It is extremely unlikely. Firstly, HIV is not transmitted through ordinary daily activities such as shaking hands or a casual kiss. In addition, you cannot become infected from things such as a toilet seat, doorknob or crockery.
If HIV-infected blood is present, the transmission of HIV in a household or other setting such as public toilets or hospitals, is rare.
HIV is a fragile virus and does not survive for very long outside the human body. You would also have to have an open cut or wound come directly in contact with the spot of blood so that they touch and the virus then possibly enters. The likelihood of all these events occuring is very rare.
Furthermore, you cannot catch HIV from kissing, from being sneezed on by someone who has HIV, from sharing baths, towels or cutlery with an HIV-infected person, from swimming in a pool or sitting on a toilet seat that someone with HIV has used, or from animals or insects such as mosquitoes.
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