How Does HIV Cause AIDS?

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

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: “What Are the Symptoms of an STD?”

“I was treated for chlamydia, but my girlfriend feels fine, so she doesn’t need to get tested.”

“The only time I don’t use condoms is for oral sex, and everything’s been OK ‘down there,’ so getting tested for sexually transmitted diseases would be pointless.”

It’s important to be able to recognize the symptoms of a sexually transmitted disease (STD). Being savvy about symptoms can push you to get tested right away if you notice that something is amiss. However, being symptom-free can lull you into a false sense of security, especially if you’ve engaged in sexual activities that could have exposed you to an infectious agent. The fact of the matter is that many people with STDs have no symptoms at all. As they say, “The most common symptom of an STD is … no symptom.” Let’s take a look at some common STDs.


The most common symptom of an STD is no symptom.


Bacterial Infections

Bacterial STDs are curable with antibiotics. They include chlamydia, gonorrhea, and syphilis — all of which can be asymptomatic, and all of which can have severe complications when they are not treated in time.

Chlamydia: Around 3 million Americans are infected with chlamydia annually, and the infection is especially common among young people (less than 25 years of age). Chlamydia can infect the penis, vagina, cervix, anus, urethra, eye, or throat. You can be afflicted with a range of symptoms: pain or a burning feeling while urinating; vaginal, cervical, or penile discharge; swelling around the anus, testicles, or vagina; and more.

However, you’re much more likely not to experience any symptoms at all — most people with chlamydia are unaware they have it. Three out of four women with chlamydia have no symptoms, and half of men with chlamydia have no symptoms. Left untreated, chlamydia can become a serious health threat. Long-term complications might lead to fertility problems and arthritis. Continue reading

Honoring Life: Arizonans Observe National Native American HIV/AIDS Awareness Day

Tuesday, March 20, 2012, is National Native American HIV/AIDS Awareness Day (NNHAAD). Started in 2007, NNHAAD is focused on promoting HIV education, prevention, and testing among Native Americans, Alaska Natives, and Native Hawaiians. Dr. Yvette Roubideaux, a former professor at the University of Arizona who is now director of Indian Health Service, has called NNHAAD a day to “celebrate our successes and plan how to best continue working in partnership to address HIV and AIDS among Native people.”


On March 16, Arizona State University will observe Native American HIV/AIDS Awareness Day with speakers, information, and free HIV testing.


Although HIV affects every segment of society in the United States, Native Americans and Alaska Natives are disproportionately affected, ranking third, after black and Latina/Latino Americans, in the rate of HIV/AIDS diagnosis. Even as high as it is, the documented rate of diagnosis most likely understates the actual rate of HIV among Native Americans and Alaska Natives. This is due to racial misidentification in collected data and poor data reporting between state and federal agencies and the Indian Health Service (IHS). Further deflating the rate of diagnosis is the concern among people from smaller Native communities about anonymity during testing and confidentiality after diagnosis. Those concerns and the stigma associated with HIV lead to a reluctance to get tested, which delays or precludes diagnosis.

To understand the high rate of HIV, it helps to look at risk factors that uniquely affect Native Americans and Alaska Natives. Dr. Anthony Dekker of the Phoenix Indian Medical Center, interviewed for the newspaper Indian Life, commented that Native American patients “have very high rates of … sexually transmitted diseases … We also know that there is a very high rate of alcohol and [substance abuse] in the American Indian/Alaska Native population. There are many reasons for that, but what happens is that when you take a population that has had high rates of substance abuse and high rates of sexually transmitted diseases, [that population] also has high rates of HIV.” A high rate of substance abuse is associated with a high rate of HIV and other STIs, since impairment can lead to risky sexual behavior, such as poorer negotiation of condom use. Continue reading