Two weeks after the first of 13,000 (and counting) floating dead pigs appeared in Shanghai waterways, nobody seems to know exactly why or where those pigs died.

Newspapers, blogs and government agencies offer theories and explanations -- cold weather and something called the porcine circovirus are the leading candidates -- but so far no official has pointed with certainty to the village or villages, farm or farms, where thousands of pigs died.

Rather, the residents of Shanghai are mostly told what allegedly didn’t cause it (an epidemic) and where it didn’t happen (Shanghai). Such rhetoric is well-suited to governments that either don’t know what they’re talking about or prefer not to talk about what they do know.

In the case of Shanghai, it’s also emblematic of bureaucrats inclined to obfuscate when confronted with a genuine public-health scare. On March 16, Xinhua, the state-owned and - operated news wire, reported that, “The municipal water affairs department said tests indicate that the city’s water quality is safe and meets national standards for drinking water.” True or not, such statements may work wonders with a bureaucrat’s superiors, but they’re unlikely to reassure a Shanghai public, which views the dead pigs as one more example of the government’s inability to protect the food supply (and is already accustomed to buying bottled water or boiling what comes from the tap).

So, what’s a bureaucrat to do? One approach is to intensify the search. But that risks the embarrassment of not finding an answer or -- much worse -- finding one you don’t want to share. Already, the ugliness of the latter possibility is coming into view. Foreign and domestic reports suggest that at least a partial cause of the tide (though not the deaths) is a recent crackdown on a lucrative trade in diseased, dead pigs for use as food.

As a result, farmers in search of a low-cost means of disposing diseased pig corpses allegedly turned to dumping. If any of this is true, it’s likely that local governments were aware that the trade, and the dumping, were occurring and failed to prevent it. Indeed, last week China’s Central Propaganda Department issued an order prohibiting licensed news organizations from covering a reporter’s inquiry into farmers being unable to afford to cremate their diseased pigs.

And as of Monday in China, the media is making a consistent effort to downplay the tide, with headlines declaring that the number of pigs being recovered is “in decline.”

But just in case it’s not, Shanghai has stationed boats on the border of neighboring Zhejiang province to intercept any floating carcasses before they enter the city limits. It’s impossible to say whether these boats will have any positive public-health benefit. But for city administrators struggling to dissociate their city from floating dead pigs, an anti-pork armada must be viewed as a pretty good investment.

(Adam Minter is the Shanghai correspondent for the World View blog and a contributor to the Ticker. Follow him on Twitter.)