New York Department of Health's website and the National Center for Biotechnology Information's report shows that geckos are not dangerous.
New York's Department of Health had reported that geckos carry bacteria called salmonella that can cause serious illness in people. People infected with salmonella may experience a mild fever and occasionally vomiting. Symptoms generally appear one to three days, but for young children and those with weakened immune systems are more likely to develop severely.
The study by the National Center for Biotechnology Information explains that house geckos are known to carry various types of pathogens in their bodies. But there are non-poisonous.
Indian Institute of Technology in their magazine said that geckos is non-toxic and does not bite. It is not known to transmit any kind of infections or diseases to humans.
By these reports it can be concluded that geckos carry bacteria called salmonella but, it is not deadliest and it does not harm the humans.