Navigation Links
HIV-1 spread through six transmission lines in the UK

Contrary to the prevailing belief that the HIV epidemic in the UK can be traced back to one source, a new study suggests that HIV spread via at least six independent virus introductions and subsequent transmission chains. The findings, published in the latest issue of the Proceedings of the National Academy of Sciences, also suggest that antiviral therapy has not had a significant impact on the growth of the epidemic and that changes in sexual behaviour have been more effective in slowing the spread of the disease.

The collaborative study led by University College London (UCL) scientists found that HIV-1 subtype B spread through the UK via at least six large transmission chains of men having sex with men, suggesting separate introductions of subtype B strains into the UK in the early-to-mid 1980s. After an initial period of exponential growth in infection rates, the spread generally slowed in the early 1990s, more likely from changes in sexual behaviour than from reduced infectiousness resulting from antiretroviral therapy.

The study by UCL, the Health Protection Agency and the University of Oxford statistically analysed the epidemic history of the HIV-1 subtype B strain from sampled gene sequence data. Molecular data on HIV-1 has become increasingly available since the introduction of routine HIV-1 gene sequencing for drug resistance. Scientists used this data to follow the changing number of infected individuals through time and estimate the demographic parameters shaping the epidemic.

During the exponential growth phase, the transmission chains had an average growth rate of a doubling of the number of people infected each year, similar to that estimated for the US subtype B epidemic during the 1980s. The average number of infections across each chain was 445, approximately 2.5% of the infected population at the time. This trend is remarkably similar to the values for the US epidemic, where the number of transmitted infections and prevalence in 1995 reached 5000 and 200,000 infections respectively.

The most recent transmission chain identified by the study shows a faster doubling time in 2003 than the other five. Current surveillance data shows a recent increase in infections amongst homosexual men in the UK , which may partly have come through this chain.

Dr Deenan Pillay of UCL's Centre for Virology says: “Our study suggests that the HIV-1 subtype B epidemic currently circulating the UK is made up of at least six established chains of transmission, introduced in the early and mid 1980s. This goes against the prevailing belief that one initial entry of HIV-1 was responsible for the spread of the epidemic.

“Since 1990 there have been important changes in Britain's social attitudes and awareness of HIV-1 and AIDS. Despite a very recent increase in high-risk behaviour among men having sex with men, a significant increase in condom use has been reported since 1990, which could explain the equilibrium reached for the number of infections.

“Antiretroviral therapy may also have impacted on transmission rates, but our evidence does not demonstrate this. You would expect growth rates to decrease in the late rather than early 1990s around the time that potent therapy became widely used if this was the case. Instead, we see little correlation between widespread availability of treatment and reduction of transmission. This is highly pertinent to the recent increase again in new HIV-1 diagnoses within the UK .

“Our study also contradicts assumptions that the HIV-1 epidemic is composed of smaller, independent epidemics defined by risk group, where we have found evidence for at least six larger sub-epidemics, which HIV monitoring, prevention and treatment programmes may want to take into account when developing new initiatives.?/p>

More than 57,700 people in Britain have been infected with human immunodeficiency virus type 1 or HIV-1 since the first identification of A ID S in 1982. Despite a recent increase in heterosexually acquired infections within the UK , predominantly originating in sub- S aharan A frica , one of the most prevalent clades (subtypes) of virus within the country remains subtype B, which is mainly transmitted through sex between men. Very little is known about how subtype B successfully invaded the British population, and more importantly, how the virus has subsequently spread and evolved.

However, given that the first UK cases of AIDS reported in 1982 were probably infected within a window of 10 years prior to that time, the currently circulating strains may not represent the first HIV-1 lineages within the UK . If earlier strains existed they may have been unsuccessful in sustaining transmission to the present, although the absence of older strains could also reflect a sampling bias in this study.


'"/>

Source:UCL


Related biology news :

1. Research advances quest for HIV-1 vaccine
2. Ancient immune defense mechanism is no match for HIV-1
3. UAB researchers confirm HIV-1 originated in wild chimpanzees
4. HIV-1s high virulence might be an accident of evolution
5. Human testis harbors HIV-1 in resident immune cells
6. HIV-1 kills immune cells in the gut that may never bounce back
7. Researchers discover new details about HIV-1 entry and infection
8. Anti-bacterial additive widespread in U.S. waterways
9. Reservoirs may accelerate the spread of invasive aquatic species, researchers say
10. Undesirable expatriates: Preventing the spread of invasive animals
11. Nanobacteria in clouds could spread disease, scientists claim
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/7/2017)... March 7, 2017 Brandwatch , the leading social ... The Prince,s Trust to uncover insights to support its reporting, ... The UK,s leading youth charity will be using Brandwatch ... and get a better understanding of the topics and issues that ... ...
(Date:3/6/2017)... March 6, 2017 Mintigo , ... today announced Predictive Sales Coach TM , its ... sales intelligence into Salesforce. This unique AI application ... sales organizations with deep knowledge of their customers ... intelligent engagement. Predictive Sales Coach extends Mintigo,s existing ...
(Date:3/2/2017)... Summary This report provides all the information ... partnering interests and activities since 2010. Download the ... Deals and Alliance since 2010 report provides an in-depth ... world,s leading life sciences companies. On demand ... of the most up to date deal and company ...
Breaking Biology News(10 mins):
(Date:3/27/2017)... , March 27, 2017 DarioHealth Corp. (NASDAQ: ... health and big data solutions, today announced that it ... coverage option for U.S. consumers who want to have ... DarioHealth has signed strategic alliance agreements with partners across ... coverage benefits, and if approved, will supply and bill ...
(Date:3/24/2017)... DUBLIN , Mar. 24, 2017 Research ... Stem Cell (hESC) Research - Global Strategic Business Report" report ... ... Cell (hESC) Research in US$ Million. Annual estimates and forecasts are ... are derived from primary and secondary research. The ...
(Date:3/24/2017)... Agenus Inc. (NASDAQ: AGEN), an immuno-oncology company ... vaccines, today announced participation at the following conferences: ... and Maidstone Life Sciences conference "Cancer Immunotherapy Conference" at ... New York, NY . Agenus will participate in ... am: Robert B. Stein , M.D., Ph.D., President, ...
(Date:3/23/2017)... March 23, 2017  Northwest Biotherapeutics (OTCQB: NWBO) ... immune therapies for solid tumor cancers, today announced ... financing it announced last Friday, March 17, 2017. ... institutional investors securities totaling 28,843,692 shares, comprised of ... 10,000,000 shares of Class C Warrants pre-funded at ...
Breaking Biology Technology: