Cells at Work's Guide to the Rogues Gallery Inside Your Body

Cells at Work brings the workings of the inner body to life in a fun way with its colorful characters, but how dangerous the bacteria to our bodies?

Cells at Work may not have seemed to be the educational thrill ride that it turned out to be at first, but in the end the series has taught us a lot about the human body, from how blood cells circulate, to where they come from, how the immune system operates, and even the way our body can sometimes fight itself when fighting intruders. While Red and White Blood Cell became memorable characters this season, the villains of Cells at Work presented daily, common threats to the human body in very anime designs, making them just as memorable. But how dangerous are these various intruders? What do they actually do? And which one of them is the worst?! We’ll be talking about the rogue’s gallery of the human body that’s popped up in Cells at Work, helping you all learn a bit more about not just the human body, but the threats posed to it by the outside (and inside…)!

Pollen Allergen

Cedar Pollen

Our first invader is the generally harmless pollen allergen. In the anime, Cedar Pollen is the culprit, but depending on where you’re located, you might encounter all different types of pollen and allergic reactions! Unlike other types of allergies, such as food allergies, the type caused by Cedar Pollen and other irritants is rarely life threatening, but instead just simply annoying, causing sneezing, itchy or watery eyes, congestion, and other sinus related symptoms. Matching their large, harmless, and clueless, anime counterparts, pollen, dust, and animal dander generally enter the body through the nasal cavity or other openings by accident and create inflammation reactions from the body. Perhaps ironically, most medications taken for these types of inflammations, known as Antihistamines, are taken to help calm the Mast cell’s response to the invasion, rather than fighting off the allergen itself. Hay fever thankfully doesn’t last very long, but if you happen to suffer from you, you certainly know how annoying it can be whenever that time of year comes around!



One of the first threats we’re introduced to in the anime is Pneumococcus, a bacteria who is also known as Streptococcus pneumoniae. In Cells at Work, Pneumococcus appears as an almost Dragon Ball Z-esque villain, with sharp talons and numerous dangerous abilities. The real Pneumococcus is indeed quite dangerous and powerful, but also very common and deceptively responsible for a number of ailments. While the first reaction might be to think pneumonia, Pneumococcus is also responsible for causing types of meningitis, bronchitis, conjunctivitis, and many other infections and diseases that mainly target the respiratory system. Pneumococcus is actually quite common in the human body, however, and even lives generally harmlessly in nasal and respiratory tracts until it becomes pathogenic, which is when the real danger starts! There are a few vaccines to prevent some of the real dangers, but it's quite common to blame Pneumococcus for many of the common colds you encounter. 

Staphylococcus Aureus

Staphylococcus Aureus

Similar to Pneumococcus, the bacteria Staphylococcus Aureus is another normal inhabitant of the human body, usually circulating around the nose and respiratory system and the skin. Represented in the anime as a haughty ojou-sama with grape theming, Staphylococcus does indeed have a somewhat grape-like shape (thus, as explained by the anime, the reason for its name!), but how dangerous is it? Staphylococcus is quite common and actually quite dangerous if it begins to become pathogenic! Like Pneumococcus, it spends a lot of time around the human body, and can even have some beneficial effects, but when it becomes pathogenic, it can be a real danger, even morphing into the dangerous MRSA! Staphylococcus tends to enter the body through abrasions in the skin, and play a large role in types of skin infections like boils, cellulitis, and atopic dermatitis (widely known as eczema). Staphylococcus also plays a big role in food poisoning, and in many cases humans come into contact with it from types of fluid from the human body like pus. There are also cases in which people who use injection medication or need implants for medical treatment have had to fend off Staphylococcus, as it tends to be enter the body through these types of openings in the body. While it may give off a haughty “Ohohohoho” and a “desu wa” in the anime, there’s certainly nothing regal or nice about this bacteria!


Vibrio & Anisakis


If you’ve ever gotten a stomach flu after eating improperly prepared seafood, you’ve likely had an encounter with the bacteria Vibrio. Although nowhere near as common as the other bacteria, Vibrio is quite dangerous, and can be very lethal! Vibrio can be easily treated, however, if caught in time, and if patients take good care to listen to their bodies, but it certainly is a potential danger to watch out for. Unlike some of the other bacteria, Vibrio strains aren’t normally occurring in the human body that turn pathological, which is why it tends to be particularly dangerous when introduced accidentally. While Vibrio can cause at the least a bad time in the bathroom, the Anisakis parasite it shares an episode with is potentially more dangerous! Also attached to seafood, Anisakis can cause Anisakiasis, and potentially even allergic reactions in certain people. Perhaps ironically, Anisakis is dangerous after its own death; after trying to burrow through the intestines, Aniksakis gets stuck and dies, and can cause blockage of the digestive system, or further infection if the larvae it sheds spread into other parts of the body. The anaphylaxis shock it can create in allergic patients is even scarier, and requires immediate life saving treatment!

Bacillus cereus

Bacillus cereus

Although portrayed as a dangerous invader in Cells at Work, Bacillus cereus is a somewhat interesting bacteria that can be as helpful as it can be harmful. Like some of the other bacteria featured in the show, Bacillus cereus is naturally occuring and populated amongst living organisms like humans. In fact, Bacillus cereus has an important job in the digestive tract, acting as one of the three types of bacteria found in the gut that compete with one another, and in so doing, help reduce the danger of bacterial infections from food. Salmonella and Campylobacter are the other two, and just like them, Bacillus cereus can be very dangerous if too much of it is found in the body! In cases of potential Salmonella problems, Bacillus can even be used as a treatment, consuming and fighting with the Salmonella bacteria. However, the biggest threat of Bacillus cereus is that it is very heat and alcohol resistant, making it quite hard to kill. One of the most common places to find Bacillus is in improperly stored food, being the main culprit of “fried rice syndrome,” appearing in food that sits at room temperature for too long. So while Bacillus cereus can help keep us healthy and protect our digestive tracts, it can also be quite dangerous, so make sure to store your food properly!



Showing up to try and opportunistically feast on a young Red Blood Cell, the dastardly Pseudomonas lives up to that depiction in the way it operates in the human body! Pseudomonas is a bacteria that has the ability to survive in conditions that many other bacteria cannot, meaning that the infections that it causes can be hard to prevent and take care of. Pseudomonas is an “opportunistic” bacteria, hunting down nutrients to sustain itself in places that few other bacteria would ever be able to survive in, and can withstand medical treatments that other types of bacteria can’t stand up against! Pseudomonas are dangerous, as they have many tricks up their sleeve to survive harsh conditions and treatments, making them particularly hard to get rid of. Pseudomonas is one of the leading causes of types of pneumonia, and tends to be the cause of hospital related infections ranging from pneumonia and UTIs. Pseudomonas are resistant to penicillin, as well as many other antibiotics due to its ability to survive where other bacteria cannot. While Pseudomonas can be helpful in controlling certain types of crops and soil conditions, it is an extremely dangerous bacteria that is very hard to get rid of, making it a somewhat infamous threat.



Speaking of the flu, one of the more dangerous rogues in Cells at Work’s list of invaders is Influenza, an infectious disease that can cause a range of symptoms from minor discomfort to lethal consequences! Often mistaken for a “cold,” or mistaken as the root cause of “stomach flu” or “24 hour flu,” Influenza is a unique and dangerous disease caused by a virus rather than a bacteria.  The Flu’s biggest danger is that it is easily passed from one person to another, making “Flu season” a yearly dangerous and unwanted season that can put numerous populations at risk of infection. While many younger people and healthy adults will shake off the flu as an irritant, or present no actual symptoms, many people who catch the Flu can suffer a range of debilitating symptoms. While Flu shots help keep the disease at bay, many people rarely get one or think they need one, meaning that Flu outbreaks are quite common across the world. To make matters worse for the overworked members of our immune systems, the Flu is constantly changing, with different strains and viruses that pop up from various places and circumstances. When you hear Flu season is coming, consider getting a flu shot, wash your hands, and if you feel ill, stay home or seek out a doctor. You don’t want to play around with the Flu or make other people ill!

Cancer Cell


Perhaps unsurprising for those who watch Cells at Work and know a bit about medical diseases, our final and most dangerous rogue is the lowly (at first!) Cancer Cell. Unlike the other invaders and unwelcome visitors mentioned here, cancer cells are not only common, but occur in almost every person’s body to some degree during life. Cancer cells are cells that don’t stop dividing, instead spreading at a dangerous rate and causing numerous debilitating and dangerous health complications, including death. While some cancers are affected by outside influences like smoking or exposure to substances like asbestos, cancer cells will also generally appear in the body during cell division, only becoming a problem when their spread is left unchecked by the immune system and they are able to grow into tumors and other health problems. Cancer benefits from a unique feature called Telomerase, which gives them an unnaturally long lifespan compared to a regular cell, which is why their endless growth and division becomes a problem if left unchecked by the body or by medical treatment. Sadly, many cancers are fatal, and it is important to learn how to properly detect and treat cancer; while the tragic fate of the Cancer cell is to be hunted by the very cells that surrounded it in the body, if left unchecked Cancer will potentially cause life threatening harm to the body.


Cells at Work certainly presents a whole host of unique dangers to the human body, but sometimes these invaders can be beneficial to ourselves, or the world around us. Others grow unwittingly inside of our own body, becoming a problem when there’s no checks or balances to take care of them early enough. Hopefully, between this article and Cells at Work, you can start identifying threats to your beloved cells early! So remember: wash your hands, properly treat cuts and wounds, cook foods to proper temperatures and store them properly, and seek medical help if you need it! Your cells are counting on you to do your part in helping them do their jobs!

Know any other interesting medical facts brought up by Cells at Work? Have a particularly favorite Cell or Invader?  Let us know in the comments!


Nicole is a features and a social video script writer for Crunchyroll. Known to profess her love of otome games over at her blog, Figuratively Speaking. When she has the time, she also streams some games. Follow her on Twitter: @ellyberries 

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