First record of a structural infestation by the bird flea Dasypsyllus gallinulae perpinnatus (Siphonaptera: Ceratophyllidae) in the San Francisco Bay Area, California, USA

Herein we present the first-known case report of a structural infestation by the bird flea (Dasypsyllus gallinulae perpinnatus) (Dale 1878) in the United States. In March of 2023, the San Mateo County Mosquito and Vector Control District was contacted by a resident in South San Francisco, CA who reported the presence of fleas inside their condominium. The resident had 2 dogs who were on oral flea medication and only 1 inhabitant out of 4 reported receiving flea bites. The front walkway, backyard, and garage were flagged and a small passerine nest was removed from a fire alarm bell in the front walkway. A total of 31 fleas (13 males, 18 females) were collected by flagging from the front entryway underneath the nest. One female flea was collected from the backyard, and 20 (9 males, 11 females) were collected by the resident from inside the house. A total of 387 fleas (163 males, 224 females) were collected from the nest of a small passerine. All life stages (egg, larvae, pupae, and adult) were observed within the nest. Additional parasites in the nest included bird lice and larval western black-legged ticks (Ixodes pacificus, Cooley and Kohls 1943). Research should be conducted into whether bird fleas are capable of transmitting avian pathogens to humans and this information should be communicated to healthcare providers as part of a One Health approach. Additionally, resources to aid in species-level flea identification should be made accessible to pest control operators as this will aid the development of targeted treatments as part of an integrated pest management plan.