Etiology, Biology

Assignment Help:

M protein of rheumatogenic GAS has distinct structural characteristics that are akin to human heart tissue, particularly sarcolemmal membrane proteins and cardiac myosin. The major factors that lead to risk of ARF are the severity of the immune response to GAS pharyngitis and persistence of GAS organisms during convalescence. A very small proportion (0.3-3 per cent) of patients suffering from GAS throat infection ultimately develop ARF and this along with a familial predisposition of ARF points to a genetic susceptibility. However, in our Indian patients a genetic linkage to HLA DR3 in patients, with ARF has been demonstrated. For confirmation of the initial diagnosis of acute rheumatic fever, evidence of prior GAS infection is required. Several rapid GAS antigen tests are available. Majority of these tests has a high degree of specificity but low level of sensitivity in clinical practice.

However, it must be stressed that a negative test does not rule out the GAS infection in the throat. At the same time in presence of a positive antigen test and positive throat culture, it is difficult to distinguish between a recent infection which can be associated with ARF and chronic carrier of GAS infection with ARF. Elevated or rising ASO titres (> 250Todd units in adults and >333 Todd units in children) are more reliable evidence of recent GAS infection than a positive culture or positive rapid antigen test and such titres are also significant for diagnosis.


Related Discussions:- Etiology

Protozoa, locomotion in protozoa

locomotion in protozoa

Digitalis toxicity, Symptoms of digitalis toxicity include anorexia, nausea...

Symptoms of digitalis toxicity include anorexia, nausea, headache, blurring or yellowing of vision, and disorientation. Cardiac toxicity may take the form of atrioventricular condu

How to calculate glycemic index, Q. How to calculate glycemic index? If...

Q. How to calculate glycemic index? If you take a certain rood and measure the rise in blood sugar in response to the food consumed in comparison with the response to an equal

What is the difference between diffusion and osmosis, Q. What is the differ...

Q. What is the difference between diffusion and osmosis? Osmosis is the phenomenon of movement of solvent particles in general, water from a region of lower solute concentratio

Coronary flow limiting stenoses, Coronary Vasoconstriction 1) Coronary f...

Coronary Vasoconstriction 1) Coronary flow limiting stenoses are caused by concentric or eccentric artherosclerotic plaques, with or without potential for local vasomotor change

Levels of prevention, Family Centred Activities to Ensure Harmonious Relati...

Family Centred Activities to Ensure Harmonious Relationship: Between various members of  the family attitudes of mutual trust, love and respect for one another need  to be  fo

What are cotyledons, What are cotyledons? Cotyledons or else seed leave...

What are cotyledons? Cotyledons or else seed leaves are structures formed by the embryo of angiosperms to absorb nutrients from the endosperm and to store and transfer these nu

State the versions of binocular movements, State the Versions of Binocular ...

State the Versions of Binocular movements Versions are movements of both eyes in the same direction. a) Dextroversions: Movements of both eyes to'the right side. b) Levov

Pisciculture, Pisciculture: This is the culturing of fishes. There is a pri...

Pisciculture: This is the culturing of fishes. There is a principal form of aquaculture called Fish farming, while other methods can come under mariculture. Fish farming main aim i

Adp-atp system of energy exchange, ADP-ATP system  of energy  exchange : ...

ADP-ATP system  of energy  exchange : In 1929 Lohmann, Fiske and  subbarow  published  their  discovery  that the energy  exchanges  compounds in all biological  systems  are t

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd