The scariest infectious diseases right now

Between the emergence of the deadly MERS and H7N9 viruses – and the success of Brad Pitt’s new movie “World War Z” in which a viral outbreak turns half the world into zombies – it’s easy to be nervous about potentially dangerous germs and bacteria lurking around on surfaces and in the air. Dr. Daniel Caplivski, director of the Travel Medicine Program and associate professor in the division of infectious diseases at Mount Sinai Medical Center in New York City, detailed some of the most worrisome infectious diseases out there right now – and what’s being done about them.


The flu pops up throughout the world every year, but the virus is at its most dangerous when a new strain emerges –  such as the H7N9 bird flu currently circulating in Asia. So far, H7N9 has sickened more than 130 people and has proven fatal to over a third of patients hospitalized with the disease, according to researchers.

“(New strains) make it difficult for (our) bodies to respond adequately,” Caplivski said. “Anytime we see something new like that we get concerned it could become a pandemic. If it does have the ability to spread from person to person, (then) because of international travel, that would be a big problem.”

Though cases of H7N9 appear to be leveling off, Caplivski noted that experts will continue to monitor the virus. In the meantime, the best protection against the flu is to get the yearly vaccine.

“The flu vaccine from year to year is based on best predictions for what strains will be circulating,” Caplivski said. “(But) there will always be some hits and misses where they don’t get the vaccine right based on what they were predicting.”

Antibiotic-resistant superbugs

Health experts in the United States have become increasingly concerned about the rise of antibiotic-resistant superbugs, bacteria that no longer respond to antibiotic treatment.

“Bacteria have found more and more ways around typical antibiotics,” Caplivski said. “There aren’t a lot of new antibiotics approved or in the pipeline, because it’s not a very profitable move. It’s more profitable to make cholesterol or weight loss drugs people will be on for the rest of their life.”

Some of the most concerning strains include CRE (carbapenem-resistant enterobacteriaceae), MRSA (Methicillin-resistant Staphylococcus aureus) and C. diff (Clostridium dificile).

Each of these superbugs can be potentially fatal in people, due to the lack of drugs available to treat them. Most of these strains are acquired in hospital settings, and Caplivski noted that it’s important to remind doctors and nurses to practice proper hand hygiene.

The Centers for Disease Control and Prevention (CDC) has more information on these different antibiotic-resistant superbugs.


Tuberculosis (TB), caused by the bacterium Mycobacterium tuberculosis, typically attacks the lungs and can be fatal if left untreated, according to the CDC. In 2011, there were 10,528  reported cases of tuberculosis in the United States, and although TB cases in the U.S. have declined since 1992, doctors remain concerned.

“It remains one of these things which is difficult to get a lot of funding (for) – another one for which we need new drugs because there are more resistant strains,” Caplivski said.

Outbreaks of TB occur periodically throughout the U.S. Recently, three high school students at Robert E. Lee High School in Springfield, Va., were diagnosed with TB and health officials are investigating whether the disease spread to any others. Additionally, TB remains a major problem in the developing world; the World Health Organization stated that 8.7 million new cases of TB were reported in 2011, and 1.4 million people died of the disease.

“If you do complete the treatment, most of the time you’ll have good success,” Caplivski said. “But some of the more resistant strains we’re seeing, especially in places like South Africa, have made it more difficult to treat.”

MERS virus

Within the past year, 60 cases of the MERS virus, a respiratory infection reported to be more deadly than SARS, have been detected throughout the world. Though most cases have appeared in Saudi Arabia, the virus has also been reported in Jordan, Qatar, the United Arab Emirates, Britain, France, Germany, Italy and Tunisia.

Though there have been no confirmed cases of the MERS virus in the U.S., the CDC is currently preparing to combat the contagion should it make its way to American soil. Based on recent reports, more than 38 deaths from MERS have been reported around the world.

“We saw how quickly things could spread via airlines in 2003 (during the SARS outbreak),” Caplivski said. “I think that those lessons have been important in global surveillance of these infectious diseases. They’re tracking at a global level whether these things are becoming more widespread and moving from person to person.”

Caplivski added that while MERS is a concern, the number of cases remains low.


About 50,000 people still become infected with the human immunodeficiency virus (HIV) in the United States each year. And the disease continues to be a huge problem throughout the world as well, with 2.5 million new cases of HIV being diagnosed in 2011, according to the CDC. Since the start of the HIV epidemic, the CDC reported that nearly 30 million people have died of AIDS, which is caused by HIV infection.

However, tremendous progress has been made regarding the treatment of people currently living with HIV.

“We’ve had a lot of great success with HIV, because we’re now using pills that are one pill taken one time a day,” Caplivski said. “They are strong medications with pretty minimal side effects.”

Yet, lack of HIV testing continues to be a problem. Based on the most recent data, about 1.1 million people in the United States were living with HIV at the end of 2009, and of those people, about 18 percent do not know they are infected.

“There are still gaps in people who don’t know they have the disease, (we’re working on) moves to get them tested and get them treated,” Caplivski said.

National HIV Testing Day is on June 27, 2013.