Mycoplasma
What is it?
Mycoplasma is a type of bacteria that can infect and cause
disease in a wide variety of animals and people. The mycoplasmas that infect
avian species not only can cause disease in commercial chickens and turkeys,
but they can also cause disease in other avian species. The Mycoplasmas that
are commonly seen in poultry include Mycoplasma
gallisepticum (MG), Mycoplasma
synoviae (MS) and Mycoplasma
meleagridis (MM). In poultry, each species of mycoplasma has distinctive disease
concerns and exhibit different characteristics, but they have a common route of
transmission, which is during the hatching process from hen to chick or poult.
Mycoplasma
gallisepticum is the most pathogenic type in poultry, meaning it has a
tendency to cause more serious disease. It typically impacts chickens as a chronic
respiratory disease with a nasal and ocular (eye) discharge and reduced egg
production. In turkeys it results in severe swollen sinuses, coughing and slow,
stunted growth. It affects poultry worldwide and is commonly seen in
noncommercial flocks including pheasants and other game birds. When large
commercial poultry operations are infected, it can cause significant economic
losses.
The National Poultry Improvement Plan (NPIP) has programs
available that allow participating breeder flocks to demonstrate they are free
from infection. The NPIP testing emphasis is focused on breeder flocks to
prevent egg transmission (transovarian). In Minnesota, turkey breeder flocks
and egg and meat-type chicken breeder flocks are required to participate. Minnesota
has been classified as MG Clean for turkeys since 1980 and MG Clean for
meat-type chickens since 2003.
Mycoplasma synoviae
most commonly impacts chickens and turkeys as upper respiratory infections or joint
and tendon infections. It is distributed worldwide and is seen primarily in
chickens and turkeys, but gamebirds and waterfowl may also be infected. Minnesota
has been classified as MS Clean for turkeys since 2003.
Mycoplasma meleagridis
only impacts turkeys. It has been associated with decreased hatchability, poor
growth and other skeletal abnormalities. Successful control programs like the NPIP
have reduced economic losses associated with the disease. Testing for MM is
voluntary, although testing in most turkey breeder flocks is very common.
How is it transmitted?
The most common route of mycoplasma disease spread in the
poultry industry is vertically through egg transmission. The bacteria can also
move through feed and water contamination, environmental contamination,
mechanical transmission on clothing and equipment, and direct contact when
flocks or birds are exposed to infected birds. MG, MS and MM are egg transmitted
diseases which have the potential to become widespread in a short time period
without proper and timely breeder flock surveillance.
What are the clinical signs?
Clinical signs may vary by the mycoplasma type, and in
general there are typically few or slight signs in adult birds. Overt signs
include reduced hatchability, mild respiratory distress, lameness and
depression, mild sinusitis (yellowish discharge of the sinus), swollen joints,
and difficulty breathing. Mycoplasma gallisepticum is usually more severe in
turkeys, which is why it’s also known as Infectious Sinusitis in turkeys.
How is it diagnosed?
There are a number of different diagnostics tests that can
be used to identify Mycoplasma infections in poultry. Mycoplasma is a routine
test among participating National Poultry Improvement Plan breeder flocks.
Samples are collected and submitted to the Minnesota Poultry Testing
Laboratory. Samples are then tested by laboratory staff and results are
reported to the flock owner and hatchery.
Is there a risk to people?
There is no known risk to humans, and poultry products are
safe to consume. However, people should practice strict biosecurity near
poultry flocks because mycoplasma can be a significant disease issue for
breeder flocks, hatcheries, poultry producers and poultry processing plants.
How can it be prevented?
A strict biosecurity program that limits or prevents
exposure to infected birds or contaminated products, equipment and people is
the best way to prevent infection. Mycoplasmas are bacteria that do not survive
for more than a few days outside the host and are vulnerable to common
disinfectants. Participants in the National Poultry Improvement Plan also help
prevent mycoplasma infections by using clean breeder flock sources and meeting
flock biosecurity standards.
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