(S (S (PP (JJ Prior) (PP (TO to) (NP (BASENP (DT the) (NN arrival)) (PP (IN of) (BASENP (NNS troops)))))) (COMMA ,) (S (BASENP (NNP Haiti)) (VP (VP (VBD had) (RB not)) (VP (VP (VBN encountered) (NP (BASENP (NNS problems)) (ADJP (JJ related) (PP (TO to) (BASENP (DT the) (NN disease)))))) (PP (IN since) (BASENP (DT the) (NNS 1800s))))))) (PERIOD .))