Fighting Emerging Infectious Diseases Fighting Emerging Infectious Diseases
Centers for Disease Control and Prevention

From mysterious respiratory disease outbreaks, to foodborne disease outbreaks, to the growing epidemic of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) and extensively drug-resistant (XDR) tuberculosis, CDC is on the front lines of the most challenging public health threats. CDC teams are working creatively and collaboratively with traditional and non-traditional partners to address root causes and identify possible solutions.

Respiratory Disease Outbreaks

Respiratory diseases are one of the leading causes of mortality in the United States and globally, yet uncovering the causes of an outbreak can be complex and challenging since many possible pathogens can be responsible.

A special respiratory working group within CDC assists states and other countries responding to respiratory outbreaks. When an urgent request is received, the team convenes within hours to discuss the possible causes for the outbreak, and to provide technical expertise and resources to public health partners.

In the past year, the group has assisted with outbreak investigations both in the United States and abroad. For example, in St. Croix, an unexplained outbreak of cough illness among schoolchildren was reported in December 2007. CDC sent an integrated respiratory outbreak team to St. Croix to assist with the field investigation. Specimens were sent to CDC, triggering a rapid, coordinated laboratory response, which in turn allowed investigators to recognize pertussis (whooping cough) as the cause. Patients and their contacts were treated with antibiotics.

CDC is helping others help themselves, too. With the scheduled launch of the new Unexplained Respiratory Disease Outbreak Web site this summer, CDC will provide tools for state and local health departments and other public health responders globally to investigate respiratory disease outbreaks.

Tracing the Sources of Foodborne Diseases, from Bagged Spinach to Kissing Bugs

The recent Escherichia coli outbreak in bagged spinach, among other outbreaks, has focused CDC’s attention on the environment in which fresh produce is grown. Photo by Rick Gelting.CDC has investigated underlying causes of several unusual and highly publicized outbreaks of foodborne illnesses recently. Escherichia coli outbreaks were traced to shredded lettuce people ate in two taco chain restaurants and to bagged spinach. A national brand of peanut butter turned out to be the source of a large Salmonella outbreak.

CDC has also assisted other nations with outbreak investigations. CDC helped to solve the mystery of a viral encephalitis outbreak among Bangladeshi children who had drunk fresh sugar palm juice collected in buckets high up in trees. CDC determined that the juice was contaminated by infected bats that at night had been drawn to the buckets of sweet-tasting liquid. Another example of a disease gone foodborne is Chagas disease in Brazil. The so-called “kissing bug” disease is well known to be caused by a bug bite. Now investigators have determined that the bugs are getting into stacks of sugar cane stored in the open that are used to make juice.

When outbreaks related to foods occur, CDC and its partners push hard to investigate all the way to the source of the contamination – often where produce is grown. This is a new, complex area of investigation focus. Water sources, raising animals and plants right next to one another, wildlife: all these factors are tied together into interwoven problems with more than one cause.

Controlling the Spread of MRSA

According to CDC’s latest findings, 85 percent of all invasive MRSA infections were associated with healthcare settings, while 15 percent of reported infections were community–associated.
Photo courtesy of CCID
MRSA, a type of staph infection resistant to all penicillin antibiotics, is on the rise–the number of MRSA infections treated in hospitals doubled nationwide from 1999 to 2005. Last October, CDC’s latest findings, published in the Journal of the American Medical Association, drew significant media attention since it coincided with some high-profile cases of high school athletes dying from MRSA. The media said that deaths from MRSA, which killed 19,000 people last year, surpassed the number of AIDS deaths in the United States.

The CDC report stated that 85 percent of all invasive MRSA infections were associated with healthcare settings, such as hospitals or nursing homes. Fifteen percent of reported infections were community-associated, where infection occurred in people without documented contact with healthcare settings.

To help combat MRSA in healthcare settings, CDC has published guidelines for the management of multidrug-resistant organisms in healthcare settings. CDC works directly with partners, too. Through CDC-supported efforts in Pennsylvania, local hospitals have successfully reduced bloodstream and MRSA infections as much as 70% by fully implementing CDC prevention recommendations.

Replicating these efforts in healthcare settings nationally and implementing basic infection control practices out in the community could dramatically reduce MRSA and other staph-related deaths and complications.

Guidelines for XDR Tuberculosis

A staff member with the International Organization for Migration works on TB disease screenings at a Burmese Refugee Camp in Thailand.
Photo by Wanda Walton.
Another key focus within CDC is working with other agencies to prevent tuberculosis (TB) globally–a job that has become more difficult with the emergence of XDR TB.

TB is spread to susceptible people through coughing. TB drug resistance develops when TB patients receive incomplete or inadequate treatment. XDR TB is caused by strains of bacteria resistant to most effective first-and second-line TB drugs. It has been found that among non-HIV infected persons, less than 30 percent of patients can be cured and more than half of those with XDR die within five years of diagnosis.

CDC technical experts work directly with host country governments and partners in countries to urgently implement improved infection control, rapid-case detection, effective treatment, surveillance for drug resistance, and expanded program capacity.