Ok, I was typing up a quick Wednesday post, but I ended up not very happy with it and tore it up. So I’m just going to post up a previous DotW that I wrote for On Dit. It is also being syndicated here at Science Creative Quarterly, which you should also check out.
Spurting viruses from your crotch
I’ll start by saying warts irk me out. Perhaps not as much as jellyfish, but they’re up there. It really sucked researching and looking up pictures for this topic; I hope you all appreciate it. In fact, appreciate it even more that I didn’t include any pictures of any warts in this article.
Nevertheless, science is not about personal preference or being irked out; it’s about the truth, even if it makes you mildly nauseated. You must accept it warts and all, one might say. Not me though, I would never stoop to such a base level of humour.
Warts in general are mostly (good scientists shy away from declaring ultimatums (unless, of course, they’re talking about definitions) and therefore use terms such as “in most cases” or “generally”. The reason for this is acknowledging that there may be exceptions to rules in some circumstances. In short, it’s to cover our arse.) caused by Human Papillomavirus (HPV). However, different types of warts are caused by different strains. Hand warts are caused by different strains from flat warts from genital warts. I could discuss the differences between the terms “strains”, “species” and “genera”, but in the end they’re completely arbitrary ways of splitting up things into groups and I’m not getting my fingers dirty with taxonomy.
According to the World Health Organisation, around 440 million people are spurting HPV from their crotches (the majority are women, due to anatomical differences). This amounts to approximately 15% of the world’s population. Most (~66%) of these people however experience no symptoms and happily go around spreading it (so to speak). The rest get some sort of symptoms in the form of ugly protrusions on their ugly protrusions. A minority of these people (and the major point of this article) have enough bad luck to have contracted a high risk strain (usually HPV 16 or 18, if you were wondering) and get cervical or penile cancer. To understand why, we have to examine the skin and warts in more detail.
Death through immortality
Skin can be very basically divided into two layers: living layer and dead layer. As you might expect, the dead layer is on top and the living layer is at the bottom, close to the muscle. This dead cell layer (the epidermis) is great at stopping bacteria and viruses from getting inside us and reproducing like China on Viagra. Viruses require living cells to replicate and bacteria need all the nutrients that living cells are filled with to grow; both being very absent from the top layer of skin. The epidermis is made by the living cells in the lower layer (the dermis) replicating, pushing upwards and (due to getting further away from the nutrients in the blood) changing into special extra-durable dead cells called keratinocytes.
HPV gets into cells of the dermis and stops them from changing into keratinocytes. The dermal cell not only stays alive, but the proteins for stopping replication are degraded: its “brake lines” for replication are effectively cut. Not only that, but also the protein that promotes replication is continually freed in the cell, producing a “stuck accelerator” effect. This means you have a population of cells that won’t stop reproducing.
Normally cells notice something wrong with themselves and commit suicide in a process called “apoptosis”. This is good for the organism (a person, in this case) because “something wrong” sometimes means virus infection. If the cell kills itself, the virus can’t reproduce inside it and the organism survives as a result. The human papillomavirus has evolved to take this into account by disabling host cell suicide proteins.
Also, cells of complex multicellular organisms have an intrinsic defence against rapidly dividing cells that can’t undergo apoptosis: when a cell copies its chromosome, it gets a little shorter. Not a whole lot, but there are bits down the end that can’t be copied for complicated reasons. It’s a bit like why you can’t write to the very edge of a notepad because of the opposing page gets in the way of the writing. But not really. Suffice to say, there is a reason, which has a low interesting index, so I won’t talk about it anymore. To combat this, there are buffer regions on the ends of the chromosomes that don’t code for anything, but they tend to run out after an average of fifty replications (this may sound like a very small number, but it allows a single cell to replicate into 250 or 1 125 899 906 842 624 cells) until bits of useful genes get lopped off and (since something looks wrong to them) the cells undergo apoptosis. However, some cells have to be able to replicate indefinitely, e.g. stem cells in the bone marrow. They are able to do this because they express large amounts of the enzyme telomerase, which simply adds bits of non-coding DNA to the end of the chromosomes. Since (almost) all the cells in your body are genetically identical, all cells have the capacity to make this protein; it’s just that they don’t because the gene for it is not activated in normal tissues. HPV activates the gene for this protein. This means the infected cell doesn’t have an upper limit to how many times it can reproduce. Biologists term this property “immortality”.
So now you have a bunch of cells that are replicating out of control and are not stopping. This leads us to the conclusion that warts are essentially tumours. If this process is strongly promoted, starts early in the lower layers, and becomes invasive (as is what happens with some infections with high risk strains of HPV), these tumours can become malignant. This means cancer and sometimes death.
Immortality through death
This is what happened to Henrietta Lacks in 1951. She was a black Baltimore woman, who came into hospital complaining of vaginal discharge. After a biopsy, she was diagnosed with cervical cancer (as a result of infection of HPV type 18) and died eight months later. Having some bright idea for some experiments, her doctor kept and cultivated the cells scraped from the tumour, producing one of medical science’s most useful tools. He named the strain “HeLa” using the first two letters of the woman’s names to protect his source’s identity at the time. These cells could be cultivated indefinitely in human tissue medium (a soup containing goodies that human tissue will grow and replicate in), due to their cancerous nature. They could be (have been and continue to be) used for some experiments that require only human cells and not an entire organism. This means that, for example, you don’t have to inject poison into rats and subject them to pain and suffering. Instead, you pour it onto a batch of HeLa cells and see if they die. This clears up many ethical problems with using test animals and also allows more accurate information (since you’re working with human cells not rat cells).
HeLa cells are now used in pretty much all medical labs around the world and have been key tools in the relieving of human suffering, in the form of vaccines, antibiotics, drugs and pathogen research. The mass of HeLa cells that have been produced is probably many times the mass of Henrietta Lacks herself. She has, in effect, been immortalised by science.
However, there has been some controversy over this usage of her tissue. This mass production of her cell lineage has all been done without the consent of her or her family. Being an African-American woman, a traditionally disempowered group, Henrietta Lacks has found some followers that have voiced their outrage to this exploitation. But, this has all been done legally. Precedence has been set that patients do not own any of their discarded tissues (such as biopsies or amputations) and that they may be commercialised (for more information, google “John Moore v. The Regents of the University of California”). Although I’m biased as a scientist and a materialist, I agree with the law. You’re not using it anyway, so why should you stop others from using or profit off of bits of you?
Treatment and prevention
Like most viral infections, there is no cure for HPV infections. Instead, most treatment is aimed at cutting or burning off the offending wart. Interferon alpha can be prescribed to reduce the size or eradicate altogether tumours, both benign and malignant. However, as with many diseases, prevention is the most effective measure against HPV infection.
The most significant prevention technique currently in place is simply reducing contact with other people’s genitals, via condoms, abstinence and decreasing number of sexual partners (Super sex hint: Just because you can’t see any warts doesn’t mean they don’t have genital warts. Asymptomatic carriers can still spread it and there’s a chance that it won’t be asymptomatic in you). Clinical trials for a vaccine against the high-risk types of HPV are underway and seem to be successful so far. So once you get vaccinated, you’ll be able to touch all the genitals you want (or not).
Chuang, TY. (2005). Warts, Genital. eMedicine.com. (Website accessed at http://www.emedicine.com/DERM/topic454.htm).
Dirasian, G. (2001) Who Owns Your Genetic Information? Institute for Health Freedom (Website accessed at http://www.forhealthfreedom.org/Publications/Informed/WhoOwns.html).
Higgins, G. (2006). Human Papillomaviruses. Infection and Immunity IIIA (University of Adelaide) lecture notes.
Kazzi, AA. (2004). Warts, Genital. eMedicine.com. (Website accessed at http://www.emedicine.com/emerg/topic640.htm)
World Health Organisation. (2006). Viral Cancers: Human Papillomavirus. WHO.int. (Website accessed at http://www.who.int/vaccine_research/diseases/viral_cancers/en/index3.html).