Members of Salmonella enterica are frequently involved in egg and egg product related human food poisoning outbreaks worldwide. In Australia, Salmonella Typhimurium is frequently involved in egg and egg product related foodborne illness and Salmonella Mbandaka has also been found to be a contaminant of the layer farm environment. The ability possessed by Salmonella Enteritidis to colonize reproductive organs and contaminate developing eggs has been well-described. However, there are few studies investigating this ability for Salmonella Typhimurium. The hypothesis of this study was that the Salmonella Typhimurium can colonize the gut for a prolonged period of time and that horizontal infection through feces is the main route of egg contamination. At 14 weeks of age hens were orally infected with either S. Typhimurium PT 9 or S. Typhimurium PT 9 and Salmonella Mbandaka. Salmonella shedding in feces and eggs was monitored for 15 weeks post-infection. Egg shell surface and internal contents of eggs laid by infected hens were cultured independently for detection of Salmonella spp. The mean Salmonella load in feces ranged from 1.54 to 63.35 and 0.31 to 98.38 most probable number/g (MPN/g) in the S. Typhimurium and S. Typhimurium + S. Mbandaka group, respectively. No correlation was found between mean fecal Salmonella load and frequency of egg shell contamination. Egg shell contamination was higher in S. Typhimurium + S. Mbandaka infected group (7.2% S. Typhimurium, 14.1% S. Mbandaka) compared to birds infected with S. Typhimurium (5.66%) however, co-infection had no significant impact on egg contamination by S. Typhimurium. Throughout the study Salmonella was not recovered from internal contents of eggs laid by hens. Salmonella was isolated from different segments of oviduct of hens from both the groups, however pathology was not observed on microscopic examination. This study investigated Salmonella shedding for up to 15 weeks p.i which is a longer period of time compared to previously published studies. The findings of current study demonstrated intermittent but persistent fecal shedding of Salmonella after oral infection for up to 15 weeks p.i. Further, egg shell contamination, with lack of internal egg content contamination and the low frequency of reproductive organ infection suggested that horizontal infection through contaminated feces is the main route of egg contamination with S. Typhimurium in laying hens.

Salmonella Enteriditis and Salmonella Typhimurium are commonly isolated during egg-related outbreaks of salmonellosis and represent a significant international public health issue. In Australia, Salmonella Typhimurium is the most common serovar identified in egg product related foodborne outbreaks. While a number of studies have investigated Salmonella shedding and host responses to infection, they have been conducted over a short time period. The present study sought to characterise bacterial shedding and host responses to infection in hens infected with only Salmonella Typhimurium or co-infected with both Salmonella Typhimurium and Salmonella Mbandaka over a 16 week period. Salmonella shedding was quantified using the most probable number and qPCR methods and was highly variable over the course of the experiment. On day 1, fecal corticosterone metabolites in birds infected with Salmonella Typhimurium (674.2 ± 109.3 pg/mg) were significantly higher than control (238.0 ± 12.62 pg/mg) or co-infected (175.4 ± 8.58 pg/mg) birds. The onset of lay occurred between weeks 6–8 post-infection (pi) and Fecal corticosterone metabolite (FCM) concentrations increased in both control and co-infected birds. Antibody responses to infection were monitored in both serum and yolk samples. Salmonella Typhimurium specific antibody was lower in co-infected animals than monoinfected animals. Bacterial loads in internal organs were characterised to determine persistence. Spleen, liver and caecal tonsils were positive for bacteria in both groups, indicating that Salmonella was not cleared from the birds and internal organ colonization could serve as a reservoir for continued bacterial shedding.

BackgroundSalmonella vaccination is one of the control measure that farmers can use to reduce bacterial shedding in their flocks. This study aimed to examine the efficacy of the Vaxsafe® ST (Strain STM-1) attenuated live vaccine administered as ocular and oral doses followed by an intramuscular (IM) dose in rearing, in reducing contamination by Salmonellae of both eggs and the environment in the commercial multi-age cage layer sheds. A randomised controlled trial was conducted up to 26 weeks post last vaccine on two different multi-age caged egg farms.ResultsNo clinical symptoms were observed following IM administration of STM-1 during rearing. Following the first two STM-1 doses, both vaccinated and unvaccinated birds exhibited antibody titres below the positive cut-off value, however after IM administration of STM-1, antibody titres in the vaccinated group were above the cut-off value. Wild type Salmonella Typhimurium was not detected during the rearing of pullets. During production, the antibody titres were significantly higher in the vaccinated group at all sampling points during this trial. There was no significant difference in the prevalence of Salmonella (detected by culture and PCR method) between the vaccinated and unvaccinated groups on the egg belt and faeces in early lay. Wild-type Salmonella spp. were consistently found in dust samples. Quantitative PCR (qPCR) assay was able to differentiate between the live vaccine strain and wild type Salmonella. The load of wild-type Salmonella in shed environment was relatively low (1.3 log10 ± 0.48 CFU/m2 of surface area).ConclusionGiven that Salmonella Typhimurium and other serovars are able to survive/persist in the shed environment (such as in dust), regular cleaning and or removal of dust from shed is important. Use of the Vaxsafe® ST vaccine in multi-age flocks is “not an ultimate intervention” for reduction of Salmonella Typhimurium because of the complexities involved in achieving control, such as the efficacy of cleaning of sheds, the lack of resting periods between batches and the possible carry over of contamination from existing flocks. Hence implementation of more than one or several interventions strategies is essential.Electronic supplementary materialThe online version of this article (10.1186/s12866-018-1201-0) contains supplementary material, which is available to authorized users.

Objective: Cytotoxicity in blood cells and genotoxic alteration in gill, liver, and kidney of Cyprinus carpio acutely (96 h) exposed to 80 mg/L oxytetracycline (OTC) including a control (non-exposed group) were evaluated in the present study. Genotoxic endpoints reflecting different types of genetic damage in cells of the liver, gill, and kidney were also determined by analysis of nuclear and cytoplasmic abnormalities. Methods: C. carpio was divided into two groups, one control and others treated with 80 mg/L OTC. After 96 h, sampling was done and slides were prepared for different tissues as well as for measuring polychromatic erythrocyte (PCE) frequency in blood. Slides were scored for micronucleus, nuclear abnormalities, swollen cells, and vacuolated cytoplasm. Results: The hereby data obtained showed a higher and significant increase in the genotoxic effect in all the tissues tested. Furthermore, gill cells showed the highest genotoxic effect followed by liver and kidney, while PCE frequency increases up to 72 h of exposure, on the other hand, a significant decrease in the value was observed at 96 h of exposure. Conclusion: The present study revealed that OTC has cytotoxic and genotoxic effect on different organs and blood cells of C. carpio at this concentration and suggests gill as sensitive tissue for genotoxic assessment.

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Rabies is a zoonosis that is 100% fatal once symptoms of the disease appear. However, it is almost 100% preventable if the prophylactic measures with proper wound wash, vaccines and immunoglobulins are taken soon after exposure to the animal bite. A general tendency has been noticed among clinicians all over the world to inject Rabies Immunoglobulins (RIG) intramuscularly, mostly in the gluteal muscle, despite the guidelines that suggest infiltrating it into the wounds. This has resulted in failures of Post Exposure Prophylaxis in many countries leading to the death of patients due to rabies. Here we discuss how giving any amount or even large amount of RIG intramuscularly (IM) is not going to neutralise rabies virus at the wound site especially during the window period, exposing the patients to the risk of rabies, whereas a small volume of RIG injected into the wound(s) is a lifesaving intervention as it neutralises the virus there and then in the wound(s) especially during the initial window period when the exposed person is unprotected, as the response to concurrent vaccination may take 10-14 days after exposure/ bite.

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A nulliparous non-descript mare presented at full term with a history of straining (utero-abdominal contractions) for the last 24 hours. Vaginal examination revealed a dead foal in posterior presentation with bilateral hip flexion and dorso-iliac left position. Pre-operatively, 5 mL Tetanus toxoid as intramuscular injection, 3g Ceftriaxone and 4 mL Dexamethasone in 3L 5% Dextrose normal saline (DNS) as intravenous infusion (i/v) was administered. The per-vaginal delivery of the foal could not be attempted due to breech presentation; therefore, caesarean section was planned. Local anaesthetic infiltration along with sedation was done for carrying out the caesarean by employing an oblique ventro-lateral approach in lateral recumbency. Intravenous fluids, antiinflammatory drugs and daily antiseptic dressing were included in post-operative management and led to uneventful recovery of mare. The authors would like to perorate the case as a rare breech presentation induced dystocia in equine and emergency caesarean by employing an oblique ventrolateral approach under local anaesthesia and sedation.