Avian malaria is not uncommon in Central Europe, as many endemic wild birds are infected with species of Plasmodium, which cause avian malaria. In most cases these blood parasites, transmitted by mosquitoes, do not produce any symptoms in endemic birds, as they have adapted to the parasites. A team of pathologists at the Vetmeduni Vienna recently showed for the first time that native birds, too, are susceptible to avian malaria. The data collected was published in the journal Parasitology Research.
In the summers of 2001 and 2004, blackbirds died on a massive scale in Austria. At that time, researchers at the Vetmeduni Vienna analysed more than 600 deceased birds and identified the Usutu virus as the cause of death. The birds had been collected in a regional effort by Austrians and were handed over to the scientists at the Vetmeduni Vienna.
Developmental stages of Plasmodium in a blood vessel of the brain, which have led to an almost complete vessel occlusion.
Photo: Herbert Weissenböck / Vetmeduni Vienna
More than ten years later, the researchers tapped once more into the extensive sample material to test the birds that died back then for avian malaria. Until then, only birds kept at Austrian zoos and originating from countries without mosquitoes had been known to be affected by avian malaria. These types of birds at the zoo typically live in Antarctica and the far north, so they have not had the evolutionary opportunity to adapt to avian malaria.
“An infection is life-threatening for penguins at a zoo, for example,” says lead author Herbert Weissenböck. “Native birds have adapted to the blood parasites over evolutionary time. Most of them carry the pathogen, but do not contract the disease. At least that’s what we thought.”
Avian malaria found in 15 percent of the examined birds
The researchers studied organs such as the liver, spleen, lungs and brain of 233 dead birds collected during the regional action programme. They found that some 15 percent of these specimens were infested with Plasmodium to such an extent that their organs were already damaged. Consequently, the researchers assume that the cause of these deaths was avian malaria.
Endemic populations of wild birds, however, are not at risk, believes Weissenböck. “Probably, only a small part of the population consistently dies of avian malaria. This has no dramatic effect on the overall population. But it is a completely new fact that native birds are susceptible at all.”
Three different Plasmodium species identified
Around 100 different Plasmodium species are known to exist. Weissenböck and primary author Nora Dinhopl identified three species in the examined birds: P. elongatum, P. vaughani and a type related to the South American P. lutzi. This new species still needs to be analysed and classified. Surprisingly a fourth subspecies quite frequent in Central Europe, P. relictum, was not present in the dead animals. “It is possible that the P. relictum found thus far does not cause as severe symptoms. We attribute the deaths to the first three subgroups”, Weissenböck reports.
Diagnostic method developed
Weissenböck and his team used a special RNA staining method that enabled them to examine the organs of dead birds. A special stain only binds to parasite RNA in tissue sections and therefore visualizes Plasmodium.
The pathologists want to further refine this method to be able to differentiate individual parasite subspecies. “Malaria is generally diagnosed in blood. Experts can see Plasmodium in red blood cells under the microscope. This was no option for the samples from our archives though. We would like to optimise our RNA staining process for blood samples as well. This would give us a sure-fire method for identifying different parasites in blood too”, Weissenböck emphasises.
Plasmodium decimates mosquitos too
The parasite is also apparently problematic for mosquitos. In a recently published study, Lithuanian partners to the University of Veterinary Medicine Vienna demonstrated that a high load of Plasmodia is also lethal to the insects. (http://link.springer.com/article/10.1007%2Fs00436-013-3733-4). “This is probably one way the mosquito population is naturally reduced every year”, says Weissenböck.
The article ” In situ hybridization and sequence analysis reveal an association of Plasmodium spp. with mortalities in wild passerine birds in Austria”, by Nora Dinhopl, Nora Nedorost, Meike M. Mostegl, Christiane Weissenbacher-Lang and Herbert Weissenböck was published in the journal Parasitology Research. http://link.springer.com/article/10.1007/s00436-015-4328-z
About the University of Veterinary Medicine, Vienna
The University of Veterinary Medicine, Vienna in Austria is one of the leading academic and research institutions in the field of Veterinary Sciences in Europe. About 1,300 employees and 2,300 students work on the campus in the north of Vienna which also houses five university clinics and various research sites. Outside of Vienna the university operates Teaching and Research Farms. http://www.vetmeduni.ac.at
Institute of Pathology and Forensic Veterinary Medicine
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-2418
Science Communication / Public Relations
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-1153
Dr. Susanna Kautschitsch | idw - Informationsdienst Wissenschaft
BigH1 -- The key histone for male fertility
14.12.2017 | Institute for Research in Biomedicine (IRB Barcelona)
Guardians of the Gate
14.12.2017 | Max-Planck-Institut für Biochemie
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
14.12.2017 | Health and Medicine
14.12.2017 | Physics and Astronomy
14.12.2017 | Life Sciences