Epidemiologic Notes and Reports Increasing Rate of
Salmonella Enteritidis Infections in the Northeastern United
States
In the last 10 years, New England and the Middle Atlantic
region*
have experienced a fivefold increase in the reported isolation rate
of
Salmonella enteritidis (Figure 3). The increase exceeds the
regional
1.7-fold increase in the collective isolation rate reported for all
other Salmonella serotypes. In 1985, S. enteritidis replaced S.
typhimurium as the single most commonly reported serotype in New
Jersey, New York, and New Hampshire. The reasons for this increase
are not understood. The median age of persons infected with S.
enteritidis increased from 10 years to 24 years between 1975 and
1985,
but the seasonality of the infections has not changed. In 1986,
investigations of outbreaks of S. enteritidis infections in the
northeastern United States implicated a variety of food vehicles,
including scrambled eggs in Connecticut, a liquid protein
supplement
in Pennsylvania, home-made ziti in New Jersey, Italian-style rice
balls in New York City, Hollandaise sauce in New York State, roast
beef in Massachusetts, and one brand of commercial frozen pasta
products in multiple states in the region. No single reservoir
that
would connect all of these outbreaks and the many sporadically
occurring cases has been detected.
On November 1, 1986, epidemiologists from state health
departments
in the Northeast and the CDC met to review the findings of recent
S.
enteritidis outbreak investigations and to discuss possible
approaches
to the improved understanding and control of S. enteritidis
infections
in the region. An S. enteritidis Working Group was established to
facilitate communication and cooperation among public health
officials
in several states and the CDC in the investigation of S.
enteritidis
outbreaks. Since the serogroup of a Salmonella isolate is often
known
before its serotype and because more than 90% of Group D isolates
in
the Northeast are S. enteritidis, a strategy was developed to
intensify the rapid investigation of outbreaks of Group D
Salmonella
in the region. The U.S. Department of Agriculture and the Food and
Drug Administration are assisting the S. enteritidis Working Group
in
investigations that suggest a food production or food processing
source for the contamination.
Reported by S Schultz, MD, Bur of Preventable Diseases, New York
City
Dept of Health, D Morse, MD, State Epidemiologist, New York Dept of
Health; W Parkin, MD, State Epidemiologist, New Jersey Dept of
Health;
GF Grady, MD, State Epidemiologist, Bur of Communicable Diseases,
Massachusetts Dept of Public Health; EJ Witte, VMD, MPH, State
Epidemiologist, Pennsylvania Dept of Health; JL Hadler, MD, MPH,
Connecticut Dept of Health Svcs; RL Vogt, MD, State Epidemiologist,
Vermont Dept of Health; E Schwartz, MD, State Epidemiologist, New
Hampshire Dept of Health and Welfare; KF Gensheimer, MD, State
Epidemiologist, Maine Dept of Human Svcs; PR Silverman, PhD, State
Epidemiologist, Delaware Dept of Health and Social Svcs; E Israel,
MD,
State Epidemiologist, Maryland Dept of Health and Mental Hygiene;
Div
of Field Services, Epidemiology Program Office, Enteric Diseases
Br,
Div of Bacterial Diseases, Center for Infectious Diseases, CDC.
Editorial Note
Editorial Note: The majority of outbreaks of non-typhoid
Salmonella
infections in the United States come from foods of animal origin,
and
this is also likely to be the case for S. enteritidis (1).
Salmonella
may be introduced into such foods on the farm, during slaughter or
processing, or during final food preparation. A broad increase in
regional rates of human infections by a specific Salmonella
serotype
indicates that a regional increase in contamination may have
occurred
at one or more of these steps in the food chain.
Recognition of the problem of S. enteritidis infections in the
northeastern United States and the intensive investigation proposed
by
the S. enteritidis Working Group are both made possible by routine
serotyping of Salmonella isolates in public health laboratories.
It
is hoped that the regional effort proposed by the S. enteritidis
Working Group to understand the epidemiology of S. enteritidis
infections in the Northeast will lead to specific control measures
for
S. enteritidis. Understanding the epidemiology of a specific
serotype
in a region of high incidence may also lead to a better
understanding
of the continuing long-term increase in salmonellosis in the United
States.
Reference
Feldman RA, Riley LW. Epidemiology of Salmonella and Shigella
infections in the United States. In: Takeda Y, Miwatani T,
eds.
Bacterial Diarrheal Diseases. Tokyo: KTK Scientific
Publishers,
1985:103-16.
*New Jersey, New York, and Pennsylvania.
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