SHM Converge Scientific Abstract ePoster Gallery-Climate Change and Babesiosis Seasonality in New England

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A retrospective chart review of adults with confirmed babesiosis at three Boston teaching hospitals from 1993 to 2024 found that the disease season in New England has expanded substantially, likely in the context of climate warming. Investigators reviewed 1,975 records, excluding cases with inadequate documentation, negative or nonstandard testing, serology-only diagnoses, pediatric cases, or probable acquisition outside New England. The final analysis included 1,130 cases identified by blood smear or serum PCR, using symptom onset rather than diagnosis date to better capture timing.<br /><br />Results showed a strong annual increase in babesiosis cases of 14.2% per year. Although cases still peaked in June and July, the chance of symptomatic disease occurring in non-summer months increased over time, with the season lengthening by about one month every three years. The average number of months per year with cases rose from 2.2 before 2000 to 9.2 after 2015.<br /><br />Possible reasons for this expansion include warmer winters reducing tick die-offs, increased winter activity during warm spells, longer activity periods for nymphal ticks in spring and fall, improved survival of tick hosts, and growing use of immunosuppressive therapies such as anti-CD20 agents.<br /><br />The study concludes that babesiosis should now be considered year-round in endemic regions, especially in patients with fever and anemia. Older adults and immunocompromised patients remain at highest risk.

Asset Subtitle

John Ross

Meta Tag

Author List John Ross, Kevin Ard

Category Research

Concept Babesiosis

Concept Incidence

Concept Seasonality

Concept Epidemiology

Concept New England

Distinguished Non-Finalist

Presenter Organization Hospital Medicine Unit, Brigham and Women's Hospital, Harvard Medical School

Presenting Author John Ross

Track Other

Keywords

babesiosis

New England

climate warming

tick-borne disease

seasonal expansion

retrospective chart review

blood smear

PCR diagnosis

immunocompromised patients

year-round risk

Babesiosis

Incidence

Seasonality

Epidemiology

New England