No vaccinations are required for travel to Bulgaria, but vaccination against typhoid and hepatitis A may be recommended.
Citizens of other European Economic Area countries (EU plus Norway, Iceland and Liechtenstein) should pick up a European Health Insurance Card (EHIC) before travel, which entitles you to the same immediate medical treatment that's available to Bulgarian nationals. However, you should also consider buying an insurance policy that covers you for the worst possible scenario, such as an accident requiring an emergency flight home.
Rabies This disease is fatal if untreated, and is a potential concern considering the number of stray dogs in Bulgaria. Do not approach feral dogs; if you are bitten by a dog, bat or any other mammal, seek medical attention immediately.
Tick-borne Encephalitis Spread by tick bites, this is a serious infection of the brain and is present in some rural areas of Bulgaria. Contraction risks are low, but if you are camping in rural areas, protect against bites by using sprays and wearing long-sleeved shirts and long trousers. Check for ticks if camping; remove any invaders head-first using tweezers and seek medical advice.
Bulgarian tap water is generally safe and drinkable, but may have an odd taste. There have been reports of contamination in some rural areas. It's best to use bottled mineral water, which is widely available and cheap.
Every major town and city has government hospitals of an acceptable, though not always high, standard. Private clinics are preferable.