Keywords: porcine pneumonic disease; Bartonella henselae; pathogenesis; clinical symptoms; prevention and control measures
Porcine pneumonic disease is a kind of acute infectious disease in sick pigs, often manifested as the phenomenon of sepsis [ ], acute inflammatory swelling of the throat and peripheral tissues, or manifested as the lungs and pleura of fibrin exudative inflammation. Typical symptoms are pharyngeal tumors, respiratory distress, and purplish skin, etc. The disease is usually autochthonous, mostly endogenous, and also contracted as a result of remaining respiratory, gastrointestinal, and surface injuries secondary to the disease. The occurrence of swine pneumonic disease is often dominated by spring and fall and wet weather. Pneumonic disease of swine spreads quickly, once infected without timely control, the mortality rate is extremely high.
1 Pathogenesis
1.1 External environment and feeding factors
Pigs that live in poor environmental conditions for a long time will lead to a decline in the body's resistance to disease, resistance to disease is weaker, the germs take the opportunity to invade the body to breed, resulting in the body of the disease, such as: cold and humid, ventilation is poor, the impact of stress factors, thieves, etc. [ ]. Improper feeding management, such as nutritional deficiencies, irrational feeding methods, poor feed quality, etc. will lead to a decline in the immunity of pigs, reducing their physiological functions, leading to pathogens invading the organism and causing infection.
1.2 Secretion infection
The main infectious source of disease is sick pigs, and the pathogens of healthy pigs with disease should not be ignored, and the exudate and feces with bacteria, such as coughing, sneezing, mosquito bites and other means of transmission, through the digestive tract, the respiratory tract and the broken skin are infected [7]; carcasses, viscera, and blood and other wastes cause infection of the surrounding environment, resulting in contamination of feed, drinking water and other infections, leading to contamination of feed, drinking water and other waste. infection, leading to contamination of feed, drinking water, etc., feed, drinking water, etc., as a medium, consumed by pigs, through the digestive tract infected with germs.
1.3 Other factors
Parasitic diseases or other infectious diseases, resulting in a decline in the pig body's ability to resist disease and immunity, the original parasitic virus in the pig body is not enough to cause disease in the weakly virulent Bartonella, due to the balance between the two parasitic organisms and parasitic breaks the loop, resulting in the Bartonella virulence enhancement, which triggered the disease, the animal organisms onset of disease.
2 Clinical symptoms and pathological changes
2.1 The most acute type
Sudden onset of sick pigs, sudden high temperatures, the temperature rises to 41 ~ 42 ℃ or more, often suddenly die, septicemia symptoms, loss of appetite, mental agitation, high degree of respiratory distress, salivation of the oral nostrils, visible mucous membranes purple in color, swollen throat, the late course of the disease, the ear, the neck and the submental skin becomes blue-purple. The skin of the ears, neck, and submental area becomes bluish-purple in the later stages of the disease [ ], and the symptoms of hemosiderosis can be seen, which is hard and hot to the touch, and there is a feeling of heat and pain, and there is a sitting posture of the dog, and finally asphyxiation, which is short-lived, with a duration of only 1-2 d.
Haemorrhagic infiltration of mucous membranes, subcutaneous, parenchyma, and plasma membranes of all the body, congestion of mucous membranes of the pharynx, redness, swelling or hemorrhage of lymph nodes all over the body, and the appearance of hemorrhagic cuts, hemorrhage of the lungs and the spleen, hemorrhages of epicardium and pericardium, and hemorrhage [ ]. pericardium are also hemorrhagic [2], and red spots are often present on the skin, abdomen, chest, and ear roots.
2.2 Acute type
Pneumonia, elevated body temperature, low energy, loss of appetite, coughing and respiratory distress manifestations, late nostrils outflow of plasma or purulent secretions, visible mucous membranes bluish-purple, skin erythema, palpation of the thoracic and abdominal repercussions of the larger, showing pain, auscultation of the rales and friction sounds. As the sick pigs will appear the symptoms of initial constipation followed by dysentery, resulting in body wasting and then suffocation and death, the course of the disease is usually about a week, the individual does not die of sick pigs will turn into a chronic course [5].
The lungs have different levels of hepatic areas, the section appears to be dark red, gray-red, gray-yellow and other different colors [3], fibrinous pneumonia, with marble-like mottling [ ], the bronchial tubes have the presence of secretions, the pleura is dark, with fibrinous attachments, the pericardium and pleura appear to be adherent phenomena, the thoracic cavity and pericardium and a large amount of effusion.
2.3 Chronic type
Initial symptoms are not obvious, manifested as chronic gastroenteritis and chronic pneumonia, the sick pigs are depressed, loss of appetite body gradually wasting, the body is weak and unwilling to walk, coughing, often accompanied by diarrhea, the individual sick pigs will be swollen joints and gamy eczema symptoms, the surface of the body hair messy, if you do not treat the disease in a timely manner, the sick pigs will gradually weaken and die in about 2 weeks. The company's website is a great source of information about the company's products and services, and the company's website.
The lungs were expanded in the hepatic area, the pneumonia lesions were stale, there were yellow or gray bad color foci lesions, and there was also caseous material [ ], and there were different levels of necrotic foci in the subcutaneous tissues as well as in the mesenteric lymph nodes [3].
3 Clinical diagnostic basis
3.1 Epidemiological characteristics
Porcine pneumonic disease often occurs in medium-sized and small sick pigs, most often in late fall and early spring and the outbreak of variable temperatures, the humid and hot seasons can also be in the improper feeding management, by the impact of the stress response, the barn environmental conditions, etc., it is easy to induce porcine pneumonic disease, usually for the sporadic or secondary infections [ ]. 12].
3.2 Clinical symptoms and pathological changes
The most acute type is characterized by sudden illness, sudden death, septicemia, redness and swelling of the neck with high fever and hardness, extremely difficult to breathe, and acute inflammation of the throat; the acute type is characterized by coughing, pain and sensitivity of the chest on palpation, accompanied by diarrhea and constipation alternately, and the lungs are characterized by the presence of hepatic phase foci and inflammation in the lymph nodes in the chest[ ]; the chronic type is not obvious at the initial stage, but will be scattered or secondary infections[ 12]. type is initially asymptomatic, but joint swelling, arthritis, and more old necrotic foci of pneumonia in the lungs occur.
3.3 Bacteriological examination
Collecting fresh diseased material from sick and dead pigs for smear microscopy, after staining with alkaline melamine solution, and then inspecting the stained material with the aid of a microscope, see Gram-negative bipolar stained short bacilli, not able to move, no flagellum exists and also do not produce spores [ ].
3.4 Biochemical experiments
Cultivation of 48h can decompose glucose, fructose and sucrose, and the production of acid without gas. Most strains can ferment mannitol, sorbitol and xylitol, can appear indigo substrate, catalase and oxidase test are positive, MR test and VP test are negative, litmus buttermilk does not change, does not liquefy gelatin to produce hydrogen sulfide as well as ammonia [ ].
3.5 Drug sensitivity test
The bacterium possesses strong sensitivity to certain antimicrobial drugs, such as quinol, gentamicin, ciprofloxacin hydrochloride, norfloxacin, kanamycin, and penicillin.
4 Control measures
4.1 Preventive measures
4.1.1 Do a good job of preventive immunization
Disease "prevention first", vaccination is the most important preventive measures to develop a proper immunization program and system [ ], every year, spring and autumn should be done to plan the immunization. Immunization, the use of pig lung disease vaccine, each head of oral or subcutaneous injection of vaccine 5mL, the immunization period of six months, the number of immunizations for two times a year.
4.1.2 Good feeding management
Scientific feeding management can make the pig's nutritional status is good, the development of scientific feeding plan, enclosure should be clean and hygienic, control the feed source and environmental hygiene, control of the small environmental climate in the house, winter to strengthen the insulation against the cold, summer to strengthen the cooling heat, to avoid the pigs by the cold, the environment is humid, poor ventilation and air conditioning, lighting is not enough to survive in the environment; should also be reasonable. Survival of the environment; should also be a reasonable arrangement of pig feeding density, to ensure that the environmental conditions are good, to narrow a variety of stress conditions, increase the herd's ability to resist disease.
4.1.3 Adhere to the principle of self-breeding and self-feeding
Promote early weaning, so that as little as possible from the outside of the introduction of seeds, but because of the need to introduce seeds from abroad must be confirmed in the absence of disease, disease-free seed farms to introduce the introduction of breeding stock must be introduced into quarantine and isolation of more than 1 month, to determine that there is no epidemic can be mixed, suspected of being a diseased rabbit should be isolated and fed immediately, to reduce the spread of disease. The rabbit should be isolated immediately to minimize the spread of disease.
4.1.4 Isolation of sick pigs and burying carcasses
The occurrence of epidemic disease, isolation of sick pigs, closed the infected area, and the harmless disposal of sick and dead pigs (deep burial, ignition, boiling) [10], the carcasses should be buried in the ground less than 1.5m deep to prevent other animals from digging and throwing and spreading the disease, and disinfection and disposal of the pig house, as well as the contaminated places and utensils should be carried out to reduce the spread of disease. The spread of the disease.
5 Therapeutic measures
5.1 Western medicine
(1) 20% sulfadiazine sodium injection, 10mL ~ 15mL for small pigs, 20mL ~ 30mL for large pigs, intramuscular or intravenous injection, 2 ~ 3 times / d, used for 3 ~ 5 d [12].
(2) Streptomycin 1g powder dissolved in 8mL distilled water, 2 times/d, 0.01g～0.02g per kilogram [ ].
(3) Ciprofloxacin hydrochloride 25mg/kg, added to 1200～2000mL of saline, intravenous infusion, for 5 d.
5.2 Traditional Chinese medicine
(1) Borax 1g, lobster brain 0.6g, Renzhongbai 1g, Dazhongye 0.6g, **** for the end of the blowing into the throat, 2～3 times / d.
(2) Ginseng, schizandra, roasted licorice 7g each, dongmai, atractylodes 10g each, porcupine 15g, 3 slices of ginger, 4 jujubes, decoction, Hou Wen one-time instillation [ ].
(3) Baibei, honeysuckle 20g each, Zhimu and Platycodon grandiflorus 30g each, Qingpi and Suzi 50g each, licorice 10g, half-summer and almonds 40g each, decocted with water to get juice, warmed up one time to be infused, 1 dose per day, used for 3 d.
(4) Yamabean root, Sagittaria japonica, and Gentiana scabra 40g each, Radix et Rhizoma Gastrodiae and Rhizoma Polygonati Odorati 25g each, Manganese nitrate, Gardenia jasminoides, and Phellodendron Bidentatum 30g each, Chai Hu, Glycyrrhizae jasminoides 15g each. Chaihu, licorice each 15g, water decoction of soup, Hou Wen irrigation, 1 time / d, used for 2 ~ 3 d.
5.3 Serum therapy
Piglets injected with 30mL, reserve pigs injected with 50mL, adult pigs injected with 70mL, after the injection after 8 ~ 12 h after the body temperature is still elevated, you can continue to inject serum once [ ].
6 Summary
(1) There are many reasons for the onset of porcine pneumonic disease, mainly due to poor immunity of the organism itself, irrational feeding management, failure to formulate a scientific immunization system, the influence of the external environment and the infection of other secretions.
(2) The course of swine lung disease can be divided into the most acute, acute and chronic three different periods of lesions.
(3) According to the epidemiological characteristics of swine pneumonia, clinical symptoms and pathological changes, laboratory tests, biochemical tests and drug sensitivity tests to make a diagnosis of swine pneumonia based on these ways and means.
(4) In the process of prevention, we should always carry out the principle of "prevention as the mainstay", formulate a reasonable immunization plan, improve environmental hygiene, control the environment of the house, less stress, regular disinfection to prevent cross-infection, and kill insects and rats on a regular basis.
(5) Do a good job of herd management and feeding, to ensure the highest body resistance and immunity.
(6) medication can be based on the degree of morbidity, choose the measurement of the drug, as well as the type of drug to decide how to give the drug, you need to choose the quality of stable, high efficacy of the drug.