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infectious disease

Snapshots of Life: Virus Hunting with Carbon Nanotubes

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H5N2 trapped in carbon nanotubes

Credit: Penn State University

The purple pods that you see in this scanning electron micrograph are the H5N2 avian flu virus, a costly threat to the poultry and egg industry and, in very rare instances, a health risk for humans. However, these particular pods are unlikely to infect anything because they are trapped in a gray mesh of carbon nanotubes. Made by linking carbon atoms into a cylindrical pattern, such nanotubes are about 10,000 times smaller than width of a human hair.

The nanotubes above have been carefully aligned on a special type of silicon chip called a carbon-nanotube size-tunable-enrichment-microdevice (CNT-STEM). As described recently in Science Advances, this ultrasensitive device is designed to capture viruses rapidly based on their size, not their molecular characteristics [1]. This unique feature enables researchers to detect completely unknown viruses, even when they are present in extremely low numbers. In proof-of-principle studies, CNT-STEM made it possible to collect and detect viruses in a sample at concentrations 100 times lower than with other methods, suggesting the device and its new approach will be helpful in the ongoing hunt for new and emerging viruses, including those that infect people.


Could Zika Virus Have Lasting Impact on Male Fertility?

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zika-histology

Caption: Immunofluorescence staining showing that the testes of Zika-free mice (left) are full of developing sperm (pink), while the testes of Zika-infected mice (right) contain very few sperm.
Credit: Prabagaran Esakky, Washington University School of Medicine, St. Louis

Recent research has shown that the mosquito-borne Zika virus has the potential to cause serious health problems, including severe birth defects in humans. But the damaging effects of Zika might not end there: results of a new mouse study show that the virus may also have an unexpected negative—and possibly long-lasting—impact on male fertility.

In work published in the journal Nature, an NIH-funded research team found that Zika infections can persist for many weeks in the reproductive systems of male mice [1]. As a result of this infection, levels of testosterone and other sex hormones drop, sperm counts fall, and, in some animals, the testicles shrink to 1/10th of their normal size, possibly irreversibly. All of this adds up to Zika-infected male mice that are significantly less fertile than their healthy counterparts—producing about a quarter as many viable offspring as normal when mated with female mice. While mice are certainly not humans, the results underscore the urgent need for additional research to examine the full spectrum of Zika’s health effects in men, women, and children of both sexes.


Feed a Virus, Starve a Bacterium?

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Woman eating hot soup in bed

Thinkstock/Stockbyte

Yes, the season of colds and flu is coming. You’ve probably heard the old saying “feed a cold and starve a fever.” But is that sound advice? According to new evidence from mouse studies, there really may be a scientific basis for “feeding” diseases like colds and flu that are caused by viruses, as well as for “starving” certain fever-inducing conditions caused by bacteria.

In the latest work, an NIH-funded research team found that providing nutrition to mice infected with the influenza virus significantly improved their survival. In contrast, the exact opposite proved true in mice infected with Listeria, a fever-inducing bacterium. When researchers forced Listeria-infected mice to consume even a small amount of food, they all died.


Zika Vaccine: Two Candidates Show Promise in Mice

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Zika Virus

Caption: Zika virus (red), isolated from a microcephaly case in Brazil. The virus is associated with cellular membranes in the center.
Credit: NIAID

Last February, the World Health Organization declared a public health emergency over concerns about very serious birth defects in Brazil and their possible link to Zika virus. But even before then, concerns about the unprecedented spread of Zika virus in Brazil and elsewhere in Latin America had prompted NIH-funded scientists to step up their efforts to combat this emerging infectious disease threat. Over the last year, research aimed at understanding the mosquito-borne virus has progressed rapidly, and we now appear to be getting closer to a Zika vaccine.

In a recent study in the journal Nature, researchers found that a single dose of either of two experimental vaccines completely protected mice against a major viral strain responsible for the Zika outbreak in Brazil [1]. Caution is certainly warranted when extrapolating these (or any other) findings from mice to people. But, taking into account the fact that researchers have already developed safe and effective human vaccines for several related viruses, the new work represents a very encouraging milestone on the road toward a much-needed Zika vaccine for humans.


Global Effort to End AIDS Would Save Millions of Lives

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Prevent HIV AIDS

Scanning electromicrograph of an HIV-infected T cell/NIAID

Almost 37 million people around the world are now infected with human immunodeficiency virus (HIV), the virus that causes AIDS [1]. But many don’t know they are infected or lack access to medical care. Even though major strides have been made in treating the infection, less than half receive antiretroviral therapy (ART) that could prevent full-blown AIDS and reduce the likelihood of the virus being transmitted to other people. Now, a new report restores hope that an end to this very serious public health challenge could be within reach—but that will require a major boost in commitment and resources.

The study conducted by an NIH-funded research team evaluated the costs and expected life-saving returns associated with ambitious goals for HIV testing and treatment, the so-called 90-90-90 program, issued by the Joint United Nations Programme on HIV/AIDS (UNAIDS) in 2014 [2]. The new analysis, based on HIV disease progression and treatment data in South Africa, finds that those goals, though expensive to implement, can be achieved cost-effectively, potentially containing the AIDS epidemic and saving many millions of lives around the globe.


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