Crimean-Congo haemorrhagic Virus
This is a well-known common virus these days which is spreading very fast and had a deadly effect on humans.this is commonly known as Congo fever.
This fever/virus has some facts which are described below.
Crimean-Congo Hemorrhagic fever (CCHF) is a viral disease that spreads through tick bite. It was first described in Crimea in 1944 and was called Crimean Hemorrhagic fever.
It was later also described in Congo, hence it was named Crimean-Congo Hemorrhagic fever. The disease is more common in Africa, Asia, East Europe and the Middle East. A recent outbreak has been reported in the Indian State of Gujarat and Pakistani state balouchistan.
Facts and figures
- Congo fever/virus outbreaks high fever.
- It has fatality rate is upto 40%.
- Transmition of this virus is from ticks and livestock animals. This virus is basicly in there blood.
- Human-to-human transmission can occur resulting from close contact with the blood, secretions, organs or other bodily fluids of infected persons.
- It is endemic in throughout the world but more commonly in Asian and African countries are well-known for example Pakistan, India, Africa etc.
- No vaccine is available for neither animal nor humans yet.
Couse of this fever
Crimean-Congo Hemorrhagic fever (CCHF) is caused by a virus belonging to a group called Nairovirus of the Bunyaviridae family. The virus infects wild as well as domestic animals like sheep and cattle through tick bites. Humans are infected when they come in direct contact with blood or tissues from infected animals or bites of infected ticks.
The hosts of the CCHF 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 is no apparent disease in these animals.
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 CCHF virus, ticks of the genus Hyalomma are the principal vector.
Crushing of infected tick could also result in infection. Infection may rarely occur if people breathe in the virus passed out in the infected animal’s excreta. Thus, people who work in close contact with livestock such as those working in agriculture, slaughterhouses and veterinary hospitals are at a higher risk of acquiring the disease.
The CCHF virus is transmitted to people either by tick bites or through contact with infected animal blood or tissues during and immediately after slaughter.
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 sterilization of medical equipment, reuse of needles and contamination of medical supplies.
Once a human is affected, the infection spreads to other people if they come in contact with the patient’s infected blood or body fluids. Infection could also spread in hospitals during injections and surgical procedures. Hospital staff that treat patients with CCHF are at a higher risk for developing the infection.
Symptoms and treatment
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 localize to the upper right quadrant, with detectable hepatomegaly (liver enlargement).
A person cannot be infected by eating well-cooked infected meat since the virus does not survive cooking. The patient may show general symptoms like high fever, headache, joint and muscle aches, nausea, stomach pain and loose motions. He may suffer from severe bleeding, jaundice, convulsions, and coma.
CCHF is diagnosed using tests like ELISA, isolation of the virus, antigen detection, and polymerase chain reaction. The patient is treated with intravenous fluids and an antiviral drug ribavarin.
The antiviral drug ribavirin has been used to treat CCHF infection with apparent benefit. Both oral and intravenous formulations seem to be effective.
Prevention and control
It is difficult to prevent or control CCHF 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.
Note: There are no vaccines available for use in animals.
Although an inactivated, mouse brain-derived vaccine against CCHF has been developed and used on a small scale in eastern Europe, there is currently no safe and effective vaccine widely available for human use.
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.
Adequate precautions should be taken to avoid being infected in epidemics. People exposed to domestic animals or those undergoing activities like hiking should wear protective gear to avoid tick bites. Hospital staff should also take adequate precautions while treating patients with the disease. Ribavarin may be administered to people coming in close contact with patients.
Response of WHO (World Health Organization)
WHO is working with partners to support CCHF surveillance, diagnostic capacity and outbreak response activities in Europe, the Middle East, Asia and Africa.
WHO also provides documentation to help disease investigation and control, and has created an aide–memoire on standard precautions in health care, which is intended to reduce the risk of transmission of blood borne and other pathogens.
Zain ul Abedien
Student at University of agriculture, Faisalabad.