Fig 3. Tree diagram with all possible states and associated probabilities for a test tick.
The probabilities are: pB (nymphal infection rate (NIPAll) of B. burgdorferi), pS (conditional probability of a successful RLB test, given infection), pSH (conditional probability that the test tick is HIS+, given RLB success), and pFH (conditional probability that the test tick is HIS+, given RLB failure). Note that pc (conditional NIPHIS, given infection) is equal to pSpSH + (1 − pS)pFH. Observable states are in boxes, and unobservable states are in ovals. Red nodes do not apply to 2009 because pS = 1.