Clarifying terms, ln denotes natural logarithm and logit(x) = ln(x)- ln(1 - x). Notice that e g(X(s))/(1 + e g(X(s))) ∈ [0,1] for any value of g(X(s)). This guarantees that all predicted prevalence rates lie between zero and unity. The overall location parameter, β0, is common to all counties while β1,…,β8, are regression coefficients for the eight non-mosquito factors, and γ1,…,γ8, are regression coefficients for the eight mosquito species. The notation 1 i (s),1 ≤ i ≤ 8, are zero-one indicators: 1 i (s) is taken as unity if the ith mosquito type is present in county s and zero otherwise.