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Co-infections and environmental conditions drive the distributions of blood parasites in wild birds
- Publication Year :
- 2016
-
Abstract
- 1. Patterns of pathogen co-occurrence can affect the spread or severity of disease. Yet due to difficulties distinguishing and interpreting co-infections, evidence for the presence and directionality of pathogen co-occurrences in wild hosts is rudimentary. 2. We provide empirical evidence for pathogen co-occurrences by analysing infection matrices for avian malaria (Haemoproteus and Plasmodiumspp.) and parasitic filarial nematodes (microfilariae) inwild birds (New Caledonian Zosteropsspp.). 3. Using visual and genus-specific molecular parasite screening, we identified high levels of co-infections that would have been missed using PCR alone. Avian malaria lineages were assigned to species level using morphological descriptions. We estimated parasite co-occurrence probabilities, while accounting for environmental predictors, in a hierarchical multivariate logistic regression. 4. Co-infections occurred in 36% of infected birds. Weidentified both positive and negatively correlated parasite co-occurrence probabilities when accounting for host, habitat and island effects. Two of three pairwise avian malaria co-occurrences were strongly negative, despite each malaria parasite occurring across all islands and habitats. Birds with microfilariae had elevated heterophil to lymphocyte ratios and were all co-infected with avian malaria, consistent with evidence that host immune modulation by parasitic nematodes facilitates malaria co-infections. Importantly, co-occurrence patterns with microfilariae varied in direction among avian malaria species; two malaria parasites correlated positively but a third correlated negatively with microfilariae. 5. We show that wildlife co-infections are frequent, possibly affecting infection rates through competition or facilitation. We arguethat combining multiple diagnostic screening methods with multivariate logistic regression offers a platform to disentangle impacts of environmental factors and parasite co-occurrences on wildlife disease.
- Subjects :
- 0106 biological sciences
0301 basic medicine
Plasmodium
Malaria, Avian
Zoology
Wildlife disease
Environment
010603 evolutionary biology
01 natural sciences
Songbirds
03 medical and health sciences
New Caledonia
Avian malaria
parasitic diseases
medicine
Prevalence
Parasite hosting
Animals
Microfilariae
Protozoan Infections, Animal
Ecology, Evolution, Behavior and Systematics
biology
Ecology
Host (biology)
Bird Diseases
Coinfection
Sequence Analysis, DNA
biology.organism_classification
medicine.disease
Haemosporida
Zosterops
Filariasis
030104 developmental biology
Animal Science and Zoology
Haemoproteus
Malaria
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....53e620c1d3056c2d9f7f2fb51d9447f0