Table 2.
Studies reporting impacts of multiple infections in free-ranging vertebrates
| Level of impact | Host level | Host taxa | Response to polyparasitism |
|---|---|---|---|
| Genetics | Inter-, intraspecific | Fish | Increased variability at MHC genes (55, 58, 61, 62) |
| Birds | Optimal allele diversity at MHC level (66, 69) | ||
| Mammals | Selection and resistance to a parasite (63, 64, 69, 73–75, 110) | ||
| MHC heterozygote superiority (76) | |||
| Immunity | Inter-, intraspecific | Fish | Increased level of immune investment (87–90) |
| Birds | Increased susceptibility to other parasites (20) | ||
| Mammals | |||
| Demography | Intraspecific | Birds | Reduced survival and/or fecundity (44, 45, 48–50, 68, 93) |
| Mammals | |||
| Body condition | Intraspecific | Mammals | Deterioration of body condition (44, 47, 49) |
| Birds | |||
| Metabolism | Interspecific | Mammals | Increase in BMR (85) |
| Behaviour | Intraspecific | Mammals | Reduced escape capacity (52) |
| Sleep duration | Interspecific | Mammals | Increase in sleep duration (87) |
| Phenotype | Intraspecific | Birds | Plumage colouration (46) |