What is TGE in pigs? Causes, symptoms, diagnosis, and effective prevention & treatment of Transmissible Gastroenteritis.

Transmissible Gastroenteritis (TGE) in pigs is a dangerous infectious disease caused by a Coronavirus, especially severe in suckling piglets. The disease is characterized by severe diarrhea, dehydration, rapid emaciation, and a high mortality rate (often up to 100% in piglets under two weeks of age).
Join Fivevet to learn about the clinical signs, causes, and effective prevention and treatment methods. 1. What Is TGE in Pigs?
Transmissible Gastroenteritis (TGE) was first recorded in the United States in the 1940s and quickly became one of the most dangerous viral diarrheal diseases affecting pig herds. The disease spreads very rapidly and often breaks out during cold seasons.
TGE causes severe losses in suckling piglets, with mortality rates that can reach nearly 100% in piglets under two weeks of age if they do not receive protective antibodies from the sow’s colostrum.
In recent years, in some countries, the frequency of TGE outbreaks has tended to decline due to the emergence and circulation of other coronaviruses such as Porcine Epidemic Diarrhea Virus. However, TGE is still considered a potential threat in pig production and remains an important subject of veterinary research, particularly in relation to immunity and disease prevention in sow–piglet herds.
2. Causative Agent of TGE in Pigs
Transmissible Gastroenteritis (TGE) is caused by the Transmissible Gastroenteritis Virus (TGEV). This virus belongs to the family Coronaviridae and the genus Alphacoronavirus.
TGEV is an enveloped, positive-sense single-stranded RNA virus. It is surrounded by a lipid envelope and possesses surface glycoprotein spikes (S protein – spike protein). These spike proteins play a crucial role in attaching the virus to receptors on the epithelial cells of the small intestine in pigs. The S protein is also the main antigen that stimulates the immune response and induces the production of neutralizing antibodies.
TGEV does not have high environmental resistance: it is easily inactivated by sunlight and high temperatures. However, under cold and humid conditions, the virus can survive for a long time in the environment. Therefore, outbreaks often occur during winter and early spring, when weather conditions in Vietnam are favorable for viral survival and transmission.
3. Epidemiology of TGE in Pigs
3.1. Susceptible Animals
Pigs of all ages can be infected with TGEV. However, disease severity varies depending on age:
- Suckling piglets (≤ 14 days old): the most susceptible group, with mortality rates reaching 90–100%.
- Weaned piglets and adult pigs: usually show milder clinical signs and have much lower mortality rates.
3.2. Routes of Transmission
TGEV spreads very rapidly within a herd, primarily via the fecal–oral route:
- Healthy pigs ingest feed, water, or feces contaminated with the virus from infected animals.
- Indirect transmission occurs through contaminated equipment, feeders, housing facilities, clothing, boots, vehicles, and farm workers.
- Importantly, recovered pigs may continue to carry and shed the virus into the environment for 2–8 weeks, serving as a persistent source of infection and increasing the risk of recurrence within the farm.
3.3. Predisposing Factors for TGE Outbreaks
Several conditions favor viral survival and rapid spread:
- Cold and humid weather.
- High stocking density and intensive production systems.
- Poor hygiene and biosecurity practices (wet housing conditions, infrequent disinfection).
4. Pathogenesis of TGE in Pigs
After entering the body via the oral route, TGEV travels to the small intestine and replicates extensively in the epithelial cells of the intestinal villi, particularly in the duodenum and jejunum.
During viral replication, TGEV:
- Destroys intestinal epithelial cells, causing severe villous atrophy.
- As the villi are damaged, the intestine loses its ability to absorb nutrients and water and becomes deficient in digestive enzymes (such as lactase).
As a result, affected pigs develop severe diarrhea, dehydration, electrolyte imbalance, and rapid emaciation. In piglets, the immune system is still immature and unable to effectively control viral replication, leading to a very high mortality rate.
5. Clinical Signs of TGE in Pigs
5.1. Suckling Piglets
Suckling piglets are the most severely affected group, and clinical signs appear very early:
- Vomiting and refusal to nurse (a typical sign, often the first to appear).
- Profuse watery diarrhea, pale yellow or gray in color.
- Rapid dehydration: sunken eyes, wrinkled skin, rough hair coat, cold body surface.
Piglets deteriorate quickly and may die within 2–5 days due to severe dehydration and electrolyte imbalance.
5.2. Weaned Piglets and Adult Pigs
In older pigs, the disease is usually milder but still causes production losses:
- Mild to moderate diarrhea, with low mortality.
- Reduced feed intake, lethargy, poor growth performance.
- Loose feces lasting several days, followed by possible spontaneous recovery.
However, when co-infections occur (such as with Porcine Reproductive and Respiratory Syndrome Virus (PRRS), Mycoplasma hyopneumoniae, or other respiratory bacterial pathogens), clinical signs become more severe and recovery is prolonged.
Piglets around three weeks of age often survive but may become stunted and grow poorly.
5.3. Sows
In sows, clinical signs are often less obvious:
- Some may show no clear symptoms if previous exposure has provided partial immunity.
- In certain cases: fever, reduced appetite, mild diarrhea, decreased or absent milk production.
Reduced milk yield further increases piglet mortality due to both starvation and dehydration.
6. Characteristic Lesions of TGE in Pigs
During necropsy of pigs affected with TGE, lesions are mainly found in the gastrointestinal tract, especially in the small intestine:
- Stomach: often contains large amounts of undigested, clotted milk; mild hemorrhages may be observed on the gastric mucosa.
- Small intestine: the intestinal wall is thin, soft, and almost translucent due to severe erosion; fluid contents can often be seen through the intestinal wall.
- Mesentery: mesenteric blood vessels and lymphatics appear more prominent than normal.
At the microscopic level (histopathology):
+ The small intestinal villi are markedly shortened and atrophied.
+ The villus height to crypt depth ratio decreases significantly, from approximately 7:1 in healthy pigs to nearly 1:1 in affected pigs.
These lesions severely impair the intestine’s ability to absorb water and nutrients, directly leading to severe diarrhea and rapid dehydration in piglets infected with TGE.
7. Diagnosis of TGE in Pigs
7.1. Clinical and Epidemiological Diagnosis
TGE should be suspected when the following typical signs are observed:
- Acute diarrhea with rapid spread throughout the herd.
- High mortality in suckling piglets.
Outbreaks occurring during cold seasons and affecting pigs of all ages, especially with nearly 100% mortality in piglets under two weeks old, strongly suggest TGE.
7.2. Laboratory Diagnosis
Definitive diagnosis requires laboratory testing:
- RT-PCR: detects TGEV RNA (commonly used and highly accurate method).
- ELISA: detects viral antigens or antibodies against TGEV in clinical samples or serum.
- Immunofluorescence (IF/IHC): detects viral antigens in intestinal tissues.
7.3. Differential Diagnosis
TGE presents clinical signs very similar to other viral diarrheal diseases in pigs and must be differentiated from:
- Porcine epidemic diarrhea (PED).
- Rotavirus infection.
Accurate differentiation is essential for appropriate control and prevention strategies.
8. Prevention and Control of TGE in Pigs
8.1. Biosecurity Measures
Because TGE spreads very rapidly, strict biosecurity is the most important measure to protect pig herds:
- Regular cleaning and disinfection of housing facilities.
- Strict control of farm visitors, vehicles, and equipment.
- Quarantine of newly introduced pigs before mixing with the herd.
Piglets are well protected only when they receive sufficient maternal antibodies. The most effective immunity against TGE is secretory IgA antibodies in colostrum and milk. Therefore, establishing strong immunity in pregnant sows is essential.
8.2. Vaccination Against TGE
Currently, TGE vaccines mainly include modified live (attenuated) and inactivated vaccines.
- Vaccination of sows aims to stimulate antibody production in colostrum to protect piglets.
- It helps enhance intestinal mucosal immunity and increase IgA levels in milk.
Common vaccination schedule:
- Primary vaccination for replacement gilts.
- Booster vaccination before breeding or approximately 2–4 weeks prior to farrowing.
8.3. Treatment of TGE in Pigs
There is currently no specific antiviral treatment for TGEV. The main goal of treatment is to reduce mortality caused by dehydration and secondary infections:
- Fluid and electrolyte therapy: administer oral rehydration solutions (ORESOL), glucose solutions, or intravenous fluids when necessary.
- Provide warmth: increase creep area temperature to reduce cold stress and energy loss.
- Supplement antibodies and immune-support products to enhance piglet resistance.
- Broad-spectrum antibiotics are used to prevent and control secondary bacterial infections such as Escherichia coli and Salmonella. This article was prepared by the Vaccine Research and Development Department of Central Veterinary Medicine Joint Stock Company No. 5 (Fivevet).
Frequently Asked Questions (FAQs)
1. What is TGE in pigs?
TGE (Transmissible Gastroenteritis) is a contagious diarrheal disease in pigs caused by a Coronavirus. It is especially dangerous for suckling piglets.
2. Why do piglets under 2 weeks of age have high mortality when infected with TGE?
Because their immune system is not fully developed, the virus destroys the small intestinal lining, leading to loss of water absorption. As a result, piglets rapidly become dehydrated, weakened and may die.
3. How does TGE spread within a herd?
The disease mainly spreads via the fecal–oral route when healthy pigs ingest contaminated feed, water, or come into contact with feces from infected pigs. It can also spread indirectly through equipment, clothing, vehicles, and caretakers.
4. Is there a specific treatment for TGE?
There is currently no specific antiviral treatment for TGE. Management mainly focuses on fluid and electrolyte replacement, keeping piglets warm, and using antibiotics to prevent secondary bacterial infections.
5. What is the most effective way to prevent TGE?
Vaccinating sows before farrowing and ensuring piglets receive adequate colostrum intake are the most effective preventive measures.