Pullorum Disease (Bacillary White Diarrhoea)

Pullorum Disease (Bacillary White Diarrhoea) is caused by salmonella pullorum. It causes acute systemic infection in young chicks and localized chronic infection in adults.

Etiology

The disease is caused by Salmonella pullorum which  belongs to the family enterobacteriaceae. It is   a highly host specific organism. It is a gram negative, facultative anaerobe, non motile and rod shaped organism.

Epidemiology

• Parent to offspring occurs.
• Infected adult will become a carrier.
• The organism persists in the ovaries and excreted in the ova.
• Fluff from chicks, heavy, dry and the bacteria rapidly spread in the incubator.

Transmission

• Transovarian transmission
• Vertical transmission from parent to chicks
• Rapid lateral spread from chick to hatcheries vice versa

Host Affected

• All avian species are susceptible but predominantly affects chickens, turkeys, and pheasants.
• All chickens less than 3 weeks are mostly susceptible.

Pathogenesis

Pullorum Disease (Bacillary White Diarrhoea) is a systemic infection in both domestic and wild species are affected.

S. pullorum has tropism for reproductive tract and developing eggs following infection with particularly high numbers in the oviduct at the point of lay.

Morbidity is 10-80%; mortality is increased in stressed or immunocompromised flocks and may be up to 100%.

The development of pathogenesis is more or less similar to pathogenesis of fowl typhoid.

Clinical Signs

Acute

• Chicks of less than 3 weeks old are mostly affected.
• Initially there is an excessive number of dead in shell chicks or deaths shortly after hatching has been noticed.
• Depression, tendency to huddle, respiratory distress, loss of appetite, excretion of white viscous dropping which adhere to feathers around the vent and mortality of 100% in severe condition.

Sub acute

• Grower birds are highly susceptible.
• Lameness, swollen hock joints in growing birds an poor growth rate is a main signs.
• Older birds appear listless with pale shrunken combs.
• Sub optimal egg production is the only sign seen in adult birds.

Necropsy Findings

Acute

• Chicks die of acute phase show no specific lesions.
• Chicks which die after hatching are likely to have peritonitis.
• Peritonitis with an inflamed un-absorbed yolk sac.
• Congestion of lungs, dark and swollen congested liver with haemorrhagic on the visible surface.
• Septicemia with liver congestion resembles dark and swollen with haemorrhage on the visible surface.
• Dilation of subcutaneous blood vessels are prominent.
• Chicks die after the development of clinical signs show typhlitis.
• Enlargement and distension of caeca with hard cast of dry necrotic material.
• Discrete, small, white, necrotic foci, often found in liver, lungs, myocardium and gizzard.

Sub acute

• Multiple grey nodules in the heart Sub-acute Growers and adults.
• Inflammation and enlargement of hock joints due to presence of excess lemon or orange colored gelatinous material around the joints.
• Abnormal ovary with ova, irregular cystic, misshapen, discoloured is featuristic and pedunculated with prominent thick stalks may be observed.
• Some infected adult birds may have small, inactive, pale ovary with underdeveloped ova.
• Inflammation of joints, peritoneum and pericardium is evident. Infertility, hatchability of infected eggs are very low.

Diagnosis

• Based on clinical signs and necropsy findings.
• Isolation and identification of organism by culture and staining.
• Sample collection Liver is an important specimen of choice for culture collected acute infection, whole blood and serum from chronic infection must be done by serological tests.
• Test for antibody detection Rapid Slide/plate agglutination test on whole blood using a stained antigen and tube agglutination test on serum can be carried out.
• Needle of 10 cm in length with a blunt end loop, white porcelain cavity plate, 0.02ml of whole blood/serum drawn from the elbow joint and brachial vein 0.02 ml of antigen polyvalent crystal violet stained antigen is required for the test.
• Within 30 seconds after mixing the know antigen with blood/serum rapid agglutination will bee seen.
• If a fine, pin-point blue granules appears either through out the mixture or at the periphery in 1-2 minutes may be considered as doubtful reactions and if reactions occur in more than 2 minutes may be taken as negative.
• While testing the turkey, geese, guinea fowl, pheasants, partridges and quails serum result should be read in 3 minutes.
• Merits Testing of flock by RPAT is quick and easy to test.
• Two consecutive clean test at an interval of one month must be done for declaring the flocks freedom from infection.
• Re-infection may occurs through environmental contamination.

Differential Diagnosis

• Fowl typhoid
• Fowl cholera
• New Castle disease

Treatment

Sulfamethazine, sulfamerazine, and sulfaquinoxaline have been used successfully to reduce the death losses in chicks and poults.

Furazolidone, a chemical derivative of furfural, checks losses in acute outbreaks. It may be incorporated in the feed at a low level for continuous feeding to prevent outbreaks and spread of the infection.

Prevention

• Eradication from breeder flocks.
• Recovered birds are resistant to infection but may remain carriers.
• Vaccines are not normally used because of the interference in the serological testing and elimination of carriers.

Control

• Sanitation and disinfection are important in hatching and brooding sections.
• Easily destroyed by disinfectant, heat, and direct sunlight.
• After each hatch, incubator egg trays and the other readily removable parts should be taken out, washed free of dirt and foreign matter, and then scrubbed with a 2-percent lye solution or other acceptable disinfectant, such as a 3-percent solution of cresylic acid.
• Lye and caustic soda aregood disinfectants.
• Precautions are necessary while using this disinfectants.
• Incubator rooms should be cleaned, brushed and washed down and cobwebs from ceilings and walls and from entire farm house.
• Formaldehyde gas is a good disinfectant for incubators during incubation or following the removal of the hatch.
• Following removal of reactors to the blood test, poultry houses and equipment should be cleaned and disinfected.