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Enteric viruses are present in the environment as a result of the discharge of poorly or untreated wastewater. The spread of enteric viruses in the environment depend to human activities like stools of infected individuals ejected in the external environment can be transmitted by water sources and back to susceptible individuals for other cycles of illness. Among the enteric viruses Rotaviruses (RV) and Hepatitis A viruses (HAV) is the most detected in wastewater causing gastroenteritis and acute hepatitis. Therefore, it is of interest to climate change, mainly temperature and carbon Dioxide (CO2) variations, on Rotavirus and Hepatitis A as a model of enteric viruses present in the aquatic environment using computational modelling tools. The results of genetic ratio showed a negative correlation between the epidemiological data and the mutation rate. However, the correlation was positive between the temperature, CO2 increase, and the rate of mutation. The positive correlation is explained by the adaptation of the viruses to the climatic changes, the RNA polymerase of the RV induces errors to adapt to the environmental conditions. The simultaneous increase in number of infections and temperature in 2010 has been demonstrated in previous studies deducing that viral pathogenicity increase with temperature increase.

Viral outbreaks can result from the consumption of contaminated bivalve mollusks. However, despite the regulation related to enteric bacteria in food products, the consumption of raw and undercooked mollusks remains linked to viral epidemics in human populations. Real-time RT-PCR is a highly sensitive approach for detecting and quantifying enteric viruses, and after eliminating enzymatic amplification inhibitors from samples of interest, sensitive and specific tests, like real-time RT-PCR, can facilitate the detection and quantification of a wide range of viruses that are concentrated in mollusk digestive tissues. The aim of the present study was to evaluate the prevalence of Group-A rotaviruses in mussel (Mytilus edulis Linnaeus, 1758) specimens (n=576) collected downstream of the Oued El Maleh Estuary, which is along the coast of Mohammedia City in Morocco, using real-time RT-PCR. Rotavirus A RNA was detected in 37.5% (n=18) of the 48 sample batches, and viral loads ranged from 0.42×101 to 1.8603×104 genomic copies per g digestive tissue. Most (72.22%) of the positive samples were collected during the wet season (September-April), and the probability of detecting rotaviruses was significantly greater during the wet season than during the dry season (P<0.001). Monitoring Rotavirus A and similar viruses in shellfish may help prevent viral contamination and preserve public health.

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Rotavirus A is the causative agent of 90% of acute gastroenteritis in children under 5, which kills 1 to 3 million children per year. Their strong resistance in the environment, their inter-species transmission as well as their power of genetic recombination can give rise to new reasserting that may be harmful to public health. The simultaneous search for the presence of rotavirus A in different environmental and clinical biotopes and matrices as well as the monitoring of the seasonal evolution of episodes is of major importance. At cost, genetic monitoring of rotaviruses shows a correlation between the presence of different genotypes of RVA in the environment and the rate of morbidity, Hence the need to monitor the emergence of new circulating strains with a view to integrating them into routine immunization programmes appropriate for each region in order to limit the spread of the disease.

In this study, a heterotrophic denitrification was designed for domestic wastewater treatment with unexpected water flows at different loading rates. Benefited from excellent removal ability COD, shorten operating time and lower maintenance cost. During the time of operation (six months), injection of nitrate was made in the influent RALBI 1 while the RALBI 2 was fed with sewage without addition of nitrate. The COD concentration in the influent of the two reactors was the same. This two reactors (RALBI1 and RALBI2) were fed with real wastewater for 172 days at 6 h HRT, the average COD removal were 71.55% and 54.82% for RALBI1 and RALBI2 respectively. The results showed that RALBI1 has good removal performance for COD compared with RALBI2. This could be due the injected nitrate in RALBI1 whose effect has further stimulated the activity of denitrifying bacteria.