( ( Pathogen ( ( ( A ( disease ( causing agent ) ) ) , ) ( especially ( a ( virus ( , ( ( bacterium or ) fungus ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB Pathogen) (NP (NP (DT A) (NN disease) (VBG causing) (NN agent)) (, ,) (NP (RB especially) (DT a) (NN virus) (, ,) (NN bacterium) (CC or) (NN fungus)))) (. .)))
Pathogen A disease causing agent, especially a virus, bacterium or fungus.
(ROOT (S (NP (NNS Pathogens)) (VP (VBZ is) (NP (NP (DT the) (NN term)) (PP (IN for) (NP (JJ disease-causing) (NNS agents))) (, ,) (PP (JJ such) (IN as) (NP (NNS bacteria) (CC and) (NNS viruses))))) (. .)))