Global flea collection specimen details: Supplementary Table 1
A total of 5128 fleas (3585 female, 1520 male and 23 unknown) were collected from 57 countries across all continents (n = 6) except Antarctica, from October 2012 to March 2017. The most common flea was the cat flea Ctenocephalides felis (n = 4772; 93.0%) inclusive of three subspecies: Ctenocephalides felis felis (n = 3856), Ctenocephalides felis strongylus (n = 32) and Ctenocephalides felis damarensis (n = 4) as well as an additional number (n = 436) that were either unable to be assigned due to ambiguous morphologies (Ctenocephalides felis “transitional”; n = 29) or were not processed for slide-mounting and thus unable to be classified to subspecies level. The second most common flea including all non-Ctenocephalides species was the dog flea Ctenocephalides canis (n = 208; 4.1%) followed by the sticktight flea Echidnophaga gallinacea (n = 195; 3.8%), Ctenocephalides orientis (n = 194; 3.8%) and the human flea Pulex irritans (n = 119; 2.3%). The remaining 1% was represented by 8 species: Echidnophaga larina (n = 24), Ctenocephalides connatus (n = 12), Ceratophyllus gallinae (n = 7), Echidnophaga myrmecobii (n = 3), Nosopsyllus fasciatus (n = 1), Leptopsylla segnis (n = 1), Xenopsylla cheopis (n = 1) and Ceratophyllus sp. (n = 1). There was a total of 49 cases of mixed flea infestations on a single host with the most common sympatry occurring between C. felis and E. gallinacea (16 cases) followed by C. felis and C. orientis (11 cases), C. felis and C. canis (9 cases) and C. felis and P. irritans (7 cases). Fleas were predominantly collected from domestic dogs and cats. This included owned and stray dogs (Canis lupus familiaris; n = 541) and owned and feral cats (Felis catus; n = 228). An additional 33 samples were collected from either cats or dogs. Other canid hosts included red foxes (Vulpes vulpes; n = 99), jackals (Canis aureus; n = 4) and a wolf (Canis lupus signatus; n = 1). A small number of samples (n = 12) were collected from other hosts, both wild and domestic. These include four domestic goats (n = 7 fleas), five Cape ground squirrels (Xerus inauris) (n = 8 fleas), one slender mongoose (Galerella sanguinea) (n = 1 flea), one Rueppell`s Starling (Lamprotornis purpuropteraone) (n = 1 flea), two humans (n = 2 fleas) and one ferret (n= 1 flea). An average of 90 fleas were collected from each country ranging between 1 (Canada and Costa Rica) and 1093 (Australia) (median = 23) from a total of 937 hosts. The largest number of fleas including all species was obtained from Oceania (n = 1560), followed by Europe (n = 1283), Asia (including eastern Russia; n = 803), Africa (n = 742), South America (n = 412) and then North America (n = 323). Only two flea species were found across all continents: C. felis and C. canis. A further two species were present across multiple continents: Pulex irritans in Europe, Oceania, North America and Africa and Echidnophaga gallinaceae from Oceania and Africa. All remaining species were bound to single continents.