Monday, May 19, 2008

Answer to Case 22

I had specified 'mice' for this week's questions, but I should have generalized it to rodents, since there is considerable overlap among the various disease-carrying species.

Tom made a great start in answering the questions. I will elaborate below. Keep in mind, this is just a list of the more common diseases - there are many more!

1. List 5 infectious diseases spread by rodents:
Tom says:
1. and 2. Rat bite fever (Streptobacillus moniliformis, Spirillum minor)
3. Hanta virus
4. Lymphocytic choriomeningitis
5. Plague & Leptospira
6. heebie jeepies (right Pritish?)

Here are some other diseases:
Lassa fever, Argentine hemorrhagic fever, Venezuelan hemorrhagic fever, hemorrhagic fever with renal syndrome, Venezuelan equine encephalitis, and tick-borne encephalitis.

Rocky mountain spotted fever, Boutonneuse fever, scrub typhus, murine typhus, tick-borne relapsing fever, Lyme disease, and salmonellosis (with S. typhimurium)

2. Rodents can act as reservoirs for which parasitic infections?:

Toxoplasma gondii (named after the African rodent it was first described in, Ctenodactylus gundi)
Chagas disease
Cutaneous and visceral leishmaniasis
(E. multilocularis and E. vogeli)
Schistosomiasis (with S. japonicum)
Hymenolepsis (Both H. nana and H. diminuta)

Tom also gave us the following:
"Just remember, these rhyming species carry lots of nasties: rats, bats, & cats (not sure about wombats...)" Although, 'man's best friend' doesn't get off the hook either - more on this in a future case of the week...

It is important to note that rodents can spread disease in a number of ways: the infectious organism can be excreted in urine and then be inhaled following aerosolization (e.g. Hanta virus) or ingested (e.g. Leptospirosis), or the organism can be directly inoculated through a bite (e.g. rat bite fever). Vectors can also be involved such as fleas, ticks, mites, mosquitoes, sand flies, and reduviid bugs. Finally, rodents may harbor a stage of the disease that is not directly infectious to humans and must first be transmitted to another non-human host (e.g. echinococcosis).

No comments: