Japanese spotted fever is a classified spotted fever disease (rickettsioses) that’s common to Japan and South Korea. The tickborne disease is usually only found in the United States when it’s imported from travelers outside the country. The disease was first discovered in Japan in 1984 and there are about 200 cases of it there annually. 

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Signs and Symptoms 

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The three most typical symptoms of Japanese spotted fever are erythema (redness of the skin), fever, and eschar (a piece of dead tissue that forms on the skin). Erythema and fever occur more commonly than eschar, however. There’s usually no pain or itching accompanying the redness. In addition, the erythema appears on the extremities, trunk, hands, and soles of the feet. 

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Until it was isolated as its own disease, cases of Japanese spotted fever were thought to be scrub typhus. The two have similar symptoms but differ in severity and usually aren’t contracted during the same times of year. 

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It’s thought that many cases of Japanese spotted fever go unreported in Japan because those afflicted don’t notice the erythema right away, nor do they associate it with a tick bite. 

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What Bacterium Causes Japanese Spotted Fever? 

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Japanese spotted fever is caused by Ricksettia japonica. This particular ricksettia agent was identified in a patient in Japan in 1987. It’s a species of bacteria belonging to the fever group Ricksettia. There are 10 human diseases worldwide that are caused by ricksettiae bacteria. These are Rocky Mountain spotted fever, Mediterranean spotted fever, Siberian tick typhus, African tick bite fever, Queensland tick typhus, Japanese spotted fever, Israeli spotted fever, Astrakhan spotted fever, Flinders Island spotted fever, and rickettsialpox. 

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All of these have the associated symptoms of fever, rash or erythema, and eschar. Some also include symptoms like headaches or fatigue. The ricksettiosis spotted fevers range in severity, with some being mild and others being life-threatening. Japanese spotted fever can be severe or fatal when left untreated. For more info about imported spotted fever diseases, check out this link from the CDC. https://www.cdc.gov/otherspottedfever/imported/index.html 

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Which Tick Carries Japanese Spotted Fever? 

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Researchers are still determining which tick species are vectors for Japanese spotted fever. So far, 3 tick species have been confirmed - Haemaphysalis longicornis (the Asian longhorned tick), H. flava, and Dermacentor taiwanensis. 

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The Asian longhorned tick has recently been discovered in the United States, in 2017. In 2019 the first bite from an Asian longhorned tick was reported. The patient was treated for Lyme disease, although it’s unknown exactly which disease afflicted this patient. http://www.cidrap.umn.edu/news-perspective/2019/06/first-us-human-bite-worrying-longhorned-tick-noted 

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Little is known about the diseases that Asian long-horned ticks could spread in the U.S., but it’s responsible for ehrlichiosis, babesiosis, Powassan virus, and Japanese spotted fever in other parts of the world. American researchers are wondering if the same pathogens could become prevalent in the United States as well.  https://newsnetwork.mayoclinic.org/discussion/infectious-diseases-a-z-why-the-asian-longhorned-tick-is-more-than-a-menace/ 

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Cures and Treatments 

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Japanese spotted fever typically develops between 2-8 days after being bitten by an infected tick. Patients are usually treated with antibiotics and recover fully. Most won’t see the fever break until 5 days after starting treatment, however. 

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Currently, there is no reported fatality rate for Japanese spotted fever, although the CDC states that the disease can be severe if left untreated. Official diagnosis of this disease is confirmed by testing blood or eschar samples in a lab setting. As this disease can develop rapidly, treatment usually starts before confirmation of the test results, though. 

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Even though Japanese spotted fever is unconfirmed in the United States, it’s still always advisable to see a doctor if you feel sick after a tick bite. 

 

Areas in Danger of Being Bitten 

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The possibility to contract Japanese spotted fever in Connecticut and in the U.S. is low, but you could be infected if you travel to a country where it’s prevalent. It’s common in Japan, South Korea, and has even been reported in China. https://wwwnc.cdc.gov/eid/article/24/11/17-0264_article 

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The preferred environments for Asian long-horned ticks in the U.S. are still unconfirmed, but it’s thought they may favor short-grass meadows in addition to wooded, tall-grass areas. Extra caution should therefore be taken when going outdoors during tick season. This is usually late spring to late summer, April – September. Although, seasonality varies on the tick species. 

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Final Thoughts 

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Whether at home or traveling abroad, prevention is the best method to keep from getting tick-borne illness. Be aware if you live in or plan to travel to an area known for tick-borne diseases or as a common tick habitat. 

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In addition, take precautions if plan to go outdoors in these areas. Use DEET repellent and consider treating your clothes in permethrin before venturing out. Cover your body as much as possible with long sleeves, pants, socks, and closed-toe shoes. And when you return home, always check yourself and your pets for ticks before going back inside. With the right prevention, you can protect yourself from tick-borne illness.