Photo/Illutration A man is vaccinated against rubella at a clinic in Tokyo's Minato Ward in September. (Asahi Shimbun file photo)

With the completion of the long Golden Week holidays, everyone needs to pay attention to their mental and physical health, whether they took time off or not.

We must be particularly vigilant against certain contagious diseases, including measles, that may be spreading from people who have just traveled at home and abroad.

Four years ago, the World Health Organization declared the extinction of Japan’s indigenous measles virus.

Yet, more than 400 measles patients have been confirmed in Japan so far this year, the worst in a decade.

Viruses carried by people who traveled in the Philippines, Vietnam or other countries are believed to be sparking small-scale outbreaks.

The disease is spreading around the world. In New York, where measles was declared eradicated years ago, several hundred cases have been confirmed, and the mayor declared a public health emergency in April.

An outbreak of dengue fever occurred in Japan in 2014, and more than 200 cases of contamination from overseas travel have since been confirmed every year.

Mosquitoes in Japan carry the virus, and it would be no surprise if an outbreak recurs.

We also need to watch out for Middle East Respiratory Syndrome (MERS), which infected about 180 people in South Korea in 2015, killing 38.

Some diseases can be asymptomatic or remain dormant for long periods. We must understand that their spread cannot be completely stopped at airports and other border checkpoints.

Regional setups are needed to allow hospitals and clinics to share data and trends of contagious diseases that may be brought in, and to deal immediately with any suspected case through collaboration with related authorities.

There is always the possibility of doctors missing initial symptoms because of their inexperience with specific diseases. Training in anticipation of hospital-acquired infections is also required.

Infections from abroad are not the only cause for concern.

Rubella, a disease that can harm fetuses, has affected more than 1,000 people in Japan this year, mainly in Tokyo. Last year, the number of rubella cases was the largest since 2013.

The U.S. Centers for Disease Control and Prevention has warned pregnant women who have never experienced rubella or are not vaccinated against it not to travel to Japan.

Many rubella patients in Japan are adult males because shots were given only to females for a certain period. The health ministry now offers antibody screenings and vaccinations for free, in principle, to men aged 40 to 57.

The measles outbreak in the United States is attributed to the large number of people who have never been vaccinated.

This goes to prove the importance of maintaining a high percentage of people who have antibodies to contagious diseases. It is vital to educate every member of the public and raise their awareness.

The number of foreign visitors to Japan, either tourists or workers, continues to grow, and the Tokyo Olympics and other big events are coming up.

It is of growing importance to reinforce measures against contagious diseases to protect the health of Japanese citizens and foreigners alike and build a safe society.

--The Asahi Shimbun, May 8