Tri-2, Wk11, Day 110 - Tuesday

Today's picture is of Rickettsia. What's rickettsia? Good question and one I should know for tomorrow's microbiology exam.

Rickettsias are small, Gram-negative coccobacilli which are microscopic obligate intracellular parasites.

That definition probably doesn't help anyone out so we'll take it piece by piece.

Rickettsia - the name of the thing in the picture

small - we're talking about 0.3 to 0.5 micrometers in diameter and 0.8 to 2.0 micrometers in length. A micrometer is one-millionth of a meter and a meter is kind of like a yard so, rickettsia are pretty darned small.

Gram-negative - this basically referes to the outer membrane of the organism. Gram-negative means the membrane is a thin peptidoglycan (as opposed to a thick one which would be referred to as Gram-positive)

......peptidoglycan - this is a polymer (large molecule) that consist of sugars and amito acids that form a mesh like layer.

coccobacilli - this refers to the type of organism and usually refers to it's shape. Cocco means round or spherical and bacilli generally means rod shaped. Maybe these little buggers come in both varieties

microscopic - like we said - these suckers are SMALL

obligate - basically meaning "out of necessity"

intracellular parasites - micro organisms that are capable of growing and reproducing inside the cells of a host.

Apparently, there are many different kinds of rickettsiae and they come in groups like the Thyphus group or the Spotted Fever Group - Scrub typhus used to be a group but it looks like that one has been reclasified.

Thyphus Fever is a systemic diseases caused by reckettsiae. Thyphus fever comes in a few varieties itself - one is known as Epidemic typhus caused by Rickettsiae Prowazekii. In 1812, epidemic typhus helped drive Napoleon from Russia; more recently, during World War I, it infected over 30 million Russians and killed 3 million.

Rocky Mountain Spotted Fever is another illness caused by Rickettsia Rickettsii.

I've got a list of 10 different Rickettsia diseases to get familiar with before tomorrow's test.

With regards to chiropractic and these many diseases, I would be heading to an MD to get whatever medicinal treatments are available. These diseases have some pretty high mortality rates - Scrub typhus or stustugamushi disease has a fatality rate of 50% if left untreated but, with antibiotics, fatalities are rare.

btw - tsutsugamushi is Japanese for "bad little bug"

off to bed!