obsolete transmissible gastroenteritis of swine

Clinical Signs and Symptoms

The obsolete transmissible gastroenteritis (TGE) of swine was characterized by several clinical signs and symptoms, which are still relevant today in understanding the disease. According to various studies [2, 6], the most common signs and symptoms of TGEV infection in pigs include:

• Diarrhea: Mild, watery to creamy, whitish-yellowish diarrhea usually occurs in 1 to 4-week-old pigs [5].
• Dyspnea and tachypnea: These are the most characteristic clinical signs, indicating respiratory distress [2].
• Periocular and eyelid edema: Swelling around the eyes and eyelids is a common sign of TGEV infection [2].
• Conjunctivitis: Inflammation of the conjunctiva, the thin membrane covering the white part of the eye, is also observed in affected pigs [2].
• Blue discoloration of the skin: This is another notable clinical sign, although its significance and prevalence are not well documented [2].

Other Clinical Signs

In addition to these primary signs and symptoms, other clinical manifestations have been reported in association with TGEV infection. These include:

• Facial paralysis: Facial paralysis with a drooping ear, deviated muzzle, flaccid lip, and lowered eyelid often develops on the affected side [7].
• Lack of menace response: The inability to respond to a threatening stimulus is another sign that may be observed in pigs infected with TGEV [7].

Lesions and Pathology

The disease also causes lesions and pathology in the large colon, leading to edema of the tissue that binds it together. This damage results in a period of diarrhea and poor nursing behavior in affected pigs [9].

Diagnostic Tests for Obsolete Transmissible Gastroenteritis (TGE) of Swine

Transmissible gastroenteritis (TGE) is a viral disease that affects swine, characterized by diarrhea and vomiting. While TGE is still a concern in some parts of the world, its incidence has declined significantly due to improvements in animal husbandry and vaccination practices.

Traditional Diagnostic Tests

In the past, diagnostic tests for TGE were primarily based on:

• Bacterial isolation: Isolating the causative agent, TGE virus (TGEV), from duodenum or colon contents, feces, or intestinal content.
• pH testing: Measuring the pH of intestinal content to determine if it was alkaline, which is a characteristic of TGE infection.

However, these traditional tests have largely been replaced by more modern and accurate diagnostic methods.

Modern Diagnostic Tests

Today, the diagnosis of TGE in swine is typically made using:

• Fluorescent antibody tests (FATs): These tests use fluorescent antibodies to detect the presence of TGEV in intestinal tissue samples.
• PCR (Polymerase Chain Reaction) assays: PCR can be used to amplify and detect specific DNA sequences of TGEV, allowing for accurate diagnosis.

Other Considerations

It's worth noting that other diseases, such as porcine epidemic diarrhea (PED), can present with similar clinical signs to TGE. Therefore, a definitive diagnosis of TGE must be made in the laboratory using one of the above-mentioned modern diagnostic tests.

References:

• [4] Transmissible gastroenteritis is a disease exclusively of swine.
• [8] The ultimate diagnosis of TGE must be made in the laboratory from the intestine of a fresh dead pig using fluorescent antibody tests (FAT's).
• [13] Porcine respiratory coronavirus (PRCV), a mutant of the transmissible gastroenteritis virus (TGEV), was first reported in Belgium in 1984.

Differential Diagnoses for Obsolete Transmissible Gastroenteritis (TGE) of Swine

Transmissible gastroenteritis (TGE) is a viral disease that affects pigs, causing diarrhea and vomiting. While TGE is still considered a significant threat to pig health in some regions, its incidence has declined significantly in recent years due to improvements in vaccination and management practices.

However, when diagnosing diseases in swine, it's essential to consider the differential diagnoses for obsolete TGE. The following conditions should be ruled out or considered in conjunction with TGE:

• Colibacillosis: A bacterial infection caused by E. coli that can lead to diarrhea and vomiting in piglets.
• Salmonellosis: A bacterial infection caused by Salmonella that can cause diarrhea, vomiting, and other systemic symptoms in pigs.
• Rotavirus: A viral infection that can cause severe diarrhea and vomiting in piglets.
• Swine Dysentery: A bacterial infection caused by Treponema hyodysenteriae that can lead to diarrhea, dysentery, and other systemic symptoms in pigs.
• S. enterica ser. Choleraesuis: A bacterial infection caused by Salmonella that can cause diarrhea, vomiting, and other systemic symptoms in pigs.

According to a review by [3], differential diagnosis is critical to control viral epidemic diarrheas in pigs. This highlights the importance of considering multiple conditions when diagnosing diseases in swine.

In addition, a study by [8] notes that TGE was suspected to be the main cause of piglet diarrhea in 1946, despite not being consistently demonstrated in all affected pigs. This suggests that TGE may still be a consideration in some cases of swine disease, although its incidence has likely declined significantly since then.

References:

• [3] Jung K. (2020). Viral epidemic diarrheas in pigs: A review of the current knowledge.
• [8] Jacobson M. (2022). The relationship between presumptive infectious agents and neonatal porcine diarrhoea (NPD).
• [4] Beltran-Alcrudo D. (2019). Introduction and exposure pathways for pig diseases.
• [5] Jacobson M. (2022). The aim of this paper is to review current knowledge on the relationship between presumptive infectious agents and neonatal porcine diarrhoea (NPD).
• [1] Dewey CE. (Routine diagnostic laboratory tests on affected piglets suggested the involvement of a number of enteric pathogens, including trans- missible gastroenteritis ...)
• [2] The differential diagnosis for nonhemorrhagic diarrhea in piglets aged upward of 14 days should include colibacillosis, salmonellosis, rotavirus ...