Solar and Climate Effects Explain the Wide Variation in Legionellosis Incidence Rates in the United States

Area of Science:

• Environmental science
• Public health
• Infectious disease epidemiology

Background:

• Legionellosis, caused by Legionella bacteria, is a growing public health concern in the US.
• Incidence rates of Legionellosis vary significantly across US states without clear explanations.

Purpose of the Study:

• To investigate the correlation between environmental factors and Legionellosis incidence rates in US states.
• To analyze the impact of precipitation, temperature, solar UV radiation, and sunshine hours on Legionellosis distribution.

Main Methods:

• Correlative analyses were performed on 2014-2016 average annual Legionellosis incidence rates.
• Environmental data including precipitation, temperature, solar UV, and sunshine hours were used.
• Robust regression models identified regional patterns and dividing lines.

Main Results:

• States west of 95°W with low precipitation (<750mm) showed low incidence rates.
• Eastern states exhibited wide incidence variations due to mixed solar effects.
• A dividing line at 40°N showed temperature increasing incidence northwards and solar radiation decreasing it southwards.
• Alaska and Hawaii had the lowest incidences due to extreme cold and high solar UV, respectively.

Conclusions:

• Environmental factors, including precipitation, temperature, and solar radiation, significantly explain the geographic variation in US Legionellosis rates.
• Findings offer insights into potential exposure pathways and inform infection prevention strategies.