Concentration and detection of hepatitis A virus and its indicator from seawater

Abstract

Hepatitis A virus (HAV) infection is the leading worldwide cause of acute viral hepatitis, and its outbreaks often occur from fecal contaminated shellfish. HAV is extremely stable in the environment and can survive 3~10 months in water. In addition, HAV can be bio-concentrated by shellfish by as much as 100 fold from fecal contaminated waters. Bacteriophage MS2 is used widely as a surrogate for HAV, and its presence has been proven to be a reliable indication of the presence of HAV. A rapid detection of viral contamination in water environments can prevent economic loss and can identify the source of contamination within a short time. However, the conventional methods for virus concentration and detection are often laborious, time consuming, and subject to clogging. Furthermore, most methods require a secondary concentration step to further reduce the final volume of samples. Hence the objective of this study was to develop a simple, rapid and inexpensive virus concentration method in aid of rapid detection. The use of granular activated carbon and zeolite were investigated. In the method, high levels of viruses (HAV or MS2) were inoculated into artificial seawater and concentrated by the adsorbents. The viruses were then eluted with protein denaturant and detected via real-time PCR (qPCR). While both adsorbents were more efficient in seawater than in fresh water, and were able to adsorb 6 logs of viruses from seawater, zeolite was able to adsorb ~99% of the viruses in less than 5 min at room temperature, and the entire concentration and detection can be done in approximately 2 h. Compared to existing methods, this method eliminated the need for a secondary concentration step, as well as the necessity to modify the pH or salinity of the seawater during concentration. The virus concentration method using activated carbon or zeolite could be a useful addition to the available methods for virus detection in seawater.