Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Identifying the time of HIV infection

20.01.2011
Genetic variety of the virus causing AIDS as a time indicator

Researchers of the Swiss HIV Cohort Study have identified a simple method to establish when a patient contracted the virus causing . The time of infection can be of importance for the treatment of the illness and it contributes to the understanding of the course of the epidemic.

Medical doctors rarely know when a patient contracted HIV. The exact point in time can only be established in the first eight weeks after infection – during the so called acute phase. If the HIV test is taken later, it remains unclear if the infection took place three months or ten years ago. But this is about to change as researchers supported by the Swiss National Science Foundation (SNSF) have discovered a simple method to determine the approximate time of infection.

Relevant to understanding the spread of the illness
According to Huldrych Günthard from the university hospital in Zurich, information regarding the time of infection is beneficial in many ways. It allows doctors to establish how quick the illness is progressing and to determine the start of treatment accordingly. It will also inform epidemiological studies interested in how the disease is spreading.

In collaboration with colleagues from the ETH Zurich, researchers of the Swiss HIV Cohort Study analysed data that is obtained in routine resistance tests. These tests examine the genetics of the virus to establish its resistance to drugs. If a patient carries a variety of HIV strains, the test reveals ambiguous results with regard to certain points in the sequences of the virus’ genetic code.

By-product of resistance testing
"For a long time, the ambiguous results of the viral sequencing were considered a by-product of the test," says Günthard. "We wondered if they were an indicator of the variety of viruses in the blood." Viral variety is a result of reproduction and evolution in the body, it increases with time and the ambiguity could therefore be an indicator for the time that has passed since infection. Günthard and his team tested this assumption by comparing the drug resistance data with an existing rudimentary method to calculate the time of infection. Additionally there are patients who know the exact time of HIV infection: e.g. patients who took the test during the acute phase or patients who took tests before and after the infection.

The study, that has now been published in the journal "Clinical Infectious Diseases", was able to show that the proportion of ambiguous sequences is indeed increasing regularly during the first eight years after infection, afterwards the increase slows down. At the moment the new method is still too imprecise to establish the exact time of infection but the researchers were able to define a threshold level that indicates with 99 percent certainty if an infection happened more than a year ago.

(*) Roger D. Kouyos, Viktor von Wyl, Sabine Yerly, Jürg Böni, Philip Rieder, Beda Joos, Patrick Taffé , Cyril Shah, Philippe Bürgisser, Thomas Klimkait, Rainer Weber, Bernard Hirschel, Matthias Cavassini, Andri Rauch, Manuel Battegay, Pietro L. Vernazza, Enos Bernasconi, Bruno Ledergerber, Sebastian Bonhoeffer, Huldrych F. Günthard and the Swiss HIV Cohort Study (2011). Ambiguous Nucleotide Calls From Population-based Sequencing of HIV-1 are a Marker for Viral Diversity and the Age of Infection. Clinical Infectious Diseases online. doi: 10.1093/cid/ciq164 (als PDF beim SNF erhältlich; E-Mail: pri@snf.ch)

Swiss HIV Cohort Study
Established in 1988, the study aims to expand our understanding of the illness and to improve patient care. All Swiss hospitals specialising in HIV (Basel, Bern, Geneva, Lausanne, Lugano, St. Gallen and Zurich) have gathered and analysed data regarding the course of the illness from over 16,000 HIV positive persons. Currently more than 7500 people participate in the Swiss HIV Cohort Study, almost a third are women.

www.shcs.ch

Contact:
Prof. Dr. med. Huldrych Günthard
Klinik für Infektionskrankheiten und Spitalhygiene
Universitätsspital Zürich
Rämistrasse 100
8091 Zürich
Tel.: +41 (0)44 255 34 50
E-Mail: huldrych.guenthard@usz.ch

| idw
Further information:
http://www.snf.ch

More articles from Health and Medicine:

nachricht Nanoparticles as a Solution against Antibiotic Resistance?
15.12.2017 | Friedrich-Schiller-Universität Jena

nachricht Plasmonic biosensors enable development of new easy-to-use health tests
14.12.2017 | Aalto University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Error-free into the Quantum Computer Age

A study carried out by an international team of researchers and published in the journal Physical Review X shows that ion-trap technologies available today are suitable for building large-scale quantum computers. The scientists introduce trapped-ion quantum error correction protocols that detect and correct processing errors.

In order to reach their full potential, today’s quantum computer prototypes have to meet specific criteria: First, they have to be made bigger, which means...

Im Focus: Search for planets with Carmenes successful

German and Spanish researchers plan, build and use modern spectrograph

Since 2016, German and Spanish researchers, among them scientists from the University of Göttingen, have been hunting for exoplanets with the “Carmenes”...

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

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...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Single-photon detector can count to 4

18.12.2017 | Information Technology

Quantum memory with record-breaking capacity based on laser-cooled atoms

18.12.2017 | Physics and Astronomy

How much soil goes down the drain -- New data on soil lost due to water

18.12.2017 | Agricultural and Forestry Science

VideoLinks
B2B-VideoLinks
More VideoLinks >>>