Crimean-Congo hemorrhagic fever (CCHF) is a severe viral disease that poses a significant threat to public health across vast geographical regions. Caused by the Crimean-Congo hemorrhagic fever virus (CCHFV), a member of the Nairoviridae family, this illness is characterized by a sudden onset of flu-like symptoms that can rapidly escalate into severe hemorrhagic syndrome with a high case fatality rate. Recognized as the most widespread tick-borne viral disease affecting humans, CCHF represents a persistent challenge due to its complex ecology, non-specific early symptoms, potential for nosocomial (hospital-acquired) outbreaks, and the current lack of a widely available, licensed vaccine.
Figure 1. Structure of Crimean-Congo Hemorrhagic Fever Virus. (Eslava, María, 2024)
CCHFV is an enveloped virus with a single-stranded, negative-sense RNA genome. Its genome is organized into three distinct segments: the Large (L) segment, which encodes the RNA-dependent RNA polymerase; the Medium (M) segment, which encodes the glycoprotein precursor that is cleaved into the surface glycoproteins Gn and Gc; and the Small (S) segment, which encodes the nucleocapsid protein. This segmented genome allows for reassortment, contributing to the virus's genetic diversity and adaptability across different geographic regions. The virus is classified as a Biosafety Level 4 (BSL-4) pathogen, reflecting its high mortality rate and the absence of effective prophylaxis or therapy.
CCHFV is a zoonotic virus, meaning it is maintained in nature through an enzootic cycle involving ticks and wild and domestic vertebrates. Ticks, particularly those of the Hyalomma genus, serve as both the vector and a reservoir for the virus. They can acquire the virus from infected animals during a blood meal and can maintain it through transstadial (across life stages) and transovarial (to the next generation) transmission.
Humans are incidental, dead-end hosts and are not involved in the virus's natural maintenance cycle. Human infection occurs through three primary routes:
| Transmission Cycle | Details |
| Tick Bites | The most common route of transmission, occurring when an infected tick bites a human. |
| Contact with Infected Animal Blood or Tissues | Individuals in close contact with viremic livestock—such as farmers, slaughterhouse workers, and veterinarians—are at high risk. The virus can enter through broken skin or mucous membranes. |
| Nosocomial Transmission | CCHFV is highly infectious in healthcare settings. Exposure to the blood or bodily fluids of an infected patient can lead to large outbreaks among medical staff and other patients, often with severe consequences. Aerosolization during medical procedures poses an additional risk. |
| Key Molecular Targets | Details |
| GP38 | Glycoprotein 38 – A secreted glycoprotein derived from the GPC. Acts as a viral toxin that directly induces endothelial hyperpermeability and vascular leakage, the hallmark of severe CCHF disease. This mechanism drives hemorrhagic manifestations and shock, independent of direct viral replication. |
| MLD | Mucin-like domain – A highly glycosylated N-terminal domain of GPC. Functions as a critical virulence factor essential for lethal disease in vivo, yet dispensable for viral replication in vitro. Deletion of MLD results in attenuated viruses that confer protective immunity, making it a promising target for live-attenuated vaccine development. |
The incubation period for CCHF varies depending on the route of infection, typically ranging from 1 to 3 days following a tick bite and 5 to 6 days after exposure to infected blood or tissues.
The disease progresses through four distinct phases:
The overall case fatality rate is estimated to be between 10% and 40%, with death usually occurring in the second week of illness due to multi-organ failure or shock.
Early diagnosis is critical for patient management and infection control. However, the initial symptoms mimic many other tropical diseases, such as malaria, dengue, and Rift Valley fever. Diagnosis is confirmed through laboratory testing, which must be conducted under high containment conditions. Common methods include real-time reverse transcription-polymerase chain reaction (RT-PCR) to detect viral RNA during the acute phase, and serological assays (ELISA) to detect IgM and IgG antibodies in the convalescent phase. There is no specific antiviral treatment approved for CCHF. Management is primarily supportive, focusing on maintaining fluid and electrolyte balance, replacing blood components, and treating secondary infections. The antiviral drug ribavirin has shown efficacy in vitro and in some clinical studies, and it is widely used off-label for treatment and post-exposure prophylaxis, particularly in resource-limited settings.
Given the absence of a licensed vaccine, prevention relies heavily on public health measures and individual awareness.
Crimean-Congo hemorrhagic fever virus remains a formidable pathogen at the intersection of veterinary science, ecology, and human medicine. Its expanding geographic range, driven by climate change and global movement of livestock, elevates it from a regional concern to a global public health priority. While significant strides have been made in understanding its molecular biology and ecology, the development of effective vaccines and targeted therapeutics remains an urgent, unmet need. As the world grows increasingly interconnected, the international community must continue to invest in surveillance, diagnostics, and research to mitigate the impact of this deadly virus.
Reference
| Target | Cat. No. | Product Name | Host | Isotype | Application | |
| CCHFV NP | CABT-B1112 | Anti-CCHFV N protein polyclonal antibody | Rabbit | IgG | ELISA, WB | Inquiry |
| DPABC-JX068 | Rabbit Anti-CCHFV Nucleoprotein polyclonal antibody | Rabbit | Antiserum | WB, ELISA | Inquiry | |
| DMABC-JX023 | Hi-Affi 6 4 Mouse Anti-CCHFV NP recombinant monoclonal antibody, clone EG5 | Mouse | IgG | ELISA | Inquiry | |
| CCHFV | DPAB-CS23001 | Rabbit Anti-CCHFV Gc Polyclonal antibody | Rabbit | IgG | ELISA | Inquiry |
| Target | Cat. No. | Product Name | Host | |
| CCHFV | DAG-WT1209 | Recombinant Crimean-Congo haemorrhagic fever virus (CCHFV) NP [His] | E. coli | Inquiry |
| DAG-WT795 | Recombinant CCHFV GP38 [His] | E. coli | Inquiry | |
| DAGF-200 | Crimean-Congo haemorrhagic fever virus (CCHFV) Gn protein [His] | HEK293 | Inquiry | |
| DAGA-3109 | Recombinant CCHFV Nucleoprotein [His] | HEK293 | Inquiry | |
| DAGA-3110 | Recombinant CCHFV Gc [His] | E. coli | Inquiry |
