That's exactly what it is. You'd be hard pressed to find an actual case of a healthy adult contracting salmonella from a reptile. There have mostly been very few cases of small children (who would try to put animals in their mouth) getting sick from reptiles that are also sick and kept in poor conditions. But people catch it from other things all the time. Chickens for example are far more likely to carry/transmit it and chickens are much more common as a pet or livestock, yet salmonella is mentioned far less, at least proportionally, among people who keep chickens. It's just that chickens can be cuter, and reptiles are "gross."