The mosquito species Anopheles gambiae transmits the most dangerous form of malaria; the Center of Infectious Disease Research is studying the disease and pursuing ways to slow its spread.

Which Diseases Cause the Most Deaths?

Shuyi Ma

Posted on Jan 26th, 2017


Which diseases claim the most lives each year, and how should we allocate our time and money to prevent and treat them?

We’re constantly mulling this question at the Center for Infectious Disease Research (CIDR), where we’re focused on understanding infectious diseases such as HIV/AIDS, tuberculosis, malaria, trypanosomiasis and leishmaniasis.

The diseases that CIDR studies cause about twice as many deaths as diabetes, and roughly the same number of deaths as car crashes and other accidents. They disproportionately affect poor and marginalized people. And unlike some other causes of death, the mortality rate for these infectious diseases has stalled – or worsened – over the last few decades.

The following graphic, adapted from the Institute for Health Metrics and Evaluation’s data visualization tools, helps illuminate how our research fits into global disease issues. The graphic illustrates the share of deaths from various causes in 2015. The larger the box, the more people died from that cause. Non-communicable, chronic diseases (in blue) took the greatest toll, causing 71% of deaths. Infectious diseases, malnutrition and birth problems (in red) accounted for 20%. The remaining 9% were due to injuries from accidents, violence and self-harm (in green).

The shade of each box is also important. The paler the color, the more progress we’ve made in reducing deaths from that cause from 1990 to 2015. The number of people who died from malnutrition, birth problems and infectious diseases (in red) has fallen significantly, dropping by 5 million from 1990 to 2015. This is largely thanks to increased funding and intensive efforts to save patients with these conditions, as well as improvements in local economies and infrastructure. For instance, vaccines for measles and tetanus have been more widely distributed, and better sanitary conditions and access to clean water have helped reduce diarrheal diseases.

But as deaths from those causes have declined, deaths from non-communicable diseases (in blue) rose by more than 12 million. This trend stems partly from the reduction of extreme poverty and concurrent increase of urbanization in many parts of the world. People have become more sedentary and have more access to junk food, tobacco and alcohol.

Still, infectious diseases, malnutrition and birth problems remain a major problem. They kill more people worldwide than cancer. And in most African countries, these ailments cause about 50 to 70% of all deaths.

Some infectious diseases, in particular, are not declining as fast as others. For instance, even though tuberculosis is curable, it is often misdiagnosed or diagnosed late, and people in developing countries frequently have trouble completing the long treatment regimen. Neglected tropical diseases such as dengue don’t receive much attention because they affect relatively few people, the patients are generally poor, and many of the pathogens are transmitted by mosquitoes, which are hard to control.

These diseases, along with HIV/AIDS, malaria, trypanosomiasis, and leishmaniasis, occupy most of our attention at CIDR. Looking back at the first graphic, they may seem like a relatively small fraction of the total. But these conditions tend to affect younger people and, in turn, cause many years of life lost. We’re trying to save as many of those years as possible.

About the Author

Shuyi Ma is a postdoctoral scientist in David Sherman’s lab at the Center for Infectious Disease Research. She studies how Mycobacterium tuberculosis responds to different drugs and applies this information to help develop more effective treatment regimens.

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