1. There is a 3% decline in cholera cases across all of the sites surveyed. This is likely due to herd immunity, which is a good thing. This phenomenon will mitigate the explosive degree to which cholera will transmit in Haiti. In other words, we do NOT expect cholera to be as bad as it was during the initial period of introduction (i.e. the first year of contact). We DO believe cholera is established now in Haiti's ecosystem, so it will be an ongoing problem.
2. The overall seasonality summarized across multiple sites is peaks at Weeks 27 (early July) and 46 (mid/late November).
3. Specific forecasts, by locale in Artibonite. Note the subtle differences when you examine the local data:
St. Michel: in Week (W) 27 the forecast is for 2 cases rising by 1 case/wk to 10 at W 34 and to 15 by W 37 the receding to 11 in W 39 and down to 2 by Ws 46-47 and minimal cases after that.
Gros-Morne, by W 35 there could be 1 case increasing to 4 cases by W 38 dropping to 1 case by W 41 and staying at zero until 1 case occurs in W 4, dropping back to minimal cases thereafter.
Terr-Neuve, 1-2 cases occur by Ws 38-40, increasing to 3 by W 50 and decreasing to minimal cases thereafter;
Ennery, cases begin with 1 case increasing to 10 cases by W 35, and then rising to 24 by W 39, dropping to 4 cases by Ws 44-46, rising to 6 cases by W 48 dropping to minimal cases by W 52 and thereafter;
Anse-Rouge there are no cases until W 36 with 1, then 2-3 by Ws 38-40, dropping to minimal cases then rising from 1 in W 46 to 7 by W 49, dropping to 1 to 2 cases by W 11 and then dropping to minimal cases thereafter;
Govaives there is 1 case in W 33, rising to 4-5 by Ws 37-38 dropping to 1 by W 42 and then minimal cases until Ws 4-5, with 2 cases by W 7 and then minimal cases thereafter;
Marmalade, there could be 1 case during period from Ws 27-33, then 2 in W 44, rising to 9 in W 47 dropping to 1 by W 52, rising to 7 by W 8, dropping to 1 by W 16, and minimal cases thereafter.
To our knowledge this has never been done before- site-specific forecasting of infectious disease that includes a tie-in with response. We thank Direct Relief International, who supports this important work.