14 Most Contagious and Killer Diseases in Japan

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In this article we'll look at a list of Japan's most contagious diseases and also a ranking of those that kill the most annually.

Japan is known to be a country that cares a lot about health! This is possible to see because even before the pandemic caused by Covid-19 they already had the habit of wearing masks to prevent illnesses and to not infect others in cases of flu.

But every country faces its outbreaks of infectious diseases due to insects and animals typical of the region, season of the year and among many other reasons.


In this article, we'll look at which diseases are the most contagious in Japan (mostly children are the victims) and which ones are killing Japanese people the most in recent years. 

01 - Influenza

It is an infectious disease caused by a virus. There are types A, B and C. The types that affect humans today are type A from Hong Kong, A from Russia and B. The symptoms are more severe than normal flu.

Symptoms are usually very high, persistent fever, coming and going; weakness and lack of appetite; pain throughout the body; sometimes vomiting and diarrhea, coughing among others.

After the diagnosis, which can be through the exam that is inserted the cotton swab in the nose, the doctor gives medicine orally. In case of worsening, return to the doctor.


You can see a Japanese Medicines Guide for allergies and flu in our article. The image below shows some of the most common remedies to treat the symptoms.

14 doenças mais contagiosas e as que mais matam no japão

02 - Measles (Hashika)

Infectious disease caused by the measles virus. Highly contagious, there are many complications associated with the disease, considered as a serious disease. Prevention is the vaccine.

There is no specific treatment for measles, but after the diagnosis, the doctor uses medications to alleviate the symptoms so as not to worsen. 


03 - Rubella (Fushin)

Contagious disease caused by the rubella virus. Also known as three-day measles. Getting rubella in early pregnancy can cause your baby to become abnormal. It also doesn't have a specific treatment, but medicines to soothe the itching and rashes. 

04 – Mumps (Otafukukaze)

Contagious disease caused by the mumps virus. If symptoms of pain or fever appear, go to hospital immediately to prevent the situation from getting worse. 

Avoid acidic foods or foods that require a lot of chewing. Avoid taking a bath (furo) in case of fever and pain.

14 doenças mais contagiosas e as que mais matam no japão

05 - Chickenpox or Chickenpox (Mizuboso)

A contagious disease caused by the herpes zoster virus. Medicines are used to prevent the spread of the “herpes zoster” virus and ease the disease.

Other oral medications and/or ointments are used against itching. In case of pus formation, antibiotics are given. 

06 – Erysipelas or Infectious Erythema (Ringobyo)

Infectious disease caused by the human parvovirus B19 virus. If it contracts during pregnancy, there is a risk of miscarriage.

There is no medicine to cure the disease. If necessary, the doctor will administer a medicine if the itching is very intense.

07 - Herpangina (Herupanguine)

It is a kind of flu that has a herpes-like blister on the tongue as one of its symptoms. It is known as the summer flu, caused by a virus. There are several viruses that cause herpangina, appearing frequently.

The disease causes a high fever of 38º to 40ºC for 1 to 4 days, blisters appear on the tongue and inside the throat, which once ruptured, turn into stomatitis, causing a lot of pain.

08 – Hand, foot and mouth disease (Teashikuchi-byo)

Infection caused by this disease virus is more common during the summer. There are several types of viruses that cause the disease, so you can get it several times. 

The improvement is even quick, but if you are unable to ingest fluids, the fever lasts for more than 3 days, you have vomiting and are tired, you should go to the hospital again. The disease got its name for causing sores on the hands, feet and mouths.

14 doenças mais contagiosas e as que mais matam no japão

09 – Sudden Rash or Infant Roseola (Toppatsusei Hasshinsho)

Infectious disease caused by the herpes virus 6 that usually affects children aged 4 months to 2 years. The fever lasts an average of 3 days. It is impossible to diagnose until the rash appears.

10 - Psycine Fever

Pharyngoconjunctival Fever or Pool Fever (Intoketsumaku netsu / Puru netsu) is a contagious disease caused by a virus. It is common to get this disease in swimming pools. 

 The fever is high from 39° to 40°C (mainly at night) and lasts for around 5 days. Causes sore throat and red eyes, headache, stomachache and diarrhea.

11 - Streptococcal infection (Yorenkin kansensho)

A contagious disease caused by streptococci. The main symptoms are fever and sore throat, but small red rashes may appear. body, hands and feet. The tongue is left with small red bubbles.

It is an extremely contagious disease so it will spread to the whole family. As long as everyone in the family doesn't recover, you will be susceptible to the disease again.


12 - Whooping Cough (Hyakunichi seki)

It is a dangerous disease for babies that can cause respiratory arrest. They also affect older children and adults, but with mild symptoms. 

13 - Contagious Mollusk (Mizuibo)

Infectious disease caused by viruses. It is characterized by clear skin tumors. When it breaks, concentrated solid white substances of virus come out. As a result of an allergic reaction to the virus, hives may appear around the lesions, causing itching.

In all the diseases mentioned above, the orientation is to stay at home (go out only for what is necessary), not to receive visitors, when going out to wear a mask. 

Information on these diseases is sourced from the Hamamatsu Channel, the City Hall website and its content portal aimed at foreigners. 

14 doenças mais contagiosas e as que mais matam no japão

14 – Japanese Encephalitis 

Japanese encephalitis is an acute infectious disease caused by a flavivirus (the Japanese encephalitis virus) capable of affecting the central nervous system. Transmission is by mosquitoes.


There are about 30 to 50 thousand cases per year in the world and, in Asia, it is the main cause of viral encephalitis in children. One person does not directly transmit Japanese encephalitis to another.

The transmission takes place through the mosquito bite infected. The Japanese encephalitis virus has wild birds and pigs as its natural hosts. 

This disease if left untreated can even lead to coma. That's why it is included in the mandatory vaccinations for those going to Japan. 

14 doenças mais contagiosas e as que mais matam no japão

12 Diseases that Kill the Most in Japan (2019)

According to the 2019 Disease Ranking, we can have a notion of the diseases that kill the most in Japan below:

  1. Alzheimer's
  2. cerebrovascular disease
  3. ischemic heart disease
  4. Lower respiratory infections
  5. Lung cancer
  6. colorectal cancer
  7. stomach cancer
  8. chronic kidney disease
  9. COPD (chronic obstructive pulmonary disease)
  10. pancreatic cancer
  11. liver cancer
  12. self-injury