Source(s): I am a Meteorologist. Isolated thunderstorms are especially common during the summer in the mid-late afternoon when it is hot and humid. This is when you see those high towering, popcorn looking clouds in the middle of the afternoon when the sun hits the grounds and heats the air up. Usually isolated storms do not cover a large area.
Salmonella enterica serovar Typhimurium (S. typhimurium) causes enteric disease in humans. It is a food-and water-borne pathogen that can be easily disseminated in a population: for instance outbreaks of salmonellosis can occur by contamination of salad.
1 Rickettsia prowazekii causes epidemic typhus, the more severe form, and is spread mainly by lice, although sylvatic typhus (also due to R. prowazekii) is found in the USA and associated with bites from the fleas of a flying squirrel.2  Rickettsia typhi causes endemic or murine typhus and is transmitted by fleas. Rickettsia typhi causes endemic or murine typhus and is transmitted by fleas. 2  The term endemic refers to the fact that there is an animal reservoir of disease maintaining the presence of typhus in a particular area. 3  Rickettsia felis is found in cats and has also been linked to endemic typhus.