The disease detectives at the Centers for Disease Control and Prevention named the top five global health threats they expect to tackle in 2014:

1. The emergence and spread of new microbes

While it’s rare, CDC scientists do come across new diseases each year. In 2013, the new Heartland virus carried by ticks was confirmed in northwest Missouri. Federal health investigators collected samples in the state after two farmers from St. Joseph were sickened by the virus that carried a novel genetic profile.

Also last year, CDC helped public health officials in the Republic of Georgia identify a new virus related to smallpox that infected shepherds there. Only one in five countries worldwide has the technology to detect and fight emerging infections, said the CDC’s director, Dr. Tom Frieden. The CDC is making disease detection a major priority in 2014, in the U.S. and abroad. New technologies and software have enabled faster DNA identification of infectious germs.

2. The globalization of travel and food supplies

Diseases that were thought to be eradicated in the U.S. are now back because of lower vaccination rates and increased international travel. In 2013, measles cases in the U.S. doubled to 175, almost all linked to foreign travel. Measles outbreaks can only be prevented if the majority of the population is vaccinated. American scientists are training their colleagues worldwide and helping build new labs to investigate outbreaks.

Disease can spread anywhere in the world within 24 hours, Frieden said. The most recent global pandemic, involving the H1N1 swine flu, spread to 23 countries within six weeks of being discovered in Mexico in 2009. Contaminants in the food supply can also spread quickly, as evidenced by the 2011 E. coli outbreak in nine states that started with romaine lettuce sold at St. Louis-area Schnucks markets.

3. The rise of antibiotic-resistant infections

Some bacteria have become resistant to several types of antibiotics, making it harder to fight infectious diseases. Drug-resistant infections are particularly dangerous for people with a compromised immune system, including those with cancer, kidney failure or organ transplants. In some cases, doctors and nurses have had to resort to less effective and more toxic antibiotics when the first-line defenses fail. Patients with antibiotic resistant infections incur longer hospital stays, long-term side effects and death. More than 2 million Americans contract antibiotic-resistant infections each year, and 23,000 die, according to the CDC.

Several drug-resistant bacteria, including forms of gonorrhea, tuberculosis, salmonella and strep are considered urgent or serious threats to public health because doctors are running out of drugs to treat these infections. The overuse of antibiotics is the main pathway for drug-resistant infections. About half of antibiotic prescriptions are considered to be unnecessary. Antibiotics given to farm animals before slaughter are another main source of resistance. The CDC is working with the FDA to reduce the use of antibiotics in the food chain.

"One of my key principles in using antibiotics properly is to make sure the patient receives the correct amount of a medication that only treats the bacteria or germs involved in the infection," said infectious disease pharmacist Ryan Moenster, associate professor at St. Louis College of Pharmacy. "If the doctor diagnoses you or a family member with a viral infection, don’t demand medication like amoxicillin because antibiotics do nothing for viral infection."

4. Inadvertent or intentional release of pathogens

The 2009 death of a scientist who caught the plague in a University of Chicago lab alarmed many in the disease research world. An estimated three of every 1,000 lab workers are sickened each year, most commonly with hepatitis, typhoid fever or tuberculosis, according to the National Institutes of Health.

Many labs employ safety officers to oversee work with cultures including flu, pneumonia, salmonella, E. coli and other pathogens.

St. Louis University, for example, houses level three bio-safety laboratories, indicating the study of biological agents that can be transmitted through the air and cause serious illness or death. The labs require specialty ventilation and other security protections and are regularly inspected by federal agents. Lab workers must pass background checks.

5. Bioterrorism

Some inhaled pathogens such as anthrax, pneumonic plague or smallpox are considered potential weapons in a bioterrorism attack. St. Louis University is studying a new plague vaccine at the behest of federal health officials for potential use in the military. The military has previously used a plague vaccine, but it caused side effects such as headaches and fever.

The CDC works with health departments in every state to conduct bioterrorism drills and train public health workers on emergency preparedness. They monitor local labs to make sure they can conduct tests quickly when a lethal substance is detected. Many of the systems were also tested during the H1N1 flu pandemic, as hospitals set up tents and secured extra ventilators for the influx of patients.