Tag Archives: retrovirus

Some Good News About Three Sexually Transmitted Viruses

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Scientists are hard at work finding ways to improve your health!

With so much bad news emblazoned across headlines in every newspaper you look at, the world might seem like a gloomy place. So let’s take one depressing subject — disease — and peel away the sad outer layer to find silver linings of optimism.

When it comes to infections, a lot of us blame one thing: germs, also known as “bugs” — “pathogens” if we’re fancy. Some people might not think of infectious diseases as being that big of a deal — after a round of antibiotics, you’ll be on the mend. Unfortunately, antibiotics only work for bacteria, but a lot of diseases are caused by other types of germs — for which antibiotics are no match. One type of germ is called a virus, and they can’t be cured. Sometimes they can be prevented with vaccines or treated with drugs. For example, the major strains of human papillomavirus (HPV) can be prevented with a vaccine called Gardasil, herpes simplex virus can be suppressed with antiviral drugs, and HIV can be controlled with antiretroviral drugs — but none of these infections can be cured. HPV is usually defeated by the immune system, but herpes and HIV are with you for life.

But it’s not all bad. Around the world, individual scientists have picked their “favorite” viruses and are devoting their lives to finding better prevention strategies, better treatments, and even cures. Let’s check in with some of the latest headlines touting the successes of science.

New Hope for a Herpes Vaccine

A herpes vaccine would be a blockbuster — given how common this sexually transmitted infection is, a preventive shot could help a lot of couples discuss their herpes status without as much fear of judgment and stigma.

Herpes might cause an “outbreak” — unpleasant symptoms that include genital sores — but afterward the virus goes dormant in the nerve cells, hiding from the immune system. In some people, the virus can come out of its dormancy to cause flare-ups of symptoms, but once it’s had its fun it retreats back to the nerve cells.

Earlier this year, media reported on a promising new candidate for a herpes vaccine. Using a completely different strategy than previous, failed herpes vaccines, the researchers behind this breakthrough targeted the part of the virus that allows it to hide from our immune systems. If this vaccine works as hoped, recipients will be able to mount an immune defense when exposed to the virus, blocking it from establishing a permanent home in nerve cells. It might even suppress outbreaks in people who already have herpes. Continue reading →

Over 90 Percent of What Planned Parenthood Does, Part 14: Rapid HIV Testing

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HIVtestingdayWelcome to the latest installment of “Over 90 Percent of What Planned Parenthood Does,” a series on Planned Parenthood Advocates of Arizona’s blog that highlights Planned Parenthood’s diverse array of services — the ones Jon Kyl never knew about.

It’s important to be tested for HIV, the sexually transmitted virus that causes AIDS. For some people, periodic HIV testing is part of their regular health care, while others might be experiencing a scare after a high-risk encounter (for example, having unprotected vaginal or anal intercourse or sharing IV equipment with someone whose HIV status you don’t know). No matter what boat you’re in, waiting a week or more to get your results from a standard HIV test might be nerve-wracking. If that sounds like you, then a rapid HIV test — which can give you results in just 40 minutes or less — might be just what the doctor ordered.

Today is National HIV Testing Day, and HIV testing has never been easier!

Here’s a quick rundown on rapid HIV testing: A negative result on a rapid HIV test is just as accurate as a negative result from a standard test — you just don’t have to wait as long to get it. However, positive results are considered “preliminary” and another blood sample must be sent to a lab for confirmation. If that result comes back negative, you will probably be asked to come back for retesting to verify that negative result.

The rapid test, just like the standard test, is an antibody test, which means it detects the presence of antibodies in your bloodstream. Antibodies are molecules produced by your immune system, and are specially designed to attach to viruses and other invaders. Each type of antibody is shaped in such a way that they can interlock with just one type of pathogen; some antibodies might specialize in attaching to a certain strain of a cold virus while others might be shaped especially for attachment to the surface of an E. coli bacterium. So, if you’re infected with HIV, your immune system will produce antibodies that are uniquely shaped to target HIV. An HIV antibody test can sort through the many types of antibodies in your bloodstream and identify only the antibodies that are shaped specifically for targeting HIV. Continue reading →

AIDS Denialism: Conspiracy Theories Can Kill

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This scanning electron micrograph from 1989 reveals HIV particles (colored green) emerging from an infected cell. Image: CDC’s C. Goldsmith, P. Feorino, E.L. Palmer, W.R. McManus

We’ve all heard various conspiracy theories; we may or may not find them credible, and we might chalk up opposing viewpoints to simple differences in opinion. Sometimes, however, conspiratorial narratives are woven around matters of life and death — and in such cases, the spread of such ideas can influence dangerous changes in behavior and even government policy.

AIDS denialism is based on the idea that human immunodeficiency virus (HIV) does not cause AIDS. Although the existence of HIV and its causal connection to AIDS has been thoroughly demonstrated by scientists, denialists either reject the existence of HIV altogether, or cast it as a harmless virus that doesn’t cause illness. Denialism often relies upon rhetorical strategies that are superficially convincing but intellectually hollow, including the cherry-picking of evidence, appeals to unreliable “experts,” and untestable claims. Denialists also might cite early AIDS research from the mid-1980s while ignoring more up-to-date findings and improved medical procedures. Such rhetoric creates a sense of legitimate debate in an area where there is none, and the only new evidence welcomed into the discourse is that which confirms preconceived notions.

Health decisions must be shaped by the best available evidence, and when denialism misinforms, one cannot make an informed decision.

If AIDS isn’t caused by HIV, what do denialists claim is behind the unique symptoms that characterize it? Some say that conditions such as malnutrition, or diseases that have been around for a long time, are simply being labeled as AIDS. Other denialists cast antiretroviral drugs as the cause, rather than the preventive treatment, of AIDS. Some claim that AIDS is caused by behavior, such as drug use or promiscuity — with some even saying that an accumulation of semen in the anus can cause AIDS. None of the claims is true — while AIDS can leave someone vulnerable to a wide variety of diseases, and while sharing IV equipment and engaging in unprotected sex can increase risk, there is only one cause: HIV. Continue reading →

How Does HIV Cause AIDS?

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diagram of a human immunodeficiency virus

Last week, we gave a general background of human immunodeficiency virus (HIV), the virus that causes AIDS by destroying the immune system. But how is HIV able to disable our immune systems so effectively, anyway? The answer lies in its structure.

HIV, just like any other virus, is made up of a tiny capsule with a small piece of genetic code inside. While most viruses we’re familiar with store their genes on a molecule called DNA, HIV contains two pieces of RNA, which is another type of gene-storing molecule. The HIV capsules also contain an enzyme called transcriptase, which “translates” the RNA into a strand of DNA that our cells can read. Our cells are then tricked into reading this DNA and producing more copies of the virus — which are then released from the host cell, at which point they are free to infect other cells. In this manner, an HIV infection slowly grows.

HIV targets our immune systems, the very mechanism that evolved to keep us safe from pathogens.

When a virus is introduced into a host’s body, immune cells pick it up and carry it to the lymphoid organs — which are a sort of meeting place for other types of immune cells, including CD4+ T helper cells (also called helper T cells). Helper T cells enlist the help of other immune cells, called killer T cells, which destroy cells infected with viruses. Helper T cells also activate the production of antibodies, molecules that are specialized to attach to a specific pathogen so that it can be destroyed. Normally, this is where the virus meets its end. Unfortunately, HIV is different from run-of-the-mill viruses in that it is specialized to invade helper T cells. Now, instead of coordinating an attack against HIV, the helper T cells have been hijacked — converted into factories for the production of yet more HIV. Continue reading →

STD Awareness: HIV and AIDS

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Our immune systems are beautiful things, refined through millions of years of evolution. The immune system’s complexity is testament to the “arms race” that has been taking place between our species and the harmful pathogens that surround us. Last century, a virus called human immunodeficiency virus (HIV) emerged, and it found a weak spot in our immune system’s armor. HIV has been exploiting this weakness ever since, and an HIV infection can eventually progress to a disease called AIDS, or acquired immune deficiency syndrome. AIDS is a condition that disables our immune system’s ability to function properly, rendering us vulnerable to a host of opportunistic infections and cancers.

Even if you don’t think you’ve been exposed, HIV testing can be a good idea.

HIV is transmitted via bodily fluids: blood, semen, pre-seminal fluid (which can be present without ejaculation), breast milk, vaginal fluids, and rectal mucus. (It can also be present in bodily fluids like amniotic fluid, cerebrospinal fluid, and synovial fluid, to which health-care workers might be exposed.) The virus is not transmitted by fluids like snot, saliva, sweat, tears, and urine — unless blood is present.

Activities that can bring you into contact with HIV-infected bodily fluids include injection drug use and sexual activities like anal, vaginal, or oral sex. It can also be transmitted to a fetus or baby during pregnancy, childbirth, or breastfeeding. In the early days of HIV, many infections occurred as a result of blood transfusions or organ transplants — though nowadays this is a rarity thanks to tissue screening. Lastly, health-care workers might be exposed to HIV through accidents involving needlesticks or cuts. Continue reading →

STD Awareness: 10 Sexually Transmitted Diseases You Probably Don’t Know About

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Giardia lamblia, a microbe that can be transmitted sexually. Image: NIH

Gonorrhea and chlamydia go back to antiquity. Syphilis took hold in Europe during the late 15th century. Herpes wasn’t on most people’s radars until the early 1980s, and human papillomavirus (HPV) was relegated to relative obscurity in the popular imagination until the HPV vaccines made their debuts less than a decade ago.

Have you heard of CMV, chancroid, or donovanosis?

But there are still a handful of sexually transmitted diseases (STDs) that you might not know about. These include incredibly common infections, as well as those caused by pathogens you might have heard of but probably don’t associate with sexual transmission. They also include infections that are very rare here in Arizona but are much more common in other parts of the world. They all deserve a closer look.

10 Trichomoniasis: What is the most common curable STD? You might guess that it’s chlamydia or gonorrhea, but according to the Centers for Disease Control and Prevention, it’s trichomoniasis (also known as trich, pronounced “trick”). This infection is caused by Trichomonas vaginalis, a single-celled parasite that is actually pretty cute as far as microbes go. What’s not so cute is its propensity to attach to your cells and degrade their surfaces, which on a large scale can produce unpleasant symptoms. Continue reading →

STD Awareness: The Future of Treatment for HIV/AIDS

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This scanning electron micrograph shows HIV particles (colored yellow) infecting a human T cell. Image: National Institute of Allergy and Infectious Diseases, National Institutes of Health

This scanning electron micrograph shows HIV particles (colored yellow) infecting a human T cell. Image: National Institute of Allergy and Infectious Diseases, National Institutes of Health

In 2006, an HIV-positive man was diagnosed with leukemia. First he received chemotherapy, and when the cancer returned his doctor recommended a stem-cell transplant with tissues obtained from a bone-marrow donor. After finding an unusually high number of compatible donors, his doctor, Gero Hütter, had a simple idea that would change the course of HIV research. Dr. Hütter knew of a rare genetic mutation that confers immunity to many strains of HIV, including the strain that infected his cancer patient. And new blood cells, including immune cells, are manufactured by bone marrow. What if he could find a bone-marrow donor with this mutation? What effect would it have on the HIV infection?

Five years after his cancer diagnosis, the man, known as the Berlin patient and recently identified as Timothy Ray Brown, is in remission from cancer … and the most sensitive tests have been unable to detect HIV anywhere in his body, despite the discontinuation of antiretroviral drugs. Scientists are a cautious lot, careful not to make grand statements without qualifying them with words like “seem” and “suggest.” But more and more, researchers are starting to say that Brown could be the first case in which a cure for HIV was attained.

Human immunodeficiency virus, or HIV, has been the focus of intense research since the 1980s, when it was identified as the causative agent of AIDS. Many anti-HIV drugs have been developed since then, though worldwide, less than a third of people who need the drugs have access to them. Those with access, however, have significantly improved health outcomes and longer life expectancy. Continue reading →