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may be a source, based on limited evidence from countries such as Australia. Humans may be infected through bites or contact with infected flea faeces on skin abrasions and will show non-specific signs of fever, rash, headache and myalgia.
Fleas may also be a source of mycoplasmal disease, with three Mycoplasma species (M. haemofelis, M. haemominutum and M. turicensis) present in cats and two in dogs (M. haemocanis and M. haematoparvum). Of these, M. haemofelis is the most pathogenic, causing severe haemolytic anaemia, especially in young animals. The other species are only likely to produce anaemia in cats with concurrent disease, or in immunocompromised or splenectomised patients. Haemoplasmas are known to be ingested by C. felis while feeding and may be detected in flea faeces, which is one possible mode of transmission, and there is recent experimental evidence of M. haemofelis transfer by fleas during feeding.
Flea-borne human diseases
Rickettsia typhi and Rickettsia felis are two major flea-borne rickettsiae of humans that are distributed throughout the world. Rickettsia typhi is acquired by fleas while feeding on rickettsemic rats. The organism infects the midgut epithelium of the flea and is shed in the feces, where it is transmitted to humans by the inoculation of R. typhi-laden flea feces onto flea bite wounds or mucous membranes[6]. Murine typhus
is characterized by the abrupt onset of fever with accompanying headache, chills, myalgia, and malaise. Rash, which is the sign that often prompts a clinician to consider a rickettsiosis, is absent in 50% and may be present in as few as 20% of those with darkly pigmented skin. Since the mid-1990s, it has been increasingly recognized as a cause of human infection throughout the world. The primary reservoir and vector of R. felis is thought to be C. felis.
1. Flea Encyclopedia. 2018
2. Lawrence AL, Hii S-F, Jirsová D, Panáková L, Ionică AM, Gilchrist K, Modrý
D, Mihalca AD, Webb CE, Traub RJ. Integrated morphological and molecular identification of cat fleas (Ctenocephalides felis) and dog fleas (Ctenocephalides canis) vectoring Rickettsia felis in central Europe. Vet Parasitol 2015; 210: 215- 223.
3. Sutton G, Burrows M. Insect jumping springs. Current Biology 2018; 28: R142-R143.
4. Moser BA, Koehler PG, Patterson RS. Effect of larval diet on cat flea (Siphonaptera: Pulicidae) developmental times and adult emergence. Journal of economic entomology 1991; 84: 1257-1261.
5. Bourne D, Craig M, Crittall J, Elsheikha H, Griffiths K, Keyte S, Merritt B, Richardson E, Stokes L, Whitfield V. Fleas and flea-borne diseases: biology, control & compliance. Companion Animal 2018; 23: 204-211.
6. Blanton LS, Walker DH. Flea-borne rickettsioses and rickettsiae. The American journal of tropical medicine and hygiene 2017; 96: 53-56.
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