COMMON BACTERIAL DISEASES OF BROILERS POULTRY
Dr.Kedar Karki
Colibacillosis (Coli form infections)
Problems attributed to coliform infections are often caused by strains
of the Escherichia coli organism. There is a marked variation in
severity. Problems range from severe acute infections with sudden
and high mortality to mild infections of a chronic nature with low
morbidity and mortality. Infections may result in a respiratory disease
from air sac infection, a septicemic (blood) disease from generalized
infections, an enteritis from intestinal infection or a combination of any
or all of these conditions. The disease may result from a coliform
infection alone as in primary infection or in combination with other
disease agents as a complicating or secondary infection. Secondary
infections commonly occur as a part of the classic air sac disease
syndrome as a complication with Mycoplasma gallisepticum
infections.
All ages can be affected; however, the acute septicemia in young
turkeys and airsacculitis in young chickens is more common in young
growing birds. High, early mortality may occur as the result of navel
infections.
The symptoms of this disease is caused by the E. coli bacteria and
the toxins produced as they grow and multiply. There are many
different strains or serological types within the group of E. coli
bacteria. Many are normal inhabitants in intestinal tracts of chickens
and turkeys and consequently are common organisms in the birds'
environment.
A marked variation exists between different strains in their ability to
cause disease. Some are severe and by themselves can cause
disease while others are supposedly harmless. All degrees of
pathogenicity exist between the two extremes.
The primary routes of invasion by the organism are the respiratory
system and the gastrointestinal tract. Omphalitis and infections in
young birds may result from entry through the unhealed navel or
penetratio