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 | 艾滋病、丙型肝炎。 |
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 radiation at peak spectrally sensitive wavelengths, without the use of toxic mercury, thus enabling compact, portable and durable point-of-need disinfection products.
Indicator Organisms
Detecting the presence of pathogenic organisms can be labor intensive, costly and time consuming. The presence of specific pathogenic bacteria can be temporally or spatially sporadic, making their isolation and characterization challenging.
To monitor the likely presence of pathogens in water, surrogate/indicator microorganisms are utilized. Surrogate microorganisms include fecal coliforms, whereE. coli是一个主要的species of the group, and fecal streptococci. Presence of fecal coliforms and fecal streptococci is indicative of water contamination with bacteria originating from the feces of either humans or animals.
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, the commonly used surrogate for testing against human Norovirus, a very contagious virus that causes vomiting and diarrhea and is the number one cause of acute gastroenteritis, is feline calicivirus (FCV). FCV and human norovirus have similar structure and belong to the same family calledCaliciviridae. Additionally, FCV is used as surrogate because human norovirus cannot be propagated in cell cultures in the laboratory for disinfection studies.
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