Sayyed Mohammad Al-Musawi, Sayyed Mohammad al-Musawi is originally from Iraq and heads up the World Ahlul Bayt Islamic League in London. Other than being involved in various humanitarian projects, he frequently responds to... Answered 3 years ago

The lizard is an animal which is harmful for human beings when it comes inside their houses, and it can cause poisoning human food, that is why we have narrations recommending killing the lizard. (Sharh Al-Kaafi, by Salih al- Maazindrani, Vol 12, page 298).

It is recommended to wash the whole hand after killing the lizard, but Ghusl is not obligatory for that.