Wednesday, October 18, 2017

Usutu virus

At least according to me flavivirus members are one of the most difficult to understand classification. Thats because, they have so many different types of viruses by their characters and too many different types. Almost every virus in this group has at least a part of its life cycle in an animal. Once in a while they pop up in a limited geographical region and are noticed by the global infection research community.

Photo 1: Eurasian blackbird (Turdus merula).
Source
One such virus which has recently grabbed some attention is Usutu virus. Usutu virus (USUV) is a member of flavivirus closely resembling Japanese encephalitis complex. It is a Group IV member, with + single stranded RNA genome. It was first identified in South Africa in 1959. USUV first came into significant notice in 2001 when there was a massive black bird mortality in eastern Vienna, Austria. Subsequently, this virus has been identified in several geographical locations. But until now, USUV was thought to be limited to bird population, except for 4 confirmed cases in humans ever to be reported. In a surveillance study, in Austria, 54 of 208 individuals tested positive for USUV-neutralizing antibodies, thus indicating exposure.
Fig 1: Phylogenetic analysis of several members of the 
JEV group and selected other mosquito-borne flaviviruses.
As a part of blood screening program in Austria, samples from July to August 2017, 12047 blood samples from donors in eastern Austria was screened for West Nile virus (WNV) infection. Of these 7 samples were found to be positive for WNV by nucleic acid testing. WNV positive samples were follow up tested by WNV- and Usutu virus (USUV)-specific RT- and RT-qPCR assays for confirmation, which showed that of the 7 positive, 6 were USUV positive only one was WNV positive. This was further confirmed using sequence analysis. Interestingly, none of these donors had or later developed any clinical symptoms.

Norbert Nowotny from Austria who is an author in the most recent paper on USUV comments, "Flavivirus-positive blood donations, both West Nile and Usutu virus positives are discarded and consequently do not pose any risk to recipients of blood donations. However, there are a number of European countries, in which West Nile virus infections did not yet occur but in which Usutu virus circulates. In these countries blood donations may not be screened for flaviviruses. On the other hand, blood recipients are frequently immunocompromised persons, in which an Usutu virus infection may result in severe disease. To increase awareness of this possibility was one of the main goals of our second study".

Considering that USUV seropositivity and genetic evidence of virus in healthy blood samples are found without any associated clinical symptoms it currently appears unlikely that this virus is significantly causing a human infection. But, given its close genetic relatedness to JEV and WNV, the virus can make a jump anytime, which is proposed to be monitored.

Reference:

Bakonyi T, Jungbauer C, Aberle S, Kolodziejek J, Dimmel K, Stiasny K et al. Usutu virus infections among blood donors, Austria, July and August 2017-Raising awareness for diagnostic challenges. Eurosurveillance. 2017;22(41).

Ashraf U, Ye J, Ruan X, Wan S, Zhu B, Cao S. Usutu Virus: An Emerging Flavivirus in Europe. Viruses. 2015;7(1):219-238.

Bakonyi T, Erdélyi K, Brunthaler R, Dán Á, Weissenböck H, Nowotny N. Usutu virus, Austria and Hungary, 2010-2016. Emerg Microbes Infect. 2017 Oct 11;6(10):e85. doi: 10.1038/emi.2017.72.

Thursday, October 05, 2017

Nobel Awards- 2017

Nobel Prize is considered as the most prestigious award for research accademics. The recipients of the award are chosen by the Nobel foundation constituted by Nobel committee of Royal Swedish Academy of Sciences, Nobel committee of Karolinska Institutet and Norwegian Nobel Committee. The award consists of a citation, gold medal and money. More than the award amount, the fame is considered as far superior.

1. Physiology / Medicine:

Photo 1: Michael Rosbash (left), Jeffrey Hall (centre)
and Michael Young (right). Source
The award goes to three scientists- Jeffrey Hall and Michael Rosbash (from Brandeis University Waltham, Massachusetts) and Michael Young (Rockefeller University) for their studies on circadian clocks. Circardian rhythm in simplest terms is a endogenous, entrainable biological system which oscillates over a period of cycling time aproximately 24hrs. It is widely seen across species from cyanobacteria to humans. The field of study called as "Chronobiology" has been shown to have important affects including human health. The functioning of circardain rhythm has been  shown to be strongly affected in conditions such as sleep disorders and several mental health disorders such as Schizophrneia.

2. Physics:

Photo 2: Rainer Weiss (left), Barry Barish (centre), and
Kip Thorne (right). Source
This award has been announced to three scientists- Rainer Weiss (Massachusetts Institute of Technology, Cambridge), Barry Barish and Kip Thorne (California Institute of Technology, Pasadena) for their work on detection of gravitational waves at Laser Interferometer Gravitational Wave Observatory (LIGO). Gravitational waves are ripples in the curvature of space-time that are generated in certain gravitational interactions and propagate as waves outward from their source at the speed of light. This phenomenon was predicted in 1916 by Albert Einstein on the basis of his theory of general relativity. Basically, when 2 massive objects such as black holes collide with each other they distort the space time around which travels through space. The pattern of this wave helps understand several astrophysical phenomenon.

3. Chemistry:

Photo 3: Jacques Dubochet (left), Joachim Frank (centre)
and Richard Henderson (right). Source
The award has been given to Richard Henderson (MRC Laboratory of Molecular Biology, Cambridge) Joachim Frank (Colombia university), and Jacques Dubochet (University of Lausanne, Switzerland) helped to develop cryo electron microscopy. Cryo-electron microscopy  or famously referred to as cryo-EM is a type of electron microscopy where the sample is studied at highly frozen temperatures. Cryogenic processing gets around the problem of treating the cells or molecules with several reagents, instead it could be seen in its native form. Cryo EM is now commonly used to study structure of viruses and there are extended 3D versions of the technique. Cryo EM- method is also slowly replacing X ray crytsallography method to study biomolecule structure.

Apart from the above Nobel Prize in Literature, Nobel Peace Prize and Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel are given, for which the winners are yet to be announced as of at the time of writing this post.