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Created on Friday, 14 August 2009 11:05
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Last Updated on Thursday, 29 November 2012 11:52
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Introduction
· Salmonella exists as numerous types, (~2000), these have different names. Typhoid fever and some cases of food poisoning in humans is causes by a Salmonella bacteria called S. typhimurium.
· S. hindmarsh is the most common causing death in ewes.
· Abortion and death in ewes is caused by S. brandenburg in New Zealand.
· S. Abortus-ovis causes abortion in the U.K., this bacteria is not found.
Survival
· Salmonella’s natural habitat is the intestine of most warm-blooded and cold-blooded animals. It survives in these carrier animals and is excreted onto pasture by animals that may show no clinical signs whatsoever.
· Salmonella under the most favourable conditions can survive for 9 months, especially in moist soil, water faecal material and animal feeds.
· Normal survival is much less than this. A few days in dry exposed conditions to a few weeks in moist sheltered conditions
Disease
· Animals that normally ingest these bacteria are not effected, however numerous factors can result in disease.
· Normally the indigenous bacteria that live in the intestine prevent Salmonella from attaching to the intestinal wall and hence invaded the new animal.
· Stress factors, such as, yarding, water and feed deprivation, antibiotic therapy and overcrowding can disrupt the normal intestinal flora predisposing an animal to bacteria colonisation.
· Why there is such a high prevalence in the autumn and early winter and not at other times of the year still remains a mystery.
Human Infection (Zoonosis)
· Salmonella of any type is capable of being spread to humans and causing disease, pathogens that can infect humans directly from animals are called Zoonoses.
· Handle all material very carefully and wash thoroughly afterwards
Prevention
· All hoggets should be vaccinated twice 3-4 weeks apart. Insuring final dose is 3 weeks prior to risk periods.
· SALVEXIN® A vaccine consisting of in active strains of Salmonella typhimurium, Salmonella hindmarsh and Salmonella bovis-morbificans.
· The vaccine does not contain S. brandenburg
· Ideally ewes should be boostered annually on high risk properties.
· Vaccinating the hoggets only will mean a greater response to the vaccine if it is used only in the face of an outbreak in older stock.
· Extreme care should be under taken during autumn not to place stress on stock. This includes feed, water, movement and over crowding.
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