27 June 2008

Crimean Congo haemorrhagic fever in Turkey and Russia

Turkey

According to unconfirmed media reports, there have been cases and deaths from Crimean Congo haemorrhagic fever (CCHF) in Turkey during 2008 [1].  Most cases have been reported to have occurred in the provinces of Tokat, Corum, Sivas, Amasya, Yozgat and Gumushane in northern Turkey. No cases have been reported from Mediterranean tourist resorts.

CCHF is an emerging disease in Turkey. Although serological evidence suggests the disease has been present in Turkey for decades, the first clinical cases were reported in 2002 [2]. In 2006 an outbreak of CCHF was reported by the World Health Organization during which 242 cases were laboratory confirmed including 20 deaths [3]. This was an increase on the number cases reported in previous years.

Russia

Between 1 January and 13 May 2008, 18 cases (including 2 deaths) of CCHF have been reported from the Southern Federal District of Russia [4]. This is an increase on the same period of 2007 when eight cases were reported.  The number of cases of CCHF has been increasing annually since 2004 in the Southern Federal District [4].

Crimean Congo haemorrhagic fever

CCHF is caused by a virus belonging to the Nairovirus genus of the Bunyaviridae family. CCHF is primarily a zoonosis with natural hosts including hares, birds, cattle, sheep, pigs and goats. The virus is endemic in many countries in Africa, eastern Europe, Asia, and the Middle East. The disease can be transmitted to humans either by the bite of an infected tick (usually ticks of the Hyalomma genus) or through direct contact with blood or other tissue from infected livestock. The majority of cases of CCHF occur amongst agricultural workers, slaughterhouse workers, and veterinarians. The disease is very low risk to travellers.

Following a bite from an infected tick the incubation period of CCHF is between one and three days, with a maximum of nine days. The incubation period is longer (5 to 6 days) after contact with blood or tissue from infected animals. Initial symptoms include rapid onset of fever, myalgia, headache and dizziness; some patients will have nausea and diarrhoea. As the disease progresses, haemorrhagic manifestations develop. In severe illness the mortality rate is approximately 30%. Early initiation of supportive treatment is essential to improve the outcome. Ribavirin has been used for treatment of CCHF, but there have been no randomised controlled trials on its efficacy [5].

Advice for travellers

There is no vaccine to protect against CCHF. Travellers to affected areas are advised to take measures to minimise their exposure to ticks. These include:

• Wear long sleeved clothing and long trousers. Trousers should be tucked into socks when walking in tick infested areas.
• Apply insect repellent to exposed skin.
• Use a permethrin based insecticide on clothing.
• Inspect for ticks and remove them immediately with tweezers or tick removers.

Animal handlers should take precautions to avoid exposure to blood and tissues.

Outbreaks of CCHF are listed in the NaTHNaC Outbreak Surveillance Database.

References

1. Promed-mail. Crimean-Congo haemorrhagic fever – Turkey (9). ProMED-mail 2008; 22 June:  20080622.1935. [Accessed 27 June 2008]. Available at

http://www.promedmail.org/pls/otn/f?p=2400:1001:245205026

2376735::NO::F2400_P1001_BACK_PAGE,F2400_P1001_

PUB_MAIL_ID:1010,72898

2. Karti SS, Odabasi Z, Korten V, et al. Crimean-Congo hemorrhagic fever in Turkey. Emerg Infect Dis [serial online]. 2004 Aug [Accessed 27 June 2008]. Available at http://www.cdc.gov/ncidod/EID/vol10no8/03-0928.htm

3. World Health Organization. Crimean Congo haemorrhagic fever in Turkey. 8 August 2006. [Accessed 27 June 2008]. Available at http://www.who.int/csr/don/2006_08_08b/en/index.html

4. Institut de Vielle Sante. Fièvre hémorragique Crimée-Conge Russie, Turquie. (Article in French). Bulletin Hebdomadaire International. No.143; 11-17 Jun 2008. [Accessed 27 June 2008]. Available at http://www.invs.sante.fr/international/bhi/bhi_170608.pdf

5. Ergonul O. Treatment of Crimean-Congo hemorrhagic fever. Antiviral Research. 2008; 78: 125-31.

Link

World Health Organization Crimean-Congo haemorrhagic fever factsheet