ProMED-mail |

Published Date: 2005-05-06 23:50:00
Subject: PRO/AH/EDR> Salmonellosis, pet rodents, 2003-2004 - USA (multistate)
Archive Number: 20050506.1258

SALMONELLOSIS, PET RODENTS, 2003-2004 - USA (MULTISTATE)
********************************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>
Date: Fri, 6 May 2005
From: ProMED-mail <promed@promedmail.org>
Source: Morbid Mortal Weekly Rep MMWR 2005; 54:429-433 [edited]
<http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5417a3.htm>

Drug-Resistant S. Typhimurium - rodents from pet stores - USA, 2003-2004
------------------------------------------------------------------------
During 2004, the Minnesota Department of Health (MDH) Public Health
Laboratory notified CDC about the isolation of multidrug-resistant
_Salmonella enterica_ serotype Typhimurium from ill hamsters from a
Minnesota pet distributor. This report describes 2 of the 1st
identified human cases associated with this outbreak, summarizes the
multistate investigation of human serotype Typhimurium infections
associated with exposure to rodents (e.g., hamsters, mice, and rats)
purchased at pet stores, and highlights methods for reducing
salmonellosis transmission from pet rodents to their owners. This is
the 1st documented salmonellosis outbreak associated with pet
rodents. Findings demonstrate that the handling of pet rodents is a
potential health risk, especially for children. Public health
practitioners should consider pet rodents a potential source of
salmonellosis.
Case Reports
------------
South Carolina: During Jun 2004, a boy aged 4 years was hospitalized
for 5 days with fever (105F [40.6C]), watery diarrhea, and abdominal
cramping. A stool culture yielded _S. enterica_ serotype Typhimurium.
9 days before the boy's illness, his family had purchased a hamster
from a retail pet store supplied by an Arkansas distributor; the
hamster was found dead 2 days after purchase.
Minnesota: During Aug 2004, a boy aged 5 years had diarrhea of 14
days' duration (initially bloody), abdominal cramps, vomiting, and
fever (103F [39.4C]). A stool culture yielded Salmonella serotype
Typhimurium. 4 days before the boy became ill, his family had
purchased a mouse from a retail pet store supplied by a Minnesota
distributor. The mouse became lethargic and had diarrhea immediately
after purchase. Even though the mouse was ill, the boy frequently
handled and kissed the mouse. A week after purchase, the mouse died;
the mouse was frozen and later submitted for testing at MDH. Cultures
of the mouse's lungs, pooled liver and spleen, and intestines yielded
growth of Salmonella serotype Typhimurium, with a pulsed-field gel
electrophoresis (PFGE) pattern indistinguishable from the boy's
isolate.
Hamster Salmonellosis
---------------------
On 30 Aug 2005, a veterinarian for the Minnesota pet distributor
called MDH about isolation of Salmonella from 2 ill hamsters
submitted to the University of Minnesota Veterinary Diagnostic
Laboratory (UMVDL). The hamsters were part of a shipment of 780
received on 1 Aug 2005 from an Iowa pet distributor [to see figures
go to original URL - Mod. LL]. A total of 243 hamsters from this
shipment were subsequently sent from the Minnesota distributor to 15
retail pet stores in 4 midwestern states. Distribution of rodents
from the Minnesota distributor ceased on 23 Aug 2005 after numerous
hamster deaths. Diarrhea was present in the majority of ill
hamsters. By 29 Aug 2005, approximately 320 (60 percent) of the
remaining 537 hamsters at the Minnesota distributor had died; the
other hamsters were euthanized.
UMVDL cultured serotype Typhimurium from the internal organs of 7
hamsters submitted for necropsy from the affected shipment. Isolates
from these hamsters were submitted to MDH for testing; they were
indistinguishable by PFGE from each other and from the Minnesota
patient isolate that was submitted to MDH through routine
surveillance. A subsequent MDH query of the PulseNet National
Salmonella Database revealed that these isolates were
indistinguishable by PFGE from a Kentucky patient's isolate and from
the South Carolina patient isolate. Historical data from the database
confirmed that this PFGE pattern was uncommon, representing 23 of 17
737 isolates in the Typhimurium database since 1998, providing
additional evidence that this cluster potentially represented a
common source outbreak.
Epidemiologic Investigation
----------------------------
Based on recognition of the Minnesota and South Carolina human cases,
CDC and MDH conducted a national search for additional human cases
associated with exposure to rodents. A review of isolates submitted
to the PulseNet National Salmonella Database in 2004 revealed 28
matching human case-isolates of serotype Typhimurium from 19 states;
patient illness onset dates ranged from Dec 2003 to Oct 2004. Of 22
patients interviewed, 13 (59 percent) had been exposed to rodents
purchased from retail pet stores(Figure); all exposures occurred
during the 8 days before illness onset. 2 (9 percent) patients
acquired salmonellosis through secondary exposure. 7 (32 percent) of
the 22 patients had no identified rodent exposure. 4 patients
remained under investigation, and 2 were lost to follow-up.
The 15 patients with primary or secondary rodent exposure were from
Illinois, Kentucky, Missouri, Pennsylvania, and South Carolina (2
cases each), Georgia, Michigan, Minnesota, New Jersey, and North
Carolina (1 case each) (Figure). Dates of illness onset ranged from
23 Dec 2003 to 28 Sep 2004. The median age of patients was 16 years
(range: 0-43 years), and 7 (47 percent) were aged <7 years. Symptoms
reported by patients with confirmed rodent exposure included
abdominal cramping (77 percent), fever (67 percent), vomiting (53
percent), and bloody diarrhea (20 percent). 6 (40 percent) patients
were hospitalized; no deaths occurred. Rodent exposures of primary
patients included mice/rats purchased to feed snakes (7 cases), pet
mice/rats (4), and pet hamsters (2). Human and animal serotype
Typhimurium isolates were uniformly resistant to ampicillin,
chloramphenicol, streptomycin, sulfizoxazole, and tetracycline
(R-type ACSSuT). Phage typing was performed on 3 human isolates at
CDC; all were determined to be definitive phage type (DT) 120.
Animal traceback investigations and environmental testing
---------------------------------------------------------
CDC, state and local health departments, and the USA Department of
Agriculture Animal Care conducted traceback investigations of rodents
from patients with confirmed rodent exposure and identified retail
pet stores, rodent distributors, and breeders (Figure).
Rodents purchased at retail pet stores were most frequently traced to
a pet distributor in Georgia or Arkansas. In Oct 2004, a retail pet
store in Illinois identified ill hamsters traced back to shipments
originating from the Iowa distributor; serotype Typhimurium was
isolated from 16 of 22 necropsied hamsters. 7 isolates were submitted
to the Illinois Department of Public Health Division of Laboratories
for PFGE testing; all were indistinguishable from previous isolates
obtained from hamsters received in Minnesota from the Iowa
distributor (Figure).
In Nov 2004, _S. enterica_ serotype Typhimurium was isolated at the
Georgia distributor from environmental cultures of rodent transport
cages, rat bins, mice pellets/bedding, and rat pellets. 3 of the 4
isolates were indistinguishable from each other by PFGE and closely
related to the outbreak PFGE pattern. The Georgia Public Health
Laboratory performed susceptibility testing of isolates from the
Georgia distributor; tests indicated multidrug-resistance (R-type
ACSSuT). Systematic environmental cultures were not obtained at the
implicated Arkansas and Iowa pet distributors or other breeders.
Information on use of antimicrobials (e.g., spectinomycin,
leptomycin, tetracycline, and nitrofurazone) was obtained from 5
rodent breeders/distributors. Routine use of antimicrobials was
documented in 4 facilities that use them for prevention of
nonspecific rodent enteritis. Delivery of antimicrobial agents in
drinking water occurred at the time of rodent weaning, before
transport, and/or on arrival at the pet distributor. 1 pet
distributor used rodent feed containing tetracycline for all rodent
feedings.
No common link was identified among the 3 main implicated pet
distributors (Arkansas, Georgia, and Iowa); the source of infected
rodents for this multistate outbreak is unknown. A systematic review
of shipping and commercial records was not possible at many of the
potentially involved rodent breeders and distributors.
[Reported by: Smith K, Boxrud D, Leano F, et from the Minnesota Dept
of Health and CDC]
Editorial Note
--------------
Each year, an estimated 1.4 million persons in the USA have
salmonellosis, leading to approximately 14 800 hospitalizations and
415 deaths (1,2). Salmonella is found in the intestinal tract of
animals and is transmitted by ingestion of feces, which might occur
from eating contaminated foods or through contact with animals or
their environments. Exposure to animals with higher frequency of
Salmonella shedding in their feces increases the risk for acquiring
salmonellosis; among pets, these include reptiles, young animals, and
animals with diarrhea (3, 4). In addition to reptiles, salmonellosis
outbreaks have been reported after handling of pet chicks, ducklings,
kittens, and hedgehogs (5-7).
Cases described in this outbreak were dispersed temporally and
geographically, and rodent purchases occurred through multiple retail
pet store chains and pet distributors; these factors might reflect
the geographic spread of _S. enterica_ serotype Typhimurium from a
common source of infection occurring earlier in the chain of pet
distributors or breeders. The recovery of serotype Typhimurium from
reusable transport containers, cages, and bins contaminated with
rodent droppings offers a potential mechanism for both the
environmental persistence and geographic spread of the organism.
Rodents subsequently transported or housed in contaminated containers
might have been exposed to the organism and become infected without
direct contact with infected rodents.
Phage typing of the _S. enterica_ serotype Typhimurium isolates
indicated DT120. Serotype Typhimurium DT120 is known to be
multidrug-resistant, possessing antibiotic-resistance gene cassettes
found also in serotype Typhimurium DT104 (8). Thus, identifying pet
rodents as an additional reservoir of multidrug-resistant serotype
Typhimurium is of public health importance. Antimicrobial agents are
ineffective at preventing Salmonella shedding and likely prolong such
shedding. The dissemination of multidrug-resistant Salmonella in pet
rodents might have been facilitated by the use of prophylactic
antimicrobials within the pocket-pet (e.g., hamsters, mice, and rats)
animal industry. This use might have contributed to disease in
colonized animals and increased shedding of Salmonella, thus
facilitating increased transmission among animals and from animals to
their human caretakers.
Public health practitioners should consider pet rodents a potential
source of salmonellosis and, when indicated, should obtain cultures
from pet rodents during an investigation. Veterinarians, animal
breeders, and distributors should consider submitting specimens to
clinical laboratories for Salmonella isolation if substantial
diarrhea-associated morbidity or mortality occurs among pet rodents
intended for sale. Heightened infection-control practices by pet
stores and distributors, including routine sanitizing of animal
transport containers and cages, might reduce transmission. Preventive
strategies (e.g., appropriate animal husbandry and hygiene practices)
could reduce the need for nontherapeutic antimicrobials to prevent
disease in rodents (9).
Consumers and animal workers should be aware that rodents, like
reptiles, can shed Salmonella; therefore, they should expect rodent
feces to be potentially infectious. Salmonella transmission to humans
can be reduced by thoroughly washing hands with soap and water after
handling rodents or their cages or bedding. Young children who are
unable to reliably wash their hands should avoid contact with rodent
feces. Additional public health recommendations for preventing
salmonellosis from reptiles might also be appropriate for preventing
salmonellosis from pet rodents (3).
1. Mead PS, Slutsker L, Dietz V, et al: Food-related illness and
death in the United States. Emerg Infect Dis 1999;5:607-25.
2. Voetsch AC, Van Gilder TJ, Angulo FJ, et al: FoodNet estimate of
the burden of illness caused by nontyphoidal Salmonella infections in
the United States. Clin Infect Dis 2004;38(Suppl):127-34.
3. CDC: Reptile-associated salmonellosis---selected states,
1998--2002. MMWR 2003;52:120-29.
4. Glaser CA, Angulo FJ, Rooney J: Animal associated opportunistic
infections in HIV-infected persons. Clin Infect Dis 1994;18:14-24.
5. CDC: Salmonellosis associated with chicks and ducklings---Michigan
and Missouri, Spring 1999. MMWR 2000;49:297-99.
6. CDC: Outbreaks of multidrug-resistant Salmonella Typhimurium
associated with veterinary facilities---Idaho, Minnesota, and
Washington, 1999. MMWR 2001;50:701-704.
7. CDC: African pygmy hedgehog--associated
salmonellosis---Washington, 1994. MMWR 1995;44:46-63.
8. Lawson AJ, Dassama MU, Ward LR, Threlfall EJ: Multiply resistant
(MR) Salmonella enterica serotype Typhimurium DT12 and DT120: a case
of MR DT104 in disguise? Emerg Infect Dis 2002;8:434-36.
9. American Veterinary Medical Association: Judicious therapeutic use
of antimicrobials. AVMA Executive Board position statement, April
2004.
<http://www.avma.org/policies/jtua_avma.asp>.
--
ProMED-mail
<promed@promedmail.org>
[This CDC report illustrates several important points:
- Rodents such as hamsters and mice can be the source of human salmonellosis;
- The use of antimicrobial agents in raising rodents for pet use can
facilitate the spread of multiresistent strains;
- The PulseNet Salmonella surveillance system is very useful in
looking back for additional cases when an epidemiologic cluster such as
this one is found. - Mod.LL]
[Hamsters & mice can also spread viruses, see:
Biggar RJ, Woodall JP, Walter PD, Haughie GE. Lymphocytic choriomeningitis
outbreak associated with pet hamsters. Fifty-seven cases from New York State.
JAMA. 1975 May 5;232(5):494-500. - Mod.JW]

See Also