A scientist separates blood cells from plasma cells to isolate any Ebola RNA in order to test for the virus at the European Mobile Laboratory in Gueckedou April 3, 2014. Hiccups, say doctors in this remote corner of Guinea, are the final tell-tale sign of infection by the Ebola virus that has killed more than 100 people since an outbreak began this year. Then come profuse bleeding, circulatory shock and death. In total, 98 people are thought to have died from the disease in Guinea and 10 more in neighbouring Liberia, according to aid workers and governments. A market town of 220,000 people near the Liberia and Sierra Leone borders, Gueckedou's makeshift clinic is on the front line of Guinea's battle to contain its first outbreak of the haemorrhagic fever, normally found in Central Africa. Picture taken April 3, 2014. (Stringer/Reuters)

The writer is global health track director at the University of Colorado School of Medicine.

“Doctora. Una consulta, por favor.”

I was in rural Peru, mentoring a group of U.S. medical students who were conducting training in basic public health to lay health-care providers. Word had gotten out that I was a doctor, and several of the lay providers came to me seeking medical advice.

The soft-spoken Peruvian man requesting this “consulta” explained that a year ago, a group of doctors from the United States had briefly set up a makeshift clinic in his village. He went to them because he was experiencing abdominal pain and weight loss, and he was given a bottle of pills and a piece of paper with instructions (in English) for taking them. The pills were methimazole, which should be given only to patients after laboratory confirmation of high thyroid levels and who are carefully monitored by a specialist. Methimazole can induce liver failure and suppress the immune system. (It can also cause birth defects when taken by a pregnant woman.)

This man was a victim of an increasingly common phenomenon: the short-term medical mission. Because of the ease of modern travel, increasing awareness of dire shortages of health care in developing countries and ubiquitous access to volunteer opportunities, participation in these missions has risen sharply over the past 20 years. Organizations providing these missions abound on the Internet, and the Association of American Medical Colleges reports that more than 30 percent of graduating medical students in 2013 took an overseas medical elective prior to graduation, compared with 6 percent in 1984. Such missions generally last one to four weeks and consist of nurses and physicians from wealthy parts of the world temporarily providing free medical services in a developing country.

Unfortunately, the care isn’t always appropriate. Because most of these volunteers are trained in the West, where medical care is highly technical and the range of disease encountered is quite specific to high-income countries, volunteers are often unfamiliar with the health issues they encounter and cannot successfully diagnose or treat these conditions without access to laboratories, X-ray machines and other technology. Then, at the end of a mission, the volunteer leaves, leaving little opportunity for follow-up or preventive care, which is crucial to maintaining health.

This is not to say that Western medical teams should never try to help in the developing world. Hands-on assistance can make all the difference during disasters and public health emergencies such as the Ebola outbreak in West Africa. But even then, expertise is everything: Right now, West Africa needs equipment, skilled nurses, infectious disease specialists and public health officials who are culturally literate, not a bunch of well-meaning Western doctors of varying specialties to drain away already-scarce resources.

An oft-repeated justification of short-term medical missions is that some medical care, no matter how compromised, is better than none. In reality, many of the areas serviced do have health care. The Peruvian man I saw, for example, was part of a network of villages that had several clinics and access to a hospital in the region. Complicating the matter, these patients may be preferentially visiting mission doctors instead of their own practitioners because of a belief that doctors from abroad will give them better care.

Additionally, medical missions are not cost-effective. It costs a lot to send volunteer doctors abroad: often $3,000 to $5,000 per person for airfare, lodging, food, visas and program fees. This amount of money could go a long way toward improving the local health-care infrastructure where these missions visit. One physician, after participating in a short-term mission, noted that, if he and his co-volunteers had donated the money they spent on traveling (approximately $30,000), they could have financed half of the construction costs for a 30-bed wing planned for a local hospital.

Web sites and social media promotions for short-term medical missions lure doctors in with promises of self-fulfillment and photos of sunburned volunteers treating smiling patients. In truth, these missions do more for the volunteer than the patients they serve. There are many global health organizations that work sustainably and effectively in global health — organizations that have a long presence in the communities they serve, work side-by-side with local health providers, invest in the local infrastructure and use outcomes research to guide what they do. Finding these organizations among the unregulated sea of opportunities that promote themselves can be daunting, but medical volunteers have a responsibility to make the effort to connect with those who are dedicated to long-term provision of health care to the global poor.