remains debated in Marfan syndrome because of a lack of data on aortic risk associated with this disease. METHODS AND RESULTS: We used our database to evaluate aortic risk associated with standardized care. Patients who fulfilled the international criteria, had not had previous aortic surgery or dissection, and came to our center at least twice were included. Aortic measurements were made with echocardiography (every 2 years); patients were given systematic ß-blockade and advice about sports activities. Prophylactic aortic surgery was proposed when the maximal aortic diameter reached 50 mm. Seven hundred thirty-two patients with Marfan syndrome were followed up for a mean of 6.6 years. Five deaths and 2 dissections of the ascending aorta occurred during follow-up. Event rate (death/aortic dissection) was 0.17%/y. Risk rose with increasing aortic diameter measured within 2 years of the event: from 0.09%/y per year (95% confidence interval, 0.00-0.20) when the aortic diameter was <40 mm to 0.3% (95% confidence interval, 0.00-0.71) with diameters of 45 to 49 mm and 1.33% (95% confidence interval, 0.00-3.93) with diameters of 50 to 54 mm. The risk increased 4 times at diameters ≥50 mm. The annual risk dropped below 0.05% when the aortic diameter was <50 mm after exclusion of a neonatal patient, a woman who became pregnant against our recommendation, and a 72-year-old woman with previous myocardial infarction. CONCLUSIONS: Risk of sudden death or aortic dissection remains low in patients with Marfan syndrome and aortic diameter between 45 and 49 mm. Aortic diameter of 50 mm appears to be a reasonable threshold for prophylactic surgery.

Dissection in Marfan syndrome: the importance of the descending aorta.

AIMS: To better characterize patients with Marfan syndrome who have survived an acute aortic dissection and to estimate the risks of events in the descending aorta. Up until now, this portion of the aorta has not been well studied but is gaining importance due to improved patient survival. METHODS AND RESULTS: We report a retrospective cohort of 100 Marfan patients who survived an aortic dissection. Dissection occurred in either the ascending aorta (AscAo) (n = 37), the descending aorta (DescAo) (n = 20), or both (As + DescAo, n = 43). During a mean follow-up of 9.8 ± 6.0 years (complete for 88% of the patients), 17 patients died and 52 had a clinical event (new aortic dissection, surgery, ischaemia, haemorrhage), 60% of which involved the descending aorta. Event-free survival was similar whatever the location of the aortic dissection. However, a better event-free survival was observed when no dissected portion of the aorta remained after surgery, which was the case in 62% (23/37) of the AscAo patients (30% incurred an event vs. 86%; P = 0.008 by log-rank test). Interestingly, the diameter of the ascending aorta was below the surgical threshold in 60% of the patients who incurred a dissection of the descending aorta, and within the normal range in 25%. CONCLUSION: The descending aorta may dissect whatever the diameter of the ascending aorta. The descending aorta is the location of most late clinical events after any dissection of the aorta. The rate of clinical events is much lower when all the dissected aorta has been removed in patients with AscAo dissection.

Retinal microvascularisation abnormalities and cardiovascular risk.

The progress of retinal imaging techniques has made retinal microvascular circulation easier to study. A number of observational studies were conducted to characterise the different abnormalities encountered and to determine the factors contributing to their onset. Three lesion groups were highlighted, including reduced arteriolar diameter, venular dilatation and retinopathy lesions. Retinal arteriolar narrowing signals the presence of hypertension (current or old) and the risk of hypertension onset. A genetic factor was implicated in this relationship. Venular dilatation and retinopathy correlate with the presence of diabetes, obesity and metabolic disorders. This association appears to be mediated partly by the presence of endothelial dysfunction and inflammation. The relationship between these abnormalities and cardiovascular risk was also studied in a number of longitudinal studies: the presence of retinal microvascular abnormalities is related with an increased risk of cardiovascular morbidity and mortality predominantly in individuals under the age of 75. More specifically, retinopathy is correlated with the presence of cerebral white matter lesions detected by MRI, an increased stroke risk and deterioration in cognitive function. On the cardiovascular level, a correlation was demonstrated between diminished coronary reserve, increased coronary calcifications observed by CT scan, coronary morbidity and mortality, and risk of heart failure. New techniques of retinal imaging, such as laser Doppler flowmetry, are still undergoing assessment and will help further to clarify these correlations.