Comparison of officacy and safety of preventive measures used against canine leishmaniasis in southern European countries:longitudinal retrospective study in 1647 client-owned dogs (2012-2016)

Abstract

The best preventive strategy for canine leishmaniosis is unknown. In the last few years, new preventive measures have become available in Europe, including vaccination against leishmaniosis and use of domperidone. The objective of the present study was to evaluate the efficacy, safety and use of different types of preventive measures against leishmaniosis in client-owned dogs. A database search of medical records was carried out in 52 private veterinary practices located in endemic areas of leishmaniosis in Spain, Italy and Portugal. Dogs recruited were initially healthy and seronegative. Dogs were retrospectively classified into healthy, infected or sick at the time of the final serology. A total of 1647 dogs were included in the study. The use of preventive measures in this population was widespread, although 10.7% did not have any preventive treatment applied. The single most utilized measure was repellents in 45.7% of dogs, followed by combination of repellents and vaccination in 23.0%, repellents and domperidone in 11.3%, vaccination in 4.2%, vaccination and domperidone in 2.7%, domperidone in 2.3%, and the combination of the three measures in 0.2% of dogs. Incidence of clinical leishmaniosis in the group with no preventive treatment applied was 12.5%. In the groups with prevention applied, the incidence was 10.1% for vaccination, 4.5% for repellents, 4.0% for repellents + vaccination, 0.5% for repellents + domperidone and no sick dogs were observed in the groups of domperidone, vaccination + domperidone, and combination of the three measures. All preventive measures resulted in a significant lower incidence of leishmaniosis compared with not applying any measure, except for vaccination alone. Overall, according to the statistical analysis, the group that performed significantly better was the combination of repellents and domperidone. Adverse events were reported in 5.2% of dogs and were significantly more common in dogs being vaccinated. However, most adverse events were mild and self-limiting. In conclusion, this is the first large-scale field study investigating the efficacy and safety of the preventive measures used routinely against leishmaniosis in client- owned dogs. Most preventive strategies used, with exception of vaccination alone, had some benefit over not applying any preventive. According to our results, the use of repellents is very important and, although lower numbers of dogs are included, use of domperidone seems to give additional benefits in preventing clinical leishmaniosis. The role of vaccination and its combination with other preventive strategies needs further study.