Leptospirosis in a Japanese urban area: a case report and literature review

Leptospirosis transmitted from a pet dog

Leptospirosis is a widespread zoonosis in tropical regions and it is not frequently recognised in developed countries. We report a case of leptospirosis transmitted from a pet dog. A middle-aged woman was referred to our emergency department with a 7-day history of fever and diarrhoea. She presented with hypotension, tachycardia, grasping pain in the entire muscle and petechiae. A detailed medical interview revealed that her pet dog had been to the veterinarian 1 month earlier with similar symptoms. We treated her with intravenous antibiotics. The patient's diagnosis of leptospirosis was confirmed by serological testing and the detection of DNA in her urine. We contacted the veterinarian and shared the information. We found that the dog had suffered from leptospirosis based on serological testing. We emphasise the possibility of leptospirosis being transmitted from pet dogs. Persistent suspicion of leptospirosis will contribute to its diagnosis and improved public health.

Severe leptospirosis in a patient with positive serological test for spotted fever rickettsiosis

Here, we report a case of a 64-year-old man with severe leptospirosis infected in an area in Japan that is non-endemic to leptospirosis. Initially, findings of high-grade fever, mild generalised arthralgia, rashes on the trunk, mild thrombocytopenia, elevated liver enzymes and renal dysfunction led to the suspicion of rickettsiosis, which was an endemic infectious disease in the area. Subsequently, leptospirosis was also considered after carefully reviewing patient history, which revealed that he may have been exposed to mice urine. Finally, leptospirosis was diagnosed after the serum indicated a positive PCR for leptospirosis. Furthermore, due to serum antibody positivity for Rickettsia japonica, false-positivity or coinfection of spotted fever rickettsiosis was suspected. Despite the delayed diagnosis, the patient recovered with antibiotic treatment. Thus, to prevent diagnostic errors, leptospirosis should be potentially considered with high suspicion in patients with acute undifferentiated fever, even in non-endemic areas of leptospirosis.

Leptospirosis infection in a homeless patient in December in Tokyo: a case report

Introduction

We report a case of severe leptospirosis that occurred during winter in Tokyo, the capital of Japan. Leptospirosis is endemic in tropical regions and extremely rare in the urban areas of Japan. Only six new cases were reported in Tokyo in 2014. Most leptospirosis cases reported in urban areas of Japan were a result of occupational hazards, and there is no previous report of leptospirosis in a homeless patient in Tokyo. We believe this report could provide a widened perspective about the clinical presentation and epidemiology of leptospirosis in Japan.

Case presentation

Our patient was a 73-year-old Asian man. He had been homeless for over 10 years, with exposure to rodents and their excrement in parks and on the streets. He presented with fever and severe inflammatory response, satisfying the diagnostic criteria for systemic inflammatory response syndrome. Laboratory findings showed multiple-organ dysfunction, including renal failure, liver failure with increased total bilirubin level, and coagulopathy with decreased platelets. We suspected leptospirosis on the basis of these clinical findings. The diagnosis was also confirmed by polymerase chain reaction first, and paired antibody titers on day 9, in the recovery period, showed positive results for three species.

Conclusions

Our patient’s case suggests that even patients without a history of traveling abroad or exposure to freshwater can develop leptospirosis in winter in urban areas in Japan. If a patient has symptoms like fever, calf pain and MOF; as a differential diagnosis we should rule outthe Leptospirosis. From the perspective of sensitivity, specificity, and clinical convenience, polymerase chain reaction could be the preferred diagnostic tool of choice.