The CDC is collaborating with public health, veterinary, and agriculture officials
in many states and the US Department of Agriculture National Veterinary Services
Laboratories (NVSL) to investigate an outbreak of Salmonella [enterica
serotype] Cotham infections linked to contact with pet bearded dragons purchased
from multiple stores in different states.
Bearded dragons are popular pet
lizards, native to Australia, that come in a variety of colors. Public health
investigators are using the PulseNet system to identify cases of illness that
may be part of this outbreak. PulseNet, the national subtyping network of public
health and food regulatory agency laboratories coordinated by CDC, obtains DNA
"fingerprints" of Salmonella bacteria through diagnostic testing with
pulsed-field gel electrophoresis, or PFGE.
On 22 Jan 2014, CDC
was notified by the Wisconsin Department of Health Services of a cluster of S.
Cotham infections with a high proportion of ill persons reporting exposure to
pet reptiles. Since 2012, there have been 12 ill persons infected with S.
Cotham in Wisconsin, and 10 (83 percent) of 12 persons reported contact with pet
bearded dragons. Wisconsin receives funding under the CDC FoodCORE (Foodborne
Diseases Centers for Outbreak Response Enhancement) program. These centers work
together to develop new and better methods to detect, investigate, respond to,
and control multistate outbreaks of foodborne diseases.
Salmonella Cotham is a rare serotype. Searching historical Salmonella
databases, CDC determined that serotype Cotham represents only 0.01 percent of
all human isolates in the USA since 1963. Before this outbreak, typically less
than 25 serotype Cotham infections were reported to PulseNet annually. Given the
rarity of the Cotham serotype and the information gathered by Wisconsin, CDC
conducted a search of PulseNet for all S. Cotham infections reported since
2012. As of 21 Apr 2014, a total of 132 persons infected with
the outbreak strain of S. Cotham have been reported from 31 states since 21
Feb 2012. The number of ill persons identified in each state is as follows
(listed in alphabetical order): Arizona (4), California (21), Colorado (2),
Florida (3), Georgia (1), Idaho (3), Illinois (6), Kansas (6), Kentucky (4),
Maryland (3), Massachusetts (1), Michigan (5), Minnesota (3), Missouri (7),
Nebraska (1), Nevada (3), New Hampshire (1), New Jersey (3), New York (10),
North Carolina (2), Ohio (1), Oregon (2), Pennsylvania (5), South Carolina (1),
South Dakota (1), Tennessee (5), Texas (6), Utah (3), Virginia (3), Washington
(4), and Wisconsin (12).
Among 132 persons for whom
information is available, dates that illnesses began range from 20 Feb 2012 to 1
Apr 2014. Ill persons range in age from less than 1 year to 79 years, with a
median age of 2 years. 58 percent of ill persons are children 5 years of age or
younger. 51 percent of ill persons are female. Among 67 ill persons with
available information, 28 (42 percent) have been hospitalized. No deaths have
been reported.
Investigation of the outbreak :
Epidemiologic, laboratory, and
traceback investigations conducted by officials in local, state, and federal
public health agencies indicate that contact with pet bearded dragons is the
likely source of this outbreak of Salmonella Cotham infections.
On 25 Mar 2014, CDC sent a questionnaire to the states involved in the
investigation to obtain more detailed information from ill persons about recent
contact with reptiles. In interviews, ill persons answered questions about
contact with animals and foods consumed during the week before becoming ill. To
date, CDC has received a total of 31 completed questionnaires. 27 (87 percent)
of 31 persons interviewed reported contact with reptiles or their environments
before becoming ill. When asked about the type of reptile, 25 (81 percent) of 31
persons reported contact with lizards; of these 25 persons, 21 (84 percent)
specifically reported contact with bearded dragons, a type of lizard. The
percentage of ill persons in this outbreak reporting contact with a reptile is
substantially higher than the percentage of USA households that reported owning
a pet reptile in a survey conducted in 2013-2014 by the American Pet Products
Association (5.6 percent). State and local health departments are continuing to
interview ill persons.
Laboratory investigation :
The Oregon State Public Health Laboratory has
isolated the outbreak strain of S. Cotham from samples from a pet bearded
dragon and its terrarium (habitat) collected from an ill person's home in Oregon.
The National Antimicrobial Resistance Monitoring
System (NARMS) is a US public health surveillance system that tracks antibiotic
resistance in foodborne and other enteric bacteria found in people, raw meat and
poultry, and food-producing animals. NARMS is an interagency partnership among
CDC, the US Food and Drug Administration (FDA), the US Department of Agriculture
(USDA), and state and local health departments.
The NARMS
human surveillance program at CDC monitors antibiotic resistance in Salmonella
and several other bacteria isolated from clinical specimens and submitted to
NARMS by public health laboratories. CDC's NARMS laboratory tested Salmonella
Cotham isolates collected from three ill persons infected with the outbreak
strain. 1 (33 percent) of the 3 isolates tested was multidrug
resistant
(defined as resistance to at least 1 antibiotic in 3 or more antibiotic
classes), and the other 2 (67 percent) isolates tested were pan susceptible (susceptible to all antibiotics tested). The multidrug resistant
isolate has shown resistance to the following antibiotics: ampicillin,
chloramphenicol, streptomycin, sulfisoxazole, tetracycline,
amoxicillin-clavulanic acid, cefoxitin, ceftriaxone, ceftiofur, and gentamicin.
One of these antibiotics, ceftriaxone, is commonly used to treat serious
Salmonella infections, including those in children. The CDC NARMS laboratory is
continuing to conduct antibiotic resistance testing on Salmonella Cotham
isolates collected from ill persons. Additional results will be reported when
they become available.
Traceback investigation :
The pet industry is working closely with CDC to
determine the source of the bearded dragons linked to this outbreak in order to
prevent additional illnesses. Through this collaboration, multiple potential
bearded dragon breeders have been identified that supply lizards to pet stores
in the United States where ill persons reported purchasing their animals. This
investigation is ongoing and CDC will update the public when more information is
available.
The information above has been communicated to Capitol Illini Veterinary Services by:
promed@promedmail.org
ProMED-mail is a program of the
International Society for Infectious
Diseases
Salmonellosis can be acquired from a variety of lizards,
including these bearded dragons,
snakes, turtles, and iguanas. Appropriate hand
hygiene is necessary to minimize this risk.
For more information on Salmonella visit the below websites.
