Fowl Typhoid

• It is an infectious septicemic disease of domestic fowls and turkeys characterized by acute manifestation having high mortality.
• Although, it is a disease of adult birds, it can cause high mortality in young chicks.
• Mortality can be as high as 26% in chicks during first month.
• Among salmonellosis of poultry, fowl typhoid is among those of greatest economic importance to poultry industry worldwide.

Etiology:

• Salmonella gallinarum
• It is gram-ve, non-motile bacillus measuring 1-2µm in length and 1-1.5 µm in breadth.
• Organism can grow in Mac-Conkey Agar.
• It can be destroyed by disinfectants like phenol, potassium permanganate, 2% formalin.

Epidemiology:

• Disease is distributed globally but has been eradicated from commercial poultry flocks in Europe, US, Canada, Australia, Japan.
• Disease has been reported from several states of India; UP, Punjab, WB, Maharashtra, Karnataka.
• According to VEC 2015, 19 outbreaks were reported from country. Out of 19601 birds, 2328 birds were found dead with mortality rate of 11.45%.
• In a study conducted by CVL, incidence of disease was reported to be 2%.
• In a study conducted in Haryana India, overall case fatality rate was found to be 71.55% during period of 2011-2013.
• Disease mostly affects adult birds usually above 12 weeks or older.
• Birds like chicken, turkey, guineafowl, peafowl and ducklings suffer naturally.
• Disease is usually presented in acute form. Some of the cases are chronic in nature where birds take upto 5 weeks to recover.

Transmission:

• Disease is transmitted both horizontally and vertically.
• Horizontal transmission occurs through ingestion of contaminated feed, water.
• gallinarum continues to exist in feces for about 1 month from where birds pick up infection.
• Recovered birds usually remains carriers and transmit to susceptible poultry birds.
• Through fomites such as attendants, clothing disease transmit from one place to another.
• Rodents, dogs may carry infected carcass from one place to another and spread the disease.
• Vertical transmission occurs through infected eggs. Bacteria are present in egg shell which gets transferred when chicks hatch out.

Pathogenesis

Clinical Findings:

• In acute forms, there is sudden death followed by drop in feed consumption.
• In laying birds, there is drop in egg production.
• Affected birds remains depressed, stand still with ruffled feathers with their eyes closed.
• Respiratory distress with rapid breathing
• Most characteristic symptoms are watery to mucoid yellowish diarrhea.
• In birds that donot dies within 2-3 days, chronic form develops. Birds shows anemia, loss of condition.
• Due to severe anemia, combs and wattle becomes pale and shrunken.
• In young chicks, symptoms are non-specific such as:
  • Weakness
  • Unwillingness to move
  • Tendency to huddle together
  • Drop in food consumption
  • Yellow pasty feces sticking around vent
  • Sometimes, there is rapid breathing and gasping

PM Findings:

• Carcass appears anemic and jaundiced if birds have died in severe acute phase.
• Important and consistent finding is liver is swollen, friable and has dark red or almost black color. Surface has bronze sheen.
• Spleen is enlarged.
• Intestine are inflamed and contains thick, sticky bile-stained material.
• If birds have died in chronic phase, carcass are emaciated and severely anemic with focal necrosis in heart, intestine, liver and pancreas.
• Pericarditis with turbid yellow fluid in pericardial sac and fibrin attached to surface of heart is feature of chronic fowl typhoid.

Diagnosis:

• Based on clinical findings and PM findings
• Isolation of organism from heart blood and other organs.
• Serological test is proven to be useful in diagnosis. Agglutination test is best for identifying salmonella.

Treatment:

• Drugs like furaltadone, cotrimoxazole, chloramphenicol, ampicillin, etc. can be used for treatment.
• Intertrim powder (Sulphadiazine + Trimethoprim) @ 1 kg per 1500 – 2500 litres of drinking water for 4 – 7 days.
• Gutsafe liquid @ 1ml/3 litr. DW, OD, for 5 days.
• Liver vital liquid (Feed supplement) @ 1ml /1 litr. DW for 5 days

Control Measures:

• Since the recovered birds remains as carrier, treatment is not effective. Best method to control disease is to remove the infected birds from flock.
• Carcass should be disposed of properly either by burying deeply or burning.
• Poultry flock should be monitored for infection by rapid plate agglutination test using pullorum antigen to detect carriers of S. gallinarum. Positive reactor birds should be culled immediately.
• Vaccination usually gives solid and long-lasting immunity. It may be given at 8 weeks of live @ 1ml SC
• Adoption of general hygienic measures as in pullorum disease and avoiding overcrowding may help in controlling the disease.
• Foot bath should be arranged at entry of poultry of house.
• All farm equipments should be regularly disinfected.
• Location of farm house should be made as per standard protocol.
• Litter contamination should be reduced. Periodic cleaning helps in removing source of infection from flock.
• Regular spraying of acaricide are essential to prevent fly and beetle population.
• Water supply pipelines should be made free from any kind of contamination.
• Feedstuff should be made free from contamination. Propionic acid may be added to feed to prevent moulding of feed.