A Summary of the epidemic of Fox Disease in 2001

In 2001, the overall situation of fox reproduction and survival of young foxes in the country was not ideal, which was a year with many problems since fox breeding in our country. In the following, the causes of diseases and deaths in fox production are analyzed, and effective preventive measures are put forward to promote the healthy development of fox industry, reduce production losses and obtain higher economic benefits.

1 artificial insemination leads to suppurative endometritis

1.1 pathogens of major infections

After extensive epidemiological investigation and pathogen isolation and identification, the main pathogen of infection was Pseudomonas aeruginosa, accounting for 90% of the total infection rate, of which about 65% were infected with Pseudomonas aeruginosa alone and about 35% with mixed infection. Co-infected bacteria include Escherichia coli, Staphylococcus aureus, Corynebacterium pyogenes, Streptococcus pyogenes, Proteus and Salmonella. In the cases of mixed infection, Pseudomonas aeruginosa was still the dominant bacteria.

1.2 cause of occurrence

① is contaminated when collecting semen, such as the penis is not disinfected and the hair around the lower abdomen and pudendal area is not soaked with disinfectant.

② semen is contaminated during dilution, if it does not have a sterile environment, operate in an unsterilized room, or even dilute semen when there is more dust on the floor and operating table.

The disinfection method of ③ utensils is improper or the disinfection temperature is low.

④ does not disinfect the vulva of female foxes or disinfects them incompletely.

Uterine mucosal injury caused by ⑤ operation technique.

1.3 Prevention

① pays attention to the disinfection of vulva, penis and surrounding hair, usually using 0.1% bromogeramine.

② dilutes semen with a sterile stove or ultra-clean table.

③ seminal needle and dilatation tube should be thoroughly disinfected. It should be boiled and sterilized for more than 30 minutes, then dried at 80 ℃ after boiling, and the dry-hot disinfection temperature should reach 80 minutes, 100 ℃, 60 minutes.

④ operating room to maintain good hygiene, no dust, do not allow unrelated personnel to enter casually. The operating room is as closed as possible to prevent direct sunlight. Ultraviolet lights are installed in the room and irradiated for at least 30 minutes 12 hours before use.

⑤ should strengthen training, improve the level of operation technology, be light and stable on the basis of proficiency, and do not blindly pursue operation speed.

15-20 days before ⑥ artificial insemination, foxes were injected with Pseudomonas aeruginosa polyvalent vaccine for prevention.

Broad-spectrum antibiotics such as Baili can be used to remove miscellaneous bacteria in vagina and uterus after ⑦ artificial insemination.

Once suppurative endometritis occurs in ⑧, gentamicin and ampicillin are used alternately, and low-dose Pituitrin is used. At the same time, the uterus is washed with liquid containing penicillin and streptomycin once a day, and glucose is supplemented intravenously if necessary.

2 causes of death of young foxes

2.1 bacterial infection

It is more prominent in some fox farms, which is basically the death of young foxes within 10 days of being born. It was confirmed by examination that the infected bacteria were mainly Escherichia coli or co-infected Gram-positive bacteria (mainly Corynebacterium) and other Gram-negative bacteria.

The route of infection has confirmed that 40% of foxes are intrafetal infections, which are caused by intrauterine infection or vertical transmission of asymptomatic mothers, and may also be caused by reproductive tract infections during childbirth, which is confirmed by bacteria isolated from the organs of foxes that have just died after delivery. However, the foxes that give birth to young foxes only show mild symptoms a few days before or after delivery, with a mortality rate of only 1% to 2%. This may be due to the strong virulence of the infected bacteria, which is also in a state of latent infection after being transmitted from the mother to the fetus. The postpartum fetus is under external stress, and the infected bacteria multiply and produce virulence, which leads to the disease of the young foxes. 60% of foxes are infected postnatally, related to bacterial contamination in the nest, and are infected through the umbilical cord or suckling. Intrafetal infection may be caused by bacteria invading into the womb during mating, but due to the weak virulence and long incubation period of bacteria, there is no pathogenicity in the early stage of pregnancy; with the increase of the number of bacteria, the virulence is also enhanced. enough to penetrate the placental barrier and enter the fetus, causing fetal infection.

The young foxes with symptoms were treated with gentamicin, kanamycin, ampicillin and ciprofloxacin lactate. the cure rate was 85%, and the effect was better if combined with drugs for lactating mother foxes. The cage was thoroughly disinfected before mating, and immediately after mating was treated with ampicillin or ciprofloxacin lactate to remove bacteria.

2.2 death caused by heat stress

It mainly occurs in the foxes born after late May. Due to the unusually high temperature, the heat stress reaction of the female fox was serious, and the young fox was not cared in the nest, resulting in the starvation of the young fox.

In order to prevent the selection of young foxes produced in that year to be kept as foxes, it is best to give birth before May 30, so as to ensure early estrus and early birth in the second year, adjust the physical condition of foxes before mating, ensure the nutritional needs of feed, and make foxes estrus early and concentrated as far as possible. reduce the number of late estrus foxes.

2.3 death caused by abnormal childbirth

Because the fetus is too many or too large, the labor process of the female fox is too long, and the postpartum female fox is highly weak, abdominal pain and mechanical damage of uterine and vaginal mucosa. the female fox often lies motionless in the delivery box, and the young fox starves to death or dies of infection because she cannot eat colostrum.

Prevention and timely examination, found that this situation, usually choose antongding, penicillin, gentamicin or norfloxacin injection. It has a good effect on analgesia and anti-inflammation for female fox.

2.4 Vitamin B1 deficiency causes death of young foxes

The onset of the disease occurred at the age of 10 murals and 30 days after birth. The performance of hindlimb paralysis, paralysis and weakness, rough or sticky coat, narcolepsy, weak or no sucking ability, sometimes paroxysmal convulsions. It usually occurs in the offspring of female foxes with more offspring.

Comprehensive analysis showed that the occurrence of the disease in some fox farms was related to the deficiency of vitamin B1 in diet, such as feeding fish or animals that had been stored for too long during pregnancy and insufficient supplementary feeding in feed. However, most fox farms or households are not lack of vitamin B1 in feed, but are caused by excessive litter production, large lactation and overload consumption of female foxes.

The content of vitamin B1 in the diet of pregnant female foxes and the freshness of feed should be ensured in each fox farm. Feed rich in vitamin B1, such as liver, milk and yeast, should be added to the feed during lactation. Vitamin B1 injection should be used to treat diseased foxes, twice a day, each time 50-100mg. At the same time, the effect of vitamin B1 supplementation to female foxes was more significant.

2.5 death caused by lack of milk in female foxes

It is mainly caused by overweight or thinness of female foxes, and also occurs in aged foxes and a small number of newborn foxes.

General injection of prolactin has a certain effect, increasing the content of milk and eggs in the diet can increase the amount of milk production.

2.6 Eperythrozoon infection

This is serious infection and epidemic of young foxes in some fox farms. The young foxes had elevated body temperature, anemia, jaundice, lack of milk or loss of appetite, weakness of hindlimbs, bloody stool, bleeding of oral mucosa and ear holes, swelling of eyelids and mouth. Most of them are nests of infection. The existence of Eperythrozoon can be confirmed by blood tests, and the infection rate of red blood cells is more than 70%. The treatment with avermectin combined with sulfonamides is effective, and the cure rate is 50%, 70%.

The prevention of infection of young foxes may be related to the infection of female foxes, but postnatal infection can not be ruled out. Due to the low immunity of young foxes, it is easy to cause infection.

Avermectin is injected into female foxes twice from December to January of the following year (according to 0.03mL/kg body weight) to kill eperythrozoon in the blood, which may be effective in preventing infection of young foxes.

2.7 death from Encephalitis

After the onset of the disease, the young fox mainly showed paroxysmal convulsions, hindlimb paralysis or sudden death, and the treatment of antibiotics and vitamin B1 were ineffective.

The results showed that almost all the young foxes were not vaccinated with encephalitis vaccine, and the young foxes were infected without protective maternal antibodies.

Regular injection of encephalitis vaccine to foxes can prevent the occurrence of encephalitis in young foxes.

3 abortion and embryo absorption

At present, abortion and embryo absorption of pregnant foxes are still prominent problems in the production of foxes in China. In addition to the embryo absorption and abortion caused by feeding deteriorated feed during pregnancy, it was determined by investigation and examination that the main cause was Gardnerella infection. The detection of Gardnerella antigen in some fox farms and empty foxes confirmed that the infection rate was as high as 60%. These fox farms have not yet used Gardnerella vaccine to immunize foxes. In addition, 2% of Pseudomonas aeruginosa natural infection caused reproductive disorders, accounting for 3%. Abortion and embryo absorption caused by deficiency or deficiency of protein, vitamins and trace elements during pregnancy accounted for 10%, 15%. Abortion and embryo absorption caused by diarrhea during pregnancy accounted for 2% and 4%. About 1% of abortions are caused by stress factors.

Prophylactic use of Gardnerella antigen detection, elimination of diseased foxes, regular injection of vaccine; injection of Pseudomonas aeruginosa vaccine 15 May 20 days before mating each year; ensure that the feed during pregnancy is stable, fresh, balanced and sufficient in various nutrients; the use of probiotics during pregnancy can effectively prevent the occurrence of bacterial diarrhea without any side effects on the fetus; in the fox pregnancy, prevent sudden noise stimulation and rough capture.