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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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