Microbiological contaminants viruses

Viruses are obligate intracellular parasites. They only exhibit activity by infecting other living organisms, thus they are not a practical concern in industrial microbiological fields. The exception is where viral contamination of the product or process represents a threat of transmission of disease. Microscopic insects and protozoans are also not addressed in this article (see Insect control technology). 

Another microbiological purity issue that has been associated with human blood is the possibility of adventitious contamination with viral pathogens. Likewise, if animal blood is used as the red cell source, a spectrum of viruses have been identified as potential contaminants and possibly as zoonotic agents that may be infectious to humans. " Therefore, in addition to the careful control of the blood used as the Hb source, the process for Hb solution preparation should employ robust virus inactivation and removal steps to reduce the risk of disease transmission. 

A number of veterinary vaccines contain components that are pathogenic in humans and which could conceivably cause disease, although the vast majority are specific to the animals they infect. An example of a disease that infects both animals and humans is rabies, and rabies vaccines are commercially and widely available. However, the problem is overcome by inactivation of the virus to produce a product that is safe for both the vaccinated animal and for those who administer it. However, as Table 14.1 indicates, some products are available that may cause disease in humans if used improperly or should accidental injection or a needle stick injury occur. Clearly, the results of human contamination and infection are microbiological and not toxicological. Nevertheless, it is worth examining these briefly for the sake of completeness and to emphasise that user safety is not the sole domain of pharmaceutical products. 

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