What to Do After Silkworm Poisoning? Practical First Aid Measures to Remember

Since May 2006, sheep in some large mutton sheep breeding parks and among some mutton sheep farmers in our county have frequently contracted liver fluke disease (fascioliasis). The characteristic of this disease is that the adult flukes of Fasciola parasitize the liver and bile ducts of sheep, causing symptoms such as swelling of the lower jaw, loss of appetite, diarrhea and anemia, and leading to acute or chronic hepatitis and cholangitis. In severe cases, it is accompanied by systemic poisoning and malnutrition; growth and development are affected, wool and meat quality are significantly reduced, large numbers of livers are condemned, and it may even cause the death of large numbers of sheep, resulting in very heavy losses.

First Aid Measures After Poisoning in Silkworm Rearing

1. Pathogen

The pathogen of sheep liver fluke disease is Fasciola, which parasitizes the liver and bile ducts of sheep. The body is flat and leaf-shaped, 20 to 35 mm long and 5 to 13 mm wide. Fresh living flukes removed from the bile ducts are brownish red, and after fixation they appear grayish white. The anterior end has a conical projection, the base widens, and it gradually narrows after the shoulder. The body surface bears many small spines. Two branched testes are arranged one behind the other in the middle-posterior part of the body.

2. Symptoms

Affected sheep are depressed, have reduced appetite, slow rumination and elevated body temperature. Edema appears on the eyelids, lower jaw, beneath the chest and in the lower abdomen. Respiration is rapid, the pulse is accelerated, and there is varying degrees of panting and drooling, with snoring sounds from the nose and irregular heartbeat. Occasional diarrhea occurs. As the disease progresses, appetite tends to disappear, catarrhal enteritis appears, and the mucous membranes are pale with anemia. The sheep's coat is rough, lusterless, brittle and easily broken, with localized hair loss. On percussion of the liver, the area of dullness is enlarged and sensitivity is increased. In some cases, death occurs 3 to 5 days after symptoms appear.

3. Necropsy Changes

Dead sheep are emaciated and anemic, with lesions especially prominent in the liver and lungs. The liver is hemorrhagic and enlarged, containing dark red cord-like structures 2 to 5 mm long. When the cut surface is squeezed, a dirty yellow viscous liquid flows out, mixed with young flukes. In animals that die from particularly severe infection, peritonitis may be seen, and sometimes there is massive hemorrhage in the abdominal cavity; the serous membrane is pale. In chronic cases, the affected areas of the liver are grayish white, the surface is uneven, and the texture becomes hard. The bile ducts are enlarged and filled with grayish brown bile and flukes. When the bile ducts are cut, a "cha! cha!" sound can be heard. The surface of the liver shows tortuous cord-like patterns, and on palpation the duct walls feel thick and hard. Some parts of the lungs have localized firm nodules, ranging in size from a walnut to a chicken egg, whose contents are a dark brown semi-liquid substance; there are 1 to 2 living or semi-decomposed flukes. The capsule of the nodule is calcified connective tissue. The color of the lung surface is normal.

4. Laboratory Examination

Samples such as liver and lung from sheep were collected aseptically by routine methods for bacterial isolation and culture. Microscopic examination revealed flukes, which were flat and leaf-shaped.

5. Diagnosis

Based on epidemiology, clinical symptoms, necropsy changes and laboratory examination, the diagnosis was confirmed as sheep liver fluke disease.

6. Prevention and Treatment

① Prevention: Strengthen feeding management and improve sanitary conditions. Disinfect the sheep house and surrounding areas with "Ding Iodine Disinfectant Solution" once a day for 3 to 5 consecutive days, and keep the environment quiet to reduce stress responses.

② Treatment: Use "bithionol" at 35 to 75 mg/kg body weight, prepared as a suspension for oral administration, once a day for 3 consecutive days. Add Vc, electrolytes and oral rehydration salts to the drinking water to reduce stress and supplement nutrition. At the same time, combine with traditional Chinese medicine treatment. Formula: sappanwood 9 g, guanzhi 9 g, areca seed 9 g, gentian 9 g, akebia stem 9 g, oriental waterplantain rhizome 9 g, magnolia bark 6 g, katsumada galangal seed 6 g. Decoct in water, remove the residue, and administer in one dose by drenching. Use for 3 consecutive days. After one course of treatment, the cure rate is above 95%.

7. Summary

① Deworm regularly to prevent healthy sheep from swallowing metacercariae. Deworm in spring and autumn each year. The feces of affected sheep should often be treated by composting and fermentation to kill the eggs in them and avoid spreading eggs through feces. Prevent sheep from swallowing metacercariae. Do not build sheep houses in low-lying wet areas, do not graze on wet pastures where Fasciola is present, and do not let sheep drink dirty water or stagnant water from ditches. When cutting grass on wet pastures, it must be cut higher. Otherwise, the cut forage should be stored for more than 6 months before feeding.

② Quarantine: Strengthen veterinary sanitary inspection. For sheep livers found to be severely infected with Fasciola, all should be condemned; for mildly infected livers, the infected parts should be condemned. The condemned livers should be boiled and then used as feed for other animals. Some sheep transferred in from other places may be in a carrier state, so parasitological examination should be carried out before transport, and only those confirmed healthy may be allowed in.

Is Silkworm Rearing Profitable  

Overall, large-scale silkworm rearing has favorable prospects over the next ten years or longer. First, with China's imminent accession to the WTO, silkworm cocoons, as a raw material for the silk industry in which our country has an absolute export advantage, are attracting more and more attention from all sectors of society.  

Second, sericulture is a major economic specialty industry in our country, and Zhejiang Province ranks first nationwide in silkworm cocoon output and other aspects. This year the State Council specially forwarded the National Economic and Trade Commission's "Notice on Opinions on Deepening the Reform of the Silkworm Cocoon Circulation System," aimed at promoting the scaling-up, industrialization and specialization of sericultural production. Zhejiang Province has designated sericultural production as a traditional industry worthy of improvement and upgrading. Shaoxing City is one of the main cocoon-producing areas in Zhejiang Province, and Shengzhou City ranks first among the counties (cities) of Shaoxing City in silkworm cocoon output.  

Third, at present our city's silkworm rearing scale is rather small, leading to poor mulberry plantation quality, low economic benefit per unit area and poor cocoon quality. Developing large-scale silkworm rearing is an inevitable need for developing and stabilizing sericultural production in our city. However, large-scale silkworm rearing is not simply an expansion of area and an increase in the number of silkworms raised, but rather intensive sericultural management based on regionalized layout, improved varieties, labor-saving management and high-quality cocoons, with the aim of improving the comparative benefit and competitiveness of sericulture.

Market Prospects for Silkworm Rearing  

Since the second half of 2013, influenced by the international supply and demand relationship for cocoons and silk, the overall climate for the national sericulture industry has improved, and sericulture in our province has also picked up. In 2014, cocoon prices were stable with a slight rise, and the economic benefits of planting mulberries and raising silkworms increased markedly. Based on the current development trend, the sericulture situation in 2015 looks favorable, and it is estimated that the price of fresh cocoons will remain above 14 yuan per kilogram.  

Planting mulberries and raising silkworms is of great significance for increasing farmers' income in our country. At present, as domestic and international market demand grows, production areas continue to concentrate toward the west, bringing new development opportunities, and the diversified development and application of sericultural resources broadens the scope of use, the silkworm industry has very good development prospects. In the face of these prospects, it is necessary to develop efficient mulberry planting and silkworm rearing techniques to meet society's needs. The efficiency of mulberry planting and silkworm rearing can be improved through two approaches: introducing superior mulberry seedlings and strengthening management between the rows, and introducing superior silkworm varieties and carrying out scientific management.

In fact, the development of the silkworm industry in our country can be considered to have a long history. As far back as ancient times in our country, there was always the development of planting mulberries and raising silkworms, and our country's silk industry not only developed relatively well domestically, but even sold well abroad, and our country is also a major silk-exporting country.