A shaky group of emerging markets could spark a financial train wreck that might lead to international currency turmoil, according to CNBC.

Alan Ruskin, global macro strategist at Deutsche Bank, warned of an economic chain reaction from problems in five countries — the so-called "Fragile Five" of Brazil, Indonesia, India, Turkey and South Africa.

He told CNBC "global contagion" could be on the way from those countries as a result of shrinking foreign investment in their economies, slower exports and weak economic growth.

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All of those factors have led to plummets in those nations' balance of payments. And when a country's balance of payments gets out of whack, its currency often gets hit in turn.

The five emerging nations endured a massive sell-off in their currencies when it appeared the Federal Reserve would begin to cut back its quantitative easing monetary stimulus, CNBC noted. They recovered somewhat after the U.S. government shutdown ended, but that only underscored the yo-yo impact of events elsewhere on the "Fragile Five."

"A rising tide lifts all boats and even the extremely vulnerable currencies like the South African rand or the Turkish lira or the Indian rupee are being helped," Luis Costa, emerging markets currency strategist at Citi, told CNBC. "This doesn't' have anything to do with what their central banks are doing."

David Bloom, global head of foreign exchange strategy at HSBC, predicted, "These currencies will face another sell-off if there is a further shock like the lack of tapering or another U.S. shutdown."

The prospect of Fed withdrawal of stimulus has already led to a cutback in allocations to the "Fragile Five" by emerging markets investors, Reuters reported.

Industry research firm Lipper confirmed that funds reduced their average weightings to those countries by more than 12 percent between March and the end of September, Reuters said.

The Financial Times wrote that currency crises are often self-fulfilling prophecies.

"A sell-off [in the stock market] can trigger a decline in the currency, which can cause yet more sell-offs as investors lose confidence in the country. Sell-offs can be based on blind panic, as well as a clear-headed analysis of a country's fundamentals. So to some extent, country rankings may prove irrelevant."

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