Treatment Methods for Cases of Bovine Actinomycosis

Actinomycosis is a chronic infectious disease of cattle, pigs and horses, and is most common in cattle. The main pathogens of this disease are Actinomyces bovis and Actinobacillus lignieresii, with Staphylococcus sometimes involved in causing the disease. Actinomyces bovis mainly attacks hard tissues and is a Gram-positive bacterium; its bacterial masses are relatively large, and the ends of the bacterial filaments are swollen and arranged in a radial pattern. Actinobacillus lignieresii mainly attacks soft tissues and is a Gram-negative bacillus; its bacterial masses are very small, and the radial arrangement is not obvious. The main feature of the disease is the development of actinomycotic swelling on the head, neck, lower jaw and tongue, and cattle aged 2 to 5 years are susceptible. When changing teeth or eating rough, prickly feed, infection often occurs because the oral mucosa is punctured, or the pathogen invades through broken skin. Therefore, the disease is generally sporadic.

1 Outbreak Situation

In August 2003, a large beef cattle fattening farm in Ji'an purchased more than 200 feeder cattle, among which several cattle had a small lump on the neck. Because the lumps were small at first and the cattle showed no other abnormal signs, the technicians did not pay attention to them. It was not until October that the lumps on these cattle gradually enlarged, and the lump on one of them began to ulcerate. The author was called to examine the animals and found 3 cattle with similar symptoms: 2 had lumps on the neck, and 1 had a lump on the head.

2 Clinical Symptoms and Pathological Changes

The body temperature, spirit and appetite of the affected cattle were all normal; the lumps were very hard and had no elasticity, were neither hot nor painful, and had clear boundaries. The lump on the head was below the orbit of the maxilla; when the lump was felt by hand, it could be sensed that the lump was connected to the jawbone. When the ulcerated lump was squeezed, dirty blood and pus flowed out, and the pus contained hard, smooth, yellowish-white tiny bacterial masses, very much like "sulfur granules." The bacterial masses were taken, smeared and stained, and were Gram-negative. Because there were no fatal cases, no necropsy examination was performed.

3 Diagnosis

Based on the clinical symptoms and the main site where the hard lump occurred, a preliminary diagnosis of bovine actinomycosis could be made. Because bovine necrobacillosis can also cause abscesses or necrosis of the skin and subcutaneous tissue of livestock, it is easy to misdiagnose as bovine necrobacillosis. Therefore, a differential diagnosis should be made from necrobacillosis: 1) Body temperature and spirit changes. Necrobacillosis mostly causes changes such as elevated body temperature, poor spirit and reduced appetite, and the lump area has a sensation of heat, pain and softness, whereas bovine actinomycosis has no such symptoms, and the lump is a hard nodule. 2) The affected sites also differ. In bovine necrobacillosis, calves are mainly affected in the oral cavity, manifesting as necrotic stomatitis and salivation; adult cattle are mostly affected in the hooves, manifesting as hoof abscesses and lameness. Bovine actinomycosis, however, mainly attacks the hard tissues or soft tissues of the head and neck, and adult cattle are rarely affected. 3) The pus flowing from the ulcerated lump is different. The pus of necrobacillosis is stringy or in clumps, while the pus of actinomycosis is granular and radiating. Through the differential comparison of the two diseases, it was diagnosed as bovine actinomycosis.

4 Prevention and Control Measures

Preventing this disease mainly means preventing injury to the skin and mucosa. Therefore, feeding rough forage should be avoided, and veterinary hygiene work should be strengthened to reduce the chance of infection; wounds should be treated promptly.

For the 3 affected cattle, different treatment measures were adopted according to the different affected sites.

For the 2 affected cattle with hard neck lumps caused by Actinobacillus lignieresii, 3 million u of streptomycin was injected around the affected area once daily until recovery. For the affected cattle that had already suppurated, the pus was first squeezed out and the area was repeatedly flushed with iodine solution once daily for 1 consecutive week.

For the affected cattle with hard lumps on the jawbone, the pathogen being Actinomyces bovis, 3.2 million u of penicillin was injected around the affected area every day for 7 consecutive days (as 1 course of treatment).

5 Summary and Experience

The affected cattle whose necks had not previously ulcerated also began to ulcerate after several days of medication, discharging bloody pus. After 1 consecutive week of use, the hard lumps of the 2 affected cattle began to gradually shrink, but the speed was relatively slow. After 1 consecutive month of use, the affected area was already very small, and the ulcerated area had scabbed over and healed, but the lump in the affected cattle with maxillary involvement subsided somewhat more slowly.

The treatment process for bovine actinomycosis is relatively long, and the lump area is relatively hard, so it is sometimes very difficult to inject at divided points; therefore, the treatment process requires sufficient patience, and the treatment process should not be interrupted.

Some sources state that for affected cattle with relatively large hard nodules, surgical excision can be used, with equal parts of iodoform and iodosulfonamide powder mixed and sprinkled into the wound, then sutured, with 10% iodoform ether injected around the wound, while potassium iodide is administered orally, giving a relatively good effect. However, because the procedure is relatively complicated, the author did not carry out comparative treatment.

Actinomycosis is easily mistaken for necrobacillosis.