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International Team Targets Newcastle Disease In Chickens

posted on May 9, 2014

The dreaded virus known as porcine (POUR-sign) epidemic diarrhea or P.E.D. is decimating America’s swine industry.

The virus thrives in cold weather, so the death toll in the U.S. soared over this past winter.  Data varies significantly on just how many pigs have died, but the USDA estimated recently that P.E.D. has played a major role in shrinking the nation’s herd by 3 percent to about 63 million pigs.

So far, there is no cure or an effective treatment.  And when the virus hits pig nurseries, reports of 90-to-100 percent mortality rates for swine less than 10 days old are not uncommon.

Biological threats, of course, are not uncommon in livestock production, but it’s been a decade since the U.S. last experienced a major outbreak of a poultry virus called Newcastle Disease.

Some developing nations, on the other hand, routinely battle outbreaks which have the potential to wipe out 75 percent of infected flocks.  But an international team of scientists is working to breed a variety of chicken that is more resistant to the virus.  Paul Yeager explains.

International Team Targets Newcastle Disease In Chickens

Scientists from the United States and Africa are teaming up to combat a disease capable of decimating a region’s poultry population. Newcastle Disease, the stronger forms of which can kill more than half of unvaccinated birds, can be particularly difficult for producers in developing nations.

Sue Lamont, Iowa State University: “In most cases, the real target for this work is going to be the smallholder farmers and the villagers. And so if they’re really having quite marginal economics and nutrition within their family and if they lose half of a good protein source that they were going to depend on that whole year, it is extremely devastating.”

The U.S. Agency for International Development’s “Feed the Future” program has awarded the scientists a $6-million grant. The team will study the genetic makeup of various chickens to determine what particular genes make some poultry more resistant to Newcastle Disease, the number one health issue affecting poultry production in Africa.

Newcastle Disease is a respiratory illness. Its symptoms include swelling around the eyes, and twisting of the head and neck. The virus causes only mild symptoms in humans, namely pink eye.

According to the World Animal Health Information Database, nearly 150,000 chickens and other domestic birds died of Newcastle Disease over the past two years. Another 1.5 million were destroyed or sent to the slaughterhouse to prevent the spread of the disease, which is highly contagious in birds. Cyprus, Israel and Libya are among the countries affected recently. The last outbreak in the United States, just over a decade ago, affected poultry in Arizona, California, Nevada and Texas. More than 3 million U.S. birds had to be destroyed.

Live-bird markets, such as this one filmed by the research team in Tanzania in early 2014, bring poultry from various villages into contact, helping spread the disease.

Sue Lamont, Iowa State University: "The weaker forms can be relatively well controlled with vaccination and routinely in the U.S. vaccines are used to protect poultry against this disease. But in developing parts of the world, there’s not enough infrastructure or there may not even be the pennies needed to buy vaccine to protect the birds."

In addition to Iowa State University, the 5-year study includes scientists from the University of California-Davis; the University of Delaware, and, in Africa, Sokoine University of Agriculture in Tanzania, and the University of Ghana.

The team will first study two lines of chickens: Leghorns, which are commonly used for egg production in the United States and are more susceptible to Newcastle disease; and Fayoumi, which have origins in Egypt and are relatively resistant to the virus. Researchers are trying to pinpoint the combinations of traits that appear to correspond with greater resistance. They will then analyze the DNA of individual chickens to understand how those seemingly relevant traits are passed on genetically.

Jack Dekkers, Iowa State University: “So once we have information on which, what genetics provides greater resistance to the disease, then we can go out and screen chickens and find the ones that have the right genes and then use those to breed the next generation of chickens.”

The scientists are looking for the same genetic makeup among African flocks in Africa to avoid introducing a breed which may not be as well-adapted to the environment, or with which African farmers may be unfamiliar. The team plans to also consider the chickens’ resistance to heat and drought.

Sue Lamont, Iowa State University: “They are interested in being sure that agriculture is ready to respond to the climate change, which we anticipate is coming, which will probably have more heat episodes in them.”

Scientists say this type of genomics work will likely lead to greater precision when breeding all kinds of livestock.

Jack Dekkers, Iowa State University:  "It is a new field that is very rapidly developing. The human genome was sequenced, and the chicken genome was sequenced in 2004. The chicken was the first livestock species for which we got the whole genome decoded. So it is all within the last decade that things have started, but it is developing very, very quickly."

“Feed the Future,” a U.S. government global hunger and food security initiative, is trying to emphasize genomics research in both crops and livestock.

Saharah Moon Chapotin, USAID: “We have had livestock and animal science research in our portfolio for many years, however, recently we wanted to increase our investment in the animal science area and so this year we awarded two new Feed the Future innovation labs: one focused on poultry and one focused on a livestock vaccine. It’s an area we are considering and thinking about how to strengthen our investments to ensure that households across the countries where we work have access to foods that have that high density of nutrition.”

In this case, the more resistant chickens will be provided to villagers in Africa, typically in association with a school. The children, as well as local women, will be trained on proper care of the birds.

Lindsay Parish, USAID: “Livestock in general, not just poultry, are sort of an investment. You can almost see them as a walking bank account.”

African women are more likely to be responsible for poultry rather than large livestock, and this research may ultimately help protect a source of income important to them and their families.

Saharah Moon Chapotin, USAID: “By increasing our investments and productivity of animals and of fish is a way to both address nutrition but also recognizes that animals are often a major asset to a household. And if they can increase the numbers of big and small animals that they keep, that gives them some resilience to economic stress.”

Jack Dekkers, Iowa State University: “The importance of having animals that can survive diseases is as great if not greater for those smallholder families than compared to our industry because their livelihood depends on it. It’s the same in North America, but it is life and death for their children.”

For Market to Market, I'm Paul Yeager.


Additional footage provided by International Livestock Research Institute (, USAID, United Nations, UC-Davis School of Veterinary Medicine, and Dmytriy Golumbevskiy.


Tags: Africa chickens food Iowa State Universtiy newcastle disease poultry virus