Clinical Updates
12 July 2010
Leptospirosis in Argentina
As of 11 June, the Ministry of Health, Argentina have reported 304 cases of leptospirosis since the beginning of 2010 [1]. This compares with 35 cases in the same period in 2009. The most affected areas are the provinces of Santa Fe (193 cases), Entre Ríos (75 cases), and Buenos Aires (27 cases), and the city of Buenos Aires (6 cases). A small number of fatal cases has been reported [2, 3].
Periodically, rainfall results in the Paraná river rising, causing flooding in the cities of Santa Fe (Santa Fe province) and Paraná (Entre Ríos province). Leptospirosis can occur following heavy rains and flooding when Leptospira spp. that have contaminated soil or other ground surfaces, are washed into flooded areas.
Leptospirosis
Leptospirosis is an infection caused by bacteria of the genus Leptospira, with worldwide distribution. Infection is transmitted through contact with infected animals (usually rats, dogs or livestock), or soil or water contaminated with the urine of infected animals. In tropical areas, there is year-round transmission with an increase in rates during periods of heavy rainfall and flooding.
Following an incubation period of seven to ten days, illness is asymptomatic, or self-limiting in most individuals. Progression can occur to fever, headache, skin rash, myalgia and meningitis. Severe illness, termed Weil’s disease, is characterised by renal and hepatic impairment and complications of arrhythmias, myocarditis, renal failure and respiratory distress, and occurs in approximately 10% of cases. Between 5% and 40% of cases are fatal, particularly in older persons.
Advice for travellers
The risk of leptospirosis in most tourist travellers to Argentina is low. Risk is higher in those who will be exposed over long time periods, such as persons travelling or living in flooded areas. Travellers to affected areas are advised to take measures to minimise their exposure to the urine of infected animals. These measures include:
- Limiting exposure to fresh water that may have been contaminated by rodent or other mammalian urine.
- Clearing rubbish from campsites and dwellings, and preventing rodent access into buildings.
- Wearing protective clothing if in direct contact with rodents, sewage or contaminated water. Cuts and grazes should be covered.
There is no human vaccine available against leptospirosis. Pre-exposure chemoprophylaxis can be considered for short term travellers with the potential for high risk exposure; these would include travellers who may be unavoidably exposed to rodents or waterways either by their planned activities or as a result of their occupation. Where indicated, doxycycline at a dosage of 200 mg weekly, commencing one to two days prior to exposure and continued while at risk, can be given [4, 5].
References
1. Ministerio de Salud de la Nación. Boletín de Vigilancia. 11 June 2010. [Accessed 12 July 2010]. [In Spanish] Available at: http://www.msal.gov.ar/htm/site/epi-noticias.asp
2. ProMEDmail 2 February 2010. Leptospirosis, Fatal – Argentina. [Accessed 12 July 2010] Available at: http://apex.oracle.com/pls/otn/f?p=2400:1001:1927048516841
847::NO::F2400_P1001_BACK_PAGE,F2400_P1001_PUB_
3. ProMEDmail 3 April 2010. Leptospirosis, Fatal – Argentina [Accessed 12 July 2010] Available at: http://apex.oracle.com/pls/otn/f?p=2400:1202:8139661847719
39::NO::F2400_P1202_CHECK_DISPLAY,F2400_P1202_PUB
4. Brett-Major DM, Lipnick RJ. Antibiotic prophylaxis for leptospirosis. Cochrane Database of Systematic Reviews 2009, Issue 3. Art. No.: CD007342. DOI: 10.1002/14651858.CD007342.pub2.
5. Takafuji ET, Kirkpatrick JW, Miller RN, et al. An efficacy trial of doxycycline chemoprophylaxis against leptospirosis. N Engl J Med 310:497-500, 1984.
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