The coronavirus has reached Canada, at least from a business perspective. On Monday, EXFO (EXFO Stock Quote, Chart, News TSX:EXF) updated its revenue guidance. The company said it now expects Q2 revenue of $55-million (U.S.) instead of the $66-million (U.S.) to $71-million (U.S.) for the second quarter of fiscal 2020. The culprit? You guessed it. "The safety of our employees, customers and partners is our top priority as the coronavirus public health emergency unfolds," said CEO Philippe Morin in a press release. "Despite these temporary disruptions, we're implementing the required actions to return to our normal course of business as quickly as possible. Demand drivers for fibre and 5G deployments remain robust on a global basis." National Bank Financial analyst Richard Tse said he expects this impact to be an extended one. "The main reason for the reduced revenue outlook is the disruption in EXFO\u2019s supply chain in China given preventive measures within the affected regions to contain the spread of the virus," he said. "At this point, Management expects revenue to accelerate in upcoming quarters as operations return to full capacity. However, given the uncertain backdrop for the virus, it\u2019s very difficult to make a call as to when that ramp will occur. " In a research update to clients today, Tse maintained his "Sector Perform" rating on EXFO, but lowered his one-year price target on the stock from (US) $4.25 to $3.75, which implied a return of negative 6 per cent at the time of publication. The analyst expects EXFO will post EBITDA of (All figures USD) $28.0-million on revenue of $273.8-million in fiscal 2020. He thinks those numbers will improve to EBITDA of $32.6-million on a topline of $308.2-million the following year. "In our view, we\u2019ve been pointing to a balanced risk-to-reward profile for EXFO in light of the early stage of 5G deployments," the analyst added. "With the growing uncertainty around the spread of the virus and the supply chain constraints in China for EXFO, this pushes the risk profile higher in the short term. We\u2019re maintaining our Sector Perform rating with a revised DCF-based target of US$3.75 (was US$4.25), which implies a valuation of 7.4x EV\/EBITDA on our F20E (was 7.1x). "