Sewage monitoring for the Covid virus began in late 2020, after several studies indicated that sewage sludge could accumulate SARS-CoV-2 RNA. This is because traces of SARS-CoV-2 can be isolated from what we throw in the toilet – and sometimes survive for up to several days after leaving the body of an infected person. According to the New Zealand Institute for Environmental Science and Research, SARS-CoV-2 RNA was detected in all but one of the 120 sewage sites by the week of April 10, the NZ Herald reported. The data showed that at the beginning of the year, only about 10% of the sites reported quantifiable amounts of virus. By mid-February, it had reached more than a quarter and by mid-March, it was present in about 90 percent of them. The latest data show that daily cases in the region have dropped to about 14% of the peak – less than 100 daily cases per 100,000, the report said. Health authorities in Victoria, Australia have identified Covid’s Omicron strain subtype BA.4 or BA.5 in wastewater samples taken from the Tullamarine catchment, ABC news reported. Sewage testing in March revealed that BA.2 had become the dominant figure in Victoria. A report by the South African Medical Research Council revealed that analysis of wastewater samples in South Africa shows an increased incidence of Covid-19 in three provinces – Gauteng, eThekwini in KwaZulu-Natal and Bloemfontein in the Free State. Samples from sewage plants in and around Johannesburg also show that Covid-19 fragments are becoming more common. The Omicron variant dominates all specimens so far sequenced with the delta variant found in individual specimens, the report revealed. “Sewage is completely independent of whether you take the test or not – everyone does injuries,” said Mark Serbos, a professor at the University of Waterloo in Ontario, according to CTVNews.ca. “Sewage is really one of our only reliable tools for determining what is happening in terms of community dominance.” As of April 2, the weekly average in the Canadian city of Waterloo for the number of copies of the N gene (well-preserved in sewage) per milliliter was about 415, representing a steady increase in Covid-19 concentration levels since mid-March. A major driver of this growth was the rapid spread of the Omicron BA.2 sub-variant within the province, the Serb said. “We have now seen that BA.2 is almost 100 percent in most wastewater [samples] we were studying “, added the Serb. Other provinces such as Alberta and British Columbia are also seeing an increase in Covid in wastewater samples. About a third of U.S. sewage sampling sites have seen an increase in Covid-19 cases nationwide, according to the latest figures from the US Centers for Disease Control and Prevention (CDC). 20220416-163202