Tag: wastewater monitoring

Categories : Diseases, Syndromes and Conditions Environmental EffectsTags :

Environmental Monitoring Offers Low-cost Tool for Typhoid Fever Surveillance

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Detection of the viruses that infect the typhoid fever bacterium in sewage indicates disease burden

Researchers can accurately track where typhoid fever cases are highest by monitoring environmental samples for viruses called bacteriophages that specifically infect the bacterium that causes typhoid fever. Senjuti Saha of the Child Health Research Foundation in Bangladesh and colleagues report these findings in a new study published February 15 in the open access journal PLOS Neglected Tropical Diseases.

Typhoid fever is a common infection in many low- and middle-income countries and causes an estimated 135 000 deaths and 14 million infections globally each year. The World Health Organization has prequalified two typhoid vaccines, but for policymakers to plan effective vaccination strategies, they need accurate, high-resolution estimates of where the burden is highest.

Traditionally, people have cultured the bacterium that causes typhoid fever from blood samples to determine where the infection is most common, but in the new paper, researchers tried a more cost-effective surveillance approach. They tested environmental water samples from sewage and other locations to detect bacteriophages specific to the water-borne pathogen that causes typhoid fever, Salmonella Typhi.

The team tested 303 water samples from two locations in Bangladesh: the urban capital city, Dhaka, and a rural district, Mirzapur. They found that bacteriophages specific for Salmonella Typhi were present in 31% of environmental samples in Dhaka, compared to just 3% of samples from Mirzapur. This corresponds to results from more than 8,400 blood cultures, in which 5% of cultures from Dhaka and 0.05% from Mirzapur tested positive.

The new results suggest that detecting bacteriophages specific for Salmonella Typhi may be a rapid environmental surveillance method that could help decision makers understand the presence of typhoid fever in the community. The researchers propose that environment monitoring of bacteriophage could be a simple, cost-effective and scalable tool to assist policy decisions on typhoid control.

The authors add: “Looking for bacteriophages in wastewater is a low-cost method for identifying typhoid hotspots without doing expensive blood cultures on thousands of people.”

Categories : Antibiotics Environmental EffectsTags :

Antibiotics Residues in Water Threaten Human Health

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Photo by Nathan Dumlao on Unsplash

In Asia, researchers found that antibiotic residues in wastewater and wastewater treatment plants risk contributing to antibiotic resistance, and the drinking water may pose a threat to human health. Published in The Lancet Planetary Health, their comprehensive analysis also determined the relative contribution of various sources of antibiotic contamination in waterways, such as hospitals, municipals, livestock, and pharmaceutical manufacturing.

“Our results can help decision-makers to target risk reduction measures against environmental residues of priority antibiotics and in high-risk sites, to protect human health and the environment,” says first author Nada Hanna, researcher at the Department of Global Public Health at Karolinska Institutet. “Allocating these resources efficiently is especially vital for resource-poor countries that produce large amounts of antibiotics.”

Antibiotics can enter the environment during their production, consumption and disposal. Antibiotic residues in the environment, such as in wastewater and drinking water, can contribute to the emergence and spread of resistance.

Major antibiotics producers and users

The researchers looked for levels of antibiotic residues that are likely to contribute to antibiotic resistance from different aquatic sources in the Western Pacific Region (WPR) and the South-East Asia Region (SEAR), regions as defined by the World Health Organization. China and India, among the world’s largest producers and consumers of antibiotics, fall within these regions.

To find the data, researchers made a systematic review of the literature published between 2006 and 2019, including 218 relevant reports from the WPR and 22 from the SEAR. They also employed a method called Probabilistic Environmental Hazard Assessment to determine where the concentration of antibiotics is high enough to likely contribute to antibiotic resistance.

Ninety-two antibiotics were detected in the WPR, and forty five in the SEAR. Antibiotic concentrations exceeding the level considered safe for resistance development (Predicted No Effect Concentrations, PNECs) were observed in wastewater, influents and effluents of wastewater treatment plants and in receiving aquatic environments. Wastewater and influent of wastewater treatment plants had the highest risks. The relative impact of various contributors, such as hospital, municipal, livestock, and pharmaceutical manufacturing was also determined.

Potential threat to human health

In receiving aquatic environments, the highest likelihood of levels exceeding the threshold considered safe for resistance development was observed for the antibiotic ciprofloxacin in drinking water in China and the WPR.

“Antibiotic residues in wastewater and wastewater treatment plants may serve as hot spots for the development of antibiotic resistance in these regions and pose a potential threat to human health through exposure to different sources of water, including drinking water,” says Nada Hanna.

Limitations to be considered when interpreting the results are the lack of data on the environmental occurrence of antibiotics from many of the countries in the regions and the fact that only studies written in English were included.

Source: Karolinska Institutet

Categories : COVIDTags :

Gauteng Peak Passes but WHO Warns not to Underestimate Omicron

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Image by Quicknews

Wastewater monitoring has shown that COVID  infections are falling in Gauteng, indicating that the Omicron wave may have peaked, while the World Health Organization warns that the variant should not be taken lightly despite its mildness.

The findings align with comments by Health Minister Joe Phaahla on Friday that the Omicron-driven wave may be peaking in the province.

Despite Gauteng’s peaking, cases are on the rise in seven of the nine provinces and last week the country saw a new high in cases. Of the infections confirmed on Thursday, Gauteng accounted for 27%, down from 72% of new infections on December 3.

However, the surge of Omicron will likely not be confined to Gauteng. “Early indications are that we might have reached the peak in Gauteng,” Dr Phaahla said in an online media briefing. “But there is a corresponding, rapid increase of cases in the other big provinces.”

He also noted a 70% increase in hospitalisations, though he stressed that this was off of a low base rate. Meanwhile, the WHO has warned that countries should not take the Omicron variant likely in spite of its apparent low severity.

“Countries can – and must – prevent the spread of Omicron with the proven health and social measures.  Our focus must continue to be to protect the least protected and those at high risk,” said Dr Poonam Khetrapal Singh, Regional Director of the WHO South-East Asia Region.

Omicron should not be dismissed as mild, she cautioned, adding that even if it does cause less severe disease, the sheer number of cases could once again overwhelm health systems. Hence, health care capacity including ICU beds, oxygen availability, adequate health care staff and surge capacity need to be reviewed and strengthened at all levels. 

The overall threat posed by Omicron largely depends on three key questions – its transmissibility; how well the vaccines and prior SARS-CoV-2 infection protect against  it, and how virulent the variant is as compared to other variants.

From what we know so far, Omicron appears to spread faster than the Delta variant which has been attributed to the surge in cases across the world in the last several months, Dr Singh said.

She added that emerging data from South Africa suggests increased risk of re-infection with Omicron, and said that there is still limited data on Omicron’s limited severity. Further information is needed to fully understand the clinical picture of those infected with Omicron, and more information is expected in the coming weeks.

Her statements echo those of WHO chief Tedros Adhanom Ghebreyesus, who earlier last week warned that health systems could still be overwhelmed by cases.