( ( ( ( ( ( The pathogens ) -LRB- ) ( usually ( viruses ( , ( ( bacteria and ) protozoans ) ) ) ) ) -RRB- ) ( in ( the ( ( fecally contaminated ) water ) ) ) ) ( ( may ( cause ( diarrhea ( or ( upper ( respiratory problems ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NP (DT The) (NNS pathogens)) (-LRB- -LRB-) (NP (RB usually) (NNS viruses) (, ,) (NNS bacteria) (CC and) (NNS protozoans)) (-RRB- -RRB-)) (PP (IN in) (NP (DT the) (ADJP (RB fecally) (VBN contaminated)) (NN water)))) (VP (MD may) (VP (VB cause) (NP (NN diarrhea) (CC or) (JJ upper) (NN respiratory) (NNS problems)))) (. .)))
The pathogens (usually viruses, bacteria and protozoans) in the fecally contaminated water may cause diarrhea or upper respiratory problems.
(ROOT (S (NP (NNS Trichomoniasis)) (VP (VBZ is) (VP (VB cause) (PP (IN by) (NP (DT a) (NN protozoa))))) (. .)))