The Chattahoochee River is an essential surface water source as it provides over 70 percent of Metro Atlanta’s drinking water, amounting to over 300 million gallons. In addition to serving as Metro Atlanta’s primary source of drinking water, the Chattahoochee River serves as a major point of discharge for industrial and municipal waste as well as urban runoff. The primary goal of this study was to assess the presence of Pepper Mild Mottle Virus in the Chattahoochee River. During a five-month period in 2014, water samples were collected at fifteen sample sites and two outfall sites in the Chattahoochee River. PMMoV was tested for in 6 out of 17 sample. A one-way ANOVA analysis (p<0.05), of concentrations across sampling locations resulted in a p-value of 0.044. As a result, it can be determined that the location of the sampling sites does result in a statistically significant difference in the PMMoV values observed. Furthermore, a one-way ANOVA analysis (p<0.05), of concentrations across sampling dates resulted in a p-value of 0.063. Therefore, it is determined that the dates on which sampling took place did not result in a statistically significant difference in the PMMoV values observed across time . Furthermore, the MS2 virus was also detected in these samples. Through a paired t-test (p<0.05), between the sample concentrations with and without MS2 presence, it was determined that there was no statistical difference in concentration of PMMoV when MS2 is present since p=0.0740 The results indicate that PMMoV was present in the Chattahoochee River due to the detection of PMMoV in the samples collected. However, additional investigations, using a larger sample size, are needed to assess PMMoV as a viable indicator of fecal contamination of ambient surface waters and recreational waters.

Un paradigme actuel en virologie est que les virus de plantes ne peuvent pas affecter les animaux vertébrés et ne sont pas pathogènes pour l'homme. Cependant, plusieurs éléments remettent en question ce paradigme. L'objectif de cette Thèse a été d'étudier si les tobamovirus peuvent être pathogènes chez l'homme. Ce manuscrit comprend :1) une revue de la littérature portant sur la présence et l'impact potentiel des virus de plantes chez les animaux dont l'homme. 2) une étude sur l'exposition humaine aux tobamovirus et les effets possibles Dans la région de Marseille, nous avons montré la présence du PMMoV dans 7.2% des selles de patients et dans 57 % des produits alimentaires à base de piment. De plus, la présence du PMMoV dans les selles de patients a pu être corrélée des signes cliniques. De plus, nous avons montré que le TMV infectieux était présent dans le tabac de toutes les cigarettes testées mais aussi dans 45 % des salives de fumeurs testées. 3) une étude in vivo. Suite à une inoculation intra-trachéal des souris avec du TMV, nous avons constaté que le virus persiste jusqu'à 14 jours dans le tissu pulmonaire et les macrophages pulmonaires. De plus, nous avons détecté du TMV dans le cytoplasme des macrophages murins jusqu'à 15 jours après inoculation. 4) une étude sur le mode de transmission du TMV à l'homme. Le TMV détecté dans la salive des fumeurs ne serait pas véhiculé par la fumée de cigarette, mais par contact avec du tabac infecté. Nos résultats suggèrent que la frontière entre virus de plantes et virus d'animaux n'est pas aussi stricte qu'il est communément admis et incitent à réévaluer l'éventuelle pathogénicité des phytovirus pour l'homme. / A current paradigm in virology is that plant viruses cannot affect vertebrates and are not pathogenic for humans. However, several recent findings challenge this paradigm. The aim of this thesis was to investigate whether tobamoviruses may be pathogenic in humans. This manuscript contains: 1) A review of the literature of the reasons why plant viruses may cross the border from plants to vertebrates and the possible impact of plant viruses in animals including humans. 2) A study on exposure to tobamovirus and possible effects of these viruses for humans. In the Marseille geographical area, we showed the presence PMMoV in 7.2% of stools from patients tested and in 57% of food products containing hot peppers. In addition, the presence of PMMoV in the stools of patients could be significantly correlated with clinical symptoms. Then, we showed that infectious TMV was present in the tobacco of all cigarettes tested and TMV RNA was detected in 45% of smokers' saliva tested. 3) In vivo study: mice intra-tracheal inoculation with TMV. The results showed the persistence until 14 days of viruses in the lung tissue and in lung alveolar macrophages of mice. In addition, we detected TMV in the cytoplasm of murine macrophages up to 15 days after inoculation. 4) A study of TMV transmission to humans through cigarette smoking. TMV does not seem to be vehicled by cigarette smoke to smoker's saliva but by direct contact with infected tobacco. Our results suggest that the boundary between plant viruses and animal viruses is not as strict as it is commonly accepted and prompt to reassess the potential pathogenicity of these plant viruses for humans.