A faulty vaccine has been identified as the cause of a costly Foot and Mouth Disease outbreak that crippled the Paraguan beef export industry in September.

French news agency Agence France-Presse reported overnight that extensive tests had confirmed that human and error and negligence during the vaccine production process were responsible for the disease being transmitted to hundreds of animals that later had to be destroyed.

"After the most recent laboratory analysis, we have confirmed that the outbreak of foot and mouth disease… came about as a result of problems with the vaccination of animals," said Daniel Rojas, head of Paraguay’s National Service for Animal Health and Quality.

"There now is no doubt that it was human error that led to the outbreak of foot-and-mouth."

The outbreak resulted in the destruction of more than 1000 cattle at the Santa Helena ranch in the province of San Pedro. It also prompted neighbouring countries to ban meat imports from Paraguay, a major blow for the country’s export-dependent beef industry.

Government officials told Agence France-Presse that the ban had cost the Paraguayan economy about $70 million per month.

Mr Rojas said it was not yet determined who would be held accountable for the mistake.

"We still have to identify at what stage in the process the problem occurred, determine who was responsible for the mistake and punish them," Rojas said, adding that the outbreak "led to significant economic losses for the country."

Paraguay was ranked as the word's eight largest beef exporter in 2010, exporting 310,000 tonnes in 2010, according to Analysing Agriculture data.  Most of its exports went to Russia and Chile.

Shotly before the September outbreak, Paraguay had been granted countrywide FMD-free with vaccination status.