r/dayz • u/runnick • Sep 20 '19
Discussion Infection and You: Diseases in DayZ
The release of 1.05 to PCs and hopefully soon to our console brethren, illness/sickness has been buffed and its effects made to be more dangerous. So, I thought I'd write a little-ish guide on one of the less understood gameplay facets of DayZ:
Diseases!
Not a completely new feature of DayZ, the disease system and diseases like Cholera, Kuru and Salmonellosis have been in game for some time. In previous iterations, the disease system was rather binary (you were either infected with the disease and all of its effects or you weren't) and catching a disease was often determined by a "dice roll". On the off chance a player was infected and didn't have the appropriate medicine, they merely needed to wait out an "infection timer". And if the player had the correct medicine, a single dose immediately removed the infection and all of its effects. This system prevented disease and illness from becoming much of a threat to anyone but the newest of players.
With the release of 1.0 all of this changed. A brand-new disease system was implemented. Adding modularity, complexity, different infection methods, player-to-player transmission and more interaction between a player's character and diseases.
Between all of these changes and the disabling/enabling and addition of new items and mechanics understanding of what and how some things work has been lost. In order to explain the disease system and, hopefully, clear up any confusion, I'm going to break it down into three parts. Part 1, Diseases & Complications, will explain what diseases are and what they are not and will explain the effects of becoming infected with a disease. Part 2, Player Immunity & Medicines, will explain how the player's immune system works to fight off infection and how the various medicines in DayZ work. Part 3, Putting It All Together, explains an example scenario in game and will show the interactions between everything in an effort to give you an idea of how things occur.
Because of the size of this guide, I've decided to leave out Disease transmission. This is already a bit of an info dump and transmission/infection has enough to it to warrant a guide of its own. I've also changed the names of some stats/variables as well some of their numbers and simplified the explanation of some mechanics to make things a little easier to understand.
Quick clarification on this term:
- Tick - Unit of time. You can think of 1 Tick as equivalent to 1 second.
## Diseases & Complications ##
- Diseases -
With the new Disease System, Diseases themselves now more closely resemble an entity (like the infected or animals), complete with its own stats.
| Stat | Range | Description |
|---|---|---|
| Disease Count | 1 - 5000 | This can be thought of like the disease's HP and can increase or decrease over time. Almost all diseases start at 1 when you get infected and have a maximum Disease Count. Depending on the disease, the maximum Disease Count can be a few hundred to several thousand. |
| Potency | 15 - 100 | This can be thought of like a disease’s strength. Determines whether or not the Disease Count grows (increase) or shrinks (decrease). |
| Growth Rate | 0.5 - 1 | If a disease can grow, how much it grows (increases in Disease Count) per tick. |
| Shrink Rate | 1 | If a disease cannot grow, how much it shrinks (decreases in Disease Count) per tick. |
| Antibiotics Resistance | 0% - 100% | This can be thought of like a disease’s dexterity/constitution. This stat reduces the effect the Antibiotics has on it. |
| Infectivity Stats | N/A | There are a few of these that determine the method(s) and ease of transmitting/becoming infected with the disease. This is outside of the scope of this guide, but I thought it was worth mentioning. |
Once a player becomes infected with a Disease, there is interaction between their Immune System and the Disease itself. Much like in real life, signs, symptoms and complications from having the Disease don't show up right away. A player can have (and transmit) a Disease for an extended period of time before their infection becomes severe enough for Complications to arise. Alternatively, a healthy player could become infected with a Disease and have their Immune System fight off the Disease completely before it ever becomes severe enough for Complications to occur.
- Complications -
Complications are the actual negative effects having a disease. Complications are responsible for causing Effects and Symptoms felt/seen by the player.
| Stat | Description |
|---|---|
| Activation Condition | At what point Complications start to occur. |
| Deactivation Condition | At what point Complications cease. |
| Effect(s) | Stat Loss. While this can be any stat, currently Water or Energy are the only two stats that are decreased. This typically happens each Tick. |
| Symptom(s) | A Symptom is a visual/audio/animation event: Coughing, Laughing, Shaking, Sneezing or Vomiting. These either have their own conditions for occurring or just happen intermittently. Symptoms may also have Effects of their own (e.g. Water loss or transmitting the Disease) |
Almost all Complications have an Activation Condition and a Deactivation Condition, an on/off switch if you will. Typically, the Activation and Deactivation Conditions are specific Disease Counts (i.e. Complications arise (or are Activated) when the Disease Count reaches x. Deactivation when the Disease Count reaches y.).
Once activated, Complications persist until the Deactivation Condition is met. For some Complications this occurs when a Disease's Count has been lowered substantially. For others, when a Disease has been completely eliminated. In the worst case, once activated, the only deactivation is the death of the player.
Activation and Deactivation counts are not the same, with Deactivation typically being much lower than Activation. Meaning that once Complications activate, they don't immediately stop (or deactivate) when a Disease's Count goes below the Activation count for its Complications. Additionally, a Disease's Maximum Count is typically far higher than its Complications' Activation/Deactivation count.
This is why two players with the same infection may have different recover times.
## The Player Immune System & Medicines ##
- Immune System -
Rather than being a passive, unchanging stat, the Immune System was designed so that choices and actions a player has made affects their immunity.
Stat-wise a player's Immune System really has only one: Immune Strength. This stat represents the overall health of a player's Immune System and its ability to fend off illness and disease. Determined by a player's Water, Energy, Health and Blood stats, a player's Immune Strength has a value between 1 and 100, with the highest value normally at 99.
Fighting Infection
Not simply a stat, the Player Immune System is also responsible initiating the "combat" between it and any infections the player may have. Every Tick a player's Immune System does the following:
- Gets every Disease a player is infected with and calculates the Immune System's current Immune Strength
- Compares each disease's Potency to the player's Immune Strength
- If the player's Immune Strength is greater than the disease's Potency, it decreases the disease's Count by its Shrink Rate.
- If the disease's Potency is equal to or greater than the player's Immune Strength, the Immune System is unable to fight off the disease and the disease's Count increases by its Growth Rate.
- Medicines -
Medicines are consumable items players can find that help fight off infection. These items, however, are not instant cures and take time to work. Like the Immune System, Medicines work every Tick to help reduce infections. There are currently 3 Medicines in DayZ explained below.
| Medicine | Duration | Effects |
|---|---|---|
| Charcoal Tablets | 5 min. | Reduces Salmonellosis Count by a little over 1 per Tick. This works in conjunction with the Immune System, so normal Salmonellosis growth or shrink still happens every Tick. |
| Tetracycline Antibiotics | 5 min. | Reduces all Disease Counts present by 4 per Tick. However, some disease has a resistance to Antibiotics which reduces, or in some cases, nullifies its effects. This works in conjunction with the Immune System, so normal disease growth or shrink still happens every Tick. |
| Vitamins | 5 min. | Boosts the Immune System's Immune Strength to 100, ensuring all but the nastiest disease's Counts will shrink every Tick. |
## Putting It All Together ##
Here I've put together an example situation, so that you can see the interactions of everything previously covered. Hopefully, this should piece everything together and give you a better understanding of the disease system and give you the tools to help you in game.
- Becoming infected -
Having recently finished hunting and skinning a wild boar you realize that you're thirsty. Having already finished your canteen, you head to the nearby town and drink from the well pump. Unfortunately, you forgot to wash your hands and now you have Cholera! Let's take a look at Cholera's stats.
Cholera
| Stat | Value |
|---|---|
| Count | 1 |
| Max Count | 1000 |
| Potency | 65 |
| Growth Rate | 0.5 |
| Shrink Rate | 1 |
| Antibio. Res. | 0% |
- Early Stages -
Now infected, every Tick your immune system is going to try and fight off the infection. You very recently had to assist a couple of players in giving their gear to you and were injured in the process. This injury and your low Water have led to a weakened Immune Strength of only 45.
Example Tick
- Since Cholera's Potency (65) is greater than your Immune Strength (45), your immune system is unable to fight off the infection and the Disease Count increases.
- Cholera's Count increases by its Growth Rate (0.5), so Cholera's Count is now 1.5.
This continues to happen each Tick and is all happening unbeknownst to you as your infection is not yet severe enough for Complications to arise.
- The Infection Worsens -
As time passes, Cholera's Disease Count eventually reaches 100. With your infection becoming severe enough, you begin to suffer from Complications of the diesase. Let's look at Cholera's Complications.
Complications
| Stat | Value |
|---|---|
| Activation Count | 100 |
| Deactivation Count | 0 |
| Effect | Water Loss: 0.5/Tick |
| Symptom(s) | Vomiting |
At first, there isn't any obvious signs that anything is wrong. Complications from your Cholera infection is causing you to lose more Water each Tick, but this is a subtle effect and not immediately noticeable. At some point, however, you vomit.
Now you are thirsty again. Although this could have been caused by the vomiting, you know that you are losing Water faster than normal and are almost certain you're sick. With no medicine on you, you head towards the nearest village and begin looking for the next best thing, food, vitamins and (clean) water.
While all of this has been happening, your Cholera infection has only continued to get worse. The vomiting and Water loss have only further weakened your Immune Strength (38) all the while Cholera's Count (400) has continued to rise. Now losing Health due to low Water and Energy, all seems lost.
- Recovery -
Unsure what to do next, you sit next to another well pump and hope for the best. Suddenly, a wild /u/Tatanko appears. After listening to your story Tatanko assesses the situation and decides to help you out. Always prepared, Tatanko drops Antibiotics and Vitamins for you and tells you to take one (1) of each. Within moments of you taking the Vitamins and antibiotics, they begin to take effect.
Example Tick
- Your Immune Strength, boosted by the Vitamins, is now 100.
- Since your Immune Strength (100) is greater than Cholera's Potency (65), your immune system begins killing off the infection and Cholera's Count decreases.
- Cholera's Count decreases by it's Shrink Rate (1).
- The Antibiotics also attack the infection. Having no Antibiotics Resistance, Cholera's Count is further decreased by 4.
So, in total your immune system, with the vitamins and antibiotics help, is reducing Cholera's Count by 5 per Tick.
Excited, you jump up to continue helping other players with their gear... and immediately throw up. Tatanko laughs and warns you that you're not out of the woods yet and to rest for a bit. This will allow your immune system and the antibiotics enough time to fight off the infection. Tatanko then gives you some food and water and tells you to take small sips/bites every few minutes. This will slowly replenish your Water and Energy and will assist in preventing additional vomiting.
Even with the help of the Vitamins and Antibiotics, it still takes some time for the Complications of your infection to disappear and for your immune system to completely defeat the infection.
Tips
- Small sips and bites. This isn't a myth. The devs have cleverly implemented ways of determining whether or not your character will vomit while he/she is sick. Trying to eat and drink a ton of water is almost a guaranteed way to ensure your character is going to throw up. If you are sick, make sure to drink and eat small amounts every few minutes to help offset Water and Energy loss from being sick.
- Vitamins, Antibiotics and Charcoal can be used proactively to prevent an infection from getting out of hand. (Although the you may want to hold on to your Antibiotics and Charcoal Tabs given their smaller amounts and relative rarity)
- Consuming multiple Vitamins, Antibiotics or Charcoal Tabs does NOT stack the effect. Instead, it refreshes their respective timers.
- Staying hydrated, energized, healthy and... bloodful? will ensure that your immune system can fight off most diseases on its own.
- Yes, Water Bottles and Canteens can spawn in with "dirty" infected water. Unless desperate, always use Chlorine Tablets or empty the bottle and refill from a well pump.
- Been playing outside without gloves on and now you have blood all over your hands? Go wash them before you eat or drink from the well pump.
- Put your jacket on before you go outside. Seriously. You don't want to catch a cold.
- There is no cure for Brain Disease/Kuru/Prion Disease. It's totally resistant to antibiotics and even with a boost from vitamins too strong for your immune system. Try not to eat other players.
I hope this helps explain what I think to be one of the more underrated aspects of the game. If you see any mistakes here or have any questions don't hesitate to send me a message.
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u/STR-6055 Sep 20 '19
Wow! Very nice write-up. I read through it once and I think you've done a terrific job. You mentioned that taking mulitple vitamins, antibiotics, etc., does not stack the effect. How about taking different medications simultaneously? Is it wise to take a vitamin and an antibiotic at the same time or should you wait until the pill effect has dissipated. As far as I know, DayZ's stat indicator will only show one pill which leads one to believe that only one medication is taking effect.