We are about a month beyond peak risk for 2018, and risk this week has fallen to about half of peak risk. We expect around 6 counties to report cases this week. Last week there was some indication that mosquito infections might continue to rise, but this week mosquito infections fell back to exactly average for this point in the year, and we do not anticipate any surprises as the season begins to wind down. Additionally, the state has dried up a little - previously it was more humid than normal, and this was expected to enhance mosquito activity.
Projected Cases for 2018
This week's estimate of total cases for 2018 is 119 cases, down five cases from 124 cases predicted last week. This is due two two influences. First, the mosquito infection rate this week was almost exactly what was predicted by the model. In previous weeks, the data kept hinting that mosquito infections might continue to climb faster than expected. Now, though, it is clear that mosquito infections this year really are just average. Second, the state has returned to average humidity for this point in the year. Previously, the state was more humid than usual, and this was expected to enhance mosquito activity, but the drier weather means less mosquito activity.
South Dakota State University has partnered with the South Dakota Department of Health to implement a program of West Nile virus (WNV) research that will support public health decision makers at the state level and mosquito control programs at the local level. Major activities include mosquito surveillance and testing for WNV, monitoring environmental risk factors using data from earth observing satellites, and using this information to predict the risk of WNV to humans across the state. This work is supported in part by a grant from the NASA Applied Sciences Public Health and Air Quality Program (NNX15AF74G).