Crimean-Congo Hemorrhagic Fever: A tick-borne disease.

 Crimean-Congo Hemorrhagic Fever, an uncommon but fatal tick-borne disease, is currently causing a significant outbreak in Iraq. It is endemic to many countries of Africa and the Middle East, so this isn't the first time, but this epidemic is more severe than usual. The World Health Organization received 212 case reports from Iraq, with 46% of them being laboratory confirmed. So far, 27 people have died, and the death toll is projected to continue to grow.

There have been at least 27 tick-borne diseases known worldwide as of 2020. Crimean-Congo Hemorrhagic Fever, sometimes known as "Nose-Bleed Fever," has existed for a long time but is currently expanding throughout numerous continents, including Europe. Crimean-Congo Hemorrhagic Fever (CCHF) is carried and transmitted most commonly by ticks of the genus Hyalomma, and has a fatality rate of up to 40%.

 There is no particular vaccine or treatment available at this time. Many different parts of the world, such as Africa, Asia, the Middle East, Russia, and the Balkans, have reported cases. In Western Europe, recent and increasingly regular outbreaks have prompted the World Health Organization to classify CCHF as a priority infection.

Crimean-Congo Hemorrhagic Fever virus belongs to the Nairoviridae family and the Bunyavirales order. It possesses a circular, negative-sense, single-stranded RNA genome. Small (S), Medium (M), and Large (L) are the three segments, each of which encodes various features of the virion. The RNA polymerase is encoded by the L segment, the glycoproteins are encoded by the M segment, and the nucleocapsid protein is encoded by the S segment.

While Crimean-Congo Hemorrhagic Fever is only harbored and spread by ticks, other Bunyaviruses have a wide range of vectors and targets. Apart from ticks, plants, protozoans, and vertebrates, members of this group can infect arthropods. All other viruses in the Bunyavirales order, with the exception of Hantaviruses and Arenaviruses, are spread by arthropods such as ticks, mosquitos, midges, and sandflies.

 Bunyaviruses are capable of rapid recombination due to their segmented genomes, increasing the likelihood of epidemics. Recombination can occur in Crimean-Congo Hemorrhagic Fever by reassortment of genomic segments and intragenic homologous recombination.

The Crimean-Congo Hemorrhagic Fever Virus is considered to have evolved between 1500 and 1100 BC. A documented incidence of hemorrhagic sickness in what is now Tajikistan in the 12th century is likely to be the first known case of CCHF. CCHF was frequent during the Crimean War in the 1850s, and it was known as Crimean Fever at the time. During the battle, it infected a large number of people, including Florence Nightingale, who was serving as a nurse, according to some sources. 

In 1944, Soviet Russian doctors discovered an illness in Crimea that they termed Crimean Hemorrhagic Fever. A virus from the Congo was identified in 1956, and it was determined in 1969 that these two strands were related, despite scientists' ignorance at the time.

CCHF is a form of hemorrhagic fever, which means it affects the capacity of the blood to clot. Fever, muscle aches, headaches, and dizziness are among the first signs and symptoms. Nausea, diarrhoea, and vomiting, as well as anxiety and confusion, may occur. Severe bruising and nosebleeds, as well as a high heart rate and pruritus, a rash formed by bleeding into the skin, are frequent as the disease worsens after a few days. After the fifth day of illness, severely unwell patients may develop kidney, liver, or lung failure, and fatalities usually occur in the second week after initiation of symptoms. Symptoms normally start to ease early in the second week in individuals who recover, however recovery is sluggish.

There is presently no vaccination approved for use in the prevention of CCHF. Despite the fact that various vaccine studies have been conducted around the world, the majority of them have been abandoned due to excessive cytotoxicity and lack of protection. There is no specific therapy, and people who are infected receive mostly supportive care.

 Ribavirin is a nucleoside that has broad-spectrum antiviral action against a variety of RNA and DNA viruses. It is most traditionally used to manage Hepatitis C. It's been tried to treat CCHF epidemics, but the evidence for its effectiveness is mixed, and it can have major side effects like anaemia and liver damage. The World Health Organization has designated CCHF as a key concern on a list of emerging infections due to a lack of viable vaccinations and treatments.

The symptoms and prognosis of infection differ dramatically from case to case, and the reason for this has remained a mystery until recently. Until recently, there was no good animal model for investigating the disease, further complicating the virus's comprehension. However, a study released in May 2022 revealed significant progress in the knowledge of factors that lead to more severe illness manifestations. Golden et al. showed that mitochondrial antiviral signalling protein (MAVS) activation and cytokine secretion contribute to the pathogenesis of Crimean-Congo Hemorrhagic Fever Virus in both cell culture and mice, identifying crucial new targets for future therapies.

People who are exposed to ticks more frequently in places where CCHF is prevalent are at a higher risk of contracting the disease. This usually affects agricultural workers, but yet another frequent route of infection is by contact with the blood of an infested animal rather than a tick bite. Slaughterhouse employees and others who come into contact with cattle on a regular basis are also at risk.

 Healthcare workers who are subjected to blood or bodily fluids without adequate protection in places where CCHF is widespread are also at risk of contracting the blood-borne virus. However, as the area of ticks that spread CCHF expands due to climate change and epidemics become more regular, the chance of developing Crimean-Congo fever increases.