Disclaimer: this has not been written by a doctor.
The most common illnesses for travelers in Central Asia are diarrhea or constipation. Make sure to always wash your hands before eating, ease yourself into the dietary habits of the region by mixing fruits and homemade meals with restaurant food, wash market produce carefully and pack some basic medicine like Motilium and Imodium in case the shit hits the proverbial fan.
In restaurants, salads and lukewarm or reheated dishes present the greatest danger.
Uzbekistan, and particularly the Pamir Highway, are the 2 places where people get sick most often.
You could drink only bottled, boiled or purified water. You could use a water filter. Or, you could simply drink the water unfiltered. Use common sense and your own past experiences to decide on a strategy.
In cities, the quality of tap water is difficult to judge. When hiking, use basic hiker’s wisdom, in the knowledge that animals graze (and shit) on very high pastures.
Dehydration is a danger for inexperienced outdoors enthusiasts. Drink enough. Avoid unpasteurised milk (it’s the stuff you buy on the market in plastic Coke bottles) or boil it before use.
Especially in Kyrgyzstan (eg. Song Kol and Tash Rabat) and Tajikistan (Pamir Highway), altitude sickness can happen to anyone.
Altitude sickness happens through a rapid ascent and subsequently staying over 2500 m (8200 ft) for more than 12 hours. As a general rule, you should not sleep more than 300-400 m higher than the night before to stay on the safe side.
Diamox is a medicine that can help with acclimatising (talk to your doctor). For the Pamir Highway, see the Pamir Highway altitude profiles. For the full lowdown on altitude sickness, check the travel doctor.
Air pollution is really bad in most of Kazakhstan’s cities, and Bishkek. Elsewhere, it’s doable; Uzbekistan’s cars run mostly on gas which makes a big difference. Take your precautions if you are sensitive.
Malaria: There are occasional cases of malaria in summer in Tajikistan, in the Khatlon region on the border with Afghanistan, an area that sees very few travelers. Transmission season generally lasts from May to October. Above 2500m you are safe. Bring DEET for travel in the region. If you are going to certain areas of Khatlon, you should perhaps consider antimalarials.
Tick-borne encephalitis: Every year a few people die after contracting tick-borne encephalitis. We advise to get vaccinated if you plan to do any hiking, as popular places like Ala-Archa near Bishkek or the mountains around Almaty and Shymkent are known to harbour this disease.
Hepatitis A: Occurs all over the region and you should be vaccinated.
Hepatitis B: Also occurs all over the region. Vaccinate if you plan on having sex with a new partner, get injections, piercings or a tattoo.
Rabies: Vaccinations are expensive and the chance of obtaining the virus is small, so you should weigh off the risks involved. If you are planning to stay in the countryside for a long time, vaccinating is worthwhile. It’s a terrible disease.
Typhoid: Especially an issue in Tajikistan and Turkmenistan. You should be vaccinated in any case.
DTP (Diphtheria, Tetanus and Polio) and MMR (Measles, Mumps and Rubella): Make sure your inoculations are up-to-date.
The travel clinic website has a good round-up of recommended vaccinations.
Generally a scary affair. There are some hospitals in the major cities which could be said to be up to standard, but medicine is definitely still behind versus the rest of the world. Doctors frequently misdiagnose, sometimes on purpose to milk you for money.
For any kind of serious illness, locals go to China or India to get treatment, or Dubai or Europe if they have more money. We suggest you do the same for anything that is not super-urgent or easy to fix like a broken leg.
Dentists are hit or miss: if you really need one, ask around in the expat community to get recommendations.