Bites from infected ticks cause Crimean Congo Hemorrhagic Fever in humans. CCHF (Congo fever) has a fatality rate of 40%. Read what doctors at Meri Sehat say.

Crimean Congo Hemorrhagic Fever

Overview

Crimean-Congo hemorrhagic fever is a viral fever that is transmitted by ticks.

Pakistan is a breeding ground for tick-borne diseases, such as Crimean-Congo hemorrhagic fever (CCHF). The disease was first characterized in 1944 in Crimea; thus, the name Crimean hemorrhagic fever was coined. Later, in 1969, the disease was recognized as a cause of illness in Congo and given its current name. CCHF is a tick-borne disease caused by a virus that causes viral hemorrhagic fever<a href="#accordion">[1]</a>. The disease has a fatality rate of 10% to 40%<a href="#accordion">[1]</a>. In addition, the disease is endemic in Africa, the Middle East, the Balkans, and Asian countries.&nbsp;

The emergence and re-emergence of CCHF in Pakistan is exclusively due to poor sanitation of farms, villages, and cities, in addition to the slaughtering of animals at numerous sites within cities. Post-slaughter piles of remains of animals are not disposed of properly, and there is an ongoing issue of inefficient tick control. Cases of CCHF have been reported in almost every province in Pakistan. Moreover, in the absence of an effective disease surveillance system, the disease, unfortunately, remains endemic in Pakistan<a href="#accordion">[2]</a>. Public education, including of farmers and healthcare workers, about the causes and transmission of disease can be the first step in curbing the disease.&nbsp;

 
A wide range of wild and domestic animals, for example, cattle, sheep, and goats are susceptible to infection in endemic areas and transmit it to humans. Animals may get infected by the bite of an infected tick and the virus remains in the bloodstream for about a week. The cycle continues when another tick bites. The virus is transmitted to people either through contact with an infected animal&rsquo;s blood or tissue after slaughtering or via tick bites.&nbsp;

Most cases are reported in people working in the livestock industry, agriculture, slaughterhouses, and veterinarians. Moreover, the virus can also spread through close contact with the blood and other bodily fluids of infected persons. Furthermore, improper sterilization of medical equipment, contamination of medical supplies, and reuse of needles can lead to hospital-acquired infections.&nbsp;

&nbsp;

Signs And Symptoms

The incubation period of the infection depends on the mode of transmission of the virus. For example, if the infection is spread through a tick bite, then the incubation period is generally 1 to 3 days. Whereas, in case of contact with infected blood or tissue, the incubation period is 6 to 13 days. The disease may present with symptoms including:&nbsp;

<ul>
	<li>Fever&nbsp;</li>
	<li>Muscle ache</li>
	<li>Dizziness&nbsp;</li>
	<li>Neck pain and stiffness&nbsp;</li>
	<li>Backache&nbsp;</li>
	<li><a href="https://merisehat.pk/disease/migraines-73">Headache</a>&nbsp;</li>
	<li>Sore eyes&nbsp;</li>
	<li>Photophobia&nbsp;</li>
	<li>Nausea&nbsp;</li>
	<li>Vomiting&nbsp;</li>
	<li>Diarrhea&nbsp;</li>
	<li>Abdominal pain&nbsp;</li>
	<li>Sore throat&nbsp;</li>
	<li>Mood swings&nbsp;</li>
	<li>Confusion&nbsp; 
	&nbsp;</li>
</ul>

After 2 to 4 days of infection, the patients may present with symptoms including:&nbsp;

<ul>
	<li><a href="https://merisehat.pk/disease/sleep-apnea-91">Sleepiness&nbsp;</a></li>
	<li><a href="https://merisehat.pk/disease/depression">Depression</a>&nbsp;</li>
	<li>Liver enlargement&nbsp;</li>
	<li>Increased heart rate&nbsp;</li>
	<li>Enlarged lymph nodes&nbsp;</li>
	<li>Rash with bleeding into the skin</li>
	<li>Kidney deterioration&nbsp;</li>
	<li>Liver failure&nbsp;</li>
	<li>Lung failure 
	&nbsp;</li>
</ul>

Causes

The disease is caused by the CCHF virus that is transmitted by the bites of infected ticks or through direct contact with blood or tissues of infected ticks, infected livestock, or infected patients. Sporadic cases and outbreaks of the disease have been reported in several regions of Asia and Africa<a href="#accordion">[3]</a>. 
&nbsp;

There are currently no screening programs for Crimean-Congo hemorrhagic fever. Laboratory tests are used for the diagnosis of Crimean-Congo hemorrhagic fever. The tests include enzyme-linked immunosorbent assay (ELISA), detection of antibodies IgG and IgM with ELISA, and real-time polymerase chain reaction (RT-PCR). 
&nbsp;

Diagnosis

The virus can be diagnosed with several laboratory tests:&nbsp;

<ul>
	<li>Enzyme-linked immunosorbent assay (ELISA)</li>
	<li>Antigen detection&nbsp;</li>
	<li>Serum neutralisation&nbsp;</li>
	<li>Reverse transcriptase-polymerase chain reaction (RT-PCR) assay and virus isolation by cell culture&nbsp;</li>
</ul>

Patients presenting after a few days of illness do not develop a measurable antibody response. Therefore, the diagnosis of these individuals is achieved by virus or RNA detection in tissue or blood samples.&nbsp;Patient samples carry an extreme biohazard risk and should only be done under biological containment conditions. For example, with heat, formaldehyde, virucides, and gamma rays. Though, if the samples have been inactivated, they can be manipulated in a basic biosafety environment<a href="#accordion">[4]</a>.

&nbsp;

Treatment

Both oral and intravenous formulations of the antiviral drug ribavirin (Ribazole) are prescribed as the first line of treatment for Crimean-Congo hemorrhagic fever.&nbsp; 
Ribavirin is an anti-viral medication used for the treatment of RSV infection, hepatitis C, and some viral hemorrhagic fevers. The drug works by stopping the virus from spreading inside the body. Patients generally show improvement on the 9th or 10th day after the onset of illness.

&nbsp;

Crimean-Congo hemorrhagic fever is a tick-borne viral hemorrhagic fever with a mortality rate as high as 60% to 80%<a href="#accordion">[4]</a>. The most common complications of CCHF include:&nbsp;

<ul>
	<li>Hemorrhage&nbsp;</li>
	<li>Shock&nbsp;</li>
	<li>DIC (disseminated intravascular coagulation)</li>
	<li>Multi-organ failure</li>
</ul>

&nbsp;

The main risk factors for exposure to the virus include:&nbsp;

<ul>
	<li>Crushing and rubbing an infected tick on the skin</li>
	<li>Slaughtering an infected animal 
	&nbsp;</li>
</ul>

<ul>
	<li>Crimean-Congo hemorrhagic fever can be prevented with the use of insect repellants and protective clothing.</li>
	<li>Agriculture workers and other workers working around animals should use insect repellents containing DEET (N,N-diethyl-meta-toluamide) on exposed skin and wear protective clothing. These are the most effective ways to ward off ticks.&nbsp;</li>
	<li>Wearing gloves is also recommended.</li>
	<li>In addition, agriculture workers should avoid contact with the blood and body fluids of livestock and humans showing signs of infection.</li>
	<li>It is further important for healthcare workers to use proper precautions to prevent occupational exposure. 
	&nbsp;</li>
</ul>

An inactivated vaccine against CCHF has been developed and is currently being used at a small scale in Eastern Europe. However, the vaccine has only been tested on mice, and there is no safe or effective vaccine available for human use. There is a need for further research to develop potential vaccines against CCHF. 
&nbsp;

Key Points

<ul>
	<li>The Crimean-Congo hemorrhagic fever is endemic in Pakistan&nbsp;and has a fatality rate of up to 40%.</li>
	<li>The virus primarily transmits through ticks and livestock animals. Human-to-human transmissions occur&nbsp;via close contact with the blood and other bodily fluids of infected persons.</li>
	<li>There is currently no vaccine available for the disease. Treatment includes oral and intravenous formulations of the antiviral drug Ribavirin.</li>
	<li>Crimean-Congo hemorrhagic fever is a notification priority disease and authorities should be informed immediately. 
	&nbsp;</li>
</ul>

[1] World Health Organization, 2013. Crimean-Congo hemorrhagic fever.

[2] Yousaf, M.Z., Ashfaq, U.A., Anjum, K.M. and Fatima, S., 2018. Crimean-Congo hemorrhagic fever (CCHF) in Pakistan: the" Bell" is ringing silently. Critical Reviews™ in Eukaryotic Gene Expression, 28(2).

[3] European Commission, 2018. Commission Implementing Decision (EU) 2018/945 of 22 June 2018 on the communicable diseases and related special health issues to be covered by epidemiological surveillance as well as relevant case definitions. Off J Eur Union, 61, pp.1-74.

[4] Bastug, A., Kayaaslan, B., But, A., Aslaner, H., Sertcelik, A., Akinci, E., Onguru, P., Yetkin, M.A. and Bodur, H., 2014. A case of Crimean-Congo hemorrhagic fever complicated with acute pancreatitis. Vector-Borne and Zoonotic Diseases, 14(11), pp.827-829.