Prevalence and seasonality of fleas associated with california ground squirrels and the potential risk of tularemia in an outdoor non-human primate research facility

Ectoparasites at primate research centers may be difficult to control, e.g. without exposing non-human primates (NHPs) to toxicants, but their impact on NHP health is poorly understood. In 2010, there was an epizootic of tularemia at the California National Primate Research Center (CNPRC) in Yolo County, California that resulted in 20 confirmed and suspect clinical cases in outdoors housed rhesus macaques (Macaca mulatta [Zimmermann]) and a 53% seroprevalence in the southern section of the colony. We studied ectoparasite burdens at the CNPRC in order to understand possible conditions at the time of the epizootic and provide data for the management of ectoparasites for the future. In 2015, we recorded 52 California ground squirrel (Otospermophilus beecheyi [Richardson]) burrow systems in the southern colony and collected 560 fleas. The largest number of fleas (n = 184) was collected in October and the most common species were Hoplopsyllus anomalus (Baker) (n = 331), Oropsylla montana (Baker) (n = 158), Echidnophaga gallinacea (Westwood) (n = 60), and Ctenocephalides felis (Bouché) (n = 11), all of which are opportunistically anthropophilic. Free, non-host-associated fleas included 12 H. anomalus, 9 C. felis, 6 O. Montana, and 1 E. gallinacea. We collected 1 H. anomalus from a rhesus macaque. Our results suggest a high potential for the rapid spread of zoonotic infectious diseases via flea transmission in primate facilities with ground squirrels and that flea control measures should be given a high priority.