Disease Takes Its Toll On Waterfowl Populations

October 10, 1997

If U.S. Fish and Wildlife Service predictions hold, this year 92 million ducks will migrate south from their northern breeding grounds. Many factors will challenge the survival of these migrants, one of which is disease. According to Dr. Lynn Creekmore, hundreds of thousands of waterfowl are presently dying from avian botulism in flyway staging sites in southern Canada and the northern U.S.

Dr. Creekmore is a wildlife disease biologist at the U.S. Geological Survey's National Wildlife Health Center in Madison, WI. It is her job to monitor the occurrence of wildlife disease events in the U.S. Dr. Creekmore points out that avian botulism is the most serious disease of waterfowl in North America and quite likely the world.

The disease can produce massive annual mortality; during this year's fall migration, Canadian biologists are estimating the losses at one southern Saskatchewan lake to be as high as 300,000 to 500,000 birds. Also this year, at the Bear River Migratory Bird Refuge, along the shores of the Great Salt Lake, U.S. Fish and Wildlife Service biologists report waterfowl mortality from botulism has reached nearly 100,000 birds. Most recently, approximately 5,600 birds are believed to have died from botulism at a National Wildlife Refuge in Illinois. What is even more troubling is that the mortality is continuing and may not end until cold weather drives the birds further south.

Avian botulism is a disease of birds resulting from the ingestion of a paralyzing toxin produced by the bacterium, Clostridium botulinum type C. The toxin is closely related to botulism toxins A and B, which are responsible for a similar food-borne disease in humans. Affected birds lose coordination and show signs of paralysis of the legs and wings and labored breathing. In advanced stages of the disease, the birds cannot hold their heads up, and often drown or suffocate.

Most outbreaks of type C botulism occur in ducks, and species such as pintails, shovelers, and mallards are among those that suffer the greatest losses. However, almost all birds are susceptible to the disease, says Dr. Creekmore, and in recent years, losses in other species, including pelicans, herons, and egrets have been increasing. Dr. Tonie Rocke, a veteran scientist also at the USGS National Wildlife Health Center, who has spent years studying botulism explains, "Often the disease will occur in one wetland and not occur in an adjacent wetland just a few yards away. If we could determine the environmental factors that trigger the disease, we may be able to devise wetland management methods to lower the risk of outbreaks and reduce mortality."

Dr. Rocke and her colleagues have made significant progress in determining the conditions that are associated with avian botulism outbreaks. The organism is widely distributed in wetland sediments and factors such as acidity (pH), salinity, and temperature apparently play major roles in increasing or decreasing the risk of outbreaks. The next step is to determine if management actions influence these key environmental conditions.

The USGS National Wildlife Health Center is the foremost wildlife diagnostic and investigative facility of its type, devoted to identifying causes and possible management responses for episodes of death or debilitation among free-ranging wild creatures throughout the United States and, on a consulting basis, other nations.

As the nation's largest earth and biological science and civilian mapping agency, the USGS works in cooperation with more than 1,200 organizations across the country to provide reliable, impartial, scientific information to resource managers, planners, and other customers. This information is gathered in every state by USGS scientists to minimize the loss of life and property from natural disasters, contribute to wise economic and physical development of the nation's natural resources, and enhance the quality of life by monitoring water, biological, energy, and mineral resources of the nation.
-end-


US Geological Survey

Related Mortality Articles from Brightsurf:

Being in treatment with statins reduces COVID-19 mortality by 22% to 25%
A research by the Universitat Rovira i Virgili (URV) and Pere Virgili Institut (IISPV) led by LluĂ­s Masana has found that people who are being treated with statins have a 22% to 25% lower risk of dying from COVID-19.

Mortality rate higher for US rural residents
A recent study by Syracuse University sociology professor Shannon Monnat shows that mortality rates are higher for U.S. working-age residents who live in rural areas instead of metro areas, and the gap is getting wider.

COVID-19, excess all-cause mortality in US, 18 comparison countries
COVID-19 deaths and excess all-cause mortality in the U.S. are compared with 18 countries with diverse COVID-19 responses in this study.

New analysis shows hydroxychloroquine does not lower mortality in COVID-19 patients, and is associated with increased mortality when combined with the antibiotic azithromycin
A new meta-analysis of published studies into the drug hydroxychloroquine shows that it does not lower mortality in COVID-19 patients, and using it combined with the antibiotic azithromycin is associated with a 27% increased mortality.

Hydroxychloroquine reduces in-hospital COVID-19 mortality
An Italian observational study contributes to the ongoing debate regarding the use of hydroxychloroquine in the current pandemic.

What's the best way to estimate and track COVID-19 mortality?
When used correctly, the symptomatic case fatality ratio (sCFR) and the infection fatality ratio (IFR) are better measures by which to monitor COVID-19 epidemics than the commonly reported case fatality ratio (CFR), according to a new study published this week in PLOS Medicine by Anthony Hauser of the University of Bern, Switzerland, and colleagues.

COVID-19: Bacteriophage could decrease mortality
Bacteriophage can reduce bacterial growth in the lungs, limiting fluid build-up.

COPD and smoking associated with higher COVID-19 mortality
Current smokers and people with chronic obstructive pulmonary disease (COPD) have an increased risk of severe complications and higher mortality with COVID-19 infection, according to a new study published May 11, 2020 in the open-access journal PLOS ONE by Jaber Alqahtani of University College London, UK, and colleagues.

Highest mortality risks for poor and unemployed
Large dataset shows that income, work status and education have a clear influence on mortality in Germany.

Addressing causes of mortality in Zambia
Despite the fact that people in sub-Saharan Africa are now living longer than they did two decades ago, their average life expectancy remains below that of the rest of the world population.

Read More: Mortality News and Mortality Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.