Methods for the Prevention and Control of Common Soft-Shelled Turtle Diseases and Key Technical Points

Soft-shelled turtle diseases can be divided into three major categories: infectious diseases caused by bacteria, molds or viruses, parasitic diseases caused by parasites, and diseases caused by other factors. Among them, the more harmful and common ones are red plastron disease, white plastron disease, red neck disease, skin rot disease, perforation disease, white spot disease, bell-shaped ciliate disease, etc. Below is an introduction to the pathogens, causes and treatment methods of various diseases.

1. Red neck disease

Pathogen. The pathogen of red neck disease is Aeromonas hydrophila, Gram-negative. Carrier turtles and contaminated pond water are the main sources of infection, and the disease may be transmitted through the digestive tract. It can occur throughout the year, with March to June being the epidemic season. At this time, the turtles have just passed the hibernation period, a great deal of nutrients in their bodies have been consumed, their constitution has declined, and their resistance to disease is poor. Aeromonas hydrophila in the pond water takes the opportunity to invade their bodies, causing infection and disease onset. Stress factors such as poor water quality, sudden change of feed, skin damage and parasites can all be predisposing causes. The mortality rate of newly hatched juvenile turtles to 2 kg parent turtles suffering from this disease reaches more than 30 percent, and after the autumn cool the incidence of this disease decreases.

Symptoms: Diseased turtles first show reduced sensitivity to external stress, slow movement, refusal to eat, and a tendency to burrow into mud and sand. Subsequently the neck becomes congested, red and swollen, red spots appear on the plastron, which gradually erode into rotten patches. The mouth and nose become red, and in severe cases there is bleeding from the mouth and nose, generalised red swelling of the whole body, cloudy and whitish eyes leading to blindness, and death after climbing ashore. Dissection shows obvious congestion of the mucosa of the esophagus and intestinal tract; the liver is swollen, brittle and easily broken, with some surfaces forming greyish-white necrotic lesions the size of needle tips, and the spleen is enlarged.

Prevention and control:

(1) Splash 0.2-0.4 g per cubic meter of Fuchlor over the whole pond, and stop feeding for 1 day.

(2) From the second day, start feeding Turtle Health, mixed into the feed at an addition rate of 1.5 percent. The amount of mixed bait should be based on being eaten within 2-3 hours. Feed continuously for 3 days.

(3) Immediately isolate captured diseased turtles for rearing, and soak them in 0.4 g per cubic meter of Turtle Clean for half an hour.

2. Skin rot disease

Pathogen: The pathogens of skin rot disease are infections caused by various bacteria including Aeromonas, Pseudomonas and Achromobacter, among which Aeromonas is the main one. The main cause of this disease is secondary bacterial infection after the turtle's body is injured.

Symptoms: The skin on the limbs, neck, tail and marginal scutes of diseased turtles is severely ulcerated or eroded, the skin tissue necroses and turns white or yellow, and even the skin of the limbs rots away, the claws fall off, and the bones are exposed. Diseased turtles can often survive for a long time, and in turtle ponds with good environmental conditions the affected parts sometimes heal naturally. In severe cases, the neck muscles and bones are exposed, the marginal scutes rot, and finally death occurs. This disease mostly occurs in ponds where the water is overly fertile, the silt is too thick and there are no disease prevention measures. The disease can be seen throughout the year and is prevalent in late spring and early summer. With increased density and deterioration of water quality, the probability of onset also increases, seriously affecting the growth and commercial value of the turtles.

Prevention and control:

(1) Prevention and control: Disinfect the turtle pond once a month with 0.2 g per cubic meter of Fuchlor or 20 g per cubic meter of quicklime.

(2) Treatment: Splash 0.3 g per cubic meter of Fuzhi for 2 consecutive days, and from the second day feed Turtle Health for 3 consecutive days, mixed into the feed at an addition rate of 1.5 percent, with the amount of mixed bait based on being eaten within 2-3 hours.

(3) Captured diseased turtles should be isolated and soaked in 0.4 g per cubic meter of Turtle Clean for 20 minutes.

3. Perforation disease

Pathogen: The pathogen of perforation disease is Aeromonas. It is caused by Aeromonas infection due to deterioration of the rearing environment, spoilage of feed, lack of vitamins in the feed, or mutual biting and transport injuries.

Symptoms: In the early stage of the disease, several or more than a dozen scabs appear on the carapace and plastron of the turtle. Soon the scabs fall off by themselves, leaving a small hole on the carapace and plastron, with inflammation at the edge of the hole and blood flowing out under light pressure. The hole then enlarges, and the shell bone becomes visible. Holes at the marginal scutes may penetrate through to the opposite side. Long-term feeding of animal feed of poor freshness and injury to the turtle's body are predisposing causes of this disease, and bacterial infection is the main causative factor. The disease can occur throughout the entire breeding cycle and is prevalent from May to July.

Prevention and control:

(1) Prevention: Frequently change the water and apply quicklime to regulate water quality and prevent deterioration, feed fresh bait, and add special soft-shelled turtle feed additive to the bait.

(2) Treatment: For each mu with a water depth of 1 m, dissolve 25 kg of quicklime in water and splash it. Or splash Fuchlor dissolved in water; from the second day, feed Turtle Health for 6 consecutive days, mixed into the bait at an addition rate of 1.5 percent, based on being eaten within 2-4 hours; isolate diseased turtles and soak them in 0.4 g per cubic meter of Turtle Clean.

4. Red plastron disease

This disease is also known as red spot disease and erythema disease, because diseased turtles suffering from it have both red spots on the plastron and symptoms of the entire plastron turning red.

Pathogen: Aeromonas punctata.

Symptoms: Diseased turtles are not easy to observe. By the time they come out of the water, climb onto the bank or burrow into mud and sand, the condition is already quite serious, so in production a good therapeutic effect is often not achieved. Diseased turtles respond very sluggishly to external stimuli and do not flee when someone approaches, making them very easy to catch. The most obvious symptom of the disease is that the entire plastron is red and swollen or in the form of red spots, accompanied by ulceration and edema. Some turtles bleed from the mouth and nose. Dissection shows severe lesions of the liver, some black and some mottled. The intestinal tract is locally or entirely congested and inflamed. Some have fluid accumulation in the abdominal cavity.

Prevention and control: