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

Cell coat, what is the job of the cell coat?

what is the job of the cell coat?

Name the source gland of leutinising hormone, Name the source gland of leut...

Name the source gland of leutinising hormone (LH). State the other hormone along with which it acts on its target cells/organ. Give their two functions.

Technique of operation, Technique of Operation :  TEE probe i...

Technique of Operation :  TEE probe is passed in all cases soon after anaesthesia. The initial steps and exposure of mitral valve are done as for open mitral valvotom

What is embryonic origin of the nervous system in vertebrate, How does the ...

How does the embryo turn from gastrula into neurula? How is the neural tube formed? What is the embryonic origin of the nervous system in vertebrates? The neurula stage is divi

Distinct ecological importance of species, The distinct ecological importan...

The distinct ecological importance of species supports functional diversity and has a direct bearing on the species composition of the site, and therefore on overall biodiversity.

Explain objective anti-arrhythmic pacemaker defibrillators, Explain Objecti...

Explain Objective Anti-arrhythmic pacemaker defibrillators? After reading this unit, you should be able to: 1 describes the classification of ant arrhythmic drugs; 2 understand

How campylobacteriosis occurs in humans, How CAMPYLOBACTERIOSIS  occurs in...

How CAMPYLOBACTERIOSIS  occurs in humans C. jejuni frequently contaminates raw chicken. Survey shows that 20-100% of retail chickens are contaminated. Many healthy chickens car

Asymptomatic or mildly symptomatic patients, Q. Asymptomatic or Mildly Symp...

Q. Asymptomatic or Mildly Symptomatic Patients? The treatment is controversial. Some give them betablockers/or calcium channel blockers like verapamil, in the hope of preventin

Determine the interphase of mitosis, Is the interphase of meiosis differen...

Is the interphase of meiosis different from the interphase of mitosis? The interphase that precedes meiosis is same to the interphase that precedes mitosis. In them the major e

Explain transfer from solid culture to liquid media, Explain Transfer from ...

Explain Transfer from Solid Culture to Liquid Media The steps involved in this technique are included herewith: 1. Sterilized inoculating loop or needle is touched carefully

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