Fowl Paratyphoid By Dr Bhavesh Zapadia

FOWL PARATYPHOID

Etiology Caused by Salmonella typhimurium S. enteriditis phage type 4 & other paratyphoid (PT) Salmonellae organism other than S. pullorum & S. gallinerum  Organism is motile, Gram negative  Ubiquitous in distribution  Stable in environment  Remain in feed & water for weeks 

Host Range  

Non host specific Found in man, chicken, animals including rodents & aquatic animals

Susceptibility 

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Young chicks are highly susceptible leading to serious illness and death. Older birds are less susceptible Without significant morbidity and mortality. Environmental and management factors influence susceptibility. Exposure to stressful conditions facilitates salmonella infection. E.g. lowering of brooder temperature by 5º to 8º C increases mortality.

Spread And Source Of Infection 

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Spread through vertical and horizontal transmission but not a true vertically transmitted disease. Infection carried on egg by Faecal contamination or nest-box dust. Lateral spread by direct contact, contaminated feed and water. Contaminated feedstuff mainly animal protein in ration like bone meal, meat meal, fish meal, etc. Biological vectors like insects, cockroach, mealworm, rats, mice etc. help in transmission.

Pathogenesis 

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Three categories of toxins are released by PT salmonellae: Endotoxin associated with lipid A produce fever, causes liver and spleen lesions. Enterotoxins (heat labile) induce a secretory response in epithilial cells leading to fluid accumulation in intestine. Cytotoxin (heat stable) cause structure damage to intestinal epithelium by inhibiting protein synthesis.

Clinical Signs 

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Disease caused by PT salmonellae is usually seen in chicks below 2 weeks of age, and rarely in birds over 4 weeks of age. Morbidity and mortality vary greatly. Death usually less than 20%, but even reach upto 100%. Affected birds are depressed, reluctant to move, and stand with their eyes closed and with ruffled feathers and drooping wings. Diarrhoea with pasting of the feathers around the vent.

Post Mortem Finding 

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Vary considerably from complete absence to a septicaemic carcass with the lung, liver, spleen and kidney swollen and congested. In chicks- inflamed, unabsorbed yolk sac. Discrete necrotic lesions in the lungs, liver and heart. Peritonitis and haemorrhagic enteritis seen in birds which donot dies in septicaemic phase. Typhlitis with caeca distended by hard white necrotic cores.

Fig

Pericarditis due to salmonella enteritidis in 4 days old broiler chick.

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Caseous plugs in the ceca of broiler chick.

th e c e c a of br oi le r c hi c k.

s i n t h e c e c a o f

b r o i l e infection in gosling. Pericarditis and Salmonella enteritidis r

perihepatitis

c

Salmonella typhimurium infection in goosling. Enlarged liver with focal necrosis.

Diagnosis 

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Isolation and identification of the causal agent from liver, gall bladder, yolksac, intestine. Serological tests- white blood test (WBT), serum agglutination test. Rapid detection technology- ELISA

Treatment 

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Enrofloxacin, pifloxacin are very effective against salmonella. Furazolidone @ 0.04% in the feed for 10 days. Spectinomycin, ampicillin and tetracyclins can also be used. however none is capable of removing infection in a flock.

Control         

Hatching egg hygiene Hatchery hygiene Biosecurity Cleaning and disinfection Rodent control programme Competitive exclusion of probiotics in feed Vaccination: available for S. enterditis Screening of flock with colored pullorum antigen Pelleting of feed

Public Health Significance 

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Salmonellae remain among the leading sources of infection of food borne illness throughout world. About 20,000 hospitalizations and 500 deaths associated with salmonella are reported anually. More than 1/3 of food borne outbreaks in USA between 1983-87 was associated with poultry meat or eggs. Thus acquire great importance because of illness caused by consumption of contaminated poultry products.

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