Ileitis, also known as porcine proliferative enteropathy (PE), is caused by L. intracellularis, which infects the intestinal tract. It is one of the most common diseases in swine farms around the world, with huge financial losses.
Mild cases of ileitis mainly develop as a progressive proliferation of immature epithelial cells and don’t trigger a significant inflammatory reaction. If there is inflammation, it is often concentrated in the terminal ileum, near where it connects to the large intestine or colon, although it may also spread to other areas of the small intestine and throughout the large intestine.
Issues can be detected from fattening to the final phases of transition, even affecting first- and second-time mothers. It is rare among sucklings and weanlings under 60 days old.
Risk factors
The risk factors related to this disease are mainly environmental:
Continuous flow farm
Constant infection from one batch to the next seems to be a significant part of the epidemiology.
Environmental changes.
Feed changes.
Many factors contribute to the prevalence and financial impact of L. intracellularis in swine farms, including age, breed, diet, herd health, use of antibiotics, vaccines, disinfectants, handling and production systems.
Main causes
Porcine ileitis is caused by Lawsonia intracellularis, bacteria that can only multiply inside cells. Although it can cause proliferative enteropathy in many mammals, it is seen most often in pigs.
When healthy pigs ingest L. intracellularis, the bacteria begin to multiply in their intestines. The infection peaks within three or four weeks of infection. Generally, infection, lesions and shedding persist for about four weeks. In some cases, however, shedding can last up to 10 weeks. At peak infection, moderate diarrhea and histological lesions can often be observed in three out of four infected animals.
Signs and symptoms
Animals with subclinical ileitis, the most common form of the disease, often present with the following symptoms:
Clinical ileitis can be broken into three categories based on the symptoms.
Proliferative hemorrhagic enteropathy: the severe acute form of the disease, associated with bloody diarrhea and high death rate. It is most common in young breeding sows.
Porcine intestinal adenomatosis: chronic, uncomplicated form of the disease characterized by thickened mucosa, which may become corrugated. Symptoms include chronic mild to moderate diarrhea.
Necrotic enteritis: chronic complex form of the disease. Animals present with severe diarrhea and wasting.
Financial losses
Proliferative enteropathy causes huge financial losses all over the world. In several European countries, epidemiological studies have put prevalence rates at between 30% and 40% of farms.
As it is often subclinical, especially in transitional swine, the costs of ileitis have been underestimated. The main cause of financial losses associated with ileitis is diminished productivity due to the illness as a result of slower growth, making feed less effective for weight gain.
Another thing that leads to huge losses is increased mortality, whether directly caused by the disease or culling infected animals.
The direct costs of ileitis have been estimated at €5 per sow affected, however this can vary widely depending on the country and severity of the disease or outbreak.
Financial losses
How to fight ileitis
Prevention
There is no one solution for all swine populations, so the best ileitis control and prevention strategy must be chosen to fit the needs of each farm.
However, it is important to remember that L. intracellularis prevalence is high at swine farms around the world and that porcine proliferative enteropathy is endemic. So, it is key to implement a series of measures to help lower cases of ileitis among animals.
Diagnosis
Enteric colibacillosis is diagnosed using productive yield logs, clinical signs, macroscopic lesions and lab results.
Intestinal samples or fresh feces can be used for PCR testing to detect L. intracellularis DNA. PCR with feces is less sensitive than using the intestinal mucosa, but has the advantage that samples can be taken from live animals.
Treatment
Treatment success depends on their ability to eliminate bacteria from the intestinal lumen and cells.
Cases of acute or hemorrhagic proliferative enteropathy require aggressive medication protocols. Sick animals must be medicated with effective antimicrobial injections and the whole batch of animals must be given water with antimicrobials for a specific period and then be reassessed.
When the cases are subclinical, however, they may not present with death but lead to lower growth parameters and greater inequality. Nevertheless, these animals can continue to spread the bacteria and so should be treated with soluble antimicrobials in their drinking water, as sick animals eat less.
Water soluble medications are a good option in large farms because the animals don’t have to be handled and feed remains the same. However, this requires in-line dosing solutions or main water tanks in covered areas or pens to ensure proper dosing.
Treatment with antibiotics like lincomycin has proven effective in controlling symptoms, diarrhea and mortality in acute cases. Combining lincomycin and spectinomycin improves the spectrum of action and helps control possible co-infections caused mainly by E. coli.
BIBLIOGRAPHY
