Figure 4.

Difference in sample- and session-level viral interaction coefficients from a Maximum Likelihood Markov Random Fields model. Virus pairs were divided into those where the interaction coefficient was higher at the session level than sample level (inclining slope, left plot) and vice versa. The grey dotted line at zero divides the plot into positive pairwise interactions (top) and negative pairwise interactions (bottom). Steep downward slopes (sample interaction >> session interaction) are consistent with co-infection or facilitation. Steep upward slopes are consistent with co-circulation, with the exception of HeV-YepPV, which showed strong negative interactions within samples (indicative of competition). In the colour scale, darker colours represent a greater absolute difference between sheet and sample level coefficients. Virus pairs with thicker lines are discussed in more detail in the text. Virus abbreviations as per Table 1.