Feline Leishmania infections have been observed all over the world and are caused by endemic species also infecting humans and other animals in those areas (figures 3 and 4).
Leishmania infantum is transmitted to cats by sand flies, as these have been shown to feed on cats and to be infected after feeding on naturally infected cats. Moreover, sand flies infected from cats transmitted the infection to dogs.
Considering that cats are a source of infection for sand flies and that cats can suffer from chronic infection, LeishVet postulates that, based on new insights in the epidemiology of leishmaniosis, infected cats can represent an additional domestic reservoir for L. infantum to humans, dogs and cats.
To date, non-vectorial transmission has not been described in cats but blood transfusion may be a source of infection of cats similar to humans and dogs.
Figure 3. Leishmania spp. detected in cats in endemic areas in the Old World (1990-2021).
Figure 4. Leishmania spp. detected in cats in endemic areas in the New World (1990-2021).
Most information regarding feline L. infantum infection has come from investigation performed within the Mediterranean basin.
The prevalence of L. infantum infection in cats, as evaluated in many studies (Table 7), is not negligible; however, it is commonly lower than the prevalence of canine infection.
Prevalence of L. infantum in cats in the Old World (diverse serological or blood PCR techniques) according to studies performed between 1982 and 2021.
| SEROLOGY (1982-2021) | BLOOD-BASED PCR (2000-2021) | |||
| Prevalence | Number of Studies | Countries | Number of Studies | Countries |
| < 5% | 22 | Albania-Cyprus-Egypt-Germany*-Greece-Italy-Portugal-Spain | 15 | Cyprus-Italy-Portugal-Qatar-Spain-Turkey |
| 5-25% | 19 | Egypt-France-Greece-Iran-Israel-Italy-Portugal-Spain-Turkey | 10 | Greece-Iran-Italy-Portugal-Spain-Turkey |
| >25% | 9 | Iran-Italy-Spain | 6 | Italy-Portugal-Spain |
* retrospective evaluation in cats travelling to and imported from endemic areas.
Most feline leishmaniosis (FeL) case reports are from European and Mediterranean endemic areas where the number of pet cats is higher. However, FeL remains rare, even in areas where the disease is common in dogs and feline infection is frequent. It is postulated that cats are therefore more resistant than dogs to L. infantum infection, but it cannot be excluded that the disease is still underdiagnosed because it is often forgotten by practitioners in both endemic and non-endemic areas and often masked by concurrent diseases. Moreover, the level of cat medical care is generally lower compared to dogs.
More than a hundred clinical cases were reported in Europe during the last three decades (Italy, Spain, France, Portugal) with some cases diagnosed (Switzerland) in cats imported from endemic regions.
Host factors predisposing to susceptibility may exist, as roughly half of the reported clinical cases have been observed in cats that could have had an impaired immune system secondary to feline immunodeficiency virus (FIV) or feline leukemia virus (FeLV) infections, immune-suppressive therapies or severe concomitant d i s e ases (malignant neoplasia).