Underwear as a promising source of information in sexual assault cases?

No means no

Great news! Besides the first, large-scale results showing the hard work of the Isala project, the daughter project GeneDoe has not stagnated.  As a master student in the biomedical sciences, I got the opportunity for the last year to work on this forensics project under the supervision of prof. Sarah Lebeer, prof Ronny Decorte and Sarah Ahannach. And so, take the first steps in research for microbiome analysis as additional evidence in sexual assault cases.

In a previous Isala blogpost Sarah Ahannach addressed the problems surrounding the high numbers of sexual assault cases, in contrast to the low amount of actual convictions. This is what the GeneDoe project aims to change, by investigating whether microbiome analysis can contribute as evidence to sexual assault cases. Hereby, these cases could potentially support on a more solid foundation to lead to correct convictions.

“Half of the victims remain silent out of fear of misbelieve. And they are right, because we actually do no not believe them. We do not believe them because when a woman tells her story, she tells of proceedings that we cannot imagine, that upset us, that we do not expect to hear and that bewilder us”

Inès Hercovich

Excuse me? Microbiome analysis as evidence?

Cases of sexual assault prove often to be complex, which mainly manifests itself in a low number of effective convictions. The cause might be rooted for example, in a deficit of evidence but also a fear of victims to not be believed or a fear for the judicial process. A multidisciplinary approach is thus desperately needed to gather as much evidence possible in an optimal way and herewith build a strong case.

The statements and physical evidence are the two main protagonists in this. Physical evidence is a collection of all kinds of possible traces such as injuries, sperm traces, saliva traces, hair, and so on. All traces that have a biological origin are collected under the term biological traces. This can be, for example, saliva, skin marks or vaginal discharge. These are therefore also the types of biological traces that we mainly focus on with GeneDoe.

When traces are collected at a crime scene, which in cases of sexual violence is often the body of the victim itself, but can also be clothing or sheets, the trace must first be identified. Various techniques are currently available for this, but in general they do have some limitations. For example, there is a high probability of false positive or false negative results and these techniques take little account on variability between individuals.

You are no longer newbies in the field of microbiome knowledge and I therefore do not surprise you with the fact that we carry a lot of bacteria in and on our bodies. These bacteria are essential for normal functioning and maintaining a healthy balance on specific body locations. Because different body locations provide different environments, all kinds of bacteria grow in these different parts of our body that feel good in those certain conditions. Just think of the moist and warm environment in the mouth or the dry and oxygen-rich place of the skin on our arm, for example.

Now let that be what we want to use for microbial fingerprinting. If every body site contains characteristic bacteria, can it be determined from which body site the trace originates on the basis of its microbial fingerprint? Microbial DNA is much more robust than human DNA because bacteria have a strong cell wall that protects the DNA against all kind of influences such as heat, humidity, and so on. As a result, microbial DNA could be detected in samples much longer than human DNA and it is a reliable and good source of information.

In addition to information about the origin of a trace, microbial fingerprints can go one step further. They could give us information about what actually happened. For example, if a victim makes a statement about unwanted kissing or biting but nothing can be seen externally, a skin sample from that particular location could provide greater clarity. If this skin sample contains specific bacteria that are characteristic of saliva, this may help support the victim’s statement. But disturbances in microbial communities could also provide information about certain actions. For example, if it could be shown that the vaginal microbiome is disrupted as a result of vaginal penetration, this could be an important factor in substantiating a case.

GeneDoe also known as Isala-junior

Clearly, there is enormous potential hidden in the human microbiome. That is why it was important to draw up a well-defined plan in order to get the most out of this year. It therefore took us a whole semester, several internal and external meetings to arrive at the final plan. But what a plan it is!

In summary, I was allowed to set up a mini-Isala version together with my supervisor Sarah Ahannach, for which we went looking for 11 enthusiastic, healthy women that wanted to contribute to an investigation into sexual violence. And we definitely found them! As with Isala, we made customized self-sampling kits that they used for various vaginal, skin and saliva swabs (you all know the drill), but in addition they wore new underwear every day for a week, following a strict planning whether or not to have sexual relations.

All samples that we received were processed according to a strict schedule. Each sample had a specific purpose. For example, we started mixing samples, applying samples to textiles to expose them to different time points, diluting samples, and so on. Long story short: various forensically relevant situations were simulated in the lab and a step-by-step plan was then followed for each sample to extract the microbial DNA and analyze the bacteria present.

Underwear as a golden source of information

Yes, you read it correctly: we received underwear worn every day for a week from all GeneDoe participants. These pieces of underwear were the goldmines of the GeneDoe project. This allowed us to monitor the vaginal microbiome in the underwear for a week, but above all to find out what the differences and/or similarities are with vaginal swabs and what the influence is of sexual relation on the vaginal microbiome. Every day we took the collected samples to the Forensic DNA laboratory in the UZA, under the supervision of Dr. Els Jehaes (be sure to read her inspirational blog about women in science here!). There we had the honor of using their facilities to subject the underwear to a brief forensic examination. Here, the focus was on whether or not we could detect Prostate-Specific Antigen (PSA), a parameter used to determine the presence of seminal fluid. Our main curiosity was whether we would be able to determine the presence of PSA as long, longer or shorter than disturbances in the vaginal microbiome, due to sexual intercourse.

Underwear with capital U

Curiously, we found that the microbiome in the underwear is much more variable than on the vaginal swabs. The vaginal swabs of our participants were almost always dominated by one type of bacteria, usually a lactic acid bacteria while the underwear contained many more different types of bacteria. This could be explained by the fact that the underwear were worn for 24 hours while a vaginal swab was only a snapshot. In addition, there are a lot of factors that can contribute to the higher variability in the underwear, just think of the presence of skin microbiome, urine, fecal microbiome, and so on.

The forensic examination of underwear showed the persistent presence of PSA after sexual intercourse. All participants changed their underwear after 24 hours and took a shower or bath and yet PSA could be detected 34 hours after sexual intercourse, which means: even if you change the underwear and take a shower, the presence of seminal fluid can still be detected after 34 hours! This can be of enormous importance when a victim does not immediately come forward after a sexual assault.

After these valuable PSA results, we were very curious about the vaginal microbiome. While we assumed that the vaginal microbiome would be severely disrupted by vaginal penetration, the warriors of our vagina turned out to be more robust than expected! In the first analyses, no major disturbances were observed in the vaginal microbiome, but small, subtle changes were observed in most of the participants. Small changes observed more strongly in the underwear than on the vaginal swabs which once again emphasizes the value of underwear. In addition, we also saw that these minor disturbances were not only present the day after sexual intercourse, but persisted over the period in which our participants were followed up.

We also went one step further. Not only did we look at the changes that took place in the vaginal microbiome after intercourse, but also the influence of time when these underwear and vaginal swabs were exposed to room temperature for a certain period of time. In sexual assault cases, 72 hours has become a gold standard. It is believed that taking vaginal swabs may still be useful for human DNA analysis up to 72 hours after the crime. We wanted to check whether the microbiome could also follow this standard and whether the microbiome analyses we performed immediately upon receipt of the samples, corresponded to analyses performed only after 72 hours. And good news! Few changes were found between the immediate analysis and the exposed samples. This means that microbiome analysis could also be useful if a victim does not immediately register.

We are not done yet

This study was a first step towards discovering the potential of microbiome analysis in sexual violence cases. The results were promising and only reveal more curiosity about the endless possibilities. Further and more extensive research is essential but I am sure it does not stop here. “No means no” and as a young woman I can only encourage that this kind of research continues and hopefully finds its way into real-world applications.

At the moment, even more in-depth bioinformatic and statistical analyses are performed on all collected data from the GeneDoe project in order to optimally use all valuable information and draw the correct conclusions. With these analyses, we will be writing a scientific manuscript and launching the valuable early conclusions of the GeneDoe project as a first in research into the influences of sexual relations on worn underwear. This manuscript will then undergo a so-called peer review, which means that various international experts in the field will assess the research. And last but not least published in a scientific journal. Stay tuned for our update on this!

The underwear girl
My name is Jana Hiers, as I was recently informed, I now go through life for some as ‘the underwear girl’. I study biomedical sciences, master in forensic sciences, at the KU Leuven. Bitten by the combination of scientific research and the forensic world, my eye fell on the existing GeneDoe project as a thesis topic and I came into contact with the Lebeerlab. Not quite knowing what to expect from my thesis year, I was offered to work as a job student during the summer months last year. Before that, I was allowed to help prepare all Isala packages together with five other job students and the entire Lebeerlab team, before they were sent out into the world. This was a first acquaintance with the lab, the atmosphere and the people I would spend my next year with to write my master’s thesis. In the past year, I have given myself completely to the GeneDoe project with great pleasure and successfully completed my master’s thesis. Because I could hardly do without it, I also worked for a few weeks as a job student in the Lebeerlab this summer. Now it’s finally over and with a small heart I left the lab for the last time a few weeks ago. The GeneDoe project will certainly not be shelved because there are still very interesting plans on the agenda within Sarah Ahannach’s PhD project. And so a next master’s student is already ready to continue working on this and she can in turn soak up the fantastic atmosphere in the Lebeerlab. I am sure she will do a great job. My job is done and handing it over is also with a small heart, but full of pride, new knowledge and experiences I am going to face the next adventures. I can only get satisfaction from the fact that I was able to contribute to Isala and GeneDoe.

Underwear girl over and out

What can you do if you have been a victim of sexual assault? Also if you have doubts!

On our national website you can find more information on sexual assault, what you can do and especially that you don’t have to go through it alone. All with the greatest respect for your privacy:

  • You can anonymously call the emergency number 106 for support at day and night
  • You can talk with professional staff on 1712 (on working days between 9h and 17h)
  • You can chat with a coworker
  • You can make an appointment with the care center for sexual violence (Zorgcentrum Seksueel Geweld)

On the website of Sensoa vzw you can find more information about unacceptable behaviour, what you can do about it and who you can contact.