#host manipulation

[drlucyalford]

In my latest paper, I ask why does the choice of host have no effect on the thermal tolerance of the emerging parasitoid? This is particularly interesting since parasitoid wasps of the Genus Aphidius are confined to the aphid host during development, making the host the sole source of nutrients for the developing parasitoid. Choice of host is known to impact a variety of parasitoid life history traits. So why not parasitoid cold tolerance? Read more here at the Journal of Insect Physiology. 

[8-nilevirus-blog]

Coevolution of the West Nile Virus with its Avian host

The West Nile Virus is dependent on producing a high viremia in its hosts to facilitate the transmission of the virus to mosquitoes, then to other hosts. Avian species are especially susceptible to the virus and allow it to replicate to extremely high concentrations in their bodies. The first US case of West Nile was in 1999 and continues to circulate today. However, studies have shown that birds collected in recent years have shown a very different response to recently isolated strains of West Nile as opposed to the earlier strains. The birds illustrated a lower mortality rate when exposed to the 1999 strain as well as some early 2000's strains; they showed a relatively increased mortality rate when exposed to recent isolation a of the virus. Also the birds showed a lower viremia when exposed to earlier strains. These factors I.e. higher mortality rates and viremia due to recent strains illustrate that the birds and the virus are in a constant battle to maintain superiority and have coevolved to one-up each other's defenses with the virus producing a higher viremia and the birds evolving to combat that. West Nile has also been shown to manipulate its hosts to reduce the immune response and facilitate its replication. A study found that the virus will actively redistribute cellular cholesterol in host cells; this redistribution downregulates an antiviral signaling response (jak-STAT), normally interferon-stimulated. This reduction in the ability for the cells to signal that they have been infected allows the virus to replicate itself without detection of the immune system effectively proliferating the next wave of the virus. Sources: http://www.ncbi.nlm.nih.gov/m/pubmed/18005741/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4214623/

[mellow-and-dramatic]

Host Manipulation

you asked me how I felt the only way to display my dismay is by putting my hands around your neck

like a parasite a reaper a virus a soul eater you controlled me manipulated me made myself hypnotized by your lies & oh, those eyes

I was lost in trance by chance never again will I burn in a fire just to keep you warm

never again will I justify a liar just to make you a little less of a pariah

never again will I expose myself out of self hatred and your own desire

[biologylair]

This Polyrhachis armata ant was infected with Ophiocordyceps unilateralis s.l, the fungus that took control of its brain and is seen sprouting from its head. Normally, worker ants that remove and isolate the bodies of dead ants infected prevent the fungus’ life cycle from being completed within the colony. O. unilateralis has come to evolutionarily overcome this limitation by manipulating an infected ant to move to a moist environment conducive to fungal reproduction and growth. The “zombie” ant is forced to bite into the underside of a leaf, its jaw locking into an unreleasable clench. The ant soon dies and the fungus reproduces asexually, spreading its spores to infect ants that come in contact with them.

Credit: David Hughes, Department of Entomology and Biology, Penn State University