SALMONELLOSIS

SALMONELLOSIS


Salmonellosis is a bacterial infection of the gastrointestinal tract that is usually associated with eating feces-contaminated food.



MORBIDITY: ++




MORTALITY: +




ETIOLOGY: BACTERIAL


Salmonellosis is caused by many serotypes of the Salmonella bacteria, which are gram-negative and facultatively anaerobic, meaning they live in the presence or absence of oxygen. Salmonella live in the intestinal tracts of people and animals; over 2000 serotypes have been identified. The two most common serotypes seen in the United States are S. enteritidis and S. typhimurium (causes typhoid fever, a human-only disease, so it will not be discussed here). Nontyphoidal salmonellosis is caused by S. enteritidis and results in the disease we associate with food poisoning. This serotype, and most others, are passed in the feces of an infected animal or person.


Some serotypes of Salmonella are species-specific and will not easily be spread to other species. Other serotypes are not species-specific, and these are the serotypes related to species-to-species spread, including the spread to people.



HOSTS


Salmonella resides in the intestinal tracts of both warm-blooded and cold-blooded animals. In people, anyone who is infected with the Salmonella organism can get sick, but it most commonly affects children under 5, elderly people, and people with compromised or weakened immune systems. Not every person or animal infected with Salmonella will become ill. Salmonella carriers often appear healthy.



TRANSMISSION


Many people become infected with Salmonella organisms by eating contaminated food, such as chicken, raw eggs, beef, milk, milk products, and vegetables (Figure 35). One outbreak of salmonellosis was caused by raw alfalfa sprouts, grown in contaminated soil. Any food of animal origin can be a potential source of infection to people. Salmonella can be found in feces, unpasteurized milk, blood, and body tissues.


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FIGURE 35 Salmonellosis.


Livestock can become infected during transport, at fairs, and at auctions, if they come in contact with infected animals. The newly infected livestock will then carry the Salmonella, either to their final destination or back home, where they will become a new source of infection to other animals or people.


Pets, especially those with diarrhea, can pass Salmonella in their feces. Transmission to people occurs when people do not wash their hands after coming in contact with the feces.


Reptiles, like snakes, iguanas, and turtles, commonly shed Salmonella; people need to wash their hands after handling any reptile, even the healthy looking ones.


Person-to-person transmission can occur if infected people do not wash their hands after using the bathroom and then handle food.


Cross-contamination can result when uncontaminated food is placed on a surface previously used for contaminated food.


Flies can transmit Salmonella on their feet as they travel from contaminated food to uncontaminated food.



SALMONELLOSIS IN ANIMALS


Salmonellosis in animals may or may not be apparent. Some animals are carriers that shed Salmonella at various intervals. Shedding may be brief, or it may occur over a long time. Other animals may develop a latent infection, in which the Salmonella organisms enter the blood system and travel to lymph nodes, where they lie dormant. Stress will most commonly cause the dormant organisms to become active.


Because salmonellosis is a disease of the gastrointestinal tract, diarrhea, sometimes bloody, is the most common clinical sign observed.



RUMINANTS


Salmonellosis affects calves primarily and is stress-related, with a high mortality rate. Adult cattle also can be affected. The clinical signs start with high fever, followed by severe diarrhea and abdominal pain. Abortion may occur. Carrier animals shed Salmonella in feces and milk. Salmonellosis is not common in sheep and goats in the United States.

Related posts:

  1. ABOUT THE DISEASES
  2. CAMPYLOBACTERIOSIS (VIBRIOSIS)
  3. MYCOBACTERIUM INFECTIONS (TUBERCULOSIS)
  4. PSITTACOSIS

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Oct 1, 2016 | Posted by in EXOTIC, WILD, ZOO | Comments Off on SALMONELLOSIS

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