When seasons change, pig diseases are frequent: learn to diagnose several common infectious diseases

In late spring and early summer, as the seasons change, the climate is unpredictable and various epidemic diseases occur frequently. Pigs are susceptible to epidemic diseases. A set of diagnostic and treatment methods for infectious pig diseases has been compiled for the reference of farmers.

1. In pig production, we often encounter pig diseases mainly manifested by typical digestive tract symptoms such as diarrhea. The causes include viral diseases, bacterial diseases, and parasitic diseases. These pig diseases all have symptoms of diarrhea and are prone to misdiagnosis, so scientific identification and timely confirmation are particularly important.

2. Yellow scour of piglets is an acute, lethal disease caused by pathogenic Escherichia coli. Affected pigs have diarrhea and pass yellow serous thin feces containing small curd flakes, then quickly become emaciated and die in a coma. The gastrointestinal tract is distended and contains large amounts of yellow liquid contents and gas; the intestinal mucosa shows acute catarrhal inflammation, and the small intestinal wall becomes thinner. It most easily occurs in 1-3 day old piglets, and individual piglets develop the disease 12 hours after birth. The morbidity and mortality rates are relatively high.

3. White scour of piglets is an acute intestinal infectious disease caused by pathogenic Escherichia coli. The feces of affected pigs are milky white or grayish white, serous or pasty, with a fishy odor and sticky texture. The intestinal mucosa has catarrhal inflammatory lesions. It mostly occurs in 10-30 day old piglets. Morbidity is moderate and mortality is low.

4. Red scour of piglets is a highly lethal enterotoxemia caused by Clostridium perfringens type C, with bloody diarrhea, a short course, high mortality, and diffuse hemorrhage or necrotic changes in the posterior segment of the small intestine. Affected pigs pass bloody thin feces containing fragments of necrotic tissue. The jejunum is dark red, the mesenteric lymph nodes are bright red, the spleen margin has small petechial hemorrhages, and the kidneys are grayish white. It mainly affects 1-3 day old piglets; piglets over 1 week old rarely develop the disease. Morbidity is high and mortality is low.

5. Swine dysentery is an intestinal infectious disease caused by pathogenic Brachyspira hyodysenteriae. The large intestinal mucosa of affected pigs develops catarrhal hemorrhagic inflammation and fibrinous necrotizing inflammation, with mucous or mucohemorrhagic diarrhea. Affected pigs have reduced appetite, and the feces become soft with strip-like mucus on the surface; later the feces become yellow and soft or watery, until the feces are full of blood and mucus. The large intestinal mucosa is swollen and covered with mucus and fibrin with blood clots; the contents are soft to thin and mixed with mucus, blood, and tissue fragments. Pigs of all ages and breeds are susceptible, but it occurs more often in pigs 7-12 weeks old. The disease has no seasonal pattern and lasts a long time.

6. Transmissible gastroenteritis of pigs is a highly contagious intestinal disease caused by porcine transmissible gastroenteritis virus (a coronavirus). Affected pigs vomit, have severe diarrhea, and become dehydrated. Piglet feces are yellow, green, or white and may contain undigested curds. Adult pigs have vomiting and grayish-brown watery diarrhea. The gastric fundus mucosa is congested and hemorrhagic, the mesentery is congested, the lymph nodes are swollen, and the intestinal wall becomes thin and translucent. Mortality is high in piglets within 10 days of age, low in pigs over 5 weeks of age, and adult pigs almost never die. It generally occurs mostly in winter and spring, with the peak incidence in January to February.

7. Porcine epidemic diarrhea is an acute contagious intestinal infectious disease caused by porcine epidemic diarrhea virus (a coronavirus). Affected pigs vomit, have diarrhea, and become dehydrated. Affected pigs have watery diarrhea, severe dehydration, depression, and reduced appetite. The small intestine is dilated and filled with yellow liquid, the mesentery is congested, the mesenteric lymph nodes are edematous, and the small intestinal villi are shortened. Pigs of all ages are infected, and morbidity is high in suckling piglets, growing pigs, or finishing pigs. The disease mostly occurs in cold seasons, with the highest incidence in December and the following January.

8. Paratyphoid of piglets is a disease caused by Salmonella, with clinical signs such as septicemia, enteritis, and abortion in pregnant sows. Affected pigs show purplish-red skin at the base of the ears, chest, under the abdomen, and hindquarters; the feces are foul-smelling, pale yellow or yellow-green, and mixed with blood, necrotic tissue, or fibrinous flakes. The spleen is enlarged, relatively hard, and dark purplish-red; systemic lymph nodes are congested and swollen, and the mesenteric lymph nodes are enlarged and cord-like. It often occurs in piglets under 6 months of age, and more often in those 1-4 months old. The disease can occur in all four seasons, and occurs more often in rainy and humid seasons.

In addition:

1. Differentiation of febrile diseases with skin erythema

(1) Marked swelling of the pharynx, acute course: swine pasteurellosis.

(2) Marked swelling of the pharynx, chronic course: swine anthrax.

(3) No pharyngeal swelling, disease in pigs of all ages, erythema does not fade under finger pressure: classical swine fever.

(4) No pharyngeal swelling, susceptible at 6 months of age, erythema does not fade under finger pressure, erythema does not protrude from the skin, unclear boundaries: swine toxoplasmosis.

(5) No pharyngeal swelling, susceptible at 6 months of age, erythema fades under finger pressure, erythema protrudes from the skin, with clear boundaries such as diamond-shaped or square: swine erysipelas.

(6) No pharyngeal swelling, mostly occurring in the extremities of piglets, lameness, neurological symptoms: Streptococcus suis.

(7) No pharyngeal swelling, mostly occurring in the limbs and extremities of piglets, skin eczema, diarrhea: paratyphoid of piglets.

2. Differentiation of epidemic diseases with obvious respiratory symptoms

(1) Normal body temperature, difficulty breathing, no nasal lesions: swine enzootic pneumonia.

(2) Normal body temperature, difficulty breathing, nasal lesions present: atrophic rhinitis of swine.

(3) Elevated body temperature, epidemic course, poor prognosis: classical swine fever.

(4) Elevated body temperature, epidemic course, benign: swine influenza.

(5) Elevated body temperature, sporadic or endemic course, poor prognosis: swine toxoplasmosis.

(6) Elevated body temperature, sporadic or endemic course, benign: swine influenza-like pseudorabies.

(7) Elevated body temperature, sporadic or endemic course, variable: swine pasteurellosis.

3. Differentiation of epidemic diseases with neurological signs

(1) Obvious neurological symptoms, nystagmus: porcine infectious encephalomyelitis.

(2) Obvious neurological symptoms, vomiting, constipation, poor porcine blood suspicion: viral encephalomyelitis.

(3) Neurological symptoms, septicemia: swine influenza-like pseudorabies.

(4) Neurological symptoms, attacks humans and livestock: porcine pseudorabies.

(5) Neurological symptoms, septicemia, progressive emaciation: swine listeriosis.

(6) Neurological symptoms, muscle rigidity: swine tetanus.

(7) Neurological symptoms, head edema in piglets after weaning: swine edema disease.

(8) Neurological symptoms, septicemia, lameness: swine encephalitis-type streptococcosis.

(9) Obvious neurological symptoms, a few affected pigs have neurological symptoms, abortion in pregnant sows and orchitis in breeding boars: swine brucellosis.

4. Differentiation of epidemic diseases with vesicles on the mouth and feet

(1) All domestic animals are equally susceptible: vesicular stomatitis of swine.

(2) Even-toed ungulates can all be infected: foot-and-mouth disease.

(3) Piglets infected: swine vesicular disease.

5. Differentiation of piglet epidemic diseases with diarrhea symptoms.

(1) Feces contain necrotic tissue or fibrin-like material: paratyphoid of piglets.

(2) Bloody mucous diarrhea: swine dysentery.

(3) Yellow-white or dark black watery or pasty thin feces: porcine rotavirus disease.

(4) Gray or yellow watery thin feces, spread quickly, vomiting, high piglet mortality: transmissible gastroenteritis of pigs.

(5) Gray or yellow watery thin feces, spread relatively slowly, low mortality: porcine epidemic diarrhea.

(6) White pasty thin feces: white scour of piglets (10~30 days old).

(7) Yellow-white pasty thin feces: yellow scour of piglets (within 7 days of age).

(8) Blood-colored pasty thin feces: bloody scour of piglets (3 days old).

(9) Red scour of piglets: segmental hemorrhagic necrosis in the jejunum and ileum.

(10) Yellow scour of piglets: catarrhal inflammation mainly in the duodenum.

(11) Rotavirus enteritis: milk curds in the stomach, diffuse hemorrhage in the mucosa of the large and small intestines, and very thin intestinal walls.

(12) Transmissible gastroenteritis: the main lesions are in the stomach and small intestine, showing congestion and hemorrhage, and containing undigested small curd masses, with thinning of the intestinal wall.

(13) Epidemic diarrhea: the lesions are in the small intestine, the intestinal wall is thin, the intestinal lumen is filled with yellow liquid, the mesenteric lymph nodes are edematous, and the stomach is empty.