Tularemia - Tularemia

Japanese: 野兎病 - やとびょう（英語表記）Tularemia

What kind of infection is it?

Tularemia is a zoonotic disease that occurs only in the Northern Hemisphere. The pathogen, Francisella tularensis, infects wild animals such as ground squirrels, rabbits, voles, foxes, and bears, birds such as pheasants and quails, livestock such as cows and sheep, and pets such as dogs and cats. More than 125 animal species are infected with this bacteria. Host ( Shuck ) It is said that lagomorphs, Rodentia ( Gesshimoku ) It can also be infected by ticks, fleas, mosquitoes, horseflies, lice, and other insects that parasitize other animals.

It is known that there are attenuated and highly virulent strains in North America, but the strain in Japan and Scandinavia is said to be of the attenuated type.

It is considered to be a bacteria that could be used in bioterrorism, and is classified as a Class 4 infectious disease under the Infectious Diseases Control Law.

How symptoms manifest

After an incubation period of 2 to 10 days, fever, Chills ( Mom ) Symptoms include headache, joint pain, etc. The type of disease varies depending on the site of bacterial invasion.

In the Western Hemisphere, approximately 85% of cases are ulceroglandular, with lymph node involvement swelling ( Chief ) Localized swelling Necrotizing ( Eshisei ) This type, where no initial lesions are found, is commonly seen in Japan.

When infection occurs through the conjunctiva, it is called the oculo-lymph node type, and causes conjunctivitis with eyelid edema (swelling) and small ulcers, as well as swelling of the lymph nodes. Other types that show swelling of the lymph nodes include the nasal lymph node type and Tonsils ( Tonsil ) There is a lymph node type.

The pulmonary type without lymphadenopathy is caused by aerosol (tiny particles suspended in the air) infection and causes pneumonia in one or both sides.

The typhoid form, which is transmitted orally through contaminated rabbit meat or water, is rare but difficult to diagnose and causes gastroenteritis, fever, toxemia and sometimes pneumonia.

Testing and diagnosis

Definitive diagnosis is made by isolation of the bacterium or serology. In the case of serological diagnosis, caution is required as there is cross-reaction with brucellosis and Yersinia infections (antibodies react with them).

Because the disease types are diverse, it is necessary to distinguish it from many infectious diseases. Streptococcus ( Contact us ) or staphylococcal infection, contagious Mononuclear ( Size ) ( ball ( nine ) ) Disease ( Sho ) , toxoplasmosis, Groin ( Sokei ) lymph Granuloma ( Meat ) , cat scratch disease, pasteurellosis, plague, etc., and in the case of typhoidal diseases, Q fever, brucellosis, malaria, salmonellosis, tuberculosis, psittacosis, legionnaires' disease, typhoid, etc. must be distinguished.

Treatment methods

Streptomycin is the drug of first choice, and chloramphenicol and tetracycline are known to cause recurrence.

What to do if you notice an illness

If you experience any of the above symptoms after visiting an endemic area, you should disclose this to your doctor, including whether you have had contact with animals.

Akio Yamada

Tularemia and rhinitis
Tularemia
(Infectious Diseases)

What kind of infection is it?

Tularemia is an acute febrile disease caused by infection with the bacterium Francisella tularensis. It is mainly transmitted by touching infected wild rabbits or mice or their carcasses, or by the bacteria entering through the hands when dissecting them. It can also be contracted by being bitten by ticks or horseflies, or by drinking or inhaling water, food, or dust contaminated with the bacteria.

In the past, many cases were reported in the Kanto and Tohoku regions. Although rare, cases still occur today. A large number of infected people are reported every year in the United States and Europe.

How symptoms manifest

The incubation period is usually 3 to 7 days, and cold-like symptoms such as sudden fever, headache, chills, muscle pain, and joint pain appear. After that, lymph nodes in the armpits and elbows often swell. In addition, the fingers where the bacteria entered may become swollen. Ulcers ( Canker ) or Necrosis ( Replying to @sarah_mcdonald ) There have been no fatal cases in Japan.

Testing and diagnosis

If symptoms such as fever or swollen lymph nodes appear after activities in the mountains or fields or contact with wild animals such as hares, tularemia is suspected and antibody tests for the tularemia bacteria in the blood, bacterial cultures from the lesions, and genetic tests are performed.

Treatment methods

Antibiotics are effective, especially when they are administered early, and may be started without waiting for test results. Tetracyclines, fluoroquinolones, streptomycin, and gentamicin are effective, but penicillins and cephalosporins are ineffective. If lymph nodes become infected, surgical incision may be necessary.

What to do if you notice an illness

When outdoors, it is important to take precautions such as avoiding tick bites and avoiding contact with sick or dead wild animals. There is no vaccine against tularemia in Japan.

Fever, headache, chills, lymph node swelling, etc., after activities in the mountains or contact with wild animals. swelling ( Chief ) If you experience any symptoms such as swelling, see a doctor immediately. The virus is not transmitted from person to person.

Kiyoshi Tanabayashi

Source: Houken “Sixth Edition Family Medicine Encyclopedia” Information about the Sixth Edition Family Medicine Encyclopedia

Japanese:

どんな感染症か

　野兎病は、北半球のみに発生する動物由来感染症です。病原菌は野兎病菌で、地リス、ウサギ、ハタネズミ、キツネ、クマなどの野生動物をはじめ、キジ、ウズラなどの鳥類、ウシ、ヒツジなどの家畜、イヌ、ネコなどのペットに感染します。125種以上の動物種が、この菌の宿主(しゅくしゅ)になるといわれています。ウサギ目、齧歯目(げっしもく)の動物に寄生するダニ、ノミ、カ、アブ、シラミなどにも感染します。

　北米には弱毒型と強毒型があることが知られていますが、日本やスカンジナビアの菌は弱毒タイプといわれています。

　バイオテロで使用される可能性のある菌とされており、感染症法で4類感染症に位置づけられました。

症状の現れ方

　2～10日の潜伏期ののち、発熱、悪寒(おかん)、頭痛、関節痛などの症状で発症します。細菌の侵入部位によって異なる病型を示します。

　西半球では約85％が潰瘍リンパ節型で、リンパ節の腫脹(しゅちょう)（はれ）を伴う局所の壊死性(えしせい)の潰瘍が現れます。この型で、初期病巣が認められないリンパ節型は日本で多くみられます。

　結膜から感染した場合は眼リンパ節型と呼ばれ、まぶたの浮腫（むくみ）ならびに小潰瘍を伴う結膜炎とリンパ節の腫脹が生じます。このほか、リンパ節腫脹を示すものには、鼻リンパ節型と扁桃(へんとう)リンパ節型があります。

　リンパ節腫脹を伴わない肺型はエアロゾル（空気中に浮遊する微小な粒子）感染によるもので、片方あるいは両側の肺炎を起こします。

　汚染されたウサギの肉あるいは水を介して経口的に感染するチフス型はまれですが、診断が難しく、胃腸炎、発熱、毒血症を示し、肺炎症状が現われることもあります。

検査と診断

　確定診断は菌の分離によって、あるいは血清学的に行います。血清診断の場合には、ブルセラ症、エルシニア感染症との交差反応（抗体がそれらとも反応してしまう）があるので注意が必要です。

　病型が多様なので、多くの感染症との区別が必要です。リンパ節型、潰瘍リンパ節型では連鎖球菌(れんさきゅうきん)あるいはブドウ球菌感染、伝染性単核(たんかく)（球(きゅう)）症(しょう)、トキソプラズマ症、鼠径(そけい)リンパ肉芽腫(にくげしゅ)、猫ひっかき病、パスツレラ症、ペストなど、チフス型ではQ熱、ブルセラ症、マラリア、サルモネラ症、結核、オウム病、レジオネラ症、チフスなどとの区別が必要です。