Leptospirosis is a febrile illness caused by infection with the sphirochete L interrogens
. It is estimated that there are more than 500 000 cases of leptospirosis annually worldwide.2
The actual figure may be higher with studies conducted in Thailand showing that leptospirosis may represent up to 20% of febrile illness of unknown origin.3
Although endemic in tropical climates, leptospirosis is increasing in temperate climates. There were six confirmed cases of leptospirosis in Dublin, Ireland, in November 2001. All were associated with canoeing on a particular stretch of the river Liffey. Four of the six cases required hospital admission but all recovered.4
Subsequent notifications have demonstrated a 57% increase in incidence of leptospirosis in Ireland from 2004–2007.5
Other outbreaks in European temperate climates have been reported, including an epidemic in German strawberry harvesters in 2007.6
Leptospirosis has the potential to become increasingly prevalent in temperate climates such as Ireland due to anticipated global warming.
Clinical manifestations of leptospirosis vary between mild symptoms (anicteric leptospirosis; about 95% of cases) to potentially life-threatening illness (icteric leptospirosis or Weil's disease) as in this case. It has an incubation period of 4–14 days and can present as a biphasic illness with the first stage presenting as an influenza-like illness.7
This is illustrated in the our patient who was given treatment for circulating pandemic H1N1 influenza virus. Common symptoms of this first stage are myalgia, particularly in lumbar and calf muscles, arthralgia, pharyngitis, non-productive cough, abdominal pain, nausea, vomiting and diarrhoea, temperature and headache. Icteric leptospirosis can move directly into the second phase of illness bypassing the brief asymptomatic phase seen in anicteric disease. This second phase is characterised by aseptic meningitis, jaundice, renal failure, uveitis, pulmonary haemorrhage, acute respiratory distress syndrome, myocarditis and rhabdomyolysis, and if severe can be associated with mortality of up to 40%.8
Animals are more frequently affected by the sphirocete leptospiral with humans accidental hosts. Humans most often become infected after exposure to environmental sources, such as animal urine, contaminated water or soil, or infected animal tissue. Leptospira can infect humans via breaks on the skin, conjunctiva or mucus membranes. Risk factors are mainly outdoor exposure to animal urine during recreational exposure such as canoeing, fresh water swimming or surfing.9
Those with occupation exposure such as farmers, sewer workers and abattoir workers are also at increased risk. Household exposure, as in this case, with infestations of infected rodents or dogs can also be a risk.
Pulmonary involvement seems to be more prevalent in the re-emergence of leptospirosis. Alveolar haemorrhage, presenting as dyspnoea and haemoptysis, is the main pulmonary manifestation seen. The emergence of massive haemoptysis and acute respiratory distress syndrome has characterised the recent changes reported in the clinical patterns of leptospirosis. The pulmonary involvement has emerged as a serious life threat becoming the main cause of death due to leptospirosis in some countries.10
An Argentinean study between 1990 and 1999 showed no severe pulmonary haemorrhage in 276 cases diagnosis. However, in an outbreak of 93 cases in 2001 two patients died due to pulmonary haemorrhage. These 2001 were the first reported cases of severe pulmonary haemorrhage caused by leptospirosis in Buenos Aires.11
The Cochrane Database of Systematic Reviews concluded that evidence from randomised controlled trials(RCTs) is insufficient to provide clear guidelines for the treatment of leptospirosis but some RCTs have shown similar outcomes in severe leptospirosis with parenteral penicillin G, doxycycline and cefotaxime.12
There is no human vaccination available against leptospirosis. The American Ammonal Hospital Association Canine Vaccine Task Force recommend L interrogens
(combined with serovars canicola and icterohaemorrhagiae)13
vaccination at 12 weeks and at 14–16 weeks with annual booster to those with reasonable risk of exposure. Other preventive measures include avoidance of potential sources such as swimming in freshwater ponds, wearing of protective clothing when working with wet soil, rodent control and protection of food from animal contamination.
- This case report serves to increase awareness of this re-emerging potentially fatal infectious disease.
- This re-emergence is associated with severe pulmonary manifestations as demonstrated in this case, which can cause morbidity and mortality.
- Early recognition and instigation of appropriate antibiotics may decrease complication rate.