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

Hybridoma, Hybridoma is the clone of plasmacytoma cells which secrete a mo...

Hybridoma is the clone of plasmacytoma cells which secrete a monoclonal antibody; commonly produced by the fusion of peripheral or splenic plasma cells taken from the immunized mo

Do moulds grow better where it is dark or light, Do moulds grow better wher...

Do moulds grow better where it is dark or light? This time leave one culture dish in a warm place where it receives light all the time. Place the other dish in a warm dark plac

Periapical radiography - criteria for endosteal implants, Q. Periapical rad...

Q. Periapical radiography - criteria for endosteal implants? Periapical radiographs are images of a limited region of the mandibular or maxillary alveolus.  Periapical radiogra

Functions of the pancreas, The pancreas performs digestive and hormonal fun...

The pancreas performs digestive and hormonal functions. The enzymes secreted by the exocrine tissue in the pancreas help in the break down of carbohydrates, fats, proteins, and

Vitamin – c, VITAMIN - C Also known as ascorbic acid / anti viral v...

VITAMIN - C Also known as ascorbic acid / anti viral vitamin / anti cancer vitamin / anti rabies vitamin / anti scurvy vitamin. It is the earliest known vitamin. It

How folate is important for pregnant women, How Folate is Important For Pre...

How Folate is Important For Pregnant Women? Folate is also important for pregnant women. Low blood levels of folate during pregnancy can cause neural tube defects-anencephaly (

What are the joints, What are the joints Joints are the place of artic...

What are the joints Joints are the place of articulation between two or more bones, or between a bone and a cartilage. Due to the presence of a number of joints, the movement

Explain the solubility in water of dietary fibre, Explain the Solubility in...

Explain the Solubility in Water of dietary fibre? Fibres that dissolve in hot water are soluble and those that do not, are insoluble. Several structural features affect solubil

Free-hand sectioning of plant tissue (stem), What are the processes involve...

What are the processes involved in the preparation of plant tissue for free hand sectioning?

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