Presence of humans, urban landscapes increase illness in songbirds

February 4, 2014

Humans living in densely populated urban areas have a profound impact not only on their physical environment, but also on the health and fitness of native wildlife. For the first time, scientists have found a direct link between the degree of urbanization and the prevalence and severity of two distinct parasites in wild house finches.

The findings are published in the Feb. 4 issue of the journal PLOS ONE. Two male house finches feed at an urban Phoenix backyard. Download Full Image

A team of researchers from Arizona State University made the discovery while investigating intestinal parasites (Isospora sp.) and the canarypox virus (Avipoxvirus) found in house finches. The group also studied the effects of urbanization on the stress response system of the finches.

Specifically, the team studied male house finches found at seven sites throughout Maricopa County in central Arizona. Each site varied in the number of people living within one kilometer (about five-eighths of a mile) – from nearly a dozen to over 17 thousand.

Researchers also considered whether the soil in each location had been disturbed and the vegetation cultivated or left in a natural state. In all, they quantified 13 different urbanization factors. They also assessed the potential relationship between oxidative stress, the degree of urbanization and parasitic infections to see whether increased infections are associated with increased stress levels.

"Several studies have measured parasite infection in urban animals, but surprisingly we are the first to measure whether wild birds living in a city were more or less infected by a parasite and a pathogen, as well as how these infections are linked to their physiological stress," said Mathieu Giraudeau, a post-doctoral associate who previously worked with Kevin McGraw, ASU associate professor with the School of Life Sciences. Giraudeau now works with the University of Zurich in Switzerland.

“We also capitalized on data gathered by the Central Arizona Phoenix-Long Term Ecological Research program to accurately measure the degree to which the landscapes at each study site were natural or disturbed by humans,” added Giraudeau.

House finches (Haemorhous mexicanus) are native to the desert southwest in the U.S., but are now found abundantly throughout North America. Male finches are five to six inches long and have colorful red, orange or yellow crown, breast and rump feathers.

Emerging infectious diseases transmitted from animals to humans

According to the study, more than half of the world’s population now lives in cities. Natural habitats and ecosystems have been dramatically altered from their original states, and there is rising concern about the spread of diseases that can be passed from urban wildlife to humans. Research also shows as much as 75 percent of the world’s emerging infectious diseases are zoonoses – those that can be transmitted from animals to humans.

“Much like the spread of human disease in populated areas, urban centers can foster increases in multiple disease types in wild animals,” said McGraw, senior author of the study. “We are now investigating the mechanism underlying this observation – are urban animals immuno-compromised and less able to fight off infections than rural ones? Or, do they acquire more disease because of increased contact with other, infected animals?"

Loss of natural habitats may drive avian parasite infections

The researchers found that the presence and seriousness of gastrointestinal parasitic infections were higher in more urbanized areas with land covered by compact soil and cultivated vegetation. Also, birds from sites with more cultivated vegetation were heavier – and significantly, heavier birds were more infected by the parasite. These internal parasites, called coccidians, live in a bird’s gut and disrupt the animal’s ability to get nutrients.

They also found that the percentage of poxvirus infections was higher in more human-populated areas, but did not find a connection to oxidative stress. The avian poxvirus, somewhat like the chicken pox virus in humans, causes lesions on the body – mostly on the feet, eyes, wings and ears, which in the late stages maybe become bloody and crusty, and lead to the loss of digits.

"Our careful analyses of land-use characteristics reveal that decreases in natural habitat may be a driving force behind increases in avian parasite infections. The same may be true in other animals. Because disease is so critical to the survival of wild animals, this is a real concern,” added McGraw. “We need to improve our understanding of how specific anthropogenic disturbances in cities are affecting the evolution of parasites and their hosts."

The authors are continuing their study of urban impacts on finches – emphasizing the behavioral and immunological impacts of humans and urban parasites on the birds.

The study was supported by two National Science Foundation grants: IOS-0923694, and BCS-1026865 with the Central Arizona  Phoenix Long-Term Ecological Research program, as well as a grant from the School of Life Sciences Undergraduate Research program.

ASU School of Life Sciences is an academic unit of ASU College of Liberal Arts and Sciences.

Sandra Leander

Manager, Media Relations and Marketing, School of Life Sciences


New gift supports actuarial science at ASU

February 4, 2014

The School of Mathematical and Statistical Sciences at Arizona State University has received a gift provided by Blue Cross Blue Shield of Arizona to support the school’s new actuarial science program.

The Phoenix-based insurance company has established the Blue Cross Blue Shield of Arizona Actuarial Science Scholarship. The company contributed $30,000 to endow the scholarship to support a School of Mathematical and Statistical Sciences student specializing in actuarial science. Download Full Image

The scholarship is the first at the School of Mathematical and Statistical Sciences that specifically benefits actuarial science majors. The school’s new actuarial science program, which is accepting students for fall 2014, will train qualified graduates to earn professional actuarial credentials, thus enhancing the workforce for insurance companies and other organizations. ASU offers the only undergraduate actuarial degree program in Arizona, and one of only a few such programs in the inter-mountain west.

Housed at the School of Mathematical and Statistical Sciences, the bachelor of science in actuarial science program was established to give students a strong background in mathematics, statistics and business. Students must pass a series of exams to become certified actuaries. The first several exams can and should be attempted during their undergraduate studies. The remaining exams can be completed while on the job.

“We’re proud to establish this scholarship in support of the School of Mathematical and Statistical Sciences and its students,” said Sandy Gibson, executive vice president and former chief actuary at Blue Cross Blue Shield of Arizona, who began her actuarial science career at ASU. A member of the new ASU Actuarial Advisory Board, Gibson added, “By providing support for the students in this new actuarial science degree at ASU, we are investing in the development and growth of the next generation of actuaries.”

Al Boggess, director of the school, said the gift “will help qualified undergraduates pursue this new degree which will prepare them for one of the most lucrative careers in the country. I sincerely thank Blue Cross Blue Shield of Arizona for their generosity.”

The first Blue Cross Blue Shield of Arizona Actuarial Science Scholarship of $1,000 will be awarded this fall to a full-time undergraduate actuarial science student at the junior or senior level. Recipients will be known as the Blue Cross Blue Shield of Arizona Actuarial Scholars.

Blue Cross Blue Shield of Arizona, an independent licensee of the Blue Cross and Blue Shield Association, is the largest Arizona-based health insurance company. The not-for-profit company was founded in 1939 and provides health insurance products, services or networks to more than 1.2 million individuals.

The School of Mathematical and Statistical Sciences is an academic unit in the College of Liberal Arts and Sciences. 

Rhonda Olson

Manager of Marketing and Communication, School of Mathematical and Statistical Sciences