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9

I can think of several (non-exclusive and non-exhaustive) hypotheses: It is maladaptive. Because it is a new virus coming from another species or because it is not adapted to our modern lifespan. Some might benefit from host immune defense (sneezing helps bacteria to spread) and death is a consequence of the selection for increasing disease symptomes to ...


7

Yes it is possible to culture plasmodia but they don't grow in a simple constituted medium. Usually RPMI supplemented with serum and erythrocytes is used for growing plasmodia ex-vivo. This article discusses the issues related to plasmodial culture in detail. The authors say that sometimes a certain growth stage (in particular gametocyte) is lost on ...


5

The species of wasp you're referring to is Glyptapanteles. I'm not sure which virus it is. http://www.newscientist.com/article/dn14053-zombie-caterpillars-controlled-by-voodoo-wasps.html?feedId=online-news_rss20 Is it possible? Of course, you have an example! Though, there is a small caveat. Some of the offspring sacrifice themselves to induce the ...


5

You're right in saying that yeast is single celled. However, moulds are described to be filamentous fungi that are multicellular. The filaments of the mould give colonies "a woolly, fluffy, or velvety appearance, sometimes punctuated with a granular or powdery aspect that is produced by the formation of asexual reproductive structures"(1). Aspergillus is ...


4

As Armatus pointed out above, all viruses are obligately intracellular, and their medical and economic importance cannot be overstated. Many bacterial species live intracellularly. The arthropod specific Wolbachia has a wide variety of consequences for its host, including alteration of reproduction and sex ratios, induction of reproductive isolation ...


4

If you have or can get access to it, you might try looking in the Incidence and Prevalence database: http://thomsonreuters.com/incidence-and-prevalence-database/ Another possibility is the GIDEON database: http://www.gideononline.com/. It is possible to sign up for a 15-day trial. For Europe, statistics are available from the WHO CISID at ...


4

The fungus releases toxins, but how exactly this alters behavior is unclear. You can read more here. Pathogen manipulation of host behavior appears to have evolved a long time ago, and cordyceps is not the only pathogen that acts like this.


4

Based on my course material, I managed to get the following list: Malaria - Plasmodium falciparum, p. malariae, p. vivax, p. ovale - female anopheline mosquito Babesiosis - Babesia devergens, babesia microti - tick ixodes ricinus Balantidiasis - Balantidium coli - waterborne Coccidiosis & toxoplasmosis - Eimeria species - waterborne Toxoplasmosis - ...


3

In model fungi, the G protein coupled receptor Gpr1 is known to sense sugars and upregulate a cAMP linked PKA pathway, while in pathogenic strains, it senses Methionine. This probably is the environmental cue that sets off fruiting. There is a recently published extensive review too: Heterotrimeric G protein signaling in filamentous fungi Reference Li, ...


3

Some parasites aren't natural hosts of humans, instead we are an accidental host in which they cannot replicate. Zoonoses such as this can be quite fatal as the parasite is not adapted to us. Although viruses are often separated, they are parasites and you can see just in influenza that the animal derived flus are more fatal than those that are well adapted ...


2

Oddly enough it is a bit difficult to find good field studies where the diet of spiders was studied. I have a feeling it's a hard thing to get funding for. Luckily some do exist. Peucetia viridans has been shown to eat from the Chrysididae family and Lepidoptera order, but I didn't find an explicit statement that it ate the larvae out of the caterpillar. ...


1

I haven't really found much on this topic (besides popular sites) but I can summarize it here: There are quite some tapeworms (or cestoda), I found numbers of up to 3500 species. They attach to the intestinal wall of the humans and then start to take up predigested food through their skin. With that, they reduce food from their host and start to grow, some ...


1

Thus, there is a significant selection pressure for humans to develop resistance but no (or almost no) pressure for toxoplasmosis to counter human resistance. Well, I think in this case "Significant" isn't qualified. Significant selective pressure can come in many forms, but as you mention about 30% of humans are infected with Toxopolasma, and the vast ...


1

This is related to Remi.b's answer, but a common reason is that sometimes parasites/pathogens actually need to kill the host to spread. A lot of viruses, in particular phages, are only released from their host by bursting out of the cell. If the parasite can't leave the host, there's no point in any of it, and death may be a good way to achieve that. A ...


1

In the study by Whitfield 1990 (1) I found the information that the parasitic wasp from family Ichneumonidae have interesting symbiotic viruses called polydnaviruses. This virus stay as provirus in the wasps genome and is transmitted vertically between subsequent generations of parasitoid. It does not harm the wasp and it is transmitted to the wasps hosts ...



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