Inspiration

The horrible reality of a bed bug problem became clear through the terrifying experience of one of our team members.

"For two months, I was always afraid to sleep," he said. "The constant itching kept me awake, night after night."

The mental stress was made worse by how hard the bugs were to find. He quickly saw the main problem: their nature to hide. "Trying to fight them was the hardest part," he mentioned, "because those bugs live in the corners and small cracks you can't reach."

Feeling desperate, he tried nearly every commercial product available—from steaming machines to various repellent sprays. But nothing worked.

"I saw the hot steam kill them on contact, but it was just a surface solution,' he explained. 'The sprays couldn't touch the bugs buried deep in the hidden corners. None of the commercial products could stop the infestation from growing."

Faced with a home he could no longer feel safe in, he was left with one last, agonizing choice: the total removal of all his furniture.

His personal story motivated our team. It became a mission to ensure no one else would be forced into that kind of extreme, painful, and costly last resort.

Researching on the Bed Bug Infestation Problem in Hong Kong

The Prevalence of Bed Bug in Hong Kong

The common bed bug has escalated into a significant public health crisis in Hong Kong, an issue deeply rooted in the city's socioeconomic fabric. Initial studies revealed severe infestations across all districts, particularly in low-income areas like Sham Shui Po (80% prevalence) and Wong Tai Sin (71%) [1]. The problem is exacerbated by Hong Kong’s unique urban environment; the proliferation of densely packed subdivided flats creates a perfect storm for rapid, uncontrollable spread through shared walls and close quarters as the bugs "hitchhike" on clothing and belongings.

The severity of this issue profoundly impacts residents' quality of life. Infestations lead to severe physical discomfort from bites, which can cause allergic reactions, intense itching, and secondary skin infections [2]. Beyond the physical toll, the emotional and mental stress is significant, often resulting in sleep deprivation, anxiety, and social stigma, eroding a resident's sense of safety and well-being within their own home. [4]

The Unseen Invasion: Bed Bugs' Global Takeover

The resurgence of bed bugs is not just a local issue; it is a global public health concern, particularly in densely populated urban centers worldwide. A huge number of infestation cases are reported in not limited to private homes, but also hotels, transportations, healthcare facilities. [5] Bed bug infestations have been documented in the U.S., France, Spain, and several other European countries.[6] In Canada, bed bug infestations were reported at 20 (31%) of 65 homeless shelters. [7] As population density and number of tourists increases, the bed bug's primary method of spreading—hitchhiking in luggage and on personal items—allows infestations to cross international borders with ease, making proactive detection and prevention a global imperative.

The Behaviour of Bed Bugs–Key Challenges to Stop the Infestation

The challenge of controlling bed bug infestations is rooted in two of their most formidable biological traits: their elusive nature and their rapid reproductive rate.

Bed bugs have evolved to be master hiders; their small, flat bodies allow them to slip into the tiniest cracks and crevices—in mattress seams, behind baseboards, within furniture joints, and even inside electrical outlets [2]. This behavior means that most of an infestation is hidden from view, making it nearly impossible to target with conventional surface sprays or visual inspections.

Compounding this challenge is their prolific reproductive capability. A single female bed bug can lay hundreds of eggs in her lifetime, and just one or two bugs transported to a new environment can quickly lead to a full-blown infestation of thousands. This combination creates a perfect storm for persistence; even if a treatment eliminates the visible bugs, the hidden survivors and their eggs can rapidly repopulate the area, leading to a frustrating and seemingly endless cycle of re-infestation. [3]

Interviewing Different Stakeholders–a Resident, the Government, and a Social Work Professor

To move beyond the statistics and understand the human reality of this problem, a direct interview with a community resident living in an old tenement was conducted. This firsthand account provided a crucial insight: the primary barrier to tackling infestations is financial, as residents are unwilling to "waste money" on costly solutions.

This finding, which highlighted a disconnect between the severity of the problem and residents’ actions, raised a critical question about institutional support, compelling us to interview a government official from the Food and Environmental Hygiene Department. Our goal was to determine the government's role and level of public awareness regarding the issue. The interview revealed a limited institutional effort in bed bug control and a general lack of public awareness. This discovery highlighted the need for alternative, non-governmental approaches.

This realization inspired the next phase of our investigation, leading us to consult with a social work professor who has conducted relevant experiments, so as to seek expert insights on non-financial barriers and potential solutions. The professor’s perspective added another layer of complexity, explaining that the time-consuming and inconvenient nature of tackling bed bugs further deters residents, thereby perpetuating the problem. This synthesis of qualitative and quantitative data demonstrates that the issue extends beyond the insects themselves, encompassing a vicious cycle of poverty, insufficient public policy, and low societal awareness.

Conclusion: Why Bed Bug is a Serious Problem

The interwoven challenges of financial burden, inconvenience, and limited public awareness, as revealed through this progressive research process, highlight why existing solutions are failing and why a vicious cycle of re-infestation persists. The prohibitive cost of professional extermination and the significant time commitment required for existing methods act as major deterrents, particularly for vulnerable, low-income households. This problem is compounded by a lack of government-led efforts and a general unawareness within the community, as confirmed by interviews with both a government staff member and a community resident.

Current Methods to Deal with Bed Bugs:

Currently, there are four main methods for eliminating bed bugs: heat treatment, insecticidal treatment, repelling treatment and attraction traps. Unfortunately, the conditions required for these treatments significantly impact their effectiveness.

Heat Treatment

Heat treatment involves raising the temperatures of a house to eliminate bed bugs. Specifically, the area must be heated to above 50 degrees Celsius for at least four hours, which requires all living creatures to be evacuated from the house. Additionally, the specialized equipment, energy consumption, and labor-intensive nature of this process result in high costs, ranging from HK$ 5000 to 15000 on average.

Insecticidal Treatment

Insecticidal treatment necessitates multiple applications of insecticides, such as pyrethrums and pyrethroids to kill bed bugs. However, these chemicals are specialized and require extensive, regular supply, which not only leads to increased overall costs, around HKD 3200 , but also extends the duration of the treatment. Other than extended length and inconvenience, the insecticides are known to be harmful to the human respiratory system, especially children and elderly. Furthermore, due to the development of insecticide resistance, it has become ineffective and unable to kill them. [8]

Repelling Treatment

This treatment mainly involves chemicals, such as essential oil and orange oil, which cost around HKD 100 to HKD 200. However, this treatment usually needs to be combined with other treatments to completely eliminate bed bugs, such as extreme temperatures, resulting in high costs and inconvenience. Other than that, these chemicals irritate the human respiratory system and skin.

Interceptor Traps and Sticky Glue Traps

Another notable method to tackle the issue of bed bugs is the use of traps. Both interceptor traps and sticky glue traps are known for their effectiveness in detecting and monitoring bed bugs, but it’s not to say that they don’t have their flaws.

To start with, interceptor traps are pitfall-style devices commonly designed to attach to furniture, such that it catches active bed bugs that are climbing around the house. However, only around 0.11% to 0.61% of the bed bug population is caught per day by the aforementioned traps, which indicates that only trapping active bed bugs may not be the most efficient way to eradicate the issue.

In addition to interceptor traps, sticky glue traps are also well known to aid in detection and monitoring of many insects, including bed bugs. It functions by having adhesive on the sides of the trap, which immobilizes the bed bugs that walk across it. Although it’s quite safe and easy to use, it only catches bed bugs which are crawling, which significantly reduces the number of bed bugs the trap is able to catch. On top of that, it has a short lifespan, as adhesives also catch dust over time, decreasing its ability to immobilise the bed bugs. This means that constant replacement and purchases are involved, making it a tiresome task.

The Urge to Develop a New Solution

According to our research and interviews, the vast majority of families experienced bed bug infestation in Hong Kong belong to the working class, making it difficult for them to afford such high expenses. Furthermore, the ineffectiveness and tiresome procedures deter the willingness of people to engage. Given these factors, all of the methods mentioned may not be suitable for residents of Hong Kong.

To break this cycle, a new solution is required. As our research concluded, this solution must not only incorporate an educational component to raise awareness but also be a practical tool that directly addresses the core barriers. To be truly effective, this intervention must satisfy a clear set of criteria: it must be affordable for low-income residents, efficient in its application, and accessible for community-wide implementation. By meeting these criteria, a new approach can offer a viable and sustainable path toward controlling bed bug infestations and improving public health in Hong Kong's most affected communities.

Our Solution–Crushing the Problem Before It Can Hatch

We propose a paradigm shift from reacting to outbreaks to proactively preventing bed bugs from entering the home in the first place. The most effective strategy is to intercept these pests at their point of origin—the travel journey. By stopping even a single bug from being unknowingly carried into a new environment, a full-blown infestation can be avoided. This preventative approach is more effective, less disruptive, and ultimately more empowering for individuals than dealing with an established and elusive colony.

Our Project

Our solution is a portable, low-cost bed bug detection kit designed to intercept them during their "hitchhiking" phase on bags or luggage. The kit releases a chemical attractant that lures any hidden bugs into a specially designed enclosure—a "happy bed bug house"—that provides an ideal harborage, encouraging them to stay.

This allows a user to see at a glance if their belongings are compromised before bringing them inside. The objective is not mass trapping, but early detection; our kit serves as a sentinel system. The capture of even a single bug provides a strong indicator of exposure, enabling preemptive action. This shift in objective allows for a strategic departure from conventional trap designs, letting us optimize for sensitivity and cost-effectiveness to ensure the kit is affordable and accessible for widespread community adoption.

The New Approach to the Production of L-lactate

The success of our detection kit hinges on a safe, effective, and cost-effective attractant. Our initial screening for bed bug attractants included host-mimicking cues (CO2​, L-lactic acid, and more) and established pheromones (Dimethyl disulfide, E-2-hexenal and more).[9] Our analysis prioritized scalability and cost-efficiency alongside efficacy. Despite the proven effectiveness of the pheromones, their production via chemical synthesis is prohibitively expensive. CO2​ was dismissed due to environmental concerns. Consequently, we selected L-lactic acid. As a ubiquitous human metabolite, L-lactic acid can be generated through sustainable and low-cost bioengineering protocols, specifically utilizing anaerobic fermentation, thereby ensuring a viable and environmentally responsible approach for large-scale attractant supply. To ensure our kit remains affordable and accessible, we have developed a novel method for producing our key attractant, L-lactic acid in a cost-effective manner. Our approach utilizes genetically modified E. coli, a bacterium renowned for its rapid growth and scalability in production.

While standard E. coli naturally produces a different isomer, D-lactic acid, we employed a two-pronged genetic engineering strategy to optimize it for our needs. First, we overexpressed the gene for L-lactate dehydrogenase (L-LDH) to boost the L-lactic acid production pathway. Second, we used RNA interference (RNAi) to repress the gene for D-lactate dehydrogenase (D-LDH), effectively shutting down the competing pathway. This innovative bio-manufacturing process allows us to create the key component of our detection kit efficiently and economically.

Proposed Application of L-lactic acid

Leveraging our understanding of bed bug transmission via personal belongings, we have developed an innovative solution for proactive home defense. Our approach capitalizes on the known attraction properties of L-lactic acid to develop a specialized, hardware-based containment system.

The device contains L-lactic acid liquid designed to lure bed bugs that have unknowingly crawled into a person's belongings by evaporation. Once a bed bug is attracted, due to its favour to hide in dark places, it would stay in our trap. This feature allows users to easily and directly observe if any bugs are present in their belongings simply by checking the kit. This device would be applied within a small, enclosed environment, such as luggage or bags.

The fundamental principle is that whether one bug or a hundred are detected from the bags, the necessary action is the same: to carry out a small-scale treatment, such as discarding the contaminated item or thoroughly cleaning it, before entering the home. This preemptive measure stops the infestation from ever developing.

Reference

[1] Fung, H. C. E., Wong, H., Chiu, S. W., Hui, J. H. L., Lam, H. M., Chung, R. Y., Wong, S. Y., & Chan, S. M. (2021). Risk Factors Associated with Bedbug (Cimex spp.) Infestations Among Hong Kong Households: A Cross-Sectional Study. Research Square (Research Square). https://doi.org/10.21203/rs.3.rs-80113/v2

[2]Akhoundi, M., Zumelzu, C., Sereno, D., Marteau, A., Brun, S., Jan, J., & Izri, A. (2023). Bed bugs (Hemiptera, cimicidae): a global challenge for public health and control management. Diagnostics, 13(13), 2281. https://doi.org/10.3390/diagnostics13132281

[3] Reinhardt, K., & Siva-Jothy, M. T. (2006). Biology of the bed bugs (Cimicidae). Annual Review of Entomology, 52(1), 351–374. https://doi.org/10.1146/annurev.ento.52.040306.133913

[4]Burrows, S., Perron, S., & Susser, S. (2013). Suicide following an infestation of bed bugs. American Journal of Case Reports, 14, 176–178. https://doi.org/10.12659/ajcr.883926

[5]Liu, B., & Pennington-Gray, L. (2014b). Bed bugs bite the hospitality industry? A framing analysis of bed bug news coverage. Tourism Management, 48, 33–42. https://doi.org/10.1016/j.tourman.2014.10.020

[6]Brimblecombe, P., Mueller, G., & Querner, P. (2024). Public and media interest in bed bugs-Europe 2023. Current Research in Insect Science, 5, 100079. https://doi.org/10.1016/j.cris.2024.100079

[7]Hwang, S. W., Svoboda, T. J., De Jong, I. J., Kabasele, K. J., & Gogosis, E. (2005). Bed bug infestations in an urban environment. Emerging Infectious Diseases, 11(4), 533–538. https://doi.org/10.3201/eid1104.041126

[8]Lewis, C. D., Levine, B. A., Schal, C., Vargo, E. L., & Booth, W. (2022). Decade long upsurge in mutations associated with pyrethroid resistance in bed bug populations in the USA. Journal of Pest Science, 96(1), 415–423. https://doi.org/10.1007/s10340-022-01505-4

[9]Weeks, E. N., Birkett, M. A., Cameron, M. M., Pickett, J. A., & Logan, J. G. (2010). Semiochemicals of the common bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), and their potential for use in monitoring and control. Pest Management Science, 67(1), 10–20. https://doi.org/10.1002/ps.2024