Richard Bogren, Elzer, Philip H. | 9/25/2012 12:41:44 AM
News Release Distributed 09/24/12
An LSU AgCenter researcher is in the forefront of a worldwide effort to protect domestic livestock from the threat of brucellosis. He is continuing a program that has focused on researching the Brucella bacteria for more than 30 years.
“Brucellosis is controlled in domestic animals in the United States,” said AgCenter researcher Phil Elzer. “The threat now is through a reservoir in wildlife.”
Domestic cattle and swine herds in the United States are considered brucellosis-free, but the economic impact of an outbreak could be in the range of $500,000.
Worldwide, brucellosis also is an economic and human health issue.
A bacterial disease that for many years infected U.S. cattle and swine, brucellosis also is known as contagious abortion or Bang’s disease. The disease causes spontaneous abortions, infertility and lowered milk production. It also can spread to humans, where it’s called undulant fever.
Brucellosis comes in many forms. Some species infect cattle; others infect sheep and goats; and some infect swine. The disease spreads among cattle and similar animals through contact with bodily fluids, including aborted fetuses.
“In most instances the only sign of infection in cattle is reproductive failure due to abortions, thus the disease is usually considered a female disease,” Elzer said. Otherwise-healthy animals contract the disease either from their mothers at birth or through contact with the aborted fetuses, afterbirth or the milk of infected females.
“Infected cattle and swine may remain carriers for life,” he said. “The bacteria can hide in the lymph glands of infected animals for years.”
Because commercial hog herds in the United States are in confinement, brucellosis isn’t a problem with them. But it can be with feral hogs.
“Brucellosis hasn’t gone away in the United States,” Elzer said. “It’s been eradicated in cattle, but we still see outbreaks.”
Elzer, a world-renown brucellosis expert, has traveled to Central and Eastern Europe to help scientists there control the disease and has been working with the Consortium for the Advancement of Brucellosis Science to address the disease in U.S. wildlife.
“The disease has a huge economic impact in the developing world,” Elzer said.
Goats and sheep comprise the primary source for meat, milk and fiber in many countries. These animals also are susceptible to brucellosis, which can lead to reproductive failure.
This can be devastating in areas where people depend on these animals, Elzer said. An estimated 500,000 people are infected by brucellosis in the world every year from contact with animals, from unsanitary food and fiber and from unpasteurized milk.
People who develop the disease begin with flu-like symptoms that then lead to greater complications, including joint and muscle problems. Although the disease is persistent and debilitating, it’s not generally fatal and can be treated with antibiotics.
To address the worldwide problem, Elzer works with scientists around the globe. He recently visited Kazakhstan, working with scientists there on a grant from the U.S. Department of Defense to help them develop diagnostic tools to identify the bacteria. He also has conducted training for scientists in Kosovo, the Republic of Georgia, Azerbaijan and Uzbekistan.
The most effective way to control brucellosis is by vaccinating animals. LSU AgCenter researchers were instrumental in evaluating a leading vaccine, and in February 1996 the U.S. Department of Agriculture Animal and Plant Health Inspection Service licensed Brucella abortus strain RB51 vaccine for use in cattle as part of the cooperative State-Federal Brucellosis Eradication Program.
The vaccine has been effective in controlling brucellosis in domestic cattle, but no vaccine is 100 percent effective, Elzer said. And the disease persists in elk and bison in the Northwest.
Brucellosis in cattle and domestic hogs has been eradicated in Louisiana and much of the United States, but the disease continues to present a struggle in cattle in Wyoming, Montana and Idaho.
According to the Consortium for the Advancement of Brucellosis Science, the last remaining source of brucellosis in the United States is in free-ranging bison and elk in the Greater Yellowstone Area, where it threatens the cattle industry.
A member of the consortium, Elzer was part of a group of experts who earlier in 2012 met to discuss and plan how the disease can be addressed in the wild.
Although all domestic cattle herds in the Greater Yellowstone Area have been vaccinated, experts believe brucellosis from wild bison and elk can still infect these animals. Because of this possibility, researchers are testing a vaccine in free-ranging elk and comparing their immune responses with vaccinated cattle.
The challenge, Elzer said, is trying to vaccinate wild animals. And because the type of brucellosis in wild elk and bison is the same one that infects cattle, it’s a national and international concern.
If a vaccine doesn’t work 100 percent, any animal with brucellosis susceptibility can cause a breach. “It’s in the wildlife,” Elzer said. “We still need research to solve problems.”Rick Bogren