Crimean-Congo hemorrhagic fever

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at October 10, 2016
StartDiseasesCrimean-Congo hemorrhagic fever

Crimean-Congo haemorrhagic fever (CCHF) is a virus that creates haemorrhagic fever outbreaks. It is endemic in the Middle East, south Asian regions, the Balkans and Africa. The disease has a fatality rate of 10-40 percent. It is a type of tick-borne disease.

Contents

Definition & Facts

CCHF is a widespread disease caused by a Nairovirus which is tick-borne. It is transmitted through ticks and livestock. The virus can also be transferred between humans through blood, organs, secretions, and other bodily fluids.

There is a record of infections acquired through hospitals and clinics, the result of inadequate medical equipment sterilization, contamination of medical supplies, and reuse of needles. The disease was first diagnosed in the Crimea in 1944. In 1969, it was noted as the cause of a spreading illness in the Congo.

Symptoms & Complaints

There is an incubation period associated with CCHF which depends upon how the virus is originally acquired. If the patient is bitten by an infected tick, the period runs an average one to three days with a maximum of nine days. If there is human-to-human contact with infected tissues or blood, the incubation period is regularly five to six days and a documented max of 13 days.

Initial symptoms can include fever, muscle aches, myalgia, neck stiffness, back stiffness, neck pain, back pain, photophobia, and headaches. As the disease develops, the patient may suffer vomiting, nausea, abdominal pain, sore throat, and diarrhea.

There can be alterations in personality, including mood swings and confusion. Soon, patients can experience depression, sleepiness and lassitude, and detectable hepatomegaly (enlarged liver).

Later signs have included fast heart rate (tachycardia), enlarged lymph nodes, and petechial rashes. The most severe stages can include hepatitis, acute kidney failure, acute liver failure, and respiratory failure.

As the illness progresses, patients can have severe bruising and nosebleeds. There may also be bleeding at injection sites. Fatality can occur in the second week of illness. If there is recovery, it usually begins around the tenth day of the illness's onset. 

Causes

CCHF hosts are made up of a variety of wild and domestic animals, including sheep, cattle and goats. Ostriches have shown a prevalence for infection in endemic areas. Most birds are resistant, while the ostrich has been seen as the origin of human outbreak. In one case, the disease's spread was directly linked to an ostrich abattoir in South Africa.

Animals are infected by bites of infected ticks. The virus will remain in the animals's bloodstream up to a week. The infected animal may continue to be bitten by ticks. There are a range of tick genera known for carrying the disease and transmitting the infection with the CCHF virus, but primarily the genus Hyalomma tick is the primary source.

Livestock workers, animal herders and slaughterhouse employees are at major risk for contracting the infection. This is because they are most likely to have unprotected contact with infectious bodily fluids and blood. Individuals and international travelers who make contact with livestock in endemic areas are also at a greater risk of being exposed, increasing the possibility of human-to-human transmission.

Diagnosis & Tests

A patient's medical history will be assessed to find evidence of possible exposure to the CCHF virus. CCHF virus infection is generally diagnosed through laboratory tests such as enzyme-linked immunosorbent assay (ELISA), antigens, serum neutralization, cell culture virus isolation, and reverse transcription polymerase chain reaction.

Immunohistochemical staining can reveal evidence of viral antigens in formalin-fixed tissue. Tests have to be conducted in stringent biological containment environments. When samples show signs of inactivation, this can be discovered through gamma radiation, virucides, heat, formaldehyde and other solutions. In these cases, operations can be performed in a basic biosafety environment.

Severely infected patients and patients in first stages may not have a measurable antibody response. In these cases, diagnosing CCHF can be achieved by RNA or virus detection in tissue or blood samples.

Treatment & Therapy

While there is no standard vaccine for CCHF to treat people or animals, a mouse-tested vaccine has been used on a small scale in Eastern Europe. Treatment is essentially supportive. Patients are often subjected to a full septic work-up. Maintenance therapies can include blood transfusion, fluid replacement, and diuretics.

Treatment can be complicated because side effects of certain treatments can increase bleeding. It was recently noted high doses of methylprednisolone demonstrated promising results. Methylprednisolone was introduced to patients intravenously for five days. The prognosis in patients that survived was good. The use of methylprednisolone has been solely observational to date but can be a treatment for CCHF patients who also show signs of virus-associated hemophagocytic syndrome.

CCHF is treated with ribavirin. Ribavirin decreases the replication of CCHF in vitro and in vivo. It has also been documented that interferon (IFN-α) inhibited CCHF growth in certain types of cells. Overall, there is no definitive therapy to confirm efficacy of treatments for CCHF.

Differential diagnosis is critical so that a careful treatment plan can be deployed. Broad spectrum antibiotics are likely to be administered. There may be therapies implemented to improve hemostasis (the stopping of bleeding). Red blood cells, thrombocyte, and fresh frozen plasma might be used in some circumstances. Treatment will consist mostly of preventative measures to stall and minimize the risk of hospital-acquired infection (also known as nosocomial infections).

Prevention & Prophylaxis

Unfortunately, tick vectors are widespread. This makes controlling the population difficult. There are attempts to manage the populace through acaricides, but these can only be employed in a well-developed livestock production facility.

Infected animals are usually discovered late in the process, if at all. Animals should be quarantined, tested and treated before delivery to slaughterhouses. Humans can reduce the risk of contact by wearing protective clothing, especially light colors. This will result in easier detection of ticks. Skin and removed clothes should be examined for ticks. If found, one should safely remove them.

Approved insect repellent should be applied. Also important are washing regularly and wearing gloves, especially if caring for or visiting ill persons.