How to Distinguish Swine Dysentery from Diarrhea? A Detailed Guide to Integrated Prevention and Control Methods

Dysentery and diarrhea in pigs are relatively common, especially in large-scale @#@227@#@ farms. On some pig farms, the harm caused by swine dysentery and diarrhea is quite serious, particularly piglet dysentery and diarrhea, which have become key factors restricting piglet survival rates. Improving the ability to clinically distinguish swine dysentery from diarrhea is of great significance for grassroots animal disease prevention and control workers and large-scale farm (household) owners to promptly adopt prevention and control measures.

1 Differences and Classification of Dysentery and Diarrhea

Dysentery and diarrhea are both clinical symptoms. What is commonly called loose stool mostly refers to diarrhea. During diarrhea, the feces do not contain viscous substances, and abdominal pain symptoms are not necessarily present. Dysentery is often accompanied by abdominal pain symptoms, and the feces contain viscous substances. Clinical diarrhea can be divided into general diarrhea and viral diarrhea; dysentery is generally divided into red dysentery, yellow dysentery, and white dysentery.

2 Clinical Characteristics of Swine Dysentery and Diarrhea

Swine dysentery is mainly seen in young pigs, including piglet red, yellow, and white dysentery, as well as piglet paratyphoid. Swine diarrhea can be seen in pigs of all ages, including swine fever and gastroenteritis caused by sudden temperature drops, feed changes, etc., toxic diseases, infectious gastroenteritis caused by coronavirus and rotavirus, piglet diarrhea caused by pseudorabies, and intermittent diarrhea caused by atypical swine fever.

Piglet red dysentery is an enterotoxemia caused by Clostridium, including Clostridium welchii type C and Clostridium perfringens type C. Clinically, it is seen in 2-day-old piglets, with the main symptoms being red viscous feces, intestinal necrosis, and high fever. The course of disease is short, and the mortality rate is high.

Yellow dysentery is caused by Escherichia coli. Clinically, it is seen in 3-5 day-old piglets as an acute, highly lethal disease characterized by yellow viscous feces. The disease has an extremely strong ability to spread through feces. As long as piglets in the same litter come into contact with the feces of diseased pigs, they can be infected and become ill.

White dysentery is seen in piglets over 5 days old, mostly at 20-30 days old, and recently has shown a trend of occurring at younger ages. The pathogen is Escherichia coli. Clinically, it is mostly seen in pig herds with poor insulation conditions in farrowing rooms. Piglets are long-term exposed to low-temperature stress and become ill, so it is also called a conditional disease. Clinically, it presents as white, grayish-white, or yellowish-white viscous feces with a fishy odor and mixed with bubbles, fear of cold, thirst, reduced appetite or refusal to eat. If not treated promptly, the mortality rate is also relatively high.

Piglet paratyphoid is mainly seen in 2-4 month-old piglets, and is also seen in young pigs over 30 days old and pigs over 6 months old; it is rare in pigs over 60 kg. The pathogen of this disease is Salmonella. Clinical features: gray or grayish-white foul-smelling loose feces; after 2-3 days, the loose feces become dark red, with slight fever or no fever; progressive emaciation, and death from exhaustion after 2-3 weeks. The mortality rate is 20%-30%. Most recovered pigs become runt pigs.

There are many causes of diarrhea, but diarrhea caused by stress factors such as temperature drops, parasitic diseases, poisoning, and sudden feed changes is mostly accompanied by indigestion. After administering antidiarrheal drugs and removing the stress factors, the condition can be quickly controlled; however, diarrhea caused by swine fever, pseudorabies, coronavirus, and rotavirus does not respond to antidiarrheal drugs. Stress-induced diarrhea is clinically characterized mainly by indigestion, with loose feces containing many incompletely digested food particles and frequent diarrhea; diarrhea in atypical swine fever alternates with constipation; diarrhea caused by viral gastroenteritis is characterized mainly by watery diarrhea, mostly occurring in 7-20 day-old piglets, with refusal to eat, excessive drinking, a disease course of 5-7 days, and a mortality rate of 40%-70%. Dead piglets show pale anemic characteristics. It is highly contagious. Often, 2-3 days after one piglet becomes ill, all piglets in the same litter are infected, and within one week, a large number of piglets in the same barn but different pens also become ill.

At present, the most common and most serious hazards are piglet yellow and white dysentery, infectious gastroenteritis (epidemic diarrhea) caused by coronavirus and rotavirus, and piglet diarrhea caused by pseudorabies. All large-scale pig farms should carry out prevention and control work effectively in light of their own actual conditions.

3 Clinical Differentiation of Dysentery and Diarrhea Diseases

During grassroots clinical diagnosis, due to the lack of testing equipment, differentiation can be started from the following aspects for comprehensive judgment.

3.1 Judge from the age of the pig: red dysentery at 2 days old, yellow dysentery at 3-5 days old, white dysentery from over 5 days old up to 1 month old, viral diarrhea at 7-20 days old, and piglet paratyphoid at 1-6 months old.

3.2 Judge from the color of the feces: red suggests red dysentery and bloody dysentery (amoebic dysentery), yellow suggests yellow dysentery, viral diarrhea, and white dysentery, white suggests white dysentery, and gray suggests piglet paratyphoid. White viscous secretions are often a feature of the early stage of intestinal inflammation. With bubbles and a fishy odor, it is white dysentery; with incompletely digested curds, it suggests yellow dysentery. Red viscous secretions are a manifestation of gastrointestinal bleeding. When the color is bright, it is mostly bleeding from the anus and rectum; when dark red, the bleeding site is in the large intestine; when dark red or purplish, it is a problem in the stomach and small intestine.

3.3 Fecal morphology: When formed feces alternate with loose stool, first consider atypical swine fever. When the loose feces contain much incompletely digested food particles, consider stress reactions such as chilling, poisoning, sudden feed changes, and parasitic diseases. When the feces contain viscous secretions, judge according to the color of the secretions. When the feces are watery, consider poisoning and viral diarrhea.

3.4 Fecal odor: Loose feces from indigestion are often accompanied by a sour odor. Feces with a fishy odor should suggest white dysentery, and a foul odor should suggest piglet paratyphoid.