Transmissible Gastroenteritis (TGE) is a highly contagious viral disease affecting pigs of all ages. This rapidly spreading illness is characterized by severe gastrointestinal symptoms.
What is Transmissible Gastroenteritis?
Transmissible Gastroenteritis (TGE) is an acute viral disease caused by the Transmissible Gastroenteritis Virus (TGEV), a type of porcine coronavirus. It affects pigs of all ages.
TGE manifests in two primary forms: an acute, epidemic form and a less severe, endemic form. The epidemic form impacts previously unexposed swine, leading to widespread illness. The endemic form is observed in herds with partial immunity or those co-infected with porcine respiratory coronavirus (PRCV), often resulting in milder symptoms and lower mortality rates.
Recognizing the Signs of TGE
The clinical signs of TGE primarily involve severe diarrhea and frequent vomiting. The severity of the disease and likelihood of survival are strongly correlated with the pig’s age.
Piglets under two weeks of age are particularly vulnerable, often experiencing mortality rates approaching 100% due to profound dehydration and electrolyte imbalances. As pigs get older, their ability to cope with the infection improves, and mortality rates decrease. Older pigs, including feeder and fattening pigs, typically exhibit milder signs such as transient diarrhea, reduced appetite, and some weight loss, with low or absent mortality.
How TGE Spreads and Where It Occurs
TGE primarily spreads through the fecal-oral route, with pigs becoming infected by ingesting contaminated feces or through direct contact with infected animals. The virus can also be transmitted indirectly via fomites, such as contaminated vehicles, farm equipment, clothing, or feed.
The virus can also travel short distances through the air via aerosols, allowing for rapid dissemination within a herd and between nearby farms. TGE is found in many major swine-raising countries globally, though it is less common in Europe, possibly due to the widespread presence of porcine respiratory coronavirus (PRCV), which offers some cross-immunity.
TGE outbreaks tend to be higher during colder months. The virus is more stable and persists longer in colder temperatures. Once introduced, it can persist on premises unless thorough cleaning and disinfection protocols are implemented.
Strategies for Prevention and Control
Preventing and controlling TGE relies heavily on stringent biosecurity measures. This includes maintaining a closed herd to minimize virus entry. If new animals are introduced, they should come from herds with no recent TGE history and undergo a quarantine period of at least 30 days, with serological testing to confirm they are virus-free.
Regular cleaning and disinfection of facilities, equipment, and vehicles are also important. The “all in/all out” system of production, which involves emptying, cleaning, and disinfecting a facility between groups of pigs, can significantly reduce virus persistence. While vaccines are available, they are generally most effective at boosting immunity in previously exposed swine rather than fully protecting a naive population during an acute outbreak.
For affected herds, supportive care for sick animals focuses on rehydration with oral electrolytes, especially for young piglets. Creating a warm environment can also aid recovery. In severe outbreaks, particularly in farrowing operations, specific management strategies might involve purposefully exposing pregnant sows and gilts to the virus weeks before farrowing. This stimulates antibody production in their colostrum and milk, thereby protecting their piglets.