A Fatal Case of Corynebacterium ulcerans Infection from Cats in Japan
The health ministry, on Jan 15, 2018 reported that a Fukuoka woman, who is in her 60’s died of Corynebacterium ulcerans infection which is suspected to be caused by infected cats. She fed homeless cats every day, and this bacterium was isolated from these cats. This infectious disease is an extremely rare case, and not only ordinary people but also veterinarians might not recognize it yet. Now let me introduce this infectious disease.
Pathogen: Corynebacterium ulcerans is the cause of the disease and is known to be closely-related with diphtheria, producing cytotoxic diphtheria toxin.
Epidemiology: The most numerous cases are reported in England. From 1989 to 2006 this bacterium was isolated in 56 cases including asymptomatic carriers. Some cases are occasionally reported in other European countries. In Japan, since 2001, 25 cases, including this case, were reported. Patients in most cases have kept cats, sometimes dogs. Most infected people were treated by the use of antibiotics, however, this case was the first fatal case in Japan.
Route of Transmission: This infectious disease is confirmed in humans, dogs, cats, cows, and various animals, and is a zoonosis presenting various symptoms in pharyngolarynx, lungs, skin, and mammary glands, among others. Transmission of the infection from milk produced by cows suffering from mammitis or arthritis has been confirmed overseas, however, recently, infection from infected dogs and cats has been widely confirmed both domestically and abroad. Human-to-human transmition has not reported domestically yet, and is very rare overseas.
Clinical Symptom: A human shows similar clinical symptoms to diphtheria. In respiratory infection, patients initially show similar symptoms to a common cold, following that, pseudomembrane or white coat develops in tonsils and pharynx accompanied with sore throat and a cough. In severe cases, patients suffer from dyspnea and can even die. Other infectious cases have symptoms including swelling of cervical lymph nodes or skin lesions. The symptoms of infected animals are basically the same as for humans, thus, common cold-like symptoms or suppuration on the skin are reported.
Diagnosis: In humans, differentiating a diagnosis with diphtheria is important owing to show similar symptoms to diphtheria. Culture tests and PCR are performed in specialized organizations. In pets, the National Institute of Infectious Diseases can identify C. ulcerans if Corynebacterium sp. are isolated from materials of dogs or cats in laboratory testing service. An application form and the address to send the strain are available from the website of the health ministry. http://www.mhlw.go.jp/bunya/kenkou/kekkaku-kansenshou18/corynebacterium_02.html
Treatment and Prevention: Antibiotics are effective. Cases of recovery cases by using macrolide antibiotic in humans were reported domestically. Diphtheria toxoid vaccine is also useful for this disease because diphtheria has the same toxoid as C. ulcerans regardless of the different stain. In infected animals, macrolide antibiotic use is also considered to be effective.
The Infectious Diseases Control Law: Human diphtheria-like disease caused by C. ulcerans do not apply this law.
How to Treat Infected Animals
By Veterinarians: Considering the spread of the infection, it is recommended to isolate and hospitalize infected animals. While treating infected animals, veterinarians need to wear gloves and masks to prevent transfer of the infection to humans and other animals. Gloves used for treatment should be disposed as infectious waste. Hospitalized pets should be given macrolide antibiotics such as erythromycin or clarithromycin. Pets treated by these antibiotics would have no possibility to cause infection unless this bacterium is isolated on re-examination.
By owners: This infectious disease is zoonosis which can be transmitted from infected dogs, cats and the other animals to humans. If pets show a cold-like symptoms such as coughing, sneezing and runny nose, dermatitis and ulcers of skin or mucous membrane, early medical examination is recommended. Furthermore, excessive contact with such pets should be avoided, and washing hands is recommended after touching them.