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Watery mouth is more commonly found in sheep, and especially in young lambs. It is known to be a contagious disease which can rapidly lead to death in the infected young lambs if they are not treated in time. The bacteria causing the disease can affect many animals including humans. Watery mouth disease is sometimes known as E. coli enterotoxaemia.


E. coli enterotoxaemia in Sheep

Also known as rattle belly, watery mouth is a bacterial infection caused by the bacteria E. Coli which occurs in lambs and in sheep. The E. coli bacteria have the ability to travel to the animal’s stomach upon entering the body and are usually dealt with, as in it denatures and destroys them, by the acidic nature of the adult sheep’s stomach. This means that they are less likely to adversely affect mature sheep. However, young lambs will not have developed this defence as their stomach contents have a pH of approximately 7 which is not acidic enough. Upon entering and then passing the stomach, the bacteria replicate and reproduce in the lamb’s intestines.


Young lambs between the ages of one and three days are therefore observed to be more susceptible to an infection of watery mouth disease. Castrating young males, in the first day following their birth, increases the stress levels of the lambs and therefore their susceptibility since they become reluctant to suckle and gain the necessary colostrum from their mother’s milk. Lambs who are twins or triplets also seem more prone to contracting the disease.


The disease is transmitted via ingestion of the E. coli bacteria and if there is not an adequate intake of colostrum. The symptoms include salivating, dehydration and sometimes, though rarely, diarrhoea. The infected lamb may die within hours. The disease is not typically zoonotic although E. coli bacteria can in themselves affect humans. Vaccinations are available to help protect against the bacterium.


Transmission of Watery Mouth

Watery mouth is usually transmitted to lambs once they’ve ingested a large amount of the E. coli bacteria which replicate in their intestines. Lambs can contract the disease following oral contact with contaminated bedding or even the wool of their own mothers infected with E. coli. Unclean udders also act as sources of infection for watery mouth to their offspring. If the quantity of colostrum taken in from lambs’ mothers is not sufficient then this can also result in a greater incidence of the disease as the necessary maternal antibodies are not passed on. Weaker members of triplet or twin lambs are also more likely to be transmitted watery mouth disease.


Transmission is more of a risk in areas where poor hygiene and wet or damp conditions are present. Concerning the spread of the disease, it is also especially rapid in areas of overcrowding where the bacteria have more opportunity to come into contact with susceptible lambs and sheep. However, it is not confined to only this type of intensive farming since it can be found in most areas since the bacteria is prevalent in the environment.


Signs and Symptoms of Watery Mouth

The signs and symptoms of watery mouth include drooling, or excess salivation. The mouth of the infected lamb will be cold to the touch, more so than other parts of the body. The infection may lead to lethargy and the young lamb will appear dull and depressed.


The abdomen will become distended. Some animals affected with watery mouth have diarrhoea whilst most do not. A reluctance to eat may be observed and gentle shaking of the lamb results in a sound coming from the stomach which leads us to the origin of the name “rattle belly”. As the disease progresses, the lamb will become dehydrated. Following this, the animal can fall into a coma and die.


Treatment of Watery Mouth

If caught in time, successful treatment is possible. Broad spectrum antibiotics may be administered. Replacing lost fluids is generally a large part of the treatment plan when dealing with infections of watery mouth. These may be given orally or be injected. The lamb may need to be kept in a warm environment to increase the body temperature. Treatment is rarely successful.


Prevention of E. coli enterotoxaemia

Watery mouth can be prevented primarily by keeping high levels of hygiene and in some cases, vaccination. Overcrowding should be avoided. This is particularly true for farms with breeding stock as it is generally lambs which are the most severely affected.


Lambs should be kept in dry areas where cleanliness is a top priority and adequate ventilation is also a requirement. Bedding should be clean and soiled bedding removed. Lambs should be monitored so that they ingest large enough quantities of colostrum in the first six hours of life to provide them with protection. In some cases tube feeding is necessary. Stored supplies of colostrum, taken from ewes with single lambs, is a good source of supplementary colostrum for lambs with a high risk of infection. Ewes should be fed so as to prevent malnutrition leading to weak lambs. Stress should be reduced so as not to discourage suckling in the essential twenty four hours of colostrum intake. This includes not castrating of tail docking the lambs in this time of their life.


Vaccines are available with the aim to reduce the possibility of infection for lambs. Despite this, colostrum is still of the utmost importance in controlling this highly infectious disease in lambs.


Diagnosis of Watery mouth and Rattle Belly

The diagnosis of this disease is simply made via observing the signs and symptoms presented by the infected lamb or sheep. Confirmation is often made after death during necropsies which may show certain tissue lesions.


Prognosis of Watery Mouth

In cases where the lamb has not been treated in time, the prognosis is poor. It rapidly advances in lambs and so can result in quick deaths. Up to a quarter of lambs on average can become infected during an outbreak and over two thirds are usual fatal infections.


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