A report of recent cases in Northern Cape reminds us that the rate of Crimean Congo hemorrhagic fever in South Africa has changed little during the past 25 years. See graph:

The following background information is abstracted from the Gideon e-book series. 1,2 Primary references are available on request.

Time and Place:
The first indigenous case of CCHF in South Africa was reported in 1981 – fatal infection acquired in Transvaal. At the time of the report, 7% of persons in the area were found to be seropositive.
- Most cases are reported in the Karoo, the Western Free State, the Northern Cape and North West Province; and most are farmers, farm laborers, hunters or abattoir workers.
- Twenty-seven fatal cases were reported during 1983 to 2009.
- 16 outbreaks were reported among animals during 1981 to 1986.

Seroprevalence surveys:
100% of giraffe (Giraffa camelopardalis), 54% of rhinoceros (Ceratotherium simium) and Diceros bicornis), 46% of eland (Taurotragus oryx), 19.5% of buffalo (Syncerus caffer), 22% of kudu (Tragelaphus strepsiceros), 17% of zebra (Equus burchelli), 6.0% of domestic dogs, 13.7% of hares, 1.7% of rodents and 0% of primates (South Africa and Zimbabwe, 1987 publication)
28% of cattle (1987 publication)

Subclinical infection is common among cattle, hares and sheep.

Vectors:
- The principal vector is Hyalomma truncatum.
- H. marginatum rufipes and H. m. turanicum have also been incriminated.

Notable outbreaks:
1984 – An outbreak (5 cases, 1 fatal) of Crimean-Congo hemorrhagic fever was reported in Orange Free State.
1985 – An outbreak (6 cases, 1 fatal) was reported at a hospital near Cape Town, among health-care workers who had contact with an index patient or his secretions.
1996 – An outbreak (32 suspect cases, 17 confirmed; one fatal) was reported at an ostrich abattoir in Oudtshoorn (Western Cape).

1. Berger SA. Infectious Diseases of South Africa, 2010, 411. pp. Gideon e-book series http://www.gideononline.com/ebooks/country/infectious-diseases-of-south-africa/
2. Berger SA. Crimean-Congo Hemorrhagic Fever: Global Status, 2010, 31. pp. Gideon e-book series http://www.gideononline.com/ebooks/disease/crimean-congo-hemorrhagic-fever-global-status/

The following background data were abstracted from Gideon e-books on Iran and Crimean-Congo hemorrhagic fever. [1,2] Primary references are available on request.

Crimean-Congo hemorrhagic fever was first reported in Iran (Khorassan Province) in 1978, when infected cattle entered the country from Pakistan and Afghanistan.

Several deaths were ascribed to this disease in Eastern Iran during 1999.

Graph notes:
1. Data include suspect cases.
2. 255 cases were reported in southeastern Iran during June 1999 to February 2004.
3. 169 cases were reported in Sistan-Baluchestan during 2000 to 2004.
4. 45 cases (16 confirmed, 3 fatal) were reported in Fars Province during 2001 to 2004.
5. 91 cases were reported from a single hospital in Zahedan during 1999 to 2003; 32 during 2005 to 2007.
6. 47 fatal cases were reported during 2000 to 2007; 19 in 2008.
Individual years:
2005 – Highest incidence in Sistan-Baluchestan.
2006 – Included 46 confirmed cases, most in Sistan-Baluchestan.
2009 – 71 cases (8 fatal) were reported during January to August.

Prevalence surveys:
28% of ticks in Ardabil Province (2004 to 2005)

Seroprevalence surveys:
0.24% in Sistan-Baluchestan Province, following the period 2000 to 2004
3.87% of exposed health care workers in Sistan-Baluchestan Province (2003)
1.8% of first-degree relatives of confirmed CCHF cases in Sistan-va-Baluchestan province (2008 publication)
13% of humans, sheep 38%, goats 36%, cattle 36%, camels 18% (1975)
39% of livestock in Ardabil Province (2004 to 2005)
33.4% of sheep tested during 2000 to 2001; with evidence of recent infection in 1.5%

Notable outbreaks:
1999 – An outbreak (3 cases) involved infection of two physicians from an index patient.
2001 – An outbreak (100 cases or more) of presumed CCHF was reported in Isfahan, Siustan, Baluchestan, Lorestan and West Azerbaijan.
2002 – An outbreak (5 cases) of suspected CCHF (3 fatal) was reported in Iran among Afghan refugees from Nimroz Province.
2002 – An outbreak (80 cases) was confirmed in Sistan-Baluchistan, with additional cases in Isfahan, Fars, Tehran, Khuzistan, Yazd, Chaharmahal-Bakhtiyari, and Hormozgan.
2009 – An outbreak (6 cases) was reported among abattoir workers in Mashad.
2009 – An outbreak (4 cases) was reported among hospital workers following contact wih an index case.

References:
1. Berger SA. Infectious Diseases of Iran, 356 pp, 1,222 refs. 2010. GIDEON e-books. http://www.gideononline.com/ebooks/country/infectious-diseases-of-iran/
2. Berger SA. Crimean-Congo Hemorrhagic Fever: Global Status, 31 pp, 385 refs. 2010. GIDEON e-books. http://www.gideononline.com/ebooks/disease/crimean-congo-hemorrhagic-fever-global-status/

In an undiagnosed case of hemorrhagic disease in China, Marjorie Pollack, a ProMED editor, used GIDEON to help figure out the differential diagnosis. From the ProMED note:

Using the database of the Global Infectious Disease and Epidemiology Network (GIDEON ) to see possible etiologies for a hemorrhagic fever syndrome in China, the most likely diagnosis would be Old World hantavirus infection (57 percent probability), followed by _Streptococcus suis_ infection (40 percent), leptospirosis (1.8 percent) and Crimean-Congo hemorrhagic fever (CCHF — less than one percent probability).

(more…)