Veterinary entomologist Greg Johnson of Montana State University said earlier this year that he considered the possibility that lice were transmitting West Nile virus to pelicans. He became suspicious after collecting very few mosquitoes in 2006, but seeing pelicans continue to die at a high rate. Johnson discovered previously that the Culex tarsalis mosquito is the primary carrier of West Nile virus in Montana and that the Medicine Lake refuge was one of the hot spots for the virus.
Many of the dead pelicans at Medicine Lake had lice crawling inside and outside of their beak, Johnson continued. Mike Rabenberg, deputy refuge manager, said external parasites -- especially pouch lice and feather lice -- are common on the Medicine Lake pelicans. The lice may be more prevalent, he said, on pelicans that are sick or weakened.
The lice were cleared, however, after Johnson sent pelican tissue samples and lice to the Centers for Disease Control and Prevention in Fort Collins, Colo. The lab tested approximately 800 lice, but none was found to have West Nile even though most came from pelicans that tested positive.
Stable flies caught Johnson's attention when he came across a bird with blood on its neck and some flies feeding on the blood during the third week of July. Stable flies look like common house flies, but they have a painful bite. They come from a different family than horse flies or deer flies, however.
"This (the stable fly scene) was very unusual because stable flies are only reported to feed on domestic livestock, humans and companion animals," Johnson said. "There are no reports in the literature of stable flies feeding on domestic or wild birds."
Johnson observed the stable flies feeding on birds several more times. He also collected about 1,300 flies and divided them into 60 groups. Eighteen of those groups tested positive for West Nile virus.
"This is the first report of stable flies feeding on wild birds, or pelicans for that matter, and the first report of stable flies infected with West Nile virus," Johnson said. "These results suggest that stable flies might be involved in amplification and/or transmission of West Nile virus at the pelican colony and possibly could serve as a vector of West Nile virus to other pelicans."
If the theory proves correct, he will have to modify some of his study methods because they currently focus on mosquitoes, Johnson said. He added that the number of captured mosquitoes was high this summer, as well as the West Nile infection rate in those mosquitoes.
As far as the relationship among lice, pelicans and West Nile virus goes, Johnson said the lice created wounds that could be a point of entry for the virus, however they don‛t pass along the virus.
"I don't think they are playing a primary role in West Nile transmission because they don't have to have blood for egg development, energy and survival," Johnson said. "Rather, they feed on epidermal or skin cells which creates wounds, causing blood to exude and then they feed on the blood. The wounds they cause may provide entry sites for West Nile virus, and the young pelicans can get infected that way."The Medicine Lake National Wildlife Refuge between Plentywood and Culbertson contains the fifth largest colony of American white pelicans in North America. Rabenberg said the colony normally includes 8,000 to 10,000 breeding adults and approximately 4,000 nests. The adult pelicans fly up to 150 miles one way a day looking for food. The Medicine Lake adults fly to other mosquito-rich areas like Terry, the Fort Peck Reservoir and the Yellowstone River. They fly into Saskatchewan and North Dakota. The adult pelicans typically winter along the Gulf coast, but some reach southern Mexico.
Evelyn Boswell | EurekAlert!
Value from wastewater
16.08.2017 | Hochschule Landshut
Species Richness – a false friend? Scientists want to improve biodiversity assessments
01.08.2017 | Carl von Ossietzky-Universität Oldenburg
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences