In a tropically warm country such as Thailand, a higher level of hygiene should be observed. It should now be a well known fact that you should treat drinking water and uncooked foods with caution. However such a level of caution should also be applied to other areas of life. This means that every small injury which would not even be worth a thought in your homeland, must be treated in Thailand. The danger that dirt will get into the wound or that insects spread an infection is simply too large.
The risks involved and way sexual diseases are spread should also be a well-known fact. Unprotected sex with different partners is like a game of Russian Roulette. Decent people will certainly pay attention to safe sex. Indecent people will not follow a well-meant piece of advice. I will therefore save myself any further instructions at this point.
Not only general medical examinations but also checking your own vaccination protection, makes sense. You should discuss which vaccinations must be given or renewed with a doctor.
If you are bitten by an animal, you should think about whether your tetanus vaccination is still effective. You should also make some thoughts about rabies is you are bitten by a dog, cat or other warm blooded animals. You must definitely visit a doctor! Once rabies has broken out it is not healable and leads inevitably to death.
Please always consider that an illness which seems like fever, might actually be a dangerous illness such as Dengue fever or malaria. The symptoms are easily confused. In a serious case, this must by confirmed by a doctor before it becomes dangerous. Time wasting highly increases the risk of death if it is malaria. In the four northern provinces Kamphaeng Phet, Nakhon Sawan, Phichit and Uthai Thani, there is a higher risk of suffering from Dengue fever at the moment. In the border regions, away from the large towns and tourist areas, the risk of malaria increases. It is advisable to shut any windows before the fall of darkness. In non-acclimatised rooms, mosquito nets should be used to protect against mosquito bites.
Apart from the above named illnesses which are relatively well known, there is also a high number of illnesses which are spread by parasites. Even bathing in inland waters can lead to schistosomiasis.
Data is provided without guarantee!
All information represents my own personal opinion.