Pullorum-Typhoid Disease
What is it?
Pullorum Disease and Fowl Typhoid are two poultry diseases
whose control and eradication strategies have shaped the poultry industry in
the U.S. They are commonly termed as one disease condition because of similar
clinical signs and disease transmission pathways; both diseases originate from
two closely related Salmonella
species. Pullorum Disease results from an infection caused by Salmonella Pullorum; Fowl Typhoid
results from an infection caused by Salmonella
Gallinarum. Pullorum-Typhoid (P-T) Disease primarily affects chickens and
turkeys, and can affect other poultry including waterfowl and game birds.
The disease has been eradicated from commercial poultry in
the U.S., thanks in large part to efforts of the National Poultry Improvement
Plan (NPIP). It does still exist in Central and South American countries,
Africa, and parts of Asia. After decades of testing and eradication efforts,
the U.S. commercial flocks are certified free of P-T Disease. However, there is
still concern it may be present in smaller backyard flocks where testing and
efforts to eradicate P-T Disease continues.
How is it transmitted?
Pullorum-Typhoid is transmitted from infected birds to their
offspring through the egg and can produce high death loss in young birds; this
is termed vertical transmission. Those that survive an infection are carriers
for life, and can infect other birds by direct contact. Pullorum-Typhoid can
also be transmitted horizontally like other poultry diseases, being spread
through feed, water, litter and poor biosecurity practices.
What are the clinical signs?
The incubation period for the disease is usually 4-6 days,
and clinical signs are different between young birds and older birds. The
hallmark sign of P-T Disease is seen in the hatchery where infected eggs result
in poor hatchability and high mortality with younger birds going off feed and exhibiting
diarrhea and depression. Older birds often show no clinical signs, but can have
decreased egg production and increased mortality.
How is it diagnosed?
Screening tests for Pullorum-Typhoid Disease are commonly
run on blood or serum samples collected from outwardly healthy birds. Tests for
P-T Disease can be conducted in the field using the Rapid Whole Blood Test
(RWBT) or can be conducted at a laboratory familiar with P-T testing. Birds with
positive RWBT results must have samples submitted for confirmatory testing. In
Minnesota, the Board coordinates the process where samples are sent to the
Minnesota Poultry Testing Laboratory.
Is there a risk to people?
P-T Disease is not considered to be a serious public health
concern.
How can it be prevented?
Pullorum-Typhoid is considered a reportable disease in most
states, and detections typically result in the depopulation of the infected
flock. The disease is not treatable. The best method of prevention is routine
Pullorum-Typhoid testing of breeder flocks, purchasing birds from National
Poultry Improvement Plan participants, and effective biosecurity.
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