Intestinal Diseases of Poultry

Question 1

describe the economic impact of poultry intestinal disease

Answer 1

1. US spends approx 350million in preventatives
2. total cost is 20cents per chicken produced in the world
3. affects feed conversion ratio, average daily gain, and avg daily feed intake even in subclin or mild cases

Question 2

describe coccidiosis

Answer 2

1. protozoan disease of chickens and turkeys
2. direct life cycle:
   -inside host: asexual and sexual
   -outside host: sporogeny; very thick outer shell = very resistant!!
3. only 1 oocyst needed
4. pathogenicity variable by species and strain
   -Eimeria praecox: parasites remain superficial (less pathogenic)
   -E. maxima, tenella, necatrix, mivati, and brunetti: deep invaders, knock out the more premature cells in the crypts = hemorrhage, can go through lamina propria and cause more damage
5. prevalence varies

6 control: therapeutics and vaccines

Question 3

describe diagnosis of coccidia

Answer 3

histopathology is the only definitive!

1. protozoan parasites of the genus eimeria
   -disease state = coccidiosis
2. 7 species in chickens, 6 species in turkey (as validated by PCR)

Question 4

describe the possible courses of infection with coccidiosis/how the immune system responds

Answer 4

1. fails to be established: inappropriate/immune host
2. established, low burden: immunity develops
   -happens when we use ionophores
   -can tolerate a short period of infection in order to establish the immunity
3. established, low burden: balanced state
4. established, high burden: host succumb, high level infection and host may die

Question 5

describe eimeria acervulina lesions

Answer 5

unique lesion: white specks in duodenal loop

Question 6

describe eimeria maxima lesions

Answer 6

+/- in duodenum

really love to hang out in jejunum
-mucus and exudate (deep invader), creates necrotic membrane in gut

largest oocyst = maxima

Question 7

describe eimeria tenella lesions

Answer 7

seen in and causes mortality in backyard birds

invades cecal pouches, deep invader that causes hemorrhage

easily tx with corid or albon, so backyard birds should be on medicated feed for best protection

Question 8

describe clostridial enteropathies

Answer 8

clostridia are present/commensal, and disease is a see saw between

healthy gut: coccidia control, feed quality, ingredients; good gut flora = no bloom of clostridia

diseased guy: intestinal epithelium damage, flora imbalance = clostridial growth
-mucus = clostridial growth (creates anaerobic env for clostridia and also is food for clostridia)

Question 9

describe clinical necrotic enteritis

Answer 9

1. gross lesions in intestines:
   -pseudomembrane in intestinal lumen
   -turkish towel appearance
   -darkened liver from toxins produced by clostridia
2. acute death most commonly seen (due to toxins)

Question 10

describe subclinical necrotic enteritis

Answer 10

1. reduced weight gain
2. reduced growth rate
3. poor FCR
4. liver damage: cholangiohepatitis
   -approx 20% condemned

Question 11

describe necrotic enteritis

Answer 11

1. causative agent: C. perfringens
   -alpha, beta, and net B toxins
   -net B typically causes enteritis
2. many predisposing factors
   -intestinal epithelial damage: coccidia, mycotoxin, rancid animal byproducts, ascaridiasis

-intestinal microflora imbalances promoted by dietary ingredients: nondigestible polysaccharides, small cereals (wheat, barley, rye)