Appropriate prevention for dogs travelling to endemic areas.
ESCCAP Expert Council by Professor Dr. Anja Joachim
Cologne. Cardiovascular dirofilariasis in dogs (Heartworm disease) is caused by Dirofilaria immitis, which as adults parasitize many other bacteria in the pulmonary artery and the right heart and lead to chronic changes in the vessel walls. Veterinary parasitologist Prof. Dr. Anja Joachim from the University of Veterinary Medicine in Vienna explains how to properly prevent dirofilariasis in dogs in everyday practice.
Clinically, this manifests itself in coughing and dyspnea, loss of fitness, vomiting and other signs of progressive pulmonary hypertension and right ventricular hypertrophy. In severe cases, it can often lead to fatal obturation stenosis of the vena cava and ventricle with disseminated intravascular coagulopathy. (DIC) Treatment of a patent infestation consists of a complex and lengthy application of arsenic-containing adulticide and measures to reduce the risk of thrombosis, so prophylaxis deserves appropriate attention.
Heartworm prevention protocols
Heartworm disease is a mosquito-borne infection that is widespread in dogs in (sub-)tropical countries. In Europe and the USA, protocols for routine heartworm prophylaxis are in place. (HWP) which are essentially based on the repeated application of anthelmintics on the activity of mosquitoes to prevent the development of adults.
Endemic areas
In Europe, D. immitis occurs in the Mediterranean countries and some eastern regions (Balkans, Romania, Hungary, parts of the Czech Republic and Slovakia) The Po Valley in northern Italy is considered a highly endemic area!
After transmission, the heartworm larvae migrate through the connective tissue and muscle fibers to the heart. This takes about five months. In the first month of this migration, the larvae are most sensitive to anthelmintics, so repeated treatment is the most reliable way to kill them. Preparations containing macrocyclic lactones are used for this purpose. (Selamectin, milbemycin or moxidectin) They are administered at four-week intervals from spring to autumn until after the end of the flight season in the tropics, all year round.
HWP scheme for travel to endemic areas
But what is recommended when dogs travel from non-endemic to endemic areas? Here too, the four-week rule for the HWP applies: Within four weeks of the start of the journey (= start of exposure) Treatment with macrocyclic lactones must be started. This therapy should be continued at intervals of four weeks until four weeks after the end of exposure.
This means that if a dog travels to Lombardy with its owners in the summer, the HWP must begin no later than four weeks after the start of the trip. This is repeated every four weeks until at least four weeks after the end of the trip. If the dog stays for 14 days, it can also be treated for the first time after its return, but this treatment must also be repeated four weeks later for complete protection.
Advantages and disadvantages of the HWP scheme
Treatment before travel in the sense of a HWP is not necessary. (final) Application after return has the advantage that gastrointestinal nematodes that were brought back as “travel souvenirs” are also eliminated (however, no cestodes, so separate therapy with praziquantel or the use of a combination preparation should be considered if necessary).
Another advantage of this scheme is that animals do not need to be treated during the trip, provided the duration does not exceed four weeks. A disadvantage is that compliance may be reduced after returning from the trip. A corresponding post-trip conversation with the owner can help to remedy this.
Professor Dr. Anja Joachim is head of the Institute of Parasitology at the University of Veterinary Medicine, Vienna (Vetmeduni Vienna). She is also a member of the independent expert organisation ESCCAP (European Scientific Counsel Companion Animal Parasites) and national representative of ESCCAP Austria.