Posted: Jun 08, 2018 7:37 am
by Calilasseia
It's time for more parasites. Which I've been pointed to by this page.

Such as Anisakis Roundworms, which will treat your stomach as a 5-star hotel while making you feel like you've eaten fresh dog poo. These roundworms have multiple hosts, including various fish (eating raw or undercooked fish is the textbook infection process in humans), crustaceans (mainly Krill), and assorted marine mammals such as Dolphins or fish-eating Seals.

Next up was an eye opener for me. I'm familiar with some Microsporidians, as these are the causative agents of some nasty tropical fish diseases. Plistophora hyphessobryconis, for example, is the causative agent of Neon Tetra Disease in that species, a condition that is invariably fatal. But now I've encountered, thanks to that website, a Microsporidian that has been documented as infecting humans, in the form of Encephalitozoon cuniculi, which as its Generic name suggests, can cause a nasty encephalitis in humans. The case in question arose after a kidney transplant, when the recipient started exhibiting unusual symptoms. It transpired that the donor was infected with the same Microsporidian species, and donor organs arising therefrom contaminated numerous recipients. Once the organism was tracked down, it was amenable to treatment, but do you want a microbe that makes you behave as if you have Parkinson's Disease getting up close and personal with you?

Next one was attached to a contact lens that hadn't been cleaned properly. Nice thought for you all to savour. This one being one of the Acanthamoeba species. Which are a known cause of blindness (Amoebic Keratitis) in people who haven't removed their contact lenses before swimming in infected waters. Other Acanthamoeba issues include Granuomatous Amoebic Encephalitis, arising when these amoebae enter the human central nervous system. Part of the problem is that these amoebae contain bacterial endosymbionts - they ingest certain bacterial species without consuming them as food, and those diverse bacterial endosymbionts can then be carried to infect whatever site the amoebae come into contact with. Given that some of the endosymbionts include Legionella species, this is pretty bad news. A few here will note with some hilarity, that one of the species in the Genus is one Acanthamoeba byersi ...

Then there's Taenia saginata, the Beef Tapeworm. Not especially dangerous to humans, but not pleasant either if you end up with one. Because one of these can grow to be 20 feet long. All of that length inhabiting your innards. However, humans aren't usually a host for this. Rather nastier is Taenia solium, the Pork Tapeworm, which doesinclude humans as preferred hosts.

Then there are the related Cestodes. Hymenolepis nana is one that selects humans as a host. Along with rodents. You pick this up if your food is contaminated with rodent dung. Another good reason to break out those traps and baits. However, one documented infection, which affected an HIV immunocompromised patient, delivered a startling secondary pathology - the tapeworm developed its own cancer, and those cancer cells spread to the patient's lung. That one was so remarkable, The New England Journal Of Medicine featured it in a paper, which the terminally curious can read here.

How about Cutaneous Larva Migrans? Say hello to Hookworms, which are the cause of this particularly hideous complaint, a principal causative species in the Americas being Ancylostoma braziliense. The vernacular name for this diseases says it all - "creeping eruption".

Then there are parasitic flatworms. One of which was found in a teenager's eyeball in Mexico. More on this particular brand of squirm here, which again led to an NEJM article.

The fun world of invertebrate zoology strikes again ...