Chicken virus confounding local growers

Monday, January 30, 2006

CARROLL COUNTY -- Area poultry growers are taking extra precautions with outbreaks of vaccine-induced laryngotracheitis, also known as LT Disease, in the county.

While the initial outbreak, which seems to have originated in neighboring Benton and Washington counties, where it is more severe, the outbreak seems to be a reaction to the Infectious Laryngotracheitis (ILT) vaccine. Its spread seems to have taken on a life of its own.

And that life is on the weird side, according to County Extension Agent Leon Duncan, who says that LT has been found at several farms in Carroll County in the past two to three weeks.

What is odd, Duncan said, is that growers with five or six houses may have an outbreak in the back of one house without it spreading to other houses, even though the grower goes in and out of the houses every day and the same equipment and feed trucks are used.

"It seems like there's no rhyme or reason to it," Duncan said.

Duncan, as well as meter readers and feed truck mechanics, are restricted from being around poultry houses during the present outbreak.

Precautions are being taken to prevent a further outbreak, including sanitizing of clothing before going from one poultry house to the next.

Morrill Harriman of the Arkansas Poultry Federation in Little Rock, said Tuesday that the vaccine-induced strain of LT is producing some mortality, but has no effect on humans. There could, however, be a significant economic impact if the outbreak becomes too severe, he said.

Attempts to reach Dr. James Martin of the poultry disease committee of the Arkansas Poultry Commission were not successful.

The current outbreak appears to have been first reported at the Cobb-Ventris Plant in Gentry, in neighboring Benton County.

LT is an acute respiratory disease caused by a herpes virus that can lead to significant losses in the broiler and layer industry. Mortality is usually in the 10 to 20 percent range, but it can run as high as 70 percent. LT can persist in a flock for as long as six weeks.

Birds suffering from a mild form of LT have watery eyes (conjunctivitis), swollen sinuses and persistent nasal discharge. A severe form is identified by violent cough, with the bird's trachea partially blocked with blood.

The disease spreads laterally and not through the egg or vertical transmission.

Controls for LT include:

* Producers should provide foot baths, coveralls, hats, masks, etc. Incineration and rendering are acceptable methods of dead bird disposal. Dusty conditions should be avoided and litter moistened before removal. The LT virus is susceptible to most disinfectants.

* Processors should schedule suspect or vaccinated flocks for last pick, catching and processing to reduce contamination of the offloading site.

* Feed companies are advised against multiple stop deliveries, and left-over feed should not be collected and reprocessed.

Catching crews should schedule infected flocks for the last catch of the night. To avoid the spread of infection, the crew needs to shower regularly, change clothing, disinfect vehicles and avoid stopping at restaurants and bars.

Service personnel should rely on the telephone and avoid farm visits as much as possible. If such a visit is necessary, service personnel should park some distance away, wear disposable biosecurity clothing and walk to the farm. Such visits to an infected flock should be scheduled for the end of the day.

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