Troglostrongylus brevior: a feline lungworm of paediatric concern.

The immature immune system of cats in their paediatric age (i.e., first six months of life) favours the establishment of infectious respiratory tract diseases mainly caused by well recognized viruses and bacteria species. Conversely, lungworm infections are less investigated during respiratory disorders in kittens. In the last decade, Troglostrongylus brevior has been found affecting the respiratory tract of cats, along with the better-known Aelurostrongylus abstrusus. Given the scant data available on the epidemiology of feline troglostrongylosis, faecal samples from 575 domestic animals living in three Italian municipalities (i.e., Bari, Messina and Siena) were screened for lungworm infection by Baermann and molecular tecniques. Animals were grouped according to their age as ≤6 months (i.e., paediatric patients), 6-24 months, or >24 months. Paediatric cats were further sub-divided in infant (2-6 weeks), weanling (6-12 weeks) and juvenile (3-6 months). Of the 575 animals tested, 241 (42.0%) were younger than 6 months, 188 (33%) were 6-24-month-old and 146 (25%) were older than 24 months. Lungworm infection was diagnosed in 84 (14.6%) of the examined cats. Of the 49 (20.3%) paediatric animals positive for lungworms, T. brevior was the nematode species most frequently diagnosed (n = 44; 89.8%), followed by A. abstrusus (n = 2; 4.1%), and three cats (6.1%) were co-infected by both species. The diagnosis of T. brevior infection was significantly associated with animals aging ≤6 months (18.2%; P < 0.01) than elder cats. Indeed, the prevalence of infection by T. brevior decreased in animals aging 6-24 months (3.2%) being not detected in cats older than two years. Results of this study indicate that paediatric cats are at higher risk of T. brevior infection compared to adults (P < 0.01).