Poultry bacterial disease①

  coli is a flagellated (tiny whip-like appendages, pushing the bacteria through water film) gram-negative bacilli. Escherichia coli disease is a general term for a type of disease caused by Escherichia coli. Poultry includes large intestine granuloma (also known as Hjarre disease), yolk sac infection, umbilitis, poultry ovarian peritonitis, and E. coli sepsis. Escherichia coli septicemia (colisepticaemia) is the result of widespread infection of E. coli and its septic metabolic waste in poultry. “coli” refers to Escherichia coli, “septic” refers to metabolic waste, and “aemia” refers to the transport of metabolic waste to the body through the blood.
  1 pathogenic
  E. coli bacteria on a medium easily lab grown, typically fermentable glucose, mannitol and lactose, but not ferment inositol. This fermentation characteristic is very important and can be used to determine bacterial characteristics. Different types or serotypes of E. coli can usually be distinguished by their O type antigens, but there are also K type (capsular) and H type antigens. Most of the E. coli that cause poultry disease belong to a small serogroup, including O1: K1, O2: K1 and O78: K80. In the broiler industry, E. coli sepsis is regarded as an “intensive disease”, which mainly affects chicks. However, as people’s awareness of the disease has increased, its impact on broiler production has been significantly reduced. E. coli sepsis is also found in other types of poultry and game birds.
  2 Epidemiology
  Escherichia coli is a member of a larger group of bacteria in the Enterobacteriaceae family. As its name suggests, this organism colonizes the digestive tract of poultry. It can be excreted in large quantities through the digestive tract of poultry, so the fecal-oral transmission route is very important. This approach can be direct or indirect, such as water or feed contaminated by feces. In addition, E. coli will exist in the environment (such as dust, litter, etc.) for a long time. Therefore, an important aspect of controlling the occurrence of colibacillosis in poultry (including E. coli sepsis) is that the broiler farm thoroughly cleans and disinfects the chicken house at the end of a production cycle, and uses an all-in-all-out production method instead of multi-age polyculture Program. In view of the special physiological structure of hens, both eggs and feces are discharged through the cloaca, which provides a perfect condition for E. coli or Salmonella to contaminate eggs through feces. This is of great significance to the epidemiology of yolk sac infection and related diseases.
  3 indicator organism
  E. coli infections and sepsis are usually secondary to other infections (usually a viral infection) or stress. When we diagnose E. coli sepsis in chickens, we should try to determine the main predisposing factors, because its management is usually important for long-term control of E. coli sepsis in a chicken farm. Typical predisposing factors include viral infections (such as infectious bronchitis, Newcastle disease, avian pneumonia virus disease, infectious bursal disease, Mycoplasma gallisepticum infection), the use of live vaccines for respiratory diseases (especially misuse), coccidia Disease, a large number of worm infections and malnutrition (such as severe malnutrition or vitamin A deficiency, etc.). In the last case, the viability of the poultry mucosa is greatly reduced, making them more susceptible to infection.
  4 pathogenesis of
  E. coli is a present in poultry gut bacteria, primarily colonize the large intestine and cecum segment. The strains of E. coli that are most closely related to E. coli sepsis also appear in the pharynx and upper trachea behind the throat, because poultry inhale contaminated dust.
  Escherichia coli can also invade chickens from the upper respiratory tract, which is caused by factors that disrupt the defense mechanism of this area. Destructive factors including cilia-suppressing viruses (such as infectious bronchitis virus and avian pneumonia virus) can hinder the function of the tiny hairs or cilia that line the trachea. Ammonia’s inhibitory effect on cilia and macrophages, which are part of the poultry defense system, can have similar consequences. These macrophages engulf and destroy foreign materials, such as invading microorganisms. E. coli invasion can also occur when the chicken’s resistance is reduced due to other stresses (such as high concentrations of dust, high temperature, and vitamin A deficiency). After passing through the respiratory tract, E. coli spreads through the blood circulation in poultry, causing damage to various internal organs. Except for most acute cases, these lesions are related to fibrin formation, so this pathogen can cause fibrinous pericarditis, fibrous perihepatitis, and fibrous peritonitis.
  5 clinical symptoms of
  broilers and turkeys at any age is almost always occurs E. coli septicemia, but the breeder, this situation occurs mainly in the egg before.
  The typical symptoms of broiler flocks are quietness, loss of appetite, then lethargy, erect feathers, and common respiratory distress. The incidence of the disease varies among chickens, and the mortality rate is usually less than 5%, but it can sometimes be higher.
  The clinical symptoms may vary due to the impact of co-infected pathogens. For example, if chickens are simultaneously infected with infectious bronchitis virus or Mycoplasma gallisepticum, respiratory symptoms may be more pronounced. If a turkey is infected with E. coli, Mycoplasma gallisepticum, and avian pneumonia virus at the same time, the infraorbital sinuses usually swell.
  Once E. coli sepsis occurs in the flock, the uniformity of the flock will decrease. This is because although some chickens did not die, they left sequelae after the onset, such as chronic restrictive fibrinous pericarditis, which would hinder heart function and affect chicken growth. In slaughter and processing plants, this chicken is often downgraded.
  In some cases, chickens have chronic claudication due to joint infections (arthritis).
  6 necropsy results
  sepsis bodies typically occur fever, dehydration, discoloration. The main organs in the body are enlarged and congested, with hepatomegaly and splenomegaly, as well as congestion of the lungs and kidneys.
  The typical symptoms are white fibrous intima visible in multiple organs, manifested as fibrinous pericarditis, fibrinous perihepatitis, fibrinous peritonitis and fibrous air sacculitis, and fibrinous pleurisy on the lung surface.
  7 local E. coli infection
  so far, people have been using E. coli septicemia (colisepticaemia) The word, in fact, only one form of E. coli septicemia disease. Colibacillosis can be defined as a local infection or systemic infection caused by pathogenic E. coli. In daily use, people tend to use E. coli sepsis to describe systemic infection. Now we will discuss local infections caused by E. coli.
  7.1 yolk sac infection or omphalitis
  omphalitis inflammation and yolk sac or navel infection is usually mixed infection of both organizations, because the yolk sac near the navel. Sometimes people use the term “soft chicken disease”. Escherichia coli can easily cause infection after entering the unhealed belly button, but if the hen suffers from salpingitis, oophoritis or artificial insemination of turkeys can also occur in-ovo infection, but this is rare.
  When yolk sac infection or omphitis occurs in chickens, people need to try to remove the source of E. coli to prevent recurrence. It is generally believed that the most common source of E. coli infection comes from contaminated eggshell feces. E. coli can also pass through the intestinal wall and flow to the yolk sac through the blood. It is also important to check that the chicks also show slow healing of the belly button. This is usually a problem with the incubator, and sometimes this is a key background factor for continued yolk sac infection/omphitis in the hatchery.
  Care must be taken when interpreting the bacterial results of the yolk sac culture, because many normal yolk sacs may also contain small amounts of E. coli, many of which may be non-pathogenic strains. The massive growth of pure E. coli from the yolk sac is the diagnostic basis for yolk sac infection; if it is a few individual colonies, it cannot be the diagnostic basis. It should also be noted that although E. coli is the most common, other factors can also cause yolk sac infection. Escherichia coli isolates associated with umbilitis often contain adhesion factors.
  If salpingitis or oophoritis causes E. coli infection in the eggs, some embryos may die before they emerge, especially during the latter stages of incubation. The incidence of omphalitis increases in the first few days after chicks emerge, reaches a peak, and then decreases. The disease is still rare by the third week, but sometimes chronic infection or residual yolk sac infection in poorly grown chicks may be found. These chickens have been fighting against Escherichia coli infection. Although they won the victory, they paid a heavy price for it-poor growth. Even if the infected E. coli strain has a low lethality and no embryos or chicks die, the survival rate and weight of the chicks will be adversely affected.
  7.2 clinical symptoms
  chicks usually swollen abdomen, umbilical vascular congestion. The typical symptoms of umbilitis are redness and edema of the belly button, with non-specific changes such as dehydration, visceral gout, weight loss, dirty cloaca, and enlarged gallbladder. Sometimes the skin around the navel becomes loose, moist and dirty, which gives rise to the term “soft chicken disease”.
  When the yolk sac is infected, the yolk sac enlarges because the yolk is not absorbed by the chicks, and the inflammatory substances also increase its quality. In this case, the yolk color, consistency and smell are usually abnormal. If chicks with yolk sac infection or omphitis can survive for several days, fibrous yolk (characterized by deposition) will appear.
  8 systemic colibacillosis
  In addition to localized E. coli infection, there are many forms of systemic E. coli disease. When a pathogenic E. coli strain with a certain toxicity enters the bloodstream, spreads rapidly throughout the body, and causes infections in various internal organs, animals will develop E. coli sepsis. E. coli sepsis can be divided into acute sepsis, subacute serositis (inflammation of the surface of the internal organs, such as the peritoneum, air sacs, pericardium or pericardium and liver surface) or chronic granulomatosis. Granuloma is a nodule of inflammatory tissue.
  E.coli septicemia 8.1 newborn chicks
  chicks hatched in the 2 D usually occurs after this type of E.coli septicemia, the mortality rate of 2 ~ 3 weeks will be higher than normal levels. E. coli sepsis in newborn chicks can cause growth and growth retardation in chicks. If it cannot be compensated in future production or processing, these chicks must be eliminated. These chicks usually suffer from complications such as osteomyelitis (bone marrow infection) or arthritis, a sequelae of their early infection with E. coli. The typical features of the disease are the blackened lungs and splenomegaly of the infected chicks, which then develop into fibrinous pericarditis, pleurisy, peritonitis and airsacculitis.
  8.2 Respiratory E. coli septicemia
  in chickens and turkeys, a common cause of E. coli E. coli sepsis through the damaged airway epithelial cells lining or after entering the bloodstream. Common causes of such damage include infectious bronchitis, avian pneumonia virus infection, Newcastle disease, inoculation of live respiratory disease vaccines, mycoplasma infection and ammonia gas.
  Studies have shown that 5 days after inoculation of Newcastle disease vaccine through the respiratory route, and then aerosol inoculation of E. coli through the same route, the clearance rate of E. coli is significantly reduced. Studies have also shown that exposure to ammonia or dust in the air can cause cilia in the upper respiratory tract of poultry to fall off.
  Cilia are tiny hairs that line the upper respiratory tract and are an important part of the respiratory tract defense mechanism. The resulting disease is usually called chronic respiratory disease (Chronic Respiratory Disease, CRD) or air sacculitis.
  Interestingly, the strain of E. coli that infects the respiratory tract of chickens is often different from the strain that infects the digestive tract. The pathological changes of this form of E. coli sepsis include bronchitis, bronchitis, pneumonia, air sacculitis, pericarditis and peritonitis. As the infection progresses, poultry air sacs thicken, and many of the previously mentioned pathological conditions develop into fibrinitis, such as fibrinous pericarditis with accumulation of fibrin and inflammatory debris. Pneumonia and/or pleuropneumonia usually occur in turkeys, while pleurisy and/or pleuropneumonia (inflammation on the surface of the pleura or lung) are more common in chickens, and there are fewer internal lung infections. Most of the deaths caused by E. coli sepsis occurred in the first 5 days after the shelling.
  8.3 intestinal E. coli septicemia
  This type of E. coli septicemia common in Turkey, rarely damage the inner wall of the digestive tract, such as turkey hemorrhagic enteritis in chickens. In these cases, the E. coli strain that causes E. coli sepsis is the same strain found in the digestive tract of poultry. At the beginning, the main lesion is the liver congestion or turning green. Within a few days, the infected poultry develops internal lesions similar to respiratory tract Escherichia coli sepsis.
  8.4 consequences of E. coli septicemia
  obvious consequence is that the incidence of E. coli septicemia in poultry death, and cellulose pericarditis occur, liver Zhou Yan and pericarditis will hinder the growth of poultry, carcass downgrade in the packinghouse. In addition, E. coli can maintain activity in specific parts of the poultry body and cause disease.
  Other diseases 9
  9.1 meningitis
  E. coli infection of the brain are rare, but the protective cover around the brain or meninges are infected, causing meningitis.
  Eye infection 9.2
  cases of E. coli infection in the eye is rare, but once the infection occurs the whole eye inflammation or infection of the whole eye, and the disease is usually more severe. After an eye infection, the first manifestation of the eye is swelling, then it becomes opaque, and finally the eye shrinks and shrinks.
  9.3 Osteomyelitis/ Synovitis/ Osteoarthritis
  When Escherichia coli in the bones, joints or bones around the joints and the joints themselves have local infections, the common sequelae of E. coli sepsis are osteomyelitis, synovitis and osteoarthritis. The blood supply in the bones and the bone’s ability to fight infections are limited, which may facilitate the development of the disease. Poultry with osteoarthritis usually limp and grow slowly. At first, the joints are swollen, heated, and painful, but over time, this fever and pain gradually disappear, and then the mobility of the joints gradually loses or weakens.
  Due to the active foci of the infected poultry, hepatomegaly and splenomegaly are common in this case. The most common joints affected by osteoarthritis are the hocks, knee joints, hip joints, wing joints and thoracic joints (spondylitis).
  9.4 sternum infectious bursitis
  infectious bursitis sternum can be seen as sequelae of E. coli septicemia, in this case, on the sternal bursa infection, inflammation, swelling.
  9.5 granuloma E.
  coli, also known as granulomatous disease Hjarre. E. coli granuloma is a nodular thickening caused by coagulative necrosis (death of tissue). E. coli granulomas are common in the liver, cecum, duodenum, and mesenteric.