2.1.1. Large-scale patterns. Both pig and mango (Mangifera indica) production tripled in peninsular Malaysia between the early 1970s and the late 1990s (figure 1c). The intensification of production of pigs and mangoes was loosely correlated during this time period. The marked decline in both end-of-year standing pig population (SPP) and annual mango production between 1998 and 1999 indicates that this correlation may reflect widespread dual use of agricultural land to produce both pigs and mangoes, with the decline in commercial mango harvest reflecting the widespread abandonment and culling of infected pig farms that occurred in the first half of 1999 (following the discovery of NiV). Table 1 . Proposed drivers of emergence. Hill outlined nine criteria to be used to assess causality for epidemiological outcomes with complex origins [19] . A useful discussion of the implementation of these criteria in disease ecology is provided by Plowright et al. [20] . This figure 1a ; [18] a Temporality is the only criterion that is logically necessary (in bold).