The Diagnosis and Epidemiology of HIV

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What's the difference between HIV and AIDS
How does HIV produce disease?
What is the origin of the HIV virus?
Epidemiology of AIDS in America
Infection and death rates
AIDS and Race
A note on heterosexual transmission
Women are the key to limiting the epidemic
The association of HIV with other sexually transmitted diseases
The transmission of AIDS between dentists and patients
A note on AIDS transmission in the third world
Africa
Latin America
China
The general diagnostic signs of AIDS
The Bangui definition of AIDS
Oral Signs of AIDS

 

What is the difference between HIV and AIDS?

HIV stands for Human Immunodeficiency Virus.  In other words, HIV stands for the organism which attacks the human immune system causing damage which makes the patient more susceptible to other diseases.  AIDS is an acronym for Acquired Immune Deficiency Syndrome.  A syndrome is simply a grouping of symptoms which occur together.  Whenever a doctor sees a particular grouping of symptoms, he can infer that the patient has a specific disease.  For example, if you come into the office sneezing, with a runny nose and complain of aching muscles and a feeling of tiredness, then the doctor may assume you have a common cold caused by rhinovirus. 

The symptoms you exhibit to the doctor make it possible for him to make a presumptive diagnosis without doing any blood tests.  AIDS is a group of symptoms which, if seen to occur together, infer to the doctor that the patient may be suffering from the HIV virus.  The symptoms of AIDS include many different disease entities, but the most common ones are included in the Bangui definition.

Not everyone infected with the virus develops AIDS, and not everyone with the signs and symptoms diagnostic of AIDS harbors the virus, especially in third world countries.  At the present time, there is no cure for the virus (HIV), however the syndrome (AIDS) can be controlled with various combinations of medications.   

How does HIV produce AIDS?

HIV attacks the immune system.  Viruses in general are not quite "living" objects.  They have no cellular apparatus of their own to metabolize food or to reproduce.  They are "molecular parasites" which means that they are really just very active chemicals that must infect a living organism in order to take over the cellular components of the host (victim) for their own purposes.  Since they are nothing more than very complex chemical molecules, they have very specific needs with regards to the type of host cells they can infect.  

HIV infects a particular component of our immune system called the "T cells".  T cells are a type of white blood cell (specifically, a type of lymphocyte) which is responsible for protecting our bodies from attack by foreign invaders such as other viruses, bacteria, yeast and various cancer cells which may arise in our bodies from time to time.  It is the ultimate irony that HIV attacks and kills the very cells that are supposed to protect us from viral, as well as other types of infections.  Since HIV kills off an important part of our immune system, an infected individual becomes vulnerable to common diseases which are generally not dangerous to people with intact immune systems.  Thus infected young persons become vulnerable to diseases generally seen only in infants whose immune systems are not fully developed, or the very old, whose immune systems are in decline.  

For example, a young healthy adult may have a chronic Herpes Simplex infection resulting in cold sores recurring on his or her lips once or twice a year.  On the other hand, a person with a compromised immune system may get such a severe flare-up of herpes simplex that he could have it all over his entire mouth and even elsewhere, and need hospitalization to recover.  Simple infections that other people can ignore while they heal become life threatening disasters for the AIDS patient.

For those interested in looking at an image of actual HIV virons (virus particles) with a schematic of the structure of the beast and a short discussion on how they infect a host and reproduce, then please click on the thumbnail image below.

What is the origin of the HIV virus?

The disease entity that later came to be known as AIDS seemed to pop out of nowhere about the year 1981.  For the general public, awareness began as a series of rumors that gay men were getting sick with illnesses that were rarely seen in modern America, and almost never seen in young men.  Many people, including some scientists and journalists attributed it to the gay lifestyle, since it seemed to be confined to that population.  In 1982, the term "AIDS" was first used to describe the syndrome.  It was not until 1984 when Dr. Robert Gallo claimed to have discovered the virus that it became widely known that AIDS was linked to a specific disease causing entity, and not simply to lifestyle issues. (In reality, the virus was first isolated at the Pasteur institute in France the year before, but the full implications of the discovery were not recognized at that time.)  As the biological characteristics of the virus were discovered over the next few years, scientists noted its similarity to SIV (simian immunodeficiency virus).  SIV was already a well known entity, and it began to be suspected that HIV was really a pre existing virus which made the jump from monkeys or apes to humans.  A 2006 news article tells the story of some modern biological sleuthing and confirms that the virus has been traced to a colony of chimpanzees in Cameroon (on the west coast of Africa). 

The epidemiology of AIDS in America (who has it, where it's been and where it's going)

Note: This section is filled with statistics.  For the most recent CDC surveillance reports available click here.  Avert.org digests these statistics and presents them in an easily understood format.  Note that statistics on epidemiologic phenomena generally remain two years behind due to the methods of collection and the need to verify their accuracy.   The most up to date statistics are currently for 2006.

The Centers for Disease Control and Prevention (CDC) is one of the 13 major operating components of the Department of Health and Human Services (HHS), which is the principal agency in the United States government for protecting the health and safety of all Americans and for providing essential human services, especially for those people who are least able to help themselves.

According to CDC figures there have been nearly a million cases of HIV diagnosed in the United States since 1981, the year when the first cases of what would eventually become known as AIDS were reported to the Center for Disease Control (CDC).  It was not until 1984 that the virus was first isolated and determined to be the causative agent of the AIDS epidemic in the United States.

From the beginning of the AIDS epidemic in 1981 until the end of 1984, about 529,113 Americans died of their HIV infection.  As of the 2004 statistics, 9,443 children under age 13 were infected and a little over half of those have died.  From 1999 through 2004, the estimated number of AIDS cases decreased 68% among children.  A 2005 article in the New York times notes:

In 1990, as many as 2,000 babies were born infected with H.I.V., the virus that causes AIDS; now, that number has been reduced to a bit more than 200 a year, according to health officials. In New York City, the center of the epidemic, there were 321 newborns infected with H.I.V. in 1990, the year the virus peaked among newborns in the city. In 2003, five babies were born with the virus.

The reason for the decline is probably due to aggressive implementation of Public Health Service guidelines including early intervention, education, and aggressive use of the drug AZT in pregnant women with HIV.   From 2001 through 2004, the estimated number of HIV/AIDS cases has shown marginal increases among males but has decreased 15% among females.  In 2004, males accounted for just over 80% of all HIV/AIDS cases since the beginning of the epidemic in 1981, while in 2004 males accounted for approximately 73% of all newly diagnosed cases.  

Infection and death rates In North America

The chart above (current to 2007) shows a graphic representation of the number of HIV cases diagnosed  versus the number of deaths in the United States during each year of the epidemic. The statistics are taken from Avert.Org.  The steep, nearly geometric rise in the number of new cases diagnosed each year until the early 1990's was alarming and caused quite a bit of hysteria at the time. The steep drop in newly reported cases during the rest of the decade confirmed that the epidemic was under control and was not about to depopulate the earth. (The figure for 1980 includes the estimate of all deaths from HIV prior to 1981 when the epidemic was first recognized.)

To place these figures in perspective, a little over a half million North Americans died of AIDS between 1960 and 2004. During the same period, more than 30 million North Americans died of cardiovascular related diseases and cancer.  Today, AIDS kills about 16,000 individuals annually in the United states.  Heart disease alone (not including other cardiovascular ailments) kills a little over 700,000 yearly, or over 38 times the number of AIDS related deaths.  These figures do not diminish the tragedy of the AIDS epidemic.  They serve, rather, to place it in context. AIDS and Race in the US  (Click this link for the statistics)

During the 1990s, the epidemic shifted steadily toward a growing proportion of AIDS cases among black people, Hispanics and women, and toward a decreasing proportion in MSM (men having sex with men), although this group remains the largest single exposure group. Blacks and Hispanics have been disproportionately affected since the early years of the epidemic. In absolute numbers, blacks have outnumbered whites in new AIDS diagnoses and deaths since 1996, and in the number of people living with AIDS since 1998.  In 2003, blacks accounted for 50% of all HIV/AIDS cases diagnosed.

AIDS and Heterosexual transmission in the US  (Click this link for the statistics)

The pie chart below shows the proportion of male to female HIV cases diagnosed in the US during 2004. The chart also shows the major routes of transmission. IDU stands for Intravenous Drug User, meaning that the virus was transferred by way of using dirty needles while injecting IV drugs. At a glance, one can see that in 2004, nearly three quarters of the patients diagnosed with HIV were males. Nearly half of all patients diagnosed with HIV were infected via male to male sexual intercourse. While only about one sixth of all males infected with HIV in 2004 were infected through heterosexual intercourse, nearly 80% of all women infected with HIV in 2004 were infected via heterosexual intercourse. 

Comparing the pie chart above (for the cases diagnosed in 2004) with the bar chart on the right (showing cumulative cases since 1981), it is not difficult to see why men have outnumbered women by more than 3 to 1 over the course of the epidemic. The number of men having sex with men (MSM), along with the better than 3 to 1 ratio of male Intravenous Drug Users (IDU's) to female IDU's tends to skew the data toward a preponderance of men. (The 3 to 1 IDU figure is computed by adding the Male IDU and the MSM plus IDU figures).  Click here for reference.

 

The multi dimensional bar chart above shows the trends of the major categories of transmission of all cases of AIDS/HIV diagnosed each year starting in 2001.   For the actual statistics, click here, .  All categories of modes of transmission have shown incremental decreases each year except for MSM men having sex with men) which shows a fairly large jump for the year 2004 (about 1,400 more in 2004 than in 2003).

Normal vaginal sexual intercourse between a man and a woman is the most important means of transmitting HIV to women. One can see this by looking at the pie chart above. Surprisingly, however, it is a less important factor in the spread of the virus from women to men. Men are approximately one third less likely to contract the HIV virus from an infected woman than the reverse. Women are more prone to infection with the virus due to the nature of their anatomy and physiology than are men. This has implications for the spread of the disease in the western world. (Anal sex, on the other hand, exposes the participants, both male and female, to a higher risk of infection than a woman having vaginal sex due to the more easily abraded nature of the lining of the rectum and intestine, a higher probability of abrasions of the skin of the penis, and a higher probability of bacterial infections.) 

 

 Women are the key to limiting the epidemic

One can easily see when considering the charts accompanying this article that women (in western nations), as a group, are less likely than men to acquire the HIV virus. This fact, in combination with the fact that a woman with the disease is less likely to pass it on to her male partners act to modify the spread of the disease in the heterosexual population. One could say that women in the US, Europe and other western countries, because of their relative freedom and their determination to exercise discretion in their choice of male sexual partners (women are also more likely to remain monogamous than are men), act as a "firebreak" on the spread of HIV in the non-IDU, heterosexual population. This is probably one of the most significant reasons why the AIDS epidemic did not spin out of control as was predicted in the popular media during the 1980's and 1990's. It has now become apparent to most people that predictions of a North American heterosexual holocaust have proven unfounded.  As the epidemic has settled into maturity since 1997, it is also apparent that a majority of those afflicted remain in the "high risk" categories of Men who have Sex with Men (MSM), and Intravenous Drug Users (IDU) of both sexes.  

Still, there is little doubt that heterosexual intercourse is the predominant mode of transmission for the HIV virus worldwide. For reasons explained below, the continent with most serious AIDS epidemic is Africa with an overall infection rate of 9% of the entire population and over one third of the population of some African nations infected with the virus.  

A note on the association of HIV with other STD's

As the sexual revolution in the US and Europe began to overtake traditional sexual morality, it started to become obvious that there was an association between the increase in the prevalence of sexually transmitted diseases and the transmissibility of the HIV virus. This association is out of proportion to the actual prevalence of HIV versus the prevalence of the unrelated STD's. In other words, persons who were infected with diseases like syphilis, gonorrhea, Chlamydia and herpes type II were more likely to pass the HIV virus along to their sexual partners than persons infected with the HIV virus alone. 

At first glance, this makes sense. The presence of these diseases produces genital ulcers which allow fluids containing HIV to be transmitted to or from either of the individuals engaged in sexual relations. However, the degree of transmissibility appears to go beyond the presence of genital ulcers suggesting that the mere presence of these diseases in persons also infected with HIV increases the likelihood of transmission of HIV. The exact mechanism for this synergistic effect is not yet apparent, however, it is clear that there is an increased incidence of viral shedding associated with coexisting STD infections. A report was published by researchers from the University of North Carolina School of Medicine in July 1997 about the results of their study in Malawi [1]. Briefly, they found that the semen of men infected by both HIV and other venereal diseases such as gonorrhea contains eight times as much HIV as that of patients infected by HIV alone. When HIV-infected men were given antibiotics to treat other STDs (Sexually Transmitted Diseases) the amount of HIV in their semen fell dramatically, reducing the chances of them infecting their partners.  Click here for a well documented and very technical paper on this subject.

[1] Myron S Cohen .Sexually transmitted diseases enhance HIV transmission:  No longer a hypothesis. The Lancet 1998 Volume 351, Issue (Supplement III) pages 5-7

You, your dentist and AIDS (The Acer case)

In September of 1990, Doctor David Acer, a dentist in a small town in Florida died of AIDS. Before his death he sent a letter to all of his patients, informing them of his health status and urging them to take an HIV test. Acer reassured them that he had always followed standard infection-control procedures. Altogether, five deaths have been blamed on the transfer of HIV from Doctor Acer to his patients.

Since that time, there have been no undisputed cases of HIV transfer from any dentist to any patient.   In addition, there have been no documented instances of dental personnel contracting HIV from their patients

Even before the wide dissemination of "universal precautions", when dentists and hygienists did not routinely wear gloves or masks, neither they, nor their patients infected each other in spite the virtual certainty the virus was present in a percentage of both the patients and the dental personnel. Bear in mind that dental personnel all over the country frequently puncture their skin accidentally with dirty dental needles, handpiece burs and other sharp instruments. If there were a perceptible risk in transmitting the AIDS virus in the dental setting, there is no question that some dental personnel would have been occupationally infected by now! 

Unfortunately, through 2002 (I am unable to find more recent statistics), the CDC did receive reports of 57 health care workers in the United States with documented, occupationally acquired HIV infection, of whom 25 have developed AIDS in the absence of other risk factors. This suggests that health care workers, (who cannot legally discover the HIV status of their patients) are at much greater risk of contracting the virus from a patient than any patient is of contracting the disease from a health care worker! However, 56 cases out of the millions of health care workers at risk still represents a miniscule percentage of the total health care population!

No one knows what were the circumstances leading to the transfer of HIV from one doctor to not one, but to five of his patients, but it is evident that those circumstances have never been reproduced during the years since Dr. Acer's death. 

The conclusion that can be drawn from this is that HIV is a fragile organism that is not easily transmitted except by aggressive sexual activity with an infected person, by blood to blood contact as in massive large bore needle sticks, or when drug abusers share their needles and syringes.  In 2003,  the total number of HIV diagnoses attributed to "other (undetermined) causes" amounted to a little more than 1%.

Cleanliness in a dental office is, of course, important. Even if HIV transmission is unlikely, it is still possible to transfer other diseases such as Hepatitis B which is documented to be transferable between medical personnel and their patients. However, in view of the facts that have come to light over the last ten years, the initial hysteria surrounding the HIV status of physicians, dentists and other health care providers was quite unwarranted. 

A note on the spread of AIDS in third world countries

It is very difficult for Americans to understand the huge cultural differences between western civilization and those cultures in which the term "civilization" does not have the same meaning as it does in Europe, Australia, North America and other first world nations. These differences permeate every aspect of the lives of the individuals in the various cultures, from everyday thought patterns to the manner in which they govern themselves. They manifest especially in the less formal aspects of peoples' lives such as their sexual practices and patterns of drug use, both of which may vary significantly from western cultural traditions. 

Africa

In Sub Saharan Africa, the AIDS epidemic has a very different epidemiological profile than it does in the west. There, the scale of the problem dwarfs the prevalence of HIV in the rest of the world. In Sub Saharan Africa, over 25 million people are infected. Sixty-four percent of all HIV positive people worldwide and 76 percent of all women with the virus are in sub-Saharan Africa. There, nearly equal numbers of males and females are infected, while males outnumber females by nearly 3 to 1 in Western countries. The reasons for this are complex, and not always easy to ascertain because they involve personal and and in some cases taboo factors that people don't like to talk about to interviewers. People, when asked about their sex lives simply do not give honest answers. 

Infection rates vary widely from country to country on the African continent due to the sometimes stark differences in the cultural affinities of the respective populations. Certainly, the social chaos in areas suffering the agonies of prolonged war, revolution and famine would lead to the wider dissemination of HIV as well as other endemic diseases. Prostitution and polygamy appear to be more widely practiced in some areas of the continent than they are in Western countries. Men are less likely to be circumcised in Sub-Sahara Africa. This increases the likelihood of inflammation and open sores around the head of the penis. These men are more likely to both contract HIV from, and to spread it to their heterosexual partners. In some parts of Sub-Saharan Africa, especially in countries located in the southern third of the continent, heterosexual anal intercourse is said to be a more widely practiced form of birth control than many people admit. (Scientific data on this is sketchy, however a study by researchers at the University of Tuebingen in Germany suggests that this is a major factor in the spread of HIV in southern Africa.) Because of the physical differences between anal and vaginal intercourse, this practice would tend to short circuit the North American female-to-ma le "firebreak" mentioned above. 

In addition, there is an increased tendency toward viral shedding in persons with untreated syphilis, gonorrhea, chlamydia, herpes and other less well known STD's. The lack of proper diagnosis and treatment of these diseases in primitive social conditions increases the risk of spreading the HIV virus. In some sub Saharan countries, the rate of reported STD infection is ten times that reported in the US, and these statistics are based on a much lower standard of surveillance than is the case in western countries. 

There is also a widespread belief in some areas of Africa that an infected male can be cured of HIV by having sex with a virgin. This erroneous belief is suspected of increasing the frequency of rape and the spread of the virus. Customs, beliefs and conditions such as these, along with an enormous number of historical, demographic, economic and cultural factors converge to increase the infection rate in Sub-Saharan Africa. 

One African bright spot is Uganda. There, the epidemic has been nearly stopped by a campaign promoting abstinence. 

"According to a U.S. Agency for International Development study, in Uganda "national HIV prevalence peaked at around 15 percent in 1991, and had fallen to five percent as of 2001. This dramatic decline in prevalence is unique worldwide."

In the mid-1980s, when it became clear that AIDS was on the rise in Uganda, President Yoweri Museveni adopted a program that, as Arthur Allen has written in The New Republic, "would become known as ABC, for Abstain, Be faithful or wear a Condom -- very much in order of emphasis."

According to a study of one Ugandan district, almost 60 percent of youths age 13-16 reported engaging in sexual activity in 1994, but by 2001, the number had plummeted to less than 5 percent. The USAID study reports that compared with men in other sub-Saharan African countries, Uganda males are "less likely to have ever had sex (in the 15-19-year-old range), more likely to be married and keep sex within marriage, and less likely to have multiple partners."

The effect on HIV rates has been nearly miraculous. Researcher Rand Stoneburner estimates that Uganda's approach has been almost as effective as an HIV vaccine. "  (Rich Lowry Dec 6, 2002)  (click here for the stats)

One should also note that there is some controversy about the reported incidence of HIV on the African continent.  The diagnosis in most areas is based on the Bangui definition--- the complex of symptoms (AIDS) exhibited by the patient--- rather than by the serological (blood) test which is the definitive test used in Western countries.  As discussed above,  numerous diseases that are endemic in Africa may produce symptoms identical to those seen in actual HIV infection. As a result, there is a substantial chance that the reported incidence of HIV in Africa may be markedly overstated, although the controversy is in the degree and significance of the over reporting. There is, understandably, a great deal of anger when a loved relative or friend is reported as having died of AIDS when the family knows that person has never engaged in behaviors known to increase the risk of contracting the virus. 

Latin America

Outside of Africa, many other third world countries have customs and practices that can appear just as exotic to American and European eyes. Upon visiting Honduras, I was surprised to learn from the Peace Corps volunteers working there that there are no laws limiting access to prescription drugs by persons without a prescription. Thus, people with no medical training can buy any prescription drug, along with needles and syringes to administer it without the intercession of a doctor. Illiterate peasants living in remote villages know that penicillin and other antibiotics can cure infections that used to be fatal, and they frequently pool their resources to buy a supply to administer to sick villagers. In order to save money, they often reuse needles and syringes. AIDS in Honduras and other Central and South American third world countries has begun to spread throughout the population as a result of this practice.

China

In china, the historical significance of opium and other narcotics is quite different than in the west. In the nineteenth century, the British and other western nations intentionally used opium as a means of opening up the otherwise insular Chinese culture to trade. (Internet search term; "opium wars" .) As a result of this historical fact, the use of narcotic drugs is widely established among the peasant population as a whole in spite of the draconian methods that the Chinese government uses to suppress them (Mao Tse-Tung threatened to execute them if they didn't give up the habit). In many poorer areas of China, large masses of the common people share needles and drug supplies thus spreading HIV very widely among the entire population (not just among isolated groups of drug abusers as in the US).

Even the public health establishment in China seems alien by western standards. The Chinese have been ruled by legalistic, bureaucratic regimes for over a thousand years. All bureaucracies (even in the US) tend to follow rigid, legalistic rules and guidelines which do not allow for swift, rational changes in procedure to cope with changing conditions (or even common sense circumstances). The incidence of HIV has exploded in China over the course of a single decade. The following quote is reprinted from The Times (of London).

The Oral signs Symptoms and abnormalities of HIV==>>

HIV, The virus==>>