Infectious disease update: What you’ll see this winter

Be on the lookout for a host of infectious diseases this winter, warns Katherine L. Heilpern, MD, FACEP, interim residency director and assistant professor in the department of emergency medicine at Emory University School of Medicine in Atlanta. "We are heading into another fairly significant season for infectious disease."

In addition to sinus infections, bronchitis, upper respiratory infections, and respiratory synsitial virus, there are many other outbreaks to watch for, stresses Paula Heitkemper, RN, BSN, CIC, infection control practitioner at the University Hospital in Cincinnati. (See related stories on streptococcal disease, p. 8, strep pneumoniae, p. 8, and drug-resistant TB, p. 9.)

Stay abreast of outbreaks occurring in your own community, says Heitkemper. "By law, infection control practitioners inform the local health department when outbreaks are occurring in the state or county. The county health departments then notify the state health departments."

With good communication, isolation can be initiated in the ED as soon as the patient arrives, says Heitkemper. "For example, I call the ED occasionally to ask physicians/staff to be watchful for certain persons in the community who may be incubating with measles or who are known to be infectious with TB, but left the hospital AMA [against medical advice]."

Here are several infectious diseases you probably will see in your ED this winter:

Escherichia coli (E. coli). "We still appear to be dealing with occasional outbreaks of E. coli," says Heilpern. "We tend to see this more in the summertime, but may see more of it this fall and winter."

Most strains of E. coli are harmless and live in the intestines of healthy humans and animals, notes Heitkemper. "However, E. coli O157: H7 produces a powerful toxin and can cause severe illness," she says. "It was not recognized as a cause of illness until 1982, due to an outbreak later traced to contaminated hamburgers."

E. coli 0157:H7 is an emerging cause of foodborne illness, stresses Heitkemper. An estimated 10,000 to 20,000 cases of infection occur in the United States each year, she says. "Infection often leads to bloody diarrhea and occasionally kidney failure. Most illness has been associated with eating undercooked, contaminated ground beef."

Person-to-person contact in families and child care centers (particularly by toddlers who are not potty-trained) is also a common mode of transmission, Heitkemper notes. "Infection can occur after drinking raw milk and after swimming in or drinking sewage-contaminated water."

All persons who suddenly have diarrhea with blood should get their stool tested for E. coli 0157:H7, advises Heitkemper. "Persons who only have diarrhea usually recover completely," she says.

• Measles. The largest measles (rubeola) outbreak since 1996 has occurred in Alaska from August to November 1998.

Thirty-three cases have been reported, says Heitkemper. The index case was imported by a visitor from Japan, she says. No endemic measles virus is circulating in the United States currently, she adds.

"There was a wild measles virus strain circulating in Japan at the time of the outbreak," she says. "The outbreak was stopped following vaccination of many who had received a first dose of measles vaccine, but not a second dose."

A first dose at age 12 months provides a 95% immunity to measles, notes Heitkemper. "A second dose should be given at least 28 days after the first dose, but prior to beginning kindergarten. This is required by schools now," she says.

Throat, urine specimens available

In the ED, obtain throat and urine specimens from suspected measles cases immediately after the rash onset, so that a type can be identified, Heitkemper says. "Suspected cases of measles should be placed in airborne precautions with negative airflow," she explains.

• Listeriosis. There was a multistate outbreak of listeriosis occurring from August 1998 through January 1999, reports Heitkemper. Fifty cases were reported in 11 states.

"There have been six deaths and two spontaneous abortions caused by eating contaminated hot dogs or deli meats," she says.

Healthy persons rarely develop severe illness with this bacteria (Listeria monocytogenes), notes Heitkemper. "Those affected are usually pregnant women, newborns, and those with impaired immunity such as those with HIV or cancer."

Listeriosis presents with a flulike illness, fever, chills, headache, and stiff neck, notes Heitkemper. There is an incubation period of two to eight weeks after ingestion of the contaminated food, and standard precautions are recommended.

• Pediatric respiratory syncytial virus (RSV) and rotavirus. In infants, RSV causes bronchiolitis, an airway infection typified by wheezing and respiratory distress, and rotavirus causes diarrhea, Heilpern says. "Both of these diseases more commonly occur in the winter months."

Both of those viruses are found throughout the United States and tend to cause disease in epidemic fashion in infants and young children, notes Heilpern. "They can spread like wildfire through day care centers and pre-schools."

Begin influenza vaccines now

• Influenza. Influenza is one of the most highly infectious diseases you will encounter, stresses Heitkemper.

The time to begin the annual influenza vaccine immunization is October or November, says Heilpern. Any patient who is being admitted to a long-term care facility or nursing home should be vaccinated, she says. The vaccine should be continued until February or March.

All ED nurses should be vaccinated against the influenza virus every year, Heitkemper recommends. "Remember that this vaccine also takes two weeks before you will develop antibodies," she says. "So if you are exposed to the influenza within the two weeks following vaccination, you can still get sick, but will probably develop a milder case."

• Whooping cough. Whooping cough outbreaks occurred in Cincinnati in the summer of 1998, reports Heitkemper. Pertussis in adolescents and young adults has been increasing in frequency through out the United States.

"Many of these cases have been occurring in previously immunized persons due to waning immunity," she says.

Whooping cough is frequently underdiagnosed because it is not recognized, she notes. The main symptom is a very characteristic, repeated, violent, and paroxysmal cough which sounds like a "whoop," she says. Paroxysms are often followed by vomiting.

The mode of transmission is by direct contact with discharges from mucous membranes, Heitkemper says. Droplet precautions are recommended by the Centers for Disease Control and Prevention, she advises. "That means wearing a mask within three feet of the patient to prevent droplets from contacting your mucous membranes." Droplet precautions do not require airborne precautions (negative air flow in an isolation room).