The village under threat

The village of Sitio Kalyong, which consists of around 800 houses, is in the southern Cabatao region of the Philippines.

All of its residents rely heavily on the hundreds of maize fields for their livelihood. At least two of the fields in the area are planted with Monsanto's YieldGard 818 variety of GM maize. The farmers affected by the GM crop were members of the B'laan tribe.

The first of three studies links a form of GM maize grown in the Philippines to allergic reactions in farming families living close by.

A second study revealed that the virus used to spread GM genes through plants was found intact in rat tissue three days after eating GM food, and was also active in farmers living near the crops.

A third study found GM viruses were able to combine with natural viruses to create hybrid viruses with unpredictable characteristics.