(S (S (PP (IN In) (NP (NP (BASENP (DT a) (NN briefing)) (PP (IN with) (BASENP (NNS reporters)))) (BASENP (NNP Thursday)))) (COMMA ,) (S (BASENP (NNP WHO) (NNP Special) (NNP Pandemic) (NNP Influenza) (NNP Advisor) (NNP Keiji) (NNP Fukuda)) (VP (VBD said) (SBAR (S (BASENP (DT the) (NN virus)) (VP (VBZ has) (VP (VBN been) (ADJP (ADVP (RB particularly)) (ADJP (ADJP (JJ active) (PP (IN in) (BASENP (DT the) (NNP Northern) (NNP Hemisphere)))) (PP (IN in) (BASENP (JJ recent) (NNS months)))))))))))) (PERIOD .))