Ticks and Pathogen Infection Rates in <i>Ixodes scapularis</i> at Two Residential Sites in Baltimore County, Maryland, USA

Reports of tick-borne diseases are on the rise globally, with Lyme disease as the most prevalent vector-borne disease in the United States. Tick and tick-borne pathogen distributions have been expanding, increasing the populations at risk for tick-vectored pathogens. In endemic regions, such as Maryland in the eastern United States, individuals and homeowners are concerned about the personal risk of exposure to these vectors and pathogens. In response, we carried out a pilot study at two residential properties in Baltimore County, Maryland. Tick drag collections were carried out March-December 2023 and resulted in the capture of 139 ticks. Collections were comprised of 114 Ixodes scapularis, 7 Dermacentor variabilis, and 18 invasive Haemaphysalis longicornis. Pathogen screening of the Ix. scapularis using qPCR and PCR revealed 42 (36.8%) infected with Borrelia burgdorferi and 3 infected with Anaplasma phagocytophilum. One tick was co-infected with both pathogens. Phylogenetic analysis of OspA genetic variability of B. burgdorferi revealed little variation both between samples and with reference sequences. The overall B. burgdorferi infection rate was higher than has been previously reported in Maryland. Whether this reflects an increase, represents variability between regional studies or is biased by relatively small sample sizes is unknown. The findings of this pilot study highlight the need for more robust tick and tick-borne pathogen surveillance in the mid-Atlantic region.