CRIMEAN-CONGO HEMORRHAGIC FEVER - TÜRKEI (14): BACKGROUND
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Date: Thu 14 Aug 2008
Source: Eurosurveillance, Volume 13, Issue 33, 2008 [edited]
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Crimean-Congo haemorrhagic fever (CCHF) is a
disease caused by a virus belonging to the
_Bunyaviridae_ family. CCHF virus isolation
and/or disease have been reported from more than
30 countries in Africa, Asia, southeastern
Europe, and the Middle East [1]. The main
transmission routes of the virus are tick-bite
and contact with tissues, body fluids and blood
of infected animals [1-4]. Nosocomial
transmission is another important route of
infection [1]. The incubation period is generally
described as 1-3 days after tick-bite and 5-6
days after exposure to infected animal or human
blood or body fluid, but it can be longer. Fever,
chills, headache, fatigue and myalgia are the
most common symptoms in the pre-haemorrhagic
period. The disease progresses to haemorrhagic
form in severe cases [1]. The fatality rate of
disease is reported between 7.5-50 percent in
hospitalised patients [4-7]. This wide range may
due to phylogenetic variation of the virus,
transmission route and different treatment
facilities [4-7].
Epidemiological situation in Turkey
-----------------------------------
Although confirmed CCHF patients or serological
evidence of the virus were being reported from
neighboring countries, there had been no evidence
of CCHF cases before 2002 in Turkey. The 1st
cases were detected in the town of Tokat in the
Kelkit Valley region in northern Turkey in 2002
[8].
Between 2002 and 2007, a total of 1820 confirmed
cases, including 92 deaths, were reported to the
Ministry of Health (MoH) of Turkey, showing an
increasing trend over the years. The majority of
cases (95 percent) were reported from middle and
eastern Anatolia, particularly from the cities of
Tokat, Sivas, Yozgat, Corum, and Erzurum [9].
Most of the cases were diagnosed between March
and October, with peak levels in June and July,
which correspond with the tick season. The
average case fatality rate between 2002 and 2007
was 5 percent, (range 4.5 percent-6.2) [9]. 70
percent of the cases had a history of tick
contact, while most of the remaining 30 percent
had a history of contact with livestock, and 3
cases were attributed to nosocomial transmission
[9] [see 1st ProMED ref. below].
Studies on ticks performed in areas where human
cases had been reported found CCHF in _Hyalomma
marginatum marginatum_ pools (10,11).
Since December 2003, CCHF is a notifiable disease
in Turkey. Cases with epidemiological risk
factors, clinical symptoms and laboratory
findings compatible with CCHF are reported to the
Ministry of Health (MoH) as probable cases. The
case definition for probable cases includes:
Epidemiological risk factors: Tick-bite or tick
contact; work in animal husbandry or farm;
contact with the body fluid of a CCHF patient;
work at a laboratory; close contact with a CCHF
case.
Clinical symptoms: Fever, haemorrhage,
headache of acute onset, myalgia/arthralgia,
lethargy, nausea/vomiting, or abdominal pain/
diarrhea.
Laboratory findings: Thrombocytopenia (platelets less than 150
000/mm3) and/or leucopenia (WBC less than 4000/mm3), elevated levels
of alanine aminotransferase (ALT), aspartate aminotransferase (AST),
lactate dehydrogenase (LDH) and creatine phosphokinase (CK).
Cases with confirmed CCHF virus RNA in the blood
or body fluid samples through RT-PCR evaluation
or IgM positivity through ELISA are considered
confirmed CCHF cases. The laboratory diagnostics
for CCHF are done on the national level in the
Virology Laboratory of Refik Saydam Hygiene
Center in Ankara.
Preliminary results in 2008
---------------------------
The 1st CCHF case in 2008 was detected and notified to the MoH on 24
Mar 2008. As of 30 Jun 2008, 688 confirmed cases have been reported: 4
in March, 57 in April, 282 in May and 345 in June 2008. Of these, 41
patients have died due to CCHF, corresponding to a case fatality rate
[CFR] of 5.96 percent. As in previous years, most of the cases were
from the Middle and Eastern Anatolia region (91 percent). Sporadic
cases (9 percent of the total) have been reported from the
southeastern and western parts of Turkey as well.
The male to female ratio was 1.07. The mean age of the patients was
44.3 plus or minus 19.5 years (range: 2-93 years). The proportion of
cases was highest among patients of working age, especially adults
from rural areas. The distribution of patients according to occupation
was 51.8 percent farmers, followed by 18.9 percent homemakers (who in
rural areas generally work in agriculture and animal husbandry), and
16.5 percent those working in the animal husbandry sector.
Regarding possible modes of transmission, 71 percent of the cases had
a history of tick bite; 21.9 percent reported unprotected contact with
blood or body fluids of domestic animals; 5healthcare workers exposed
to patients' blood and body fluids by mucosal contact have been
diagnosed as nosocomi al CCHF cases until the end of June 2008. None
of them died.
Control measures
-----------------
A scientific advisory commission was set up by
MoH in 2003. This commission meets regularly, and
its recommendations regarding treatment options,
isolation measures, suggestions for disinfection,
and approach in handling the deceased have been
put in action.
In 2004, MoH in collaboration with the Ministry
of Agriculture and Rural Affairs (MARA) initiated
a surveillance and control programme including
education regarding the disease and its
transmission routes, tick removal, handling
tick-bite cases, protected contact with animals,
prevention of nosocomial infections and early
detection of cases. This programme has been
conducted throughout the whole country, and
especially intensively in the epidemic region. It
has been updated in 2007.
In 2008, brochures, posters and TV spots
informing about the risk of CCHF infection were
updated and distributed to educate the public and
the healthcare workers. In the epidemic area,
education programmes have been conducted door to
door by provincial health directorates under the
MoH. These included information regarding
inspecting body for ticks, removing ticks as soon
as possible, limiting exposure to body fluids or
blood of livestock and using permethrine
repellent 0.5 percent for treating clothes. The
MoH collaborates closely with the MARA regarding
tick combat in livestock at the central and
provincial level.
Conclusion
----------
Cases of CCHF have been reported in Turkey since
2002, mostly in spring and summer and in middle
and eastern Anatolia. This has been associated
with factors such as climatic features
(temperature, humidity, etc.), changes of vector
population, geographical conditions, flora, wild
life and the animal husbandry sector [12]. The
number of cases has been increasing over the
years, which may also be due to better awareness
of health care personnel and the public about the
disease in addition to the above factors [9].
[By G R Yilmaz 1, T Buzgan1, M A Torunoglu1, A
Safran1, H Irmak1, S Com1, Y Uyar2, A Carhan2, E
Ozkaya2, M Ertek2 1 Ministry of Health, Primary
Health Care Directorate, Ankara,Turkey 2 Refik
Saydam Hygiene Center, Ankara, Turkey]
References:
1. Whitehouse CA. Crimean-Congo Hemorrhagic
Fever. Antivir Res. 2004;64(3):145-60.
2. Hoogstraal H. The epidemiology of tick-borne
Crimean-Congo haemorrhagic fever in Asia, Europe
and Africa. J Med Entomol. 1979;15:307-417
3. Schwarz TF, Nsanze A, Ameen AM. Clinical
features of Crimean-Congo Haemorrhagic Fever in
the United Arab Emirates. Infection.
1997;40:364-7.
4. Ozkurt Z, Kiki I, Erol S, Erdem F, Yilmaz N,
Parlak M, et al. Crimean-Congo hemorrhagic fever
in Eastern Turkey: clinical features, risk
factors and efficacy of ribavirin therapy. J
Infect. 2006;52(3): 207-15.
5. Ergonul O, Celikbas A, Baykam N, Eren S,
Dokuzoguz B. Analysis of risk-factors among
patients with Crimean-Congo haemorrhagic fever
virus infection: severity criteria revisited.
Clin Microbiol Infect. 2006 Jun;12(6):551-4
6. Cevik MA, Erbay A, Bodur H, Gulderen E, Bastug
A, Kubar A, et al. Clinical and laboratory
features of Crimean-Congo Hemorrhagic Fever:
predictors of fatality. Int J Infect Dis.
2008;12(4):374-9.
7. Centers for Disease Control and Prevention.
Crimean-Congo Haemorrhagic Fever. Factsheet.
Available from:
<
http://www.cdc.gov/ncidod/dvrd/spb/mnpa ... s/cchf.htm>
8. Gozalan A, Esen B, Fitzner J, Tapar FS, Ozkan
AP, Georges-Courbot MC, et al. Crimean-Congo
haemorrhagic fever cases in Turkey. Scand J
Infect Dis. 2007;39(4):332-6.
9. Yilmaz GR, Buzgan T, Irmak H, Safran A, Uzun
R, Cevik MA, et al. The epidemiology of
Crimean-Congo Hemorrhagic Fever in Turkey:
2002-2007. Int J Infect Dis. In press 2008.
10. Tonbak S, Aktas M, Altay K, Azkur AK, Kalkan
A, Bolat Y, et al. Crimean-Congo Hemorrhagic
Fever Virus: Genetic Analysis and Tick Survey in
Turkey. J Clin Microbiol. 2006;44(11):4120-4.
11. Whitehouse CA, Hottel H, Deniz A, et al.
Molecular detection of Crimean-Congo Haemorrhagic
Fever virus in ticks from Turkey. In: American
Society of Tropical Medicine and Hygiene 55th
Annual Meeting, November 12-16, 2006, Atlanta,
Georgia, USA.
12. Estrada-Pena A, Vatansever Z, Gargili A,
Aktas M, Uzun R, Ergonul O, et al. Modeling the
spatial distribution of Crimean-Congo Hemorrhagic
Fever outbreaks in Turkey. Vector Borne Zoonotic
Dis. 2007;7(4):667-78.
--
Communicated by:
ProMED-mail <
promed@promedmail.org>
[From zero cases before 2002 to 688 cases so far in 2008 certainly
qualifies CCHF to be considered as an emerging disease in Turkey. -
Mod.CP]
