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

Splenic abscess, Splenic infarction is a common complication of left-sided ...

Splenic infarction is a common complication of left-sided IE (40 per cent of cases). Only 5 per cent of patients with splenic infarction will develop splenic abscess. This infectio

Three sources of energy which do not depend on fossil fuel, Name three sour...

Name three sources of energy which do not depend on fossil fuel. Sources of energy which do not rely on fossil fuel are water (hydroelectric generation), wind, tidal power, wav

Describe tr murmur and vsd murmur in details- heart diease, Describe TR Mur...

Describe TR Murmur and VSD murmur in details? TR Murmur :   Characteristic: Holosystolic murmur, loudest at left lower-sternal border and becomes louder with inspiration (Carv

Define incision - endodontic surgery, Define Incision - Endodontic Surgery ...

Define Incision - Endodontic Surgery Incisions are accomplished by using one of four scalpel blades: No. 11, No.  12, No. 15, and No. 15-C Horizontal incision should be m

Foot-and-mouth disease - viral disease, F o o t - a n d - m o u ...

F o o t - a n d - m o u t h disease Foot-and-mouth disease (FMD) is an extremely contagious viral disease of cloven footed animals most notably cattle, pig and she

What, what are mendal low

what are mendal low

Threatened species - wildlife, Threatened Species - Wildlife Many plan...

Threatened Species - Wildlife Many plant and animal species are threatened by the possibility of extinction. However, the seriousness of the threat varies. For example, a spec

Measurement of light intensity, Measurement of Light Intensity How do w...

Measurement of Light Intensity How do we measure the intensity of a source of light falling on a surface? You know that light spreads out uniformly in all directions from a sou

Ecology.., examples of pyramid of energy

examples of pyramid of energy

Which organs are protected by the skull, Which organs are protected by (a) ...

Which organs are protected by (a) the skull, (b) the rib cage, (c) the vertebrae?   a) The skull safe the brain, b) the rib cage safes the heart, lungs, liver and spleen,

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