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

Proteins, Amino Acid - compound with an amino group and a carboxyl group a...

Amino Acid - compound with an amino group and a carboxyl group attached to a central carbon Proteins make up 50% of dry mass of cells in our bodies E.g. of proteins are

What are the limits of pest control, How could knowledge of a pest organism...

How could knowledge of a pest organism's tolerance limits be used in pest control? Pesticides could be developed that make those limits narrower, environmental conditions could

What will happen without enough insulin, Q. What will happen without enough...

Q. What will happen without enough insulin? Without enough insulin two things can happen. Firstly, the cells of the body will be unable to use the glucose in the blood for ener

What is acetobacter, Q. What is Acetobacter? These bacteria, also known...

Q. What is Acetobacter? These bacteria, also known as "vinegar bacteria", cause significant spoilage in the wine industry but are necessary for vinegar production. The importan

How is the cerebrum anatomically divided, How is the cerebrum anatomically ...

How is the cerebrum anatomically divided? The cerebrum is divided into two cerebral hemispheres, the right and the left. Each hemisphere is made of four cerebral lobes: frontal

Fusarium toxins, Another important genus of mycotoxin producers is Fusarium...

Another important genus of mycotoxin producers is Fusarium, many species of which produce members of the trichothecene family of mold metabolites like deoxynivalenol, neosolaniol a

Methods by which diseases are transmitted, There are several methods by whi...

There are several methods by which a disease-causing organism can be transferred from the reservoir to the host organism. Direct contact : Disease - causing organism may be tr

Which are the three parts of the small intestine, Which are the three parts...

Which are the three parts of the small intestine? The small intestine is separated into three portions: duodenum, jejunum and ileum. Digestion System - Image Diversity: smal

Gene targeting in somatic cells, Gene targeting in somatic cells: Since t...

Gene targeting in somatic cells: Since the pioneering work with sheep at Roslin cloning by nuclear transfer has now been exemplified in a number of other livestock species includ

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