A 2015 outbreak of flea-borne rickettsiosis in San Gabriel Valley, Los Angeles County, California

• Published in: PLoS neglected tropical diseases 2018-04, Vol.12 (4), p.e0006385-e0006385
• Main Authors: Nelson, Kimberly, Maina, Alice N, Brisco, Angela, Foo, Chelsea, Croker, Curtis, Ngo, Van, Civen, Rachel, Richards, Allen L, Fujioka, Kenn, Wekesa, J Wakoli
• Format: Article
• Language: English
• Subjects: Adult; Aged; Animals; Antibodies; Antibodies, Bacterial - blood; Biology and Life Sciences; Cat Diseases - parasitology; Cats; Causes of; Community health care; Control; Ctenocephalides felis; Deoxyribonucleic acid; Development and progression; Diagnostic tests; Disease control; Disease Outbreaks; Diseases and pests; DNA; DNA sequencing; Enzyme-linked immunosorbent assay; Epidemiology; Feral populations; Fever; Flea Infestations - parasitology; Flea Infestations - veterinary; Fleas; Funding; Gene sequencing; Genetic aspects; Humans; Immunoglobulin G; Infections; Insect Vectors - microbiology; Insect Vectors - physiology; Laboratories; Los Angeles - epidemiology; Male; Medical research; Medicine and Health Sciences; Middle Aged; Molecular chains; Mosquitoes; Outbreaks; Public health; Rickettsia; Rickettsia felis; Rickettsia felis - genetics; Rickettsia felis - immunology; Rickettsia felis - isolation & purification; Rickettsia felis - physiology; Rickettsia Infections - blood; Rickettsia Infections - epidemiology; Rickettsia Infections - microbiology; Rickettsia Infections - transmission; Rickettsia typhi; Rickettsial diseases; Rickettsiosis; Siphonaptera; Siphonaptera - microbiology; Tropical diseases; Typhus; Vectors (Biology); Xenopsylla cheopis; Zoonoses
• ISSN: 1935-2735; 1935-2727; 1935-2735
• DOI: 10.1371/journal.pntd.0006385

Although flea-borne rickettsiosis is endemic in Los Angeles County, outbreaks are rare. In the spring of 2015 three human cases of flea-borne rickettsiosis among residents of a mobile home community (MHC) prompted an investigation. Fleas were ubiquitous in common areas due to presence of flea-infested opossums and overabundant outdoor cats and dogs. The MHC was summarily abated in June 2015, and within five months, flea control and removal of animals significantly reduced the flea population. Two additional epidemiologically-linked human cases of flea-borne rickettsiosis detected at the MHC were suspected to have occurred before control efforts began. Molecular testing of 106 individual and 85 pooled cat fleas, blood and ear tissue samples from three opossums and thirteen feral cats using PCR amplification and DNA sequencing detected rickettsial DNA in 18.8% of the fleas. Seventeen percent of these cat fleas tested positive for R. felis-specific DNA compared to under two (