News
31 May 2012
Hantavirus and Haemorrhagic Fever with Renal Syndrome (HFRS): situation in Europe
An increase in the number of hantavirus infections has been reported in Europe.
Germany
Between October 2011 and 27 April 2012, 852 human hantavirus (likely to be Puumala virus) infections have been reported in Germany, of which 580 (68 per cent) were in the southern federal state of Baden-Wurttemberg. Cases in this state have risen earlier than usual this year and are greater than for the same months (October to April) in previous years. The early rise could be due to the abundance of beech nuts during 2011 (the main diet of the rodent reservoir of hantavirus) which may have resulted in a surge in bank vole numbers during winter 2011 and spring 2012 [1]. Numbers of cases are expected to increase during the coming months.
Russia
Between January and April 2012, the Russian Federation has reported an increased incidence of haemorrhagic fever with renal syndrome (HFRS). The unusually high number of cases is thought to be due to fluctuation in temperatures, lack of snow during the winter and an increase in the rodent population [2 – 4].
Between January and April 2012 a total of 1,469 cases of HFRS were reported with incidence rate of 1.05/100,000, compared with 0.19/100,000 for the same time period in 2011. South-eastern parts of the Russian Federation (Districts in the Federal region of Volga) reported 89 per cent of all cases. As of 18 May 2012, the highest incidence rates of HFRS were registered in the Udmurt (Udmurtskaya) Republic (15.1/100,000), the Republic of Mordovia (9.5/100,000) and the Penza region (6.9/100,000) [2]. In the first four months of January to April 2012, 156 cases of HFRS were reported in the Republic of Bashkortostan, an incidence rate of 3.8 per 100,000 population compared to 1.1 per 100,000 for the same period in 2011 [4].
Slovenia
Between 1 January and 18 April 2012, 26 cases of HFRS were notified in Slovenia, compared with 15 cases reported in the entire year of 2011. This number of cases for these months is unusually high. Most of the cases have been reported in the endemic regions of Novo Mesto, Murska Sobota and Ljubljana [5].
Hantavirus infection
Hantaviruses are a group of viruses, with different geographical distributions and specific rodent hosts, belonging to the family Bunyaviridae. Distribution of hantaviruses is expanding in Europe, with six genotypes identified so far. Puumala hantavirus is the most common hantavirus in Europe [6], for which bank voles are the reservoir hosts. Humans can become infected when they inhale virus particles from rodent excreta (urine, faeces or saliva). Risk factors for rodent exposure may be linked to occupational or leisure activities.
Hantaviruses cause two major clinical syndromes each with a wide spectrum of severity depending on the causative virus:
a) Haemorrhagic fever with renal syndrome (HFRS)
The incubation period is commonly between two and four weeks and symptoms include fever, hypotension, bleeding and renal failure. Recovery can be protracted.
The CFR may be up to15%; illness caused by Puumala virus usually results in less severe symptoms and has a lower CFR (0.1-0.4%) [6].
Most cases of hantavirus infection resolve spontaneously over two to three weeks, however, severe cases can require intensive supportive care. Ribavirin may be useful in severe disease [6-7].
b) Hantavirus pulmonary syndrome (HPS)
Hantaviruses found only in the Americas cause hantavirus pulmonary syndrome. The incubation period is typically one to two weeks and symptoms include fever, myalgia and gastrointestinal symptoms. In severe cases there can be progressive respiratory and cardiac involvement, with a case fatality rate (CFR) of 40-50%[7].
Advice for travellers
The risk of hantavirus in most travellers is low. However, those who may be in close proximity with rodents, such as travellers undertaking activities in rural areas, e.g. camping or hiking should take the following precautions:
- Wash hands thoroughly before eating.
- Avoid direct contact with rodents or their excreta.
- Inside areas frequented by rodents should be moistened and cleaned with disinfectant and then vacuumed whilst wearing a mask and gloves.
- Take measures to avoid attracting rodents, such as keeping food covered and not storing firewood inside.
There is no vaccine to protect against hantavirus infection.
Information on other specific health risks for travellers can be found on the NaTHNaC Country Information Pages.
References
1. Boone I, Wagner-Wiening I, Reil D, Jacob J, Rosenfeld UM, Ulrich RG, Lohr D, Pfaff G. Rise in the number of notified human hantavirus infections since October 2011 in Baden-Württemberg, Germany. Euro Surveill. 2012; 17(21). [Accessed 31 May 2012]. Available at: http://www.eurosurveillance.org/ViewArticle.aspx?
2. Rospotrebnadzor. Press release. The sanitary and epidemiological situation. Infectious diseases in the Russian Federation in January-April 2012. [In Russian], 18 May 2012. [Accessed 31 May 2012]. Available at: http://goo.gl/bLNHp
3. Rospotrebnadzor. Press release. Hemorrhagic fever with renal syndrome in the Udmurt Republic - a situation exacerbated by the epidemic. [In Russian], 12 May 2012. [In Russian], [Accessed 31 May 2012]. Available at:
http://18.rospotrebnadzor.ru/news
4. Rospotrebnadzor. Press release. The situation on the incidence of hemorrhagic fever with renal syndrome (HFRS) in the Republic of Bashkortostan. [In Russian], 12 May 2012. [Accessed 31 May 2012]. Available at:
5. Kraighera A, Frelih T, Korva M, Avsic T, Increased number of cases of haemorrhagic fever with renal syndrome in Slovenia, January to April 2012. Euro Surveill. 2012; 17(21). [Accessed 31 May 2012]. Available at:
http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=
6. Health Protection Agency. Hantaviruses. [Accessed 31 May 2012]. Available at:
http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/
7. Field VF, Ford L, Hill DR eds. Hantavirus. In: Health Information for Overseas Travel, National Travel Health Network and Centre, London, UK, 2010.
Links
Health Protection Agency. Hantavirus
European Centre for Disease Control: Hantavirus factsheet
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