Inter-specific interactions between parasites impact on parasite intra-hostdynamics, host health, and disease management. Identifying and understandinginteraction mechanisms in the wild is crucial for wildlife disease management.It is however complex because several scales are interlaced. Parasite–parasite interactions are likely to occur via mechanisms at the within-host level,but also at upper levels (host population and community). Furthermore, interactionsoccurring at one level of organization spread to upper levels throughcascade effects. Even if cascade effects are important confounding factors, weargue that we can also benefit from them because upper scales often provide away to survey a wider range of parasites at lower cost. New protocols andtheoretical studies (especially across scales) are necessary to take advantage ofthis opportunity.