Pathogens is a term reserved to identify those disease causing micro-organisms in our environment— whether virus, bacteria, protozoan, fungus or other. Pathogens can be found in the water we consume, air we breathe and surfaces we touch. The young, particularly those under the age of 5, the elderly and the immune compromised are most at risk from infection by these attackers.
Some pathogens can be easily eliminated from the environment while others, due to their physical structure and size, are resistant to many forms of disinfection.
| Difficulty | Species | Examples |
|---|---|---|
| High | Bacterial Endospores | Clostridium (difficile, tetani), Bacillus (subtillus, Anthrax) |
| Mycobacteria | M. tuberculosis | |
| Small non-enveloped viruses | Norovirus, Poliovirus | |
| Fungi | Candida, Aspergillus | |
| Gram negative Bacteria | Acinetobacter, E. coli | |
| Large non-enveloped viruses | Rotavirus | |
| Gram positive Bacteria | Staphylococcus (MRSA), Enterococcus (VRE) | |
| Low | Enveloped viruses | HIV, Hepatitis C. |
Many biological studies have proven that when the appropriate dosage of UV light is applied to a target pathogen, it effectively inactivates the DNA or RNA of the pathogen. This inactivation means that the microbe is no longer able to cause infection.
Deep ultraviolet (UVC) LEDs emit higher intensity light, at peak spectrally sensitive wavelengths without the use of toxic mercury-enabling compact, portable and durable point-of-need disinfection products.
Indicator Organisms
Detecting the presence of pathogenic organisms can be challenging. The presence of specific pathogenic bacteria may be sporadic and erratic, and the isolation and culture of these bacteria is not straightforward.
To help combat this risk it is typical to look for indicator organisms, that is micro-organisms whose presence indicates a probable presence of pathogens. E. coli is a well-known indicator organism in water treatment.
Target vs. Surrogate Organisms
When designing disinfection systems, it might not be practical or safe to use the actual target pathogen in testing. Microbiological testing is frequently performed using surrogate microorganisms in place of the target organisms.
For example, a surrogate for testing against seasonally encountered Norovirus (flu) is bacteriophage MS2—a member of a family of closely related bacterial viruses that includes bacteriophage Qβ. MS2 has a similar structure and behavior to Norovirus without the disease-causing effects in humans, so it is often used in disease transmission studies for the flu.
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