No 34b - 2011

Leptospirosis

Leptospira are zoonotic bacteria for which rats comprise the primary reservoir, EPI-NEWS 02/05 (pdf). The bacteria are excreted in rat urine and transfers from urine or contaminated freshwater through contact with mucous membranes, small abrasions or "soaked", but seemingly intact skin. After an incubation period of 1-2 weeks (2-30 days), the typical disease onset includes influenza-like symptoms and often conjunctival reddening. In serious cases, Weil's disease, vital organ failure is developed in the course of few days and particularly affected are the function of liver and kidneys and the coagulation system. The condition may be treated with penicillin or other antibiotics. There exists no vaccine against leptospirosis. Clinical leptospirosis is notifiable on Form 1515.

Leptospirosis 2005-2010

In the period 2005-2010, 42 cases of leptospirosis were notified. Patients were aged 13-86 years, the median age was 46 years; 36 (86%) were males and six females. A total of 26 (62%) were infected in Denmark according to notifications. Of these, 18 were infected after occupational exposure: 14 after water contact frequented by rats, and four after direct contact with rats, Table 1. Persons with no occupational exposure were primarily infected in connection with hunting & fishing or sailing on streams and lakes. The number of cases peaked in the September-December period.

Two leptospirosis cases were notified after torrential rain storm in Copenhagen on 2 July 2011. Both cases were previously healthy, middle-aged males who had spent many hours in knee-high water emptying cellars of water following the rain storm. Furthermore, one of them had found a dead rat in his home. None of the patients had worn protective clothing. The first patient presented with an intense headache, high fever, dry cough, vomiting and right-sided abdominal pain one week after the rain storm and was admitted six days after onset with increasingly yellowing of skin and eyes. The patient died two days after admission due to pulmonary haemorrhage and heart failure. In the other patient, disease onset occurred three days after the rain storm in the form of influenza-like symptoms, fever and headache. He was admitted a week after onset and was eventually declared healthy after 26 days. One of the patients was diagnosed by PCR blood sampling and the other was diagnosed on the basis of clinical manifestations only

Diagnostics

The microbiological diagnosis is made during the acute course by PCR in a urine or blood sample taken before initiation of antibiotics treatment. In case of continued clinical suspicion, the PCR analysis should be supplemented by testing for Leptospira antibodies, which are normally only detectable seven days after disease onset and in most cases not until after 14 days after onset. In Denmark, Leptospira diagnostics are only performed at Statens Serum Institut.

Commentary

Leptospirosis is a rare, but serious disease and symptoms are often unspecific. Early initiation of antibiotic treatment reduces the risk or serious complications. Leptospirosis prevention consists in combating rat infestation and consistent use of personal protection gear to avoid direct contact with mice or rats or contact to water which may contain rat urine. Physicians should be particularly aware of the diagnosis in patients with relevant exposures, including exposure in connection with torrential rain storms.

(C. Kjelsø, L. Müller, Dept. of Epidemiology, A.K. Jensen, S. Villumsen, DBMP, T.E. Hansen, Gentofte Hospital, C.B. Christiansen, Copenhagen University Hospital)

Botulism

Botulism is a rare disease caused by the spore-forming bacterium Clostridium botulinum. The bacterium forms a toxin which destroys nerves and paralyses body  muscles, including the thorax muscle function. There are three types: Food-borne, infant, and wound botulism.

Botulism 1985-2010

Since 1985, eight cases of botulism have been observed in Denmark, including three cases of infant botulism. Two of the infants are believed to have been infected by honey. In the five remaining cases, food-borne infection was suspected from inadequately conserved foods where the bacterium could multiply and form the toxin. Specifically, suspicion comprised the following foods: Seal meat, vegetable paste and garlic in chilli oil, EPI-NEWS 05/03 (pdf)

July 2011 botulism case

In July 2011, a young male was admitted to hospital with gastrointestinal symptoms and progressive paresis including visual disturbances, dysphagia and respiratory insufficiency. On suspicion of botulism, treatment with botulism antitoxins was initiated. The diagnosis was subsequently confirmed and a tofu and a vegetarian paste were the possible sources of infection why both products were withdrawn. Culture of vegetarian paste and sub-sequent inoculation on mice did not confirm C. botulinum or botulinum toxin, and the product was subsequently cleared. The tofu had smelled and tasted foul, but was no longer available for testing. The infection presumably transferred from a single jar of contaminated tofu. 

Diagnostics

Botulism in humans is diagnosed by a mouse bioassay in which serum from the patient is injected into mice which are then tested for botulism. Botulism in foods is detected by culture of C. botulinum from which PCR testing can detect the toxic gene. 

Commentary

Botulism is a rare, but very serious illness. Suspected cases should immediately be notified by phone to Medical Officers of Health and subsequently in writing on Form 1515. The primary diagnosis is made clinically and assessment of indication for anti-toxin treatment should be made in collaboration with the Department of Epidemiology, which has a 24-hour contact service.

(L. Müller, C. Kjelsø, P. Valentiner-Branth, Department of Epidemiology, A.K. Jensen, DBMP)

 24 August 2011