Differences Between Three Soft-Shelled Turtle Diseases and Their Prevention and Treatment Methods

In the process of soft-shelled turtle farming, some farmers cannot clearly distinguish white spot disease, white spot fungus disease and saprolegniasis, and blindly and indiscriminately use drugs when treating turtle diseases, thus affecting the effectiveness of disease prevention and treatment. Therefore, based on recent years of practice at soft-shelled turtle farms, the author summarizes the differences between the above diseases and comprehensive prevention and treatment methods as follows.

I. Differences between white spot disease, white spot fungus disease and saprolegniasis in soft-shelled turtles

1. Different pathogens: the pathogen of white spot disease is Aeromonas hydrophila, Aeromonas sobria, etc.; the pathogen of white spot fungus disease is Mucor, which belongs to the fungal family Mucoraceae, hence it is also called mucormycosis; the pathogen of saprolegniasis is aquatic fungi such as Saprolegnia, Achlya and Leptomitus.

2. Different water temperatures at which the diseases prevail: white spot disease is a turtle disease that appears at high temperatures and easily prevails when the water temperature is 25-30°C; while white spot fungus disease and saprolegniasis are turtle diseases that appear at low temperatures and prevail when the water temperature is 10-20°C.

3. Different sizes of turtles affected: white spot disease mainly affects hatchling and juvenile turtles, especially causing the greatest harm within 1 month of hatching and within 1 month of being moved into the greenhouse; white spot fungus disease mainly affects juvenile turtles; saprolegniasis can affect hatchling, juvenile, adult and brood turtles.

4. Different lesion symptoms: the lesions of white spot disease usually do not exceed the size of a soybean, with bead-like protrusions within the skin; after pricking them open, white pus can be seen; in severe cases the white spots enlarge, with uneven edges and ulceration, mainly distributed on the abdomen and limbs; the lesions of white spot fungus disease are mainly distributed on the back, limbs, neck and abdomen, etc.; at the white spots the epidermis gradually necroses and sloughs off, or even bleeds, followed by secondary bacterial infection and concurrent skin rot disease. When the fungus parasitizes the throat of the turtle, the turtle gradually dies due to difficulty breathing, and microscopic examination shows white mycelium; saprolegniasis, also called skin mold disease or white hair disease, is characterized by grayish-white cotton-like mycelium growing on the limbs, neck and other parts of the diseased turtle; it is soft, thick and dense, affecting the turtle's movement, and the turtle gradually dies due to reduced appetite and emaciation.

II. Comprehensive prevention and treatment

1. White spot disease

(1) Prevention: Thoroughly disinfect the culture pond. Generally, 150 g/cubic meter of quicklime or 20 g/cubic meter of strong chlorin can be used for disinfection. Cultivate the water quality, fertilize the water before releasing the fry, and keep the pond water tender green with a transparency of 25-30 cm. Regulate the water quality well and carry out regular disinfection. Keep the water temperature at 28-29°C; too low a water temperature affects the turtle's feeding and growth, while too high a water temperature causes the pond water quality to deteriorate quickly and makes the turtles prone to disease. Feed high-quality complete compound feed, and by strengthening nutrition, improve the disease resistance of the turtles.

(2) Treatment: Completely replace the water in the pond of diseased turtles. On the first day, splash the whole pond with 500 g/cubic meter of baking soda and 500 g/cubic meter of table salt; on the third day, splash the whole pond with 0.3 g/cubic meter of strong chlorin (or 0.2 g/cubic meter of bromochlorohydantoin); 20-30 g/cubic meter of erythromycin can also be splashed over the whole pond, with good bactericidal and bacteriostatic effects. Add 1%-3% antibacterial and antiviral Chinese herbal medicine to the feed, and add 1‰-2‰ of vc and ve to regulate the internal environment of the turtle and enhance immunity; continuous feeding for 5-6 days constitutes one treatment course.

2. White spot fungus disease

(1) Prevention: Thoroughly clear the pond. Generally, 150 g/cubic meter of quicklime or 100 ml/cubic meter of formalin is used. Operate in a standard and careful manner so as not to injure the turtles. Fertilize the water quality, control the transparency at about 30 cm, and regulate the water quality well to inhibit the growth and reproduction of the fungus. Use antibiotics with caution when preventing white spot fungus disease, because antibiotics have the effect of promoting the development of this disease.

(2) Treatment: Smearing method: isolate the diseased turtles, smear the lesions with erythromycin ointment once a day for 3-5 consecutive days; after smearing, wait until air-dried or sun-dried in the sun, then place them in the isolation pond. Dipping method: bathe in a 4% table salt solution for 5 minutes, or soak for a long time in 4 mg/L methylene blue. Splashing method: splash the whole pond with a mixture of 500 g/cubic meter of table salt and 500 g/cubic meter of baking soda, or splash the whole pond with 5 g/cubic meter of potassium permanganate. Sun-drying method: place the diseased turtles in the sun for 1 hour, once a day, repeated several times; this method has a relatively good effect on juvenile turtles with early-stage disease. Add 2‰ ve to the feed and use continuously for 10-15 days.

3. Saprolegniasis

(1) Prevention: Prevent injury to the turtles. Keep the water quality fresh, because polluted water can corrode the skin of hatchling and juvenile turtles, allowing the fungus to take the opportunity to parasitize the body surface. Frequently add 2‰ ve to the feed to improve the turtles' resistance to fungus.

(2) Treatment: Splash the whole pond with a mixture of 500 g/cubic meter of table salt and 500 g/cubic meter of baking soda. Soak for a long time in 5-10 g/cubic meter of potassium permanganate, which has a relatively good effect on saprolegniasis in hatchling and juvenile turtles.