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== Mortality from infectious diseases ==
== Diagnosis र therapy ==
The field of ''infectious diseases'' also occupies itself with the [[diagnosis]] र [[Medication|therapy]] of [[infection]].
=== Diagnosis ===
''Diagnosis'' is initially by medical history र physical examination, र imaging (such as [[X-ray]]s), but the principal tool in infectious रोग is the [[microbiological culture]]. In a culture, a [[growth medium]] is provided for a particular agent. After inoculation of a specimen of diseased fluid or tissue onto the medium, it is determined whether bacterial growth occurs. This works for a number of [[bacterium|bacteria]], for example [[Staphylococcus]] or [[Streptococcus]].
Certain agents cannot be [[microbiological culture|cultured]], for example the above-mentioned ''[[Treponema pallidum]]'' र most [[virus]]es. The first [[serology|serological]] markers were developed to diagnose [[syphilis]] (the [[Wassermann test]], later replaced by the [[VDRL]] र [[TPHA]] tests). Serology involves detecting the [[antibody|antibodies]] against an infectious agent in the patient's [[blood]]. In [[immunocompromised]] patients (e.g. [[AIDS]]), [[serology]] can be troublesome, because the antibody reaction is blunted.
A more recent development is direct detection of [[virus|viral]] proteins and/or DNA in [[blood]] or [[secretion]]s. This can be done by [[PCR]] (polymerase chain reaction), involving the amplification of viral DNA र its subsequent detection with anti-DNA probes.
==== Infectious रोगको बर्गिकरण ====
One way of proving that a given रोग is "infectious", is to satisfy [[Koch's postulates]] ([[Robert Koch]]), which demand that the [[infectious agent]] is identified in patients र not in controls, र that patients who contract the agent also develop the रोग. These postulates were tried र tested in the discovery of [[Mycobacteria]] as the cause for [[tuberculosis]]. Often, it is not possible to meet some of the criteria, even in diseases that are quite clearly infectious. For example, ''[[Treponema pallidum]]'', the causative [[spirochete]] of [[syphilis]], cannot be [[microbiological culture|cultured]] in vitro - however the organism can be cultured in rabbit testes].
[[Epidemiology]] is another important tool used to study रोग in a population. For infectious diseases it helps to determine if a रोग [[outbreak]] is sporadic (occasional occurrence), [[endemic (epidemiology)|endemic]] (regular cases often occurring in a region), [[epidemic]] (an unusually high number of cases in a region), or [[pandemic]] (a global epidemic).
=== Therapy ===
When a [[microbiological culture|culture]] has proven to be positive, the sensitivity (or, conversely, the [[antibiotic resistance]]) of an agent can be determined by exposing it to test doses of [[antibiotic]]. This way, the [[microbiology|microbiologist]] determines how sensitive the target [[bacterium]] is to a certain antibiotic. This is usually reported as being: '''S'''ensitive, '''I'''ntermediate or '''R'''esistant. The ''[[antibiogram]]'' can then be used to determine optimal therapy for the patient. This can reduce the use of [[broad-spectrum antibiotic]]s र lead to a decrease in [[antibiotic resistance]].
==== The work of an infectiologist ====
[[Physician|Doctors]] who specialise in the [[medicine|medical treatment]] of infectious रोग are called ''infectiologists'' or ''infectious रोग specialists''. Generally, [[infection]]s are initially diagnosed by [[primary care]] physicians or [[internal medicine]] specialists. For example, an "uncomplicated" [[pneumonia]] will generally be treated by the [[internist]] or the [[pulmology|pulmonologist]] (lung physician).
The services of the infectious रोग team are called for when:
* The रोग has not been definitively diagnosed after an initial workup
* The patient is [[immunocompromised]] (for example, in [[AIDS]] or after [[chemotherapy]]);
* The [[infectious agent]] is of an uncommon nature (e.g. [[tropical रोग]]हरु);
* The रोग has not responded to first line [[antibiotic]]s;
* The disease might be dangerous to other patients, र the patient might have to be isolated.
The work of the infectiologist therefore entails working with patients र doctors on one hand र [[laboratory science|laboratory scientists]] र [[immunology|immunologists]] on the other hand.
=== इतिहास ===
[[Anton van Leeuwenhoek]] ([[1632]]-[[1723]]) advanced the science of microscopy, allowing easy visualization of bacteria.
[[लोइस पास्चर|Louis Pasteur]] proved beyond doubt that certain diseases can be caused by infectious agents, र developed a vaccine for rabies.
[[Robert Koch]], mentioned above, gave the study of infectious diseases a scientific basis by formulating [[Koch's postulates]].
[[Edward Jenner]], [[Jonas Salk]] र [[Albert Sabin]] developed successful vaccines for [[Smallpox]] र [[polio]], reducing the threat of these debilitating diseases.
[[Alexander Fleming]] discovers the world's first antibiotic Penicillin which in turn inspired the discovery of the other [[antibiotics]] available today.
[[Gerhard Domagk]] develops [[Sulphonamides]], the first broad spectrum synthetic antibacterial drugs.
== यो पनि हेर्नुहोस्। ==
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