In spite of medical advances and greater than ever rate of development in third world countries, unknown diseases remain one of the primary causes of deaths around the world. Even in the United States, unknown infectious disease causes over 16,000 deaths every year.
When someone dies of unknown diseases in the United States or other industrialized countries, protocol demands that an autopsy is performed. When this is done, the major organs in the torso are removed and inspected. In most cases, they are weighed and examined for any obvious signs of disease or damage. The brain is also removed, weighed, and inspected. If nothing is readily noticeable, then tissue samples are taken and inspected under the microscope. If that still reveals nothing, then the samples go to a laboratory dedicated to the diagnosis of infectious disease
This continual war between disease and cure has yielded numerous advances, helping people all over the world live longer and healthier lives. Another tool in the medical professional’s arsenal for the detection of diseases are symptoms that occur in combinations that by themselves, do not denote anything alarming. For example, take polycystic ovary syndrome (PCOS). This disease presents itself with irregular menstrual cycles, excessive hair growth, thickening of the skin, and the inability to lose weight. Again, individually, these symptoms aren’t alarming. However, taken as a whole, PCOS becomes an apparent diagnosis.
However, there are times when an infectious disease presents a series or combination of symptoms that leaves nearly everyone stumped. In those cases, again, tissue samples head to a laboratory that is able to detect and diagnose them. It doesn’t matter if it’s emerging diseases that have migrated from the third world, such as Hantavirus, or West Nile, or diseases once thought to be nearly eliminated like pertussis, the detection of disease has become paramount.
Investigative laboratories play an important part in the detection of these mysterious diseases, using five specific procedures. Once the tests are completed, the tissue samples are either destroyed or stored. In some cases, they are shipped to other laboratories so that tests can be replicated and diagnoses confirmed. Of course, these infectious samples can’t be sent through the mail. In these cases, labs and hospitals rely on specialized couriers, such as Pacific BioMaterial Management, Inc. to transport and handle the samples.
The four specific tests that labs use to identify unknown pathogens are microscopy, culturing, immunologic tests, and nucleic acid identification tests.
The normal method of identifying an unknown disease is through culturing. However, growing a culture can take weeks or even longer, delaying the final results. To supplement this, the other four tests are often run in conjunction with culturing. That’s because even though cultures take longer, they are still essential for testing the efficacy of drug treatments.
After culturing and isolating the unknown disease, a laboratory can use functional identification methods. Often a series of tests are used, which can involve mass spectroscopy and other chromatographic techniques. A new test called matrix-assisted laser desorption ionization time of flight (MALDI-TOF) can yield results in under an hour, where older methods traditionally took one to two days.
Microscopy is a faster way of identifying an unknown disease. This is a more thorough extension of the microscopic examination that is done during the autopsy. The cultures are treated with a variety of stains that help identify specific pathogens by increasing their contrast against a non-stained background. These range from the general Gram stain and various fluorescent stains to the more complicated Gomori-Wheatley stain. Each stain is used to identify a specific type of pathogen or bacterial body.
Immunologic tests are used to detect diseases by looking for specific responses of the body to them. These either use antigens to detect antibodies, or antibodies to detect antigens. By detecting these, they help identify the unknown pathogen in the samples.
The final method used in labs to identify pathogens is nucleic acid-based testing. In nucleic acid testing, a pathogen’s DNA or RNA is extracted and then compared to a national database. These tests can either be single-targeted or they can be multiplex, able to detect two or more microorganisms. The drawback to a multiplex test is that it is considerably less sensitive than a single-target test and can sometimes return inconsistent false positives.
Article Submitted By Community Writer
