In 2009, researchers from Dartmouth and University of New Hampshire identified a potential ALS cluster in Enfield, New Hampshire. Nine cases of sporadic ALS were found in Enfield near Lake Mascoma. ALS incidence was 10-25 times higher than expected.
Image from Caller et al. (2009)
In 2013, the Dartmouth researchers published a study that identified ALS clusters in New Hampshire, Vermont, and Maine. This was a much larger scale study, involving 688 ALS cases. Within these 3 states, 11 clusters were found. The incidence of ALS in the identified clusters ranged from 2.58 to 6.0 times greater than normal.
Image from Caller et al. (2013)
Even more recently, researchers identified census tracts within the Northeast with a high incidence of ALS, called ALS “hot spots.” Hot spots were identified in all 3 states studied, and in particular were found around Hanover, New Hampshire and Burlington, Vermont. The census tracts around Burlington are in proximity to Lake Champlain, a lake known to experience cyanobacterial blooms.
Image from Torbick et al. (2015)
References:
- Caller, T.A., Doolin, J.W., Haney, J.F., Murby, A.J., West, K.G., Farrar, H.E., Ball, A., Harris, B.T., Stommel, E.W. (2009). A cluster of amyotrophic lateral sclerosis in New Hampshire: A possible role for toxic cyanobacteria blooms. Amyotrophic Lateral Sclerosis, sup2: 101-108.
- Caller, T.A., Chipman, J.W., Field, N.C., Stommel, E.W. (2012). Spatial analysis of amyotrophic lateral sclerosis in Northern New England, USA, 1997-2009. Muscle Nerve, 48: 235-241.
- Torbick, N., Corbiere, M. (2015). A Multiscale Mapping Assessment of Lake Champlain Cyanobacterial Harmful Algal Blooms. Int J Environ Res Public Health, 12: 11560-11578.