Prevention and treatment of black dolphin pasteurellosis

Pathogen

Pasteurella multocida is a gram-negative, obtusely round, oval-shaped short bacilli. Tissue smears of diseased materials were stained by Giemsa or Wright's method, and the bacteria were deeply stained at the poles.

Popular characteristics

30% to 75% of guinea pigs have Pasteurella multocida in the mucosa and tonsils of the upper respiratory tract, but are asymptomatic. When the resistance of guinea pigs is reduced by various factors (sudden change of temperature, poor feeding and management, long-distance transportation, etc.), Pasteurella multocida multiplies in large numbers, and its virulence increases, thus causing the disease. The disease can occur all the year round, but it is more common in spring and autumn, showing sporadic or endemic epidemic, mainly through digestive tract or respiratory tract infection.

Symptoms and pathological changes

Symptoms and pathological changes vary according to the virulence of bacteria, the route of infection and the course of disease, which are often divided into the following types.

1. Septic type: most of them showed acute process and often died in 1-3 days. Depressed spirit, do not eat, body temperature above 40 ℃, shortness of breath, serous or purulent nose, sometimes dysentery. Before death, his body temperature dropped, his whole body trembled and his limbs twitched. Some died suddenly without obvious symptoms. Autopsy showed that nasal mucosa was congested with sticky secretions; larynx and tracheal mucosa were congested and bleeding, with red foam in the lumen; severe lung congestion, hemorrhage and edema; epicardial bleeding spots; hepatomegaly, congestion, degeneration, and often many necrotic spots; intestinal mucosal congestion and bleeding; chest and abdominal cavity with more yellowish fluid. Subacute is often transformed from rhinitis type and pneumonia type, the course of disease is about 1-2 weeks, and eventually dies of failure. The main symptoms are mucous purulent nose, often sneezing and difficulty breathing. Slightly higher body temperature and loss of appetite. Sometimes diarrhea, swelling of joints and inflammation of conjunctiva are seen. Autopsy showed that the lung was fibrotic pleuropneumonia, even abscess formation; pleural effusion; nasal and tracheal mucosa congestion, bleeding, with sticky secretions; lymph nodes red, swollen.

2, rhinitis type: more common, the course of disease can be up to several months or longer. The main symptoms are serous, mucous or mucous purulent nasal juice. Sick guinea pigs often sneeze and cough and wipe their nose with front claws, making the coat around the nostrils wet, bonded or even shedding, and the skin around the upper lip and nostrils inflamed and swollen. Mucopurulent nasal fluid forms scabs around the nostrils and blocks the nostrils, making it difficult to breathe and snoring. Such as bacteria invading the eyes, ears, subcutaneous and other parts, can cause conjunctivitis, keratitis, otitis media, subcutaneous abscess and mastitis. Autopsy showed that the nasal mucosa was flushed, swollen or thickened, and sometimes eroded, with serous, mucous or purulent secretions on the surface of the mucosa. The mucosa of paranasal sinus and paranasal sinus is also congested, red and swollen, and secretions accumulate in the sinus.

3. Pneumonia type: it often shows acute process. Although there are pneumonia lesions, but it is difficult to find pneumonia symptoms in clinical treatment, some die quickly, some only have loss of appetite, high body temperature and mental depression. The nature of the lung lesion is fibrinous suppurative pleuropneumonia. According to the eye view, the lesions are mostly located in the anterior and lower part of the apical lobe, cardiac lobe and diaphragmatic lobe, including consolidation, incomplete expansion, abscess and small gray nodules. There is often cellulose attachment between the lung pleura and the pericardium. As shown in the picture

4. Otitis media type: otitis media is also known as torticollis disease. Simple otitis media often has no obvious symptoms, but if the disease spreads to the inner ear and brain, the diseased guinea pigs show torticollis symptoms, and in severe cases, the guinea pigs roll to the inclined side of the head and neck until they reach the fence. If meninges and brain parenchyma are injured, motor disorders and other neurological symptoms can occur. Suppurative tympanitis and tympanitis were found by autopsy. There is a white creamy exudate in one or both sides of the tympanum; this exudation flows out of the external auditory canal when the tympanic membrane is ruptured. If the inflammation spreads from the middle ear and inner ear to the brain, suppurative meningoencephalitis can be seen.

5. Other disease types: Pasteurellosis in guinea pigs can also be characterized by suppurative conjunctivitis, endometritis (female guinea pigs), epididymis and orchitis (male guinea pigs) and suppurative inflammation of subcutaneous and organs everywhere. The conjunctiva and uterine mucosa showed suppurative catarrhal changes, with purulent secretions on the surface and pus in the uterine cavity. Other tissues and organs are mainly abscesses.

Differential diagnosis

This etiology shows a variety of disease types, so it should be distinguished from the following diseases.

The main results are as follows: 1. It is different from bronchial septicemic brucellosis in guinea pigs: although there is catarrhal rhinitis or lung abscess in guinea pigs, there is no otitis media, and the pathogen is pleomorphic Bordetella bronchisepticum.

2, different from staphylococcal disease: the main lesions of staphylococcal disease are abscess and foot dermatitis, abscess mostly occurs in subcutaneous and muscle, lung and other viscera are rare, no suppurative rhinitis, otitis media and other lesions.

Treatment method

1. Guinea pigs should be raised by themselves, and it is forbidden to introduce guinea pigs casually; when they must be introduced, they should be quarantined and observed for one month before healthy people can enter the field.

2. Strengthen the work of raising, management, hygiene and epidemic prevention, and strictly prohibit livestock, poultry and wild animals from entering the field.

3. Guinea pig farms with this disease can be vaccinated with guinea pig Pasteurella multocida vaccine or avian pasteurellosis vaccine.

4. As soon as the disease is found, measures of isolation, treatment, elimination and disinfection shall be taken immediately.

The oral dose of sulfamethazine (sm) was 0.1g / kg body weight, once a day, and the intramuscular injection dose was 0.07g / kg body weight, twice a day for 4 days.

Precautionary measures

The prevention of this disease should depend on the establishment of good environmental hygiene conditions. Pasteurella multocida-free guinea pigs can be established by caesarean section.