( ( Watch ( for ( protozoan diseases ) ) ) . )
(ROOT (S (VP (VB Watch) (PP (IN for) (NP (NN protozoan) (NNS diseases)))) (. .)))
Watch for protozoan diseases.
(ROOT (S (NP (NP (JJ Protist) (NNS diseases)) (PP (IN in) (NP (NNS humans)))) (VP (VBP are) (VP (VBN caused) (PP (IN by) (NP (NN protozoa))))) (. .)))