Rough estimates indicate that annually some 500 million people cross state boundaries on planes. And travellers, luggage and cargo are often accompanied by pathogens. The epidemiological risk connected with air transport results from the presence of people who are in the asymptomatic stage of an infectious disease and they can infect other travellers. Many serious cases of diseases have been caused by bacterial infections transmitted by passengers of international airlines who travel to other continents.
Salmonella is considered a natural compound of reptile gastrointestinal tract flora and the rate of asymptomatic carriers can reach 100%. The prevalence varies in tested populations and depends on many factors, such as habitat, diet, intermittent shedding, but also on the culture method used in the study. Reptiles carry a wide variety of Salmonella serotypes including those specific for cold-blooded animals, but also those belonging to Salmonella enterica subsp. enterica. Salmonella in reptiles may be transmitted both horizontally by direct contact between individuals or via a contaminated environment as well as vertically. Colonized reptiles are considered a human health risk and direct contact is not a prerequisite for transmission. Infants, pregnant women, elderly and immune-compromised persons are at an increased risk for reptile-associated Salmonella infections. Detailed studies are necessary to evaluate the prevalence in pet reptile populations and potential consequences for humans.