The highly contagious swine flu, which usually affects pigs, has killed at least 100 people in Mexico and spread to Europe. The real question is, could this virus have been a pandemic waiting to happen? Ozge Ibrahim finds out. As governments around the world move swiftly to contain the spread of a flu virus that combines swine, avian and human influenza, the US Department of Agriculture is monitoring the health of its livestock but has yet to ban the movement of pork produce at its borders. Other countries, however, have been fast to enforce a ban. Today, China announced it had banned imports of live pigs and pork products from Mexico and three US states. Shipments starting from 26 April from Mexico and Texas, California and Kansas will be returned or destroyed, China’s General Administration of Quality Supervision, Inspection and Quarantine said. "); //]]>--> Indonesia has also suspended pork imports together with other measures to help control the movement of people in and out of the country’s borders. And the Philippines announced on the the 26 April that it had temporarily banned the import of hogs and pork products from Mexico and the US. More than just swine flu There are many different types of swine flu. The current cases involve the H1N1 strain of the type A influenza virus. The human strain has been confirmed in laboratory tests to be from the H1N1 virus. The US Agriculture Department (USDA), which has the power to shut down the movement of food produce, has said there is no evidence that swine have been infected with the virus. In a separate statement, the US Department of Agriculture said: "USDA has in place, and did so before the last week's events, a surveillance system to monitor animal health." As an additional precautionary measure, the USDA said it will "reach out to agriculture officials in every state to affirm that they have no signs of this virus type in their state". The department is also keen to stress that swine flu viruses are not transmitted by food, which means the virus cannot be contracted from eating pork or pork products. Cooking pork to an internal temperature of 160°F usually kills all viruses and other food-borne pathogens. While people do not normally catch it, humans can contract the virus, usually if they have been in close contact with pigs. Poor pig health The pig industry has been under scrutiny for many years with farming and agriculture practises a source of controversy and debate around the world. According to analyst estimates, pig diseases in costs British pig producers at least £50m a year. Earlier this month, New Zealand’s pork chairman Chris Trengrove warned the NZ Ministry of Agriculture's release of provisional import health standards would allow pig meat containing the porcine reproductive and respiratory syndrome (PRRS) virus to be widely distributed in NZ, putting the country's pork industry at unnecessary risk. The virus leads to sows aborting and a slow and painful death for piglets. The disease, which does not affect humans, is rated as the main enemy of the pork industry worldwide. Critics of farming practises argue that the widespread policy of treating pigs and other farm animals in close proximity before outbreaks of diseases can lead to antibiotic-resistant strains of disease forming. Coupled with the sheer amount of diseases pigs can develop, pig farmers are faced with a challenge to keep their produce healthy. An outbreak of foot and mouth disease in Britain in 2001 led to the slaughter of thousands of infected animals to contain the virus. British laws aimed at preventing the spread of foot and mouth disease were relaxed in 2003 although global agriculture organisations and governments are still quick to move to contain any minor outbreaks. While experts are yet to confirm whether swine flu has spread to humans from Mexican pig farms, agricultural practises and hygiene methods may come under fire once more information is known. Although devastating for the farming and food processing industries, viruses such as PRRS and foot and mouth rarely affect humans. With further information and warnings on the spread of the disease expected from the World Health Organisation over the coming days, every step of the food supply chain will be affected by this deadly flu outbreak.