Download om the Institute of Zoology1 (Director: Univ

Verh.ber. Erkrg. Zootiere (2007) 43.
Extended abstract
FATAL CASE OF SALMONELLA TYPHIMURIUM INFECTION IN A CHERRY
CROWNED MANGABEY (CERCOCEBUS TORQUATUS)
SPECK S1, PAULY A2, STARK R1*
1Leibniz
Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, GERMANY;
[email protected]
2Tierpark Berlin-Friedrichsfelde, Am Tierpark 125, 10307 Berlin, GERMANY
*current address: Institute of Anatomy, Histology and Embryology, Free University Berlin, Koserstr. 20,
14195 Berlin, GERMANY
Summary
In October 2005 an adult female cherry-crowned mangabey (Cercocebus torquatus) died per acutely
at Tierpark Berlin-Friedrichsfelde. One day later one of the adult males within the same group of
mangabeys showed signs of diarrhea. Pathological and bacteriological investigations performed at the
Leibniz Institute for Zoo and Wildlife Research revealed Salmonella typhimurium as the causative
agent. This is the first report of a fatal case of Salmonella typhimurium infection in a non-human
primate.
Introduction
Salmonella infection is well known in humans, livestock, and wild animals. Most of the Salmonella
serotypes belong to Salmonella (S.) enterica subspecies enterica with mammals and birds as their
main hosts. In animals, two major forms of disease occur: enteritis and septicemia, but the infection
may even result in abortion due to systemic disease (LIBBY et al., 2004). Host-adaptation has been
described for several S. enterica serovars. Host-adapted serovars (e.g. Typhi, Gallinarum,
Abortusovis) typically cause severe systemic disease in a limited number of related species. Within
this group of serovars exceptions exist like Dublin and Choleraesuis which are able to cause disease
in more than one species. Non-host-adapted serotypes like typhimurium and enteritidis are mainly
associated with gastroenteritis in a wide range of host species (UZZAU et al., 2000). Various
Salmonella enterica serovars have been recovered from free-ranging wildlife and zoo animals
including primates (OKOH and ONAZI, 1980; THURMAN et al., 1983; OCHOLI et al., 1987; MÖRNER,
2001). Approximately 50 % of Salmonella recovered from wild animals belong to Serovar typhimurium,
followed by dublin and enteritidis (BRÖMEL, 1994). Our report describes a fatal case of salmonellosis in
a captive cherry crowned mangabey (Cercocebus torquatus) caused by Salmonella Typhimurium.
Case report
A male cherry crowned mangabey was born into a group of 18 (15 males, 3 females) animals at
Tierpark Berlin-Friedrichsfelde. Veterinary attention was sought as the newborn mangabey was weak
and revealed signs of trauma and, therefore, was euthanized the same day. The animal was stored at
4 °C and submitted to the Leibniz Institute for Zoo and Wildlife Research (IZW) for diagnostic
investigations the next day. Four days later the mother (8 yr) died per acutely and was immediately
forwarded to the IZW. One day after the mother died one male mangabey had signs of diarrhea and
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was treated with Terramycin ad us. vet. (Pfizer) 500 mg/day i.m. initially, and 250 mg/day i.m. for two
more days. All animals of this group were fed on diet (black tea, rusk, boiled carrots and potatoes,
bananas). Desinfection trays were established and all cages were cleaned and desinfected using
Lysovet®PA (Schülke & Mayr). Fecal samples of all mangabeys (n = 18) were collected for
bacteriological investigation.
At necropsy the predominant macroscopical findings of the adult female mangabey were severe
dilatation and hyperaemia of the small intestine. Watery yellow ingesta containing blood and mucus
were accumulated in parts of the jejunum, ileum and colon. Multiple small white foci suggestive of
necrosis were found in the liver. The uterine mucosa was thickened and hyperaemic zones of
placentation were visible but considered as normal puerperial state. No other morphological changes
were visible. The newborn mangabey only revealed multiple acute haemorrhages on the surface of
the whole brain.
Tissue samples (heart, lung, liver, intestine, kidney, uterus, and brain) collected during necropsy were
fixed in 4 % neutral buffered formalin, processed routinely and embedded in paraffin. Sections were
cut at 5 µm and stained with haematoxylin and eosin, and according to Gram.
Histological examination of the adult female revealed severe diffuse neutrophilic reaction of all tissue
layers of the gut, follicular hyperplasia of the Peyer´s patches as well as a moderate submucosal
oedema with degeneration and thrombosis of submucosal vessels. Large numbers of Gram-negative
organisms were present in the gut lumen, on the surface of the brush border and within enterocytes.
Multifocal necrotizing hepatitis and a diffuse infiltration of neutrophils in the periportal areas were
present in the liver. Investigation of the uterus showed zones of placentation infiltrated with blood and
hyperplasia of the mucosa. Few Gram-negative organisms were within the uterine epithelium as well
as Gram-negative bacteria and neutrophils in the lumen of the uterus. In additon, mild multifocal
interstitial pneumonia was present in the lung.
Examination of the brain of the newborn mangabey revealed mild perivascular lymphoid infiltration and
multifocal submeningeal haemorrhage. There were no other histopathological changes detected within
the remaining tissues.
For bacteriological investigation, small and large intestine, liver, and uterus from the adult female
mangabey as well as all fecal samples were directly cultured on 5 per cent sheep blood agar (Oxoid),
Gassner medium (Oxoid), MacConkey agar (Oxoid), CIN agar (Oxoid) and xylose-lysinedesoxycholate /Salmonella-Shigella Mod agar (XLD/SS Mod agar; Oxoid). In parallel, samples were
placed in Rappaport-Vassiliadis (Oxoid) and tetrathionate-brilliant green-bile (TBG) broth (Oxoid) and
incubated for 24 h at 42 °C followed by subculture onto XLD/SS Mod agar. Agar plates were incubated
at 37 °C for 24 - 48 h. Primary identification of bacterial isolates was based on Gram staining, cellular
morphology, catalase and oxidase reaction. Species identification was carried out by using
conventional biochemical tests (BISPING and AMTSBERG, 1988; QUINN et al., 2000). Samples from the
newborn were stored in formalin but not subjected to bacteriological investigation.
Besides Escherichia coli and alpha-haemolytic streptococci, a Salmonella isolate was recovered from
all tissues and all faecal samples. The isolates were kindly serotyped at the National Salmonella
Reference Laboratory in Berlin as Salmonella typhimurium with the antigenic formula 1,4,5,12:i:1,2.
The phagetype was RDNC. All isolates were susceptible to ampicillin, gentamicin, streptomycin,
amoxicillin/clavulanic acid, kanamycin, sulphomethoxazole/thrimethoprim, chloramphenicole,
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nalidixinic acid, tetracyclin, ciprofloxacin, neomycin, colistin, ceftiofur, florfenicole, and spectinomycin.
Fecal samples investigated remained positive for 3 weeks. Treatment was changed to Baytril® 2.5 %
ad us. vet. oral solution (Bayer Health Care) for all animals according to susceptibility testing of
Salmonella isolates. Animals were medicated for seven days and thereafter no further Salmonella
isolates were obtained.
Discussion
Salmonella typhimurium is a zoonotic non-host-adapted serotype frequently isolated from a variety of
vertebrate hosts with and without clinical signs. It is most often involved in gastroenteritis, only
occasionally leading to septicemia but it has also been described in abortion in sheep, cattle and
guinea-pigs (HUNTER et al., 1976; OKEWOLE et al., 1989). In our case, S. typhimurium 1,4,5,12:i:1,2
was identified in the intestine, liver, and uterus of a mangabey four days postpartum. Based on
histopathological and bacteriological findings the animal died of Salmonella-septicemia. The route of
infection was most likely haematogenous rather than from the intestine to the liver via the bile duct
system. Presumably the uterus was colonized also by hematogenous spread rather than by an
ascending genital tract infection. The cervix is functionally closed during normal pregnancy and serves
as an effective barrier against ascending infections from the vagina. Besides other factors immunity is
influenced by the hormonal status and due to several reasons pregnancy predisposes to certain types
of infection. In the pregnant female infectious agents in a latent stage may become activated and
invade the gravid uterus leading to abortion or stillbirth. Microorganisms which are not generally
regarded as primary abortifacient may still cause abortion or result in weak offspring under appropriate
conditions (JONES et al., 1997). In the case of the mangabey the placenta was not subjected to histopathological and bacteriological investigation but placental lesions induced by bacterial colonisation
might have prevented oxygen and nutrient delivery to the fetus resulting in a weak pup delivered at
term. In utero infection late in gestation could be an alternative explanation but Gram-negative
bacteria were not detected in tissues of the fetus. One male mangabey from the same enclosure had
diarrhea and all fecal samples investigated were also positive for S. typhimurium. Clinical sings were
not observed in other animals suggesting a latent status of infection with S. typhimurium within this
group of mangabeys. However, the source of infection remained unknown. The outbreak could not be
related to food as food for all primates was prepared in the same facility and none of the other
primates fell ill. Food indiscriminately provided by visitors could possibly be the source of infection but
native rodents and birds which have access to the outside enclosure might be the most likely
transmitters of Salmonella. To the author’s knowledge, this is the first fatal case of S. typhimurium
infection in a non-human primate.
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