Bayer Animal Health has announced that Seresto, it's flea and tick collar for cats and dogs, has now been granted approval to be used to reduce the risk of canine leishmaniosis via transmission by sand flies for up to 8 months.

Canine leishmaniosis is caused by the protozoan Leishmania infantum, which is found in most continents1L. infantum is most commonly transmitted through the bite of sand flies and Bayer says there is a growing concern among parasitologists that the distribution of the disease is increasing due to climate change and more frequent pet travel.

Dr. Markus Edingloh, Head of Global Veterinary Scientific Affairs at Bayer Animal Health, said: "We are seeing more cases of canine leishmaniosis in areas where the disease had not previously been found. Dogs travelling and imported from endemic areas are of particular concern for introduction of the disease, while climate change is contributing to the spread of the vector.

It is therefore vital that veterinarians are aware of the disease and are recommending appropriate protection for dogs travelling to, or living in, endemic areas."

In dogs, there are a wide range of potential clinical signs associated with leishmaniosis including generalised lymphadenopathy, weight loss, lethargy, pyrexia, cutaneous lesions, ocular lesions and neurological or vascular disorders, while the severity of disease can vary from mild to life threatening2,3. In humans L. infantum tends to be responsible for the most severe form of leishmaniosis, visceral leishmaniasis, which can be fatal.

While distribution is worldwide, L. infantum is particularly prevalent in South America and the Mediterranean, with annual cases of zoonotic visceral leishmaniasis in people estimated to be 3,500 in Brazil and 875 in the Mediterranean1.

In some areas, over 80% of canine leishmaniosis cases may be asymptomatic1. However, the infection level in asymptomatic dogs is such that these dogs, in addition to the dogs showing clinical disease, can still be responsible for the spread of disease4. Therefore protection against infection to help control spread is vital for both human and dog health, as clinical cases will not always be obvious.

The non-profit scientific association, LeishVet, recommends that prevention should include the use of a long-acting topical insecticide throughout the period of sand fly activity: "Long-acting topical insecticides applied to dogs living in or travelling to endemic areas should be maintained during the entire risk period of potential exposure to/or activity of sand flies."

Bayer says that Seresto, which contains imidacloprid and flumethrin in a slow release collar, has been found to significantly reduce the risk of infection with Leishmania infantum in dogs for up to eight months. Three clinical field studies, performed in endemic areas, indicated a significant reduction in the risk of Leishmania infantum transmission by sand flies in treated dogs compared to non-treated dogs. The efficacy in the reduction of the risk of infection with leishmaniosis ranged from 88.3 to 100% 5,6,7.

For more information, visit


  1. Otranto, D. et al. (2013) The prevention of canine leishmaniasis and its impact on public health. Trends in Parasitology. July 2013, Vol 29;7, 339-345
  2. BSAVA Infectious Diseases Factsheet – Leishmania. October 2016
  3. LeishVet Guidelines. Canine and Feline Leishmaniosis. February 2018
  4. Quinnell RJ, Courtenay O (2009). Transmission, reservoir hosts and control of zoonotic visceral leishmaniasis. Parasitology 136:1915-1934
  5. Otranto D, Dantas-Torres F, de Caprariis D, et al. Prevention of canine leishmaniosis in a hyper-endemic area using a combination of 10% imidacloprid/4.5% flumethrin. PLoS One. 2013, Vol.8, p.e56374.
  6. Brianti E, Gaglio G, Napoli E, et al. Efficacy of a slow-release imidacloprid (10%)/flumethrin (4.5%) collar for the prevention of canine leishmaniosis. Parasite & Vectors. 2014, Vol.7, p.327.
  7. Brianti E, Napoli E, Gaglio G, Falsone L, et al. Field Evaluation of Two Different Treatment Approaches and Their Ability to Control Fleas and Prevent Canine Leishmaniosis in a Highly Endemic Area. PLoS Negl Trop Dis. 2016, Vol.10, p.9

PS: Whilst you're here, take a moment to see our latest job opportunities for vets.