Yersinia species isolated from sheep with enterocolitis

Multiple factors correlating with wing malformations in the population of Parnassius apollo (Lepidoptera: Papilionidae) restituted from a low number of individuals: A mini review

The Apollo butterfly, Parnassius apollo (Linnaeus), was common in Europe over 100 years ago, but currently it is considered as near threatened. Different conservation programs have promoted the persistence of this species; however, it is still endangered. An example of such programs was the action devoted to reestablish the Apollo butterfly population in Pieniny National Park (Poland) from only 20-30 individuals which had survived till the last decade of the 20th century. This reintroduction has been successful; however, unexpected developmental problems appeared. Butterflies with deformed or reduced wings became frequent in the population living in the natural habitat, and particularly among those reared under seminatural conditions (in the same environment, but fenced by a net). Until recently, reasons for these malformations remained unknown. However, reports published during last months indicated that there are genetic, biochemical, and microbiological factors contributing to this phenomenon. In the malformed individuals, lesions in the wingless gene and dysfunctions of laccase 1 and 2 were found to be significantly more frequent than in normal insects. A large fraction of butterflies with deformed or reduced wings was devoid of the prokaryotic symbiont Wolbachia, which was present in most normal individuals. Moreover, Yersinia pseudotuberculosis (Pfeiffer) Smith and Thal, and Serratia sp., bacteria pathogenic to insects, were detected in the biological material from both normal and malformed butterflies from this population. These findings are summarized and discussed in this review, in the light of conservation of insects and restitution of their populations from a low number of individuals.

Outbreaks of diarrhoea ('winter scours') in weaned Merino sheep in south-eastern Australia

OBJECTIVE

Identify the cause of outbreaks of diarrhoea during winter that are not attributable to gastrointestinal nematodes in weaned Merino sheep in the high rainfall regions of south-eastern Australia and determine the efficacy of antimicrobials used to treat this syndrome.

METHODS

We investigated 45 outbreaks on 24 farms. Faecal samples from affected animals were cultured for Yersinia, Campylobacter and Salmonella spp. Risk factors, including rainfall, temperature and worm egg count (WEC), were assessed. Yersinia spp. were identified with molecular tests and susceptibility to four antimicrobials was determined.

RESULTS

Yersinia pseudotuberculosis serotype III and virulent Y. enterocolitica were most frequently isolated. The frequency and severity of disease varied between region, farm and year. Yersinia pseudotuberculosis was detected only during winter, but Y. enterocolitica was present in all seasons. Pathogenic Yersinia species were more often isolated when WECs exceeded 500 eggs/g. A high proportion of Y. enterocolitica and Y. pseudotuberculosis were resistant to sulfafurazole (64% and 86.9%, respectively).

CONCLUSIONS

A bacterial enteritis caused by pathogenic Yersinia was the cause of the winter scours syndrome in the 24 flocks investigated. The use of molecular testing increased the sensitivity of detection and identification of Yersinia spp. No clear association between weather, WEC and disease was established, suggesting complex interactions between risk factors are more important than any single factor. Sulfonamides should not be routinely used to treat this syndrome. Rather, during an outbreak the targeted use of an effective antimicrobial, such as oxytetracycline, should be integrated with grazing management strategies, including moving affected mobs onto lower risk pastures and decreasing the stocking rate.

Faecal shedding of pathogenic Yersinia enterocolitica determined by qPCR for yst virulence gene is associated with reduced live weight but not diarrhoea in prime lambs

Associations between faecal shedding of pathogenic Yersinia enterocolitica (based on the yst virulence gene) with growth, carcass weight and diarrhoea were investigated using an observational longitudinal study of 1200 crossbred prime (meat) lambs on eight Australian farms. Live weight, breech faecal soiling score (scale 1-5) and faecal consistency score (FCS; scale 1-5) were recorded, and faecal samples collected from each lamb on three sampling occasions; weaning (≈12 weeks of age), post-weaning (≈19 weeks) and pre-slaughter (≈29 weeks). Hot standard carcass weight was measured at slaughter. Faecal samples were screened for presence and concentration of pathogenic Y. enterocolitica using quantitative PCR. Associations of pathogenic Y. enterocolitica detection and shedding intensity with lamb health and production were assessed using general linear models (carcass weight), linear mixed effects models (live weight, FCS and breech soiling score) and non-parametric tests (FCS and breech soiling score). Prevalence for non-pelleted faeces (FCS ≥ 3.0) and diarrhoea (FCS ≥ 4.0) were compared with the two-tailed z-test, odds ratios and relative risk. Lambs shedding pathogenic Y. enterocolitica were 3.78 kg lighter post-weaning (P < 0.001) and 2.61 kg lighter pre-slaughter (P = 0.035) compared to lambs in which pathogenic Y. enterocolitica was not detected. Higher faecal concentration of pathogenic Y. enterocolitica was associated with lower live weight (P < 0.001). There was no association between pathogenic Y. enterocolitica detection and carcass weight. Overall, there was no evidence of association between pathogenic Y. enterocolitica detection and diarrhoea (higher FCS, higher risk for non-pelleted faeces or diarrhoea, or higher breech soiling score). Only one flock had increased relative risk for non-pelleted faeces associated with pathogenic Y. enterocolitica detection, and one other flock had increased relative risk for diarrhoea associated with pathogenic Y. enterocolitica detection. This is the first report of an association between reduced sheep live weight and pathogenic Y. enterocolitica based on the presence of the yst gene for heat stable enterotoxin determined by qPCR in sheep. Notably, impacts on live weight were observed in the absence of diarrhoea.

Scientific Opinion on the public health hazards to be covered by inspection of meat from sheep and goats

A risk ranking process identified Toxoplasma gondii and pathogenic verocytotoxin-producing Escherichia coli (VTEC) as the most relevant biological hazards for meat inspection of sheep and goats. As these are not detected by traditional meat inspection, a meat safety assurance system using risk-based interventions was proposed. Further studies are required on T. gondii and pathogenic VTEC. If new information confirms these hazards as a high risk to public health from meat from sheep or goats, setting targets at carcass level should be considered. Other elements of the system are risk-categorisation of flocks/herds based on improved Food Chain Information (FCI), classification of abattoirs according to their capability to reduce faecal contamination, and use of improved process hygiene criteria. It is proposed to omit palpation and incision from post-mortem inspection in animals subjected to routine slaughter. For chemical hazards, dioxins and dioxin-like polychlorinated biphenyls were ranked as being of high potential concern. Monitoring programmes for chemical hazards should be more flexible and based on the risk of occurrence, taking into account FCI, which should be expanded to reflect the extensive production systems used, and the ranking of chemical substances, which should be regularly updated and include new hazards. Control programmes across the food chain, national residue control plans, feed control and monitoring of environmental contaminants should be better integrated. Meat inspection is a valuable tool for surveillance and monitoring of animal health and welfare conditions. Omission of palpation and incision would reduce detection effectiveness for tuberculosis and fasciolosis at animal level. Surveillance of tuberculosis at the slaughterhouse in small ruminants should be improved and encouraged, as this is in practice the only surveillance system available. Extended use of FCI could compensate for some, but not all, the information on animal health and welfare lost if only visual post-mortem inspection is applied.

Prevalence of breech-strike in mulesed, clipped and unmulesed Merino hoggets in south-eastern Australia

OBJECTIVE

To compare the prevalence of breech flystrike ('breech-strike') on 12-20-month-old Merino hoggets that were mulesed, had breech and tail clips applied ('clipped') or were left unmulesed but treated strategically with long-acting insecticide.

DESIGN

A cohort study on three farms in southern Victoria.

METHODS

Three treatment groups were established at lamb marking on each farm. The unmulesed group was treated with dicyclanil when 12 months old in September or October ('early-season treatment'). The prevalence of breech-strike and key risk factors, including soiling of the breech with faeces ('dag') and urine ('stain'), and breech wrinkle, were compared between the groups.

RESULTS

Over all the farms, breech-strike occurred on 1.1% of mulesed sheep and 7.7% of clipped sheep. Clipped sheep had a relative risk of breech-strike of 18.2-, 16.8- and 3.0-fold that of mulesed sheep on the three farms. Unmulesed sheep treated with dicyclanil had a similar prevalence of breech-strike to that of mulesed sheep (overall 0.9%, range 0-2.5%), but had significantly more dag, stain and wrinkle.

CONCLUSION

Early-season treatment of unmulesed sheep prevented most breech-strikes during the spring and early summer, and offers a short- to medium-term option for the control of breech-strike in south-eastern Australia. There were some benefits associated with using clips, namely less dag and stain, and a shorter time spent crutching. However, to control breech-strike the clipped sheep should be treated the same as unmulesed sheep. Reducing the prevalence and severity of dag will be a major component of strategies to control breech-strike of Merinos in this region.

Prevalence of Anti-Yersinia Outer Protein Antibodies in Goats in Lower Saxony

Little is known about the prevalence of caprine yersiniosis in Germany. Only few cases are reported every year. The intention of the survey was to provide representative data on the seroprevalence of anti-Yersinia antibodies in goats in the German state of Lower Saxony. A commercially available Western blot kit was used to identify caprine and ovine anti-Yersinia antibodies against five proteins [YopM, H, D, E and V-antigen (V-Ag)]. Of the 681 investigated goat sera, 449 (66%) had anti-Yop/V-Ag antibodies. Only two of 28 animal holdings housed sero-negative goats. Boxplot analysis showed that the number of non-reactive animals is correlated to the size of a herd and the fact of milk production, respectively. A tendency was observed that various management factors may influence the anti-Yersinia antibody status. No statement was possible on the impact of keeping additional carrier animals such as pigs, cows or sheep on a farm or the type of husbandry on the seroprevalence of anti-Yersinia antibodies. This study provides trend-setting data for yersiniosis in goat-holdings. The impact on consumer health, i.e. especially for risk groups-like people allergic to cow milk and the impact on the profit of a farm will have to be elucidated in further studies.

Caprine Enteritis Associated with Yersinia pseudotuberculosis Infection

Yersiniosis was prevalent among a caprine herd during the late autumn of 2003 in Iwate Prefecture, Japan. The disease affected 29 of about 100 lactating goats, but not dried or nonparous goats, mature male goats or kids. Four animals died within an epidemic period of 20 days. Affected animals developed decreased milk production with subsequent watery diarrhea, neutrophilia with increased band forms and multiple microabscesses characteristic of yersiniosis in the intestinal mucosa from the jejunum to caecum as well as in the mesenteric lymph nodes. Y. pseudotuberculosis serotype III was isolated from intestinal contents and mesenteric lymph nodes. The organism was also cultured from clinically normal dried animals. The outbreak might have been precipitated by multiple stress factors, such as lactation, cold weather, Corynebacterium pseudotuberculosis infection resulting in abscess formation and tapeworm and coccidium parasitisms.

Outbreaks of yersiniosis caused by Yersinia pseudotuberculosis in farmed cervids

Yersiniosis, caused by Yersinia pseudotuberculosis, was diagnosed in 25 deer submitted to the Veterinary Diagnostic Laboratories of the Ontario Ministry of Agriculture and Food from 8 farms in Ontario, Canada, over the 4-year period of January 1990 to December 1993. The organism was cultured, usually in large numbers, from the intestines and, less frequently, mesenteric lymph nodes and/or the spleen of 13 red deer (Cervus elaphus), 6 elk (C. e. canadiensis), 4 fallow deer (Dama dama), and 2 red deer-elk hybrids. Outbreaks occurred almost exclusively in the fall (September-November) and affected recently weaned calves, 4-6 months old. Sudden death usually signalled the start of an outbreak. Outbreaks often occurred during inclement weather; usually a sudden cold snap, with or without rain, after a period of relatively mild fall weather. At necropsy, the animals were usually emaciated and dehydrated, and the perineum and tail were sometimes fecally stained. The small and large intestines were congested and filled with serofibrinous and/or seroanguineous fluid. Mesenteric lymph nodes were edematous and congested. Microabscesses surrounding large bacterial colonies in the lamina propria in the jejunum and ileum were typical lesions seen histologically. Peyer's patches were depleted and sometimes contained microabscesses. Purulent lymphadenitis associated with bacterial colonies was the prominent histologic lesion in mesenteric lymph nodes.