Monday 6 June 2022

Thirteen confirmed deaths and fourteen suspected in an outbreak of Crimean-Congo Haemorrhagic Fever in Iraq.

Between 1 January to 22 May 2022, the health authorities of the Republic of Iraq notified World Health Organization of 212 cases of Crimean-Congo Hemorrhagic Fever, of which 115 (54%) were suspected and 97 (46%) laboratory-confirmed; there were 27 deaths, 14 in suspected cases and 13 in laboratory confirmed cases, according to a Press Release issued on 1 June 2022. The number of cases reported in the first five months of 2022 is much higher than that reported in 2021, when 33 laboratory confirmed cases were recorded. Cases have been reported in several areas (governorates) in Iraq and the outbreak may pose additional pressure to an already over-stretched health care system.

Between 1 January and 22 May 2022, 212 cases of Crimean-Congo Hemorrhagic Fever have been reported to the World Health Organization from the Iraqi health authorities of which 169 (80%) were reported in April and May alone. Of the 212 cases, 115 were suspected and 97 laboratory confirmed.  Twenty seven deaths occurred overall, of which 13 were in laboratory confirmed cases.

The Iraq Central Public Health Laboratory confirmed the cases by polymerase chain reaction. Among confirmed cases, most had direct contact with animals, and were livestock breeders or butchers. Just over half of the confirmed cases were 15 to 44 years old (52, or 54% of the total number of reported cases) and of male gender (60, or 62% of the total number of reported cases).

Nearly 50% of confirmed cases (47, or 48% of the total number of reported cases) were reported in Thiqar Governorate, southeast Iraq, and the remainder of cases were reported from 12 different governorates; Missan (13), Muthanna (7), Wassit (6), Diwaniya (4), Baghdad Karkh (4), Kirkuk (3), Basrah (3), Najaf (3), Nineveh (3), Baghdad-Rusafa (2), Babylon (1) and Karbala (1).

Distribution of laboratory confirmed cases of Crimean-Congo Hemorrhagic Fever by governorate, Iraq, 1 January to 22 May 2022. World Health Organization.

Crimean-Congo Haemorrhagic Fever is a viral haemorrhagic fever usually transmitted by ticks. It can also be contracted through contact with viraemic animal tissues (animal tissue where the virus has entered the bloodstream) during and immediately post-slaughter of animals. Crimean-Congo Haemorrhagic Fever outbreaks constitute a threat to public health services as the virus can lead to epidemics, has a high case fatality ratio (10-40%), potentially results in hospital and health facility outbreaks, and is difficult to prevent and treat. Crimean-Congo Haemorrhagic Fever is endemic in all of Africa, the Balkans, the Middle East and in Asia. 

The disease was first described in the Crimea in 1944 and given the name Crimean Haemorrhagic Fever. In 1969 it was recognised that the pathogen causing Crimean Haemorrhagic Fever was the same as that responsible for an illness identified in 1956 in the Congo. The linkage of the two place names resulted in the current name for the disease and the virus.

Crimean-Congo Haemorrhagic Fever is caused by the Crimean-Congo Haemorrhagic Fever Orthonairovirus, a negative-sense single-strand RNA Virus closely related to the Viruses that cause Dugbe Fever, Nairobi Sheep Disease, and Kasokero Fever. It is spread principally by Hard-bodied Ticks of the genus Hyalomma. These Ticks are not generally found north of the 50th Parallel North, providing a limit on the spread of the disease, although it is possible that a warming climate could lead to the Ticks and the Virus spreading further north.

The hosts of the Crimean-Congo Haemorrhagic Fever Virus include a wide range of wild and domestic Animals such as Cattle, Sheep and Goats. Many Birds are resistant to infection, but Ostriches are susceptible and may show a high prevalence of infection in endemic areas, where they have been at the origin of Human cases. For example, a former outbreak occurred at an Ostrich abattoir in South Africa. There has also been at least one reported case of a person becoming infected with Crimean-Congo Haemorrhagic Fever from a Tick carried on a migrating Bird.

Animals become infected by the bite of infected Ticks and the Virus remains in their bloodstream for about one week after infection, allowing the Tick-Animal-tick cycle to continue when another Tick bites. Although a number of tick genera are capable of becoming infected with Crimean-Congo Haemorrhagic Fever Virus, Ticks of the genus Hyalomma are the principal vector.

The Crimean-Congo Haemorrhagic Fever Virus is transmitted to people either by Tick bites or through contact with infected Animal blood or tissues during and immediately after slaughter. The majority of cases have occurred in people involved in the livestock industry, such as agricultural workers, slaughterhouse workers and veterinarians.

Human-to-Human transmission can occur resulting from close contact with the blood, secretions, organs or other bodily fluids of infected persons. Hospital-acquired infections can also occur due to improper sterilisation of medical equipment, reuse of needles and contamination of medical supplies.

The length of the incubation period depends on the mode of acquisition of the Virus. Following infection by a Tick bite, the incubation period is usually one to three days, with a maximum of nine days. The incubation period following contact with infected blood or tissues is usually five to six days, with a documented maximum of 13 days.

Onset of symptoms is sudden, with fever, myalgia, (muscle ache), dizziness, neck pain and stiffness, backache, headache, sore eyes and photophobia (sensitivity to light). There may be nausea, vomiting, diarrhoea, abdominal pain and sore throat early on, followed by sharp mood swings and confusion. After two to four days, the agitation may be replaced by sleepiness, depression and lassitude, and the abdominal pain may localise to the upper right quadrant, with detectable hepatomegaly (liver enlargement).

Other clinical signs include tachycardia (fast heart rate), lymphadenopathy (enlarged lymph nodes), and a petechial rash (a rash caused by bleeding into the skin) on internal mucosal surfaces, such as in the mouth and throat, and on the skin. The petechiae may give way to larger rashes called ecchymoses, and other haemorrhagic phenomena. There is usually evidence of hepatitis, and severely ill patients may experience rapid kidney deterioration, sudden liver failure or pulmonary failure after the fifth day of illness.

The mortality rate from Crimean-Congo Haemorrhagic Fever is approximately 30%, with death occurring in the second week of illness. In patients who recover, improvement generally begins on the ninth or tenth day after the onset of illness. Patients with fatal disease, as well as in patients in the first few days of illness, do not usually develop a measurable antibody response and so diagnosis in these individuals is achieved by Virus or RNA detection in blood or tissue samples. Tests on patient samples present an extreme biohazard risk and should only be conducted under maximum biological containment conditions. However, if samples have been inactivated (e.g. with virucides, gamma rays, formaldehyde, heat, etc.), they can be manipulated in a basic biosafety environment.

It is difficult to prevent or control Crimean-Congo Haemorrhagic Fever infection in Animals and Ticks as the Tick-Animal-Tick cycle usually goes unnoticed and the infection in domestic Animals is usually not apparent. Furthermore, the tick vectors are numerous and widespread, so Tick control with acaricides (chemicals intended to kill Ticks) is only a realistic option for well-managed livestock production facilities.

Human cases of Crimean-Congo Haemorrhagic Fever are mainly treated with general supportive care. The antiviral drug Ribavirin, both oral and intravenous formulations, has been used to treat Crimean-Congo Haemorrhagic Fever infection. However, no evidence from randomised clinical trials has demonstrated the effectiveness of Ribavirin for treating Crimean-Congo Haemorrhagic Fever. There is currently no vaccine available for either people or Animals.

In the absence of a vaccine, the only way to reduce infection in people is by raising awareness of the risk factors and educating people about the measures they can take to reduce exposure to the Virus.

In Iraq Crimean-Congo Haemorrhagic Fever has been reported in Iraq since 1979 when the disease was first diagnosed in ten patients. Since then, six cases were reported between 1989 and 2009; 11 cases in 2010; three fatal cases were reported in 2018; and more recently 33 confirmed cases including 13 deaths (a mortality rate of 39%) were reported in 2021.

Sheep and Cattle husbandry are very common in Iraq. Studies have shown that these Animals are regularly infested with Ticks, mainly Hylomma species, the principal vector of Crimean-Congo Haemorrhagic Fever.

Thiqar Governorate is divided into rural (42% of the governorate) and urban (58%) areas, where livestock farming of Sheep, Goats, Cattle, Camels, and Buffalo is an important source of livelihood, especially for the rural population. Subsistance farming is common in villages where Animal barns are located near houses and all family members take care of domestic Animals. In these settings, Crimean-Congo Haemorrhagic Fever may be transmitted from domestic Animals to Humans.

There is an increased risk of further spread of Crimean-Congo Haemorrhagic Fever within Iraq due to the upcoming religious holiday, Eid al-Adha in July, because more Camels, Cows, and Sheep will be slaughtered during that period. Additionally, international cross-border transmission cannot be ruled out given the increased population movement and possible Animal exportation associated with the holiday. During Ramadan, which took place in March and April 2022, the number of Crimean-Congo Haemorrhagic Fever cases steadily increased, and the geographical spread of the disease expanded to more governorates.

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