Transit time estimation of drying springs in Uttarakhand region using environmental tritium concentration.

Many parts of the Uttarakhand state, situated in the hilly terrain of the Himalayan region of India are facing acute water crisis due to the drying up of the perennial springs which are the only source of potable water in those regions. Tritium (3H), the radioactive isotope of hydrogen (half-life of 12.32 years) and also a part of water molecule (in the form of HTO) acts as a very useful tracer in estimating the transit time of the hydrological systems. Tritium concentrations of three springs (S-1, S-2 and S-3) were monitored consecutively for three years (2017-2019) to better constrain the transit time estimation. The tritium concentrations of the springs are found to vary between 3.66 and 4.15 TU. All the springs show gradual decrease in tritium concentration with the passage of time indicating the diminishing percentage of freshly recharged modern water component. Among various lumped parameter models, the piston-flow model (PFM), exponential mixing model (EMM), exponential piston-flow model (EPM) and partial exponential mixing model (PEM) have been employed in this study. The historical record of weighted mean concentration of tritium in precipitation available for the Uttarakhand region is taken as input function in the modelling procedure. The application of various LPMs (PFM, EMM, EPM and PEM) indicates that the transit time of the S-1 spring ranges from 1.26 to 1.46 years whereas for S-2 spring, the transit time is found to vary from 5 months to 1.1 years. The MTT of S-3 spring ranges from 5 months to 11 months. The relatively short residence time of these springs indicates the actively recharged system. The estimation of accurate transit time is thus very crucial for understanding the renewability of the spring water systems.

Genetic and Molecular Characterization of H9N2 Avian Influenza Viruses Isolated from Live Poultry Markets in Hubei Province, Central China, 2013-2017.

H9N2 subtype avian influenza virus (AIV) is an influenza A virus that is widely spread throughout Asia, where it jeopardizes the poultry industry and provides genetic material for emerging human pathogens. To better understand the epidemicity and genetics of H9 subtype AIVs, we conducted active surveillance in live poultry markets (LPMs) in Hubei Province from 2013 to 2017. A total of 4798 samples were collected from apparent healthy poultry and environment. Real-time RT-PCR revealed that the positivity rate of influenza A was 26.6% (1275/4798), of which the H9 subtype accounted for 50.3% (641/1275) of the positive samples. Of the 132 H9N2 viral strains isolated, 48 representative strains were subjected to evolutionary analysis and genotyping. Phylogenetic analysis revealed that all H9N2 viral genes had 91.1%-100% nucleotide homology, clustered with genotype 57, and had high homology with human H9N2 viruses isolated from 2013 to 2017 in China. Using a nucleotide divergence cutoff of 95%, we identified ten distinct H9N2 genotypes that continued to change over time. Molecular analysis demonstrated that six H9N2 isolates had additional potential glycosylation sites at position 218 in the hemagglutinin protein, and all isolates had I155T and Q226L mutations. Moreover, 44 strains had A558V mutations in the PB2 protein and four had E627V mutations, along with H9N2 human infection strains A/Beijing/1/2016 and A/Beijing/1/2017. These results emphasize that the H9N2 influenza virus in Hubei continues to mutate and undergo mammalian adaptation changes, indicating the necessity of strengthening the surveillance of the AIV H9N2 subtype in LPMs.

Antibiotic resistance gene reservoir in live poultry markets.

OBJECTIVES: The heavy use of antibiotics in farm animals contributes to the enrichment and spread of antibiotic resistance genes (ARGs) in "one-health" settings. Numerous ARGs have been identified in livestock-associated environments but not in Chinese live poultry markets (LPMs). METHODS: We collected 753 poultry fecal samples from LPMs of 18 provinces and municipalities in China and sequenced the metagenomes of 130 samples. Bioinformatic tools were used to construct the gene catalog and analyze the ARG content. PCR amplification and Sanger sequencing were used to survey the distribution of mcr-1 gene in all 753 fecal samples. RESULTS: We found that a low number of genes but a high percentage of gene functions were shared among the poultry, human and pig gut gene catalogs. The poultry gut possessed 539 ARGs which were classified into 235 types. Both the ARG number and abundance were significantly higher in poultry than that in either pigs or humans. Fourteen ARG types were found present in all 130 samples, and tetracycline resistance (TcR) genes were the most abundant ARGs in both animals and humans. Moreover, 59.63% LPM samples harbored the colistin resistance gene mcr-1, and other mcr gene variants were also found. CONCLUSIONS: We demonstrated that the Chinese LPMs is a repository for ARGs, posing a high risk for ARG dissemination from food animals to humans under such a trade system, which has not been addressed before.

[The effects of closure to live poultry markets on Avian influenza A (H7N9) epidemics in China].

Since March 2013, China had experienced five seasonal epidemics related to Avian influenza A (H7N9). An unprecedented outbreak of H7N9 epidemic started from September 2016, with 730 cases reported till June 30(th) 2017, in mainland China that caused profound influences on both social development and health of the people. As an emerging infectious disease, information on pathogenic characteristics, transmission patterns and other epidemiological features of H7N9 virus somehow remained unclear. Data from previous studies suggested that the live poultry market (LPM) seemed to have served as main places where H7N9 virus got originated, mutated, spread and thus infected the human beings. Hence, closure of LPMs was suggested a major measure to control and prevent H7N9 epidemics in China. However, the effectiveness of different ways of LPM closures on H7N9 epidemics had been controversial. This study systemically summarized the effects of different ways of LPM closures on H7N epidemics from previous studies, aiming to provide references for developing a better program on H7N9 control and prevention in the country.

The effects of closure to live poultry markets on Avian influenza A (H7N9) epidemics in China / 中华流行病学杂志

Since March 2013,China had experienced five seasonal epidemics related to Avian influenza A (H7N9).An unprecedented outbreak of H7N9 epidemic started from September 2016,with 730 cases reported till June 30th 2017,in mainland China that caused profound influences on both social development and health of the people.As an emerging infectious disease,information on pathogenic characteristics,transmission patterns and other epidemiological features of H7N9 virus somehow remained unclear.Data from previous studies suggested that the live poultry market (LPM) seemed to have served as main places where H7N9 virus got originated,mutated,spread and thus infected the human beings.Hence,closure of LPMs was suggested a major measure to control and prevent H7N9 epidemics in China.However,the effectiveness of different ways of LPM closures on H7N9 epidemics had been controversial.This study systemically summarized the effects of different ways of LPM closures on H7N epidemics from previous studies,aiming to provide references for developing a better program on H7N9 control and prevention in the country.

The effects of closure to live poultry markets on Avian influenza A (H7N9) epidemics in China / 中华流行病学杂志

Since March 2013,China had experienced five seasonal epidemics related to Avian influenza A (H7N9).An unprecedented outbreak of H7N9 epidemic started from September 2016,with 730 cases reported till June 30th 2017,in mainland China that caused profound influences on both social development and health of the people.As an emerging infectious disease,information on pathogenic characteristics,transmission patterns and other epidemiological features of H7N9 virus somehow remained unclear.Data from previous studies suggested that the live poultry market (LPM) seemed to have served as main places where H7N9 virus got originated,mutated,spread and thus infected the human beings.Hence,closure of LPMs was suggested a major measure to control and prevent H7N9 epidemics in China.However,the effectiveness of different ways of LPM closures on H7N9 epidemics had been controversial.This study systemically summarized the effects of different ways of LPM closures on H7N epidemics from previous studies,aiming to provide references for developing a better program on H7N9 control and prevention in the country.