Many of us attempt to avoid thinking about them, while others have come to terms with them.
Whatever your feelings on parasites, scientists can learn a lot about ecology, health, and the environment from them.
Consider which animals have parasites in common.
It's a straightforward question with far-reaching ramifications for food webs, endangered species, and even climate change.
In a world where human and animal hosts are becoming increasingly intertwined, it's also vital to understand disease transmission.
However, answering this issue is difficult, especially when dealing with endangered and vulnerable species.
Parasites inside gastrointestinal organs
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A viable answer has emerged from an international study conducted by a UC Santa Barbara researcher.
Scientists discovered a complete network of gastrointestinal pathogens exchanged among 17 wild and farmed ruminant species using DNA from huge herbivores, as per ScienceDaily.
The study, which appeared in the Proceedings of the Royal Society B, gives light to parasite diversity trends at the wildlife-livestock interface.
The authors discovered that gastrointestinal parasites infect hosts with comparable gut types and phylogenetic histories and that domesticated animals play a key role in this network.
When lead author Georgia Titcomb first got her hands dirty with large animal dung, she was a Ph.D. student at UC Santa Barbara.
She wanted to know how huge, wild, and domestic animals may share parasites at water sources where they congregate while working on her dissertation.
Using traditional ways of physically identifying and counting parasite eggs, however, she became more agitated.
They'd peek through the microscope and see eggs that were all identical.
There was no way of knowing if the amorphous tiny oval I discovered in cow feces might infect an antelope.
To determine the prevalence and diversity of parasites in 17 big herbivore species identified at Mpala Research Centre in central Kenya, the researchers employed DNA metabarcoding, a technique that amplifies a short strand of DNA in a sample and compares it to sequences in a genetic database.
They were able to evaluate a wide variety of parameters that may explain their parasite infections since the scientists had such a diverse group of herbivores in one study area, Titcomb added.
The researchers looked at a variety of factors, including a host's body size, food, and social group size, and discovered a few crucial trends.
Titcomb indicated that the host's genetic heritage was the most essential aspect.
The parasites were more closely connected to the hosts.
The impacts of host species identity, characteristics, and phylogeny on prevalence, richness, and phylogenetic diversity were studied using two sets of models.
To begin, researchers calculated the amount of variation explained by host species identity using GLMs (with Binomial, Poisson, and Gaussian error structures for prevalence, richness, and phylogenetic diversity, respectively).
Second, they used GLMMs (MCMCglmm) with random effects for host species and sampling bout to see if log-transformed body mass, amount of vegetation cover material in the diet, and digestion type (foregut/hindgut) influenced pathogen occurrence, diversity, and taxonomic diversity.
With significant evidence of host-parasite cophylogeny, their research revealed robust indications of host species identity in affecting parasite mOTU prevalence, richness, and phylogenetic diversity.
Similar discoveries in host-parasite interactions and host-microbiome connections support this cophylogenetic signal.
Zebras have a high mOTU diversity, and equids are known to be infected by a variety of small strongyles, with this family Strongylidae parasitizing hindgut fermenters in particular.
Grant's gazelle and elephants, on the other hand, exhibited mOTU richness equivalent to zebras; scientists don't have a good explanation for this, given these organisms are phylogenetically and biologically distinct.
More mechanistic understanding might be gained by incorporating knowledge of host immunity and parasite natural history.
