Massachusetts arbovirus update

Find local risk levels for Eastern Equine Encephalitis (EEE) and West Nile Virus (WNV) based on seasonal testing from June to October.

Risk maps

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What does your city or town's EEE or WNV risk level mean? View the keys:

• Key to Color Coding on EEE Risk Map | (Accessible version)
• Key to Color Coding on WNV Risk Map | (Accessible version)

EEE and WNV risk level by city/town

Download:

 2025 EEE and WNV risk level and data (Excel)

Archived:

2024 EEE and WNV risk level and data – Final (Excel)

2023 EEE and WNV risk level and data – Final (Excel)

2022 EEE and WNV risk level and data (Excel)