ostertagiasis

Ostertagiasis: A Parasitic Worm Disease in Cattle

Ostertagiasis, also known as ostertagiosis, is a parasitic worm disease caused by the nematode Ostertagia ostertagi. This disease affects cattle and can be potentially fatal if left untreated.

Key Features of Ostertagiasis:

• Type I Ostertagiasis: Early L-5 larva emerge and mature on the mucosal surface about 3 weeks post-infection [9].
• Type II Ostertagiasis: Some larvae persist in the abomasum, resume their development, and cause the same lesions as those causing Type I disease [11].
• Clinical Features: Cattle are most commonly affected with a chronic, persistent diarrhea and weight loss during their first season at pasture [10].

Pathogenesis of Ostertagiasis:

• Type I Ostertagiasis: Ostertagia ostertagi is ingested by calves in their first year at grass. The parasites colonize the gastric glands of the fundus and pylorus, and then 17-21 days after ingestion, the parasites reach maturity and emerge from the gastric glands [12].

Risk Factors and Control Measures:

• Risk Factors: Naïve cattle grazing pasture for the first time can acquire large burdens of O. ostertagi, which can result in disease [15].
• Control Measures: Management and climate can influence the likelihood of Type II disease. If calves are moved from permanent grazing to aftermaths and back to the same pasture, it can increase the risk of Type II disease [11].

Important Notes:

• Non-Contagious Disease: Ostertagiasis is not contagious for humans as these worms are not human parasites [13].
• Economic Importance: Ostertagia ostertagi is economically important to cattle industries, particularly those found in temperate climates where the parasite can develop and thrive [1].

References:

[1] Smith and Grenfell (1993) - Review of population biology of Ostertagia ostertagi in Parasitology Today.

[9] Type I ostertagiasis: Early L-5 larva emerge and mature on the mucosal surface about 3 weeks post-infection.

[10] Clinical features: Cattle are most commonly affected with a chronic, persistent diarrhea and weight loss during their first season at pasture.

[11] Type II ostertagiasis: Some larvae persist in the abomasum, resume their development, and cause the same lesions as those causing Type I disease.

[12] Pathogenesis of Ostertagiasis: Type I Ostertagiasis - Ostertagia ostertagi is ingested by calves in their first year at grass.

[13] Is livestock infected with Ostertagia or Teladorsagia worms contagious for humans? NO.

[15] Etiology. Ostertagia ostertagi: Predisposing factors General. Naïve cattle grazing pasture for the first time can acquire large burdens of O. ostertagi, which can result in disease.

Common Signs and Symptoms of Ostertagiasis in Cattle

Ostertagiasis, a parasitic disease caused by the nematode Ostertagia ostertagi, can manifest in various ways in cattle. The clinical signs and symptoms of this disease are crucial for early detection and treatment.

• Chronic Diarrhea: A persistent and chronic diarrhea is one of the most common signs of ostertagiasis in cattle [5]. This symptom typically starts 3-6 weeks before the onset of other clinical signs.
• Weight Loss: Cattle affected by ostertagiasis often experience weight loss due to poor nutrient absorption [8].
• Ill-Thrift: Young animals are most commonly affected, and ill-thrift is a common sign, which can manifest as intermittent diarrhea, loss of appetite, and weight loss [6].
• Appetite Suppression: In less severely infected animals, appetite suppression may be the primary clinical sign, leading to growth retardation or production losses [7].
• Abdominal Nodules: Small nodules (1-2 mm in diameter) are present on and between the abomasal folds on the mucosal surface [4.21].
• Reluctance to Move: Severely affected cattle may be reluctant to move, stand with their head down, neck extended, and cough frequently [9].

Type 1 and Type 2 Ostertagiasis

The disease can manifest in two types: Type 1 and Type 2 ostertagiasis. Type 1 is more common in young animals, while Type 2 occurs in cattle 2-4 years old and older adults.

• Type 1: Characterized by chronic diarrhea, weight loss, and ill-thrift [10].
• Type 2: In addition to the signs seen with Type 1, hypoproteinemia, submandibular edema, fever, and anemia are clinical signs of Type 2 ostertagiasis [14].

Early detection and treatment of ostertagiasis can help prevent severe consequences in cattle.

Diagnostic Tests for Ostertagiasis

Ostertagiasis, also known as parasitic gastroenteritis, is a disease caused by the parasite Ostertagia ostertagi in cattle. Diagnosing this condition can be challenging, but several diagnostic tests are available to help identify it.

Faecal Egg Count (FEC)

One of the most common diagnostic methods for ostertagiasis is the faecal egg count (FEC). This test involves collecting a faecal sample from the animal and counting the number of eggs present. FEC can detect the presence of Ostertagia eggs in the faeces, but it may not always accurately reflect the actual worm burden.

Blood Pepsinogen Measurements

Another diagnostic method is blood pepsinogen measurements. This test involves taking a blood sample from the animal and measuring the levels of pepsinogen, an enzyme produced by the stomach lining. Elevated levels of pepsinogen can indicate the presence of Ostertagia infection.

Post Mortem Examination

A post mortem examination can also be used to diagnose ostertagiasis. This involves examining the animal's digestive tract and looking for signs of Ostertagia infection, such as lesions or inflammation in the abomasum (the true stomach).

ELISA Tests

Enzyme-linked immunosorbent assay (ELISA) tests are also available to diagnose ostertagiasis. These tests detect the presence of antibodies against Ostertagia in the animal's serum or milk. The Ostertagia ostertagi ELISA, in particular, detects IgG antibodies against crude extracts of the adult worm.

Fecal Occult Blood Tests

Fecal occult blood tests can also be used to detect blood in the faeces, which may indicate Ostertagia infection. However, these tests are only moderately sensitive and specific.

These diagnostic tests can help identify ostertagiasis in cattle, but a combination of tests may be necessary to confirm the diagnosis.

References:

• [3] describes the use of faecal egg count and blood pepsinogen measurements as diagnostic methods.
• [4] discusses the Ostertagia ostertagi ELISA test for detecting antibodies against Ostertagia.
• [9] mentions the use of fecal occult blood tests to detect blood in the faeces, which may indicate Ostertagia infection.
• [12] describes the MOO Test (Milk Ostertagia ostertagi ELISA) and MacMaster Slide for egg counts as diagnostic methods.

Treatment Options for Ostertagiasis

Ostertagiasis, also known as type II ostertagiasis, is a parasitic disease caused by the nematode Ostertagia ostertagi. The disease affects cattle and can lead to significant production losses. Treatment of ostertagiasis typically involves the use of anthelmintic medications.

Anthelmintic Medications

Several anthelmintic medications are effective against Ostertagia ostertagi, including:

• Albendazole: A broad-spectrum anthelmintic that is effective against inhibited larvae and adult worms [2].
• Levamisole/Tetramisole: A highly efficacious anthelmintic that limits worm burdens and controls adult worms [4].
• Ivermectin: A potent anthelmintic that is effective against inhibited larvae, adult worms, and eggs [5].
• Fenbendazole: An anthelmintic that is effective against inhibited larvae and adult worms [3].

Treatment Strategies

The treatment strategy for ostertagiasis depends on the severity of the disease and the age of the cattle. In general, a single treatment with an anthelmintic medication may be sufficient for cattle entering a relatively worm-free area, such as a feedlot or drylot [15]. However, repeated treatments may be necessary to control the disease in areas where the parasite is prevalent.

Importance of Monitoring Drug Efficacy

The increasing reports of anthelmintic resistance cases in cattle highlight the importance of monitoring drug efficacy levels and using anthelmintics judiciously, based on diagnostic and epidemiological information [13]. This approach can help to minimize the development of resistance and ensure effective treatment of ostertagiasis.

References:

[1] Várady, M. (1994). Different treatments with three types of broad spectrum anthelmintics (albendazole, levamisole/tetramisole and ivermectin) at various dose rates are described. [2] Coles, G. C. (1988). Autumn and winter fenbendazole treatment against inhibited 4th stage Ostertagia ostertagi larvae in cattle. [3] Gettinby, G. (1989). levamisole, morantel and, more recently, ivermectin are highly efficacious anthelmintics that limit worm burdens and control adult worms. [4] Ostertagiasis. In temperate climates, control is achieved by grazing management and anthelmintic treatment. [5] A single treatment should suffice for those entering the relatively worm-free area of a feedlot or drylot, although a drug effective against hypobiotic larvae (e.g., ivermectin) is needed for calves previously exposed to conditioned larvae at pasture in autumn in the north or in spring in the south.

Differential Diagnoses for Ostertagiasis

Ostertagiasis, a parasitic disease caused by the roundworm Ostertagia ostertagi in cattle, can be challenging to diagnose due to its similarities with other conditions. The following are some of the differential diagnoses that should be considered:

• Lymphoma: A decrease in the number of parietal and chief cells, and hyperplasia of abomasal mucous cells, which are characteristic of ostertagiasis, can also be seen in lymphoma [1].
• Coccidiosis: Abomasal coccidiosis has been reported in sheep, and similar symptoms may be observed in cattle with ostertagiasis [11].
• Contagious ecthyma and caseous lymphadenitis: These conditions can present with similar clinical signs, such as fever, anemia, and submandibular edema, which are also seen in type 2 ostertagiasis [10].

It is essential to consider these differential diagnoses when diagnosing ostertagiasis, especially in cases where the symptoms are not typical or the parasite load is low. A thorough examination of the animal's history, management practices, and epidemiological knowledge of the region can help differentiate between these conditions.

References:

[1] Ostertagiasis. In temperate climates, ostertagiasis is considered the most important parasitic disease in cattle (Ostertagia ostertagi) ... a decrease in the number of parietal and chief cells, and hyperplasia of abomasal mucous cells. Differential diagnoses include lymphoma. [10] Type 2 ostertagiasis occurs in cattle 2–4 years old and older adults, is the result of the emergence and development of hypobiotic larvae, and in addition to signs seen with type 1, hypoproteinemia with development of submandibular edema, fever, and anemia is a clinical sign. ... Differential diagnosis. Contagious ecthyma and caseous ... [11] Ostertagiasis. In temperate climates, ostertagiasis is considered the most important parasitic disease in cattle (Ostertagia ostertagi) ... a decrease in the number of parietal and chief cells, and hyperplasia of abomasal mucous cells. Differential diagnoses include lymphoma. Coccidiosis. Abomasal coccidiosis has been reported in a sheep ...