* Prothena shares drop 9 percent (Updates with latest share price) : LONDON (Reuters) - Hedge fund Kerrisdale Capital has taken a short position in drugmaker Prothena, a company backed by UK investor Neil Woodford, calling it “the next big biotech blowup”. Shares in the company, which is headquartered in Ireland and listed on Nasdaq, fell 9 percent on Wednesday following the news. Kerrisdale said it believed Prothena’s main asset NEOD001, an antibody used to treat a rare disease called amyloidosis, is likely to fail its ongoing clinical effectiveness trials.