'Transport infrastructure' determines spread of HIV subtypes in Africa

December 4, 2012, Wolters Kluwer Health

Road networks and geographic factors affecting "spatial accessibility" have a major impact on the spread of HIV across sub-Saharan Africa, according to a study published online by the journal AIDS, official journal of the International AIDS Society.

Using sophisticated and detailed databases, Dr Andrew J. Tatem of the University of Florida and colleagues have found "coherent spatial patterns in -1 subtype distributions" across Africa. The researchers write, "A comprehensive understanding and evidence-base on accessibility, travel and mobility in resource poor settings would…provide a valuable resource for the strategic planning of disease control." The article is available on the AIDS journal homepage and in the November 28 print edition.

Molecular HIV Data Overlaid on Spatial Accessibility Maps…

Dr Tatem and his team performed a spatial analysis of the distribution of HIV for the years 1998 to 2008 to explore the impact of transportation networks and geography on the spread of HIV. Molecular data on specific HIV subtypes were obtained and analyzed in relation to "detailed and complete" spatial datasets on Africa-wide road networks.

In addition to roads, the data included a wide range of factors affecting "spatial accessibility," such as land cover, settlement locations, bodies of water, and topography. Sophisticated models were used to calculate not just the distance between locations, but also the ease of traveling from one place to another.

Even simply laying a chart of HIV subtypes over a map of travel times between settled areas makes the link between spatial accessibility and HIV subtype "clearly evident." Dr Tatem and coauthors write, "[C]lusters of similar subtype distributions are well connected and easily accessible from one another, whereas regions of low accessibility separate groupings of similar subtype distributions."

…Show Role of Travel in Spread of HIV Subtypes

Transport networks and ease of travel—rather than the straight-line distances between locations—provided a much better explanation for the distribution of HIV subtypes. The data showed clustering of certain subtype distributions in well-connected regions—such as the western, eastern, and southern Africa and Ethiopia—that are separated by areas of "limited connectivity."

In contrast, the difficulty of travel in certain areas of central Africa likely restricted the spread of HIV, the researchers suggest. "The relatively poor connectivity in central Africa likely contributed to the slow initial growth of the epidemic in the first half of the 20th century," according to Dr Tatem and colleagues. The same factor may explain why HIV rates remained relatively low in central , while soaring elsewhere.

Although the study has some important limitations, it adds important evidence for understanding how transport infrastructure and geography have affected—and will continue to affect—the spread of HIV. The authors hope that the modeling techniques used can be extended to map cultural and other factors affecting HIV subtype distribution and transmissibility. More accurate data on "actual volumes and flows of human travel" could also lend new insights.

"The increased travel and mobility of people may lead to the accelerated spread of new variants and the further diversification of the global HIV epidemic," Dr Tatem and coauthors write. They believe that ongoing efforts to monitor the spread of HIV subtypes could have important implications for developing effective prevention and treatment strategies.

Explore further: New book on HIV from Cold Spring Harbor Laboratory Press

Related Stories

New book on HIV from Cold Spring Harbor Laboratory Press

December 15, 2011
The worldwide AIDS epidemic makes research on HIV, the disease processes it induces, and potential HIV therapies among the most critical in biomedical science. Furthermore, the basic biology of HIV infections provides a model ...

Hope for more options in couples where one partner is HIV positive

November 15, 2011
In sub-Saharan Africa, couples in long-term relationships where one partner is HIV-positive and the other is HIV-negative (HIV serodiscordant couples) could benefit from anti-AIDS drugs (antiretroviral therapy) given either ...

Recommended for you

War in Ukraine has escalated HIV spread in the country: study

January 15, 2018
Conflict in Ukraine has increased the risk of HIV outbreaks throughout the country as displaced HIV-infected people move from war-affected regions to areas with higher risk of transmission, according to analysis by scientists.

Researchers offer new model for uncovering true HIV mortality rates in Zambia

January 12, 2018
A new study that seeks to better ascertain HIV mortality rates in Zambia could provide a model for improved national and regional surveillance approaches, and ultimately, more effective HIV treatment strategies.

New drug capsule may allow weekly HIV treatment

January 9, 2018
Researchers at MIT and Brigham and Women's Hospital have developed a capsule that can deliver a week's worth of HIV drugs in a single dose. This advance could make it much easier for patients to adhere to the strict schedule ...

New long-acting, less-toxic HIV drug suppresses virus in humanized mice

January 8, 2018
A team of Yale researchers tested a new chemical compound that suppresses HIV, protects immune cells, and remains effective for weeks with a single dose. In animal experiments, the compound proved to be a promising new candidate ...

Usage remains low for pill that can prevent HIV infection

January 8, 2018
From gritty neighborhoods in New York and Los Angeles to clinics in Kenya and Brazil, health workers are trying to popularize a pill that has proven highly effective in preventing HIV but which—in their view—remains woefully ...

Researchers find clues to AIDS resistance in sooty mangabey genome

January 3, 2018
Peaceful co-existence, rather than war: that's how sooty mangabeys, a monkey species found in West Africa, handle infection by SIV, a relative of HIV, and avoid developing AIDS-like disease.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.