Planning a trip abroad? If you’re going to be out of the country longer than six months, you may come home with some unwelcome souvenirs.

Researchers writing in the journal Emerging Infectious Diseases found that compared with travelers abroad for less than a month, those who’d been on the go for six months or longer had higher rates of a variety of diseases.

Medical records obtained from health clinics overseas showed long-term travelers had higher rates of malaria, irritable bowel syndrome, intestinal parasites, inactive tuberculosis and several other diseases. They also were more likely to have psychological problems.

The study authors say long-term travelers were more likely to be abroad for business, research or volunteer work, while those traveling for shorter periods were more likely to be tourists. Long-term travelers also were more likely to visit South America and sub-Saharan Africa, and to be plagued by illnesses they got from an insect or animal, or through contact with other people.

The researchers emphasized the importance of pre-travel education for people departing on long voyages, and of access to medications and rapid-results tests that travelers can use themselves.

The Centers for Disease Control and Prevention suggests people planning an international trip should learn about diseases common in their destinations, see a doctor before departing and pack a travel health kit to bring on the voyage. While traveling you should take precautions to prevent insect bites and steer clear of potentially-dangerous foods. Follow these tips, and hopefully you can stay on the road… and out of the clinic.