Investigating the effect of ribavirin treatment on genetic mutations in Crimean-Congo haemorrhagic fever virus (CCHFV) through next-generation sequencing.

Crimean-Congo haemorrhagic fever (CCHF) is the most widespread tick-borne viral haemorrhagic fever affecting humans, and yet a licensed drug against the virus (CCHFV) is still not available. While several studies have suggested the efficacy of ribavirin against CCHFV, current literature remains inconclusive. In this study, we have utilised next-generation sequencing to investigate the mutagenic effect of ribavirin on the CCHFV genome during clinical disease. Samples collected from CCHF patients receiving ribavirin treatment or supportive care only at Sivas Cumhuriyet University Hospital, Turkey, were analysed. By comparing the frequency of mutations in each group, we found little evidence of an overall mutagenic effect. This suggests that ribavirin, administered at the acute stages of CCHFV infection (at the World Health Organization-recommended dose) is unable to induce lethal mutagenesis that would cause an extinction event in the CCHFV population and reduce viremia.

Crimean-Congo Hemorrhagic Fever Virus: Current Advances and Future Prospects of Antiviral Strategies.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a widespread, tick-borne pathogen that causes Crimean-Congo hemorrhagic fever (CCHF) with high morbidity and mortality. CCHFV is transmitted to humans through tick bites or direct contact with patients or infected animals with viremia. Currently, climate change and globalization have increased the transmission risk of this biosafety level (BSL)-4 virus. The treatment options of CCHFV infection remain limited and there is no FDA-approved vaccine or specific antivirals, which urges the identification of potential therapeutic targets and the design of CCHF therapies with greater effort. In this article, we discuss the current progress and some future directions in the development of antiviral strategies against CCHFV.

Novel Broad-Spectrum Antiviral Inhibitors Targeting Host Factors Essential for Replication of Pathogenic RNA Viruses.

Recent RNA virus outbreaks such as Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Ebola virus (EBOV) have caused worldwide health emergencies highlighting the urgent need for new antiviral strategies. Targeting host cell pathways supporting viral replication is an attractive approach for development of antiviral compounds, especially with new, unexplored viruses where knowledge of virus biology is limited. Here, we present a strategy to identify host-targeted small molecule inhibitors using an image-based phenotypic antiviral screening assay followed by extensive target identification efforts revealing altered cellular pathways upon antiviral compound treatment. The newly discovered antiviral compounds showed broad-range antiviral activity against pathogenic RNA viruses such as SARS-CoV-2, EBOV and Crimean-Congo hemorrhagic fever virus (CCHFV). Target identification of the antiviral compounds by thermal protein profiling revealed major effects on proteostasis pathways and disturbance in interactions between cellular HSP70 complex and viral proteins, illustrating the supportive role of HSP70 on many RNA viruses across virus families. Collectively, this strategy identifies new small molecule inhibitors with broad antiviral activity against pathogenic RNA viruses, but also uncovers novel virus biology urgently needed for design of new antiviral therapies.

Efficacy of favipiravir (T-705) against Crimean-Congo hemorrhagic fever virus infection in cynomolgus macaques.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a widely distributed hemorrhagic fever virus found throughout Eastern Europe, Africa, the Middle East and Asia. It is spread through bites from infected ticks, animal husbandry and can also be acquired in the healthcare setting during care of infected patients. In humans, CCHFV can cause a sudden onset of a non-specific febrile illness that can rapidly progress to severe hemorrhagic manifestations. Currently, there is no widely available vaccine and although ribavirin has been suggested for the treatment of CCHFV, clinical efficacy in both animal models and humans is inconsistent suggesting more potent antivirals are needed for CCHFV. Favipiravir is approved in Japan for the treatment of influenza virus infections and has shown promise against other highly pathogenic RNA viruses including CCHFV with demonstrated efficacy in the type I interferon deficient mouse model. In this report we utilized the cynomolgus macaque model to evaluate the efficacy of once- and twice-daily favipiravir treatment against CCHFV infection. We found that favipiravir treatment suppressed viremia and viral shedding when treatment was initiated 24 h post-infection and viral burdens in key tissues trended lower in favipiravir-treated animals. Our data indicate that favipiravir has efficacy against CCHFV in vivo in a non-human primate model of infection.

Inactivation of three emerging viruses - severe acute respiratory syndrome coronavirus, Crimean-Congo haemorrhagic fever virus and Nipah virus - in platelet concentrates by ultraviolet C light and in plasma by methylene blue plus visible light.

BACKGROUND: Emerging viruses like severe acute respiratory syndrome coronavirus (SARS-CoV), Crimean-Congo haemorrhagic fever virus (CCHFV) and Nipah virus (NiV) have been identified to pose a potential threat to transfusion safety. In this study, the ability of the THERAFLEX UV-Platelets and THERAFLEX MB-Plasma pathogen inactivation systems to inactivate these viruses in platelet concentrates and plasma, respectively, was investigated. MATERIALS AND METHODS: Blood products were spiked with SARS-CoV, CCHFV or NiV, and then treated with increasing doses of UVC light (THERAFLEX UV-Platelets) or with methylene blue (MB) plus increasing doses of visible light (MB/light; THERAFLEX MB-Plasma). Samples were taken before and after treatment with each illumination dose and tested for residual infectivity. RESULTS: Treatment with half to three-fourths of the full UVC dose (0·2 J/cm2 ) reduced the infectivity of SARS-CoV (≥3·4 log), CCHFV (≥2·2 log) and NiV (≥4·3 log) to the limit of detection (LOD) in platelet concentrates, and treatment with MB and a fourth of the full light dose (120 J/cm2 ) decreased that of SARS-CoV (≥3·1 log), CCHFV (≥3·2 log) and NiV (≥2·7 log) to the LOD in plasma. CONCLUSION: Our study demonstrates that both THERAFLEX UV-Platelets (UVC) and THERAFLEX MB-Plasma (MB/light) effectively reduce the infectivity of SARS-CoV, CCHFV and NiV in platelet concentrates and plasma, respectively.

Identification of the crucial parameters regarding the efficacy of ribavirin therapy in Crimean-Congo haemorrhagic fever (CCHF) patients: a systematic review and meta-analysis.

OBJECTIVES: Recently, ribavirin has been suggested as a therapeutic approach in Crimean-Congo haemorrhagic fever (CCHF) patients; however, there are controversial findings about its efficacy. In the current study, a meta-analysis was systematically performed to assess the effectiveness of ribavirin administration regarding CCHF patient survival and to explore the most important influential parameters for its efficacy. METHODS: All of the outcomes of the clinically studied CCHF patients who were treated with ribavirin were included in the meta-analysis. RESULTS: Overall, 24 studies met our criteria. Although the studies did not have high quality there was no heterogeneity and publication bias across studies. The results indicated that the administration of ribavirin to CCHF patients significantly decreased the mortality rate (by 1.7-fold) compared with those who did not receive this medication. Furthermore, it was found that the prescription of ribavirin in the initial phase of disease was more effective, and a delay in the start of treatment resulted in a 1.6-fold increase in mortality rate. In addition, interventional therapy resulted in an ∼2.3-fold reduction in the mortality rate of those who received ribavirin along with corticosteroids compared with those who were treated with ribavirin monotherapy. CONCLUSIONS: This meta-analysis reveals that ribavirin should be considered as a crucial antiviral drug in the therapeutic approach used for CCHF patients, especially in early phases of the disease. Additionally, it seems that the administration of corticosteroids alongside ribavirin can play an effective role in alleviation of the disease status, particularly in haemorrhagic phases.

In silico structural elucidation of RNA-dependent RNA polymerase towards the identification of potential Crimean-Congo Hemorrhagic Fever Virus inhibitors.

The Crimean-Congo Hemorrhagic Fever virus (CCHFV) is a segmented negative single-stranded RNA virus (-ssRNA) which causes severe hemorrhagic fever in humans with a mortality rate of ~50%. To date, no vaccine has been approved. Treatment is limited to supportive care with few investigational drugs in practice. Previous studies have identified viral RNA dependent RNA Polymerase (RdRp) as a potential drug target due to its significant role in viral replication and transcription. Since no crystal structure is available yet, we report the structural elucidation of CCHFV-RdRp by in-depth homology modeling. Even with low sequence identity, the generated model suggests a similar overall structure as previously reported RdRps. More specifically, the model suggests the presence of structural/functional conserved RdRp motifs for polymerase function, the configuration of uniform spatial arrangement of core RdRp sub-domains, and predicted positively charged entry/exit tunnels, as seen in sNSV polymerases. Extensive pharmacophore modeling based on per-residue energy contribution with investigational drugs allowed the concise mapping of pharmacophoric features and identified potential hits. The combination of pharmacophoric features with interaction energy analysis revealed functionally important residues in the conserved motifs together with in silico predicted common inhibitory binding modes with highly potent reference compounds.

Use of ribavirin in viruses other than hepatitis C. A review of the evidence. / Uso de ribavirina en virus distintos de la hepatitis C. Una revisión de la evidencia.

Ribavirin is a molecule with antiviral activity against different viruses. In clinical practice, it has made its niche almost exclusively for the treatment of the hepatitisC virus. However, there are other diseases in which it could be of benefit and it has the advantage of being suitable for oral, intravenous and inhaled administration. We conducted a review of the indications of the main drug agencies (Spanish, European and American) and other possible indications, mainly haemorrhagic fevers and coronavirus.

Favipiravir (T-705) but not ribavirin is effective against two distinct strains of Crimean-Congo hemorrhagic fever virus in mice.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a cause of serious hemorrhagic disease in humans. Humans infected with CCHFV develop a non-specific febrile illness and then progress to the hemorrhagic phase where case fatality rates can be as high as 30%. Currently there is lack of vaccines and the recommended antiviral treatment, ribavirin, has inconsistent efficacy in both human and animal studies. In this study we developed a model of CCHFV infection in type I interferon deficient mice using the clinical CCHFV isolate strain Hoti. Mice infected with strain Hoti develop a progressively worsening and ultimately fatal disease. We utilized this model along with our established model using the prototypical CCHFV strain 10200 to evaluate treatment with ribavirin or the antiviral favipiravir. While ribavirin treatment was able to suppress viral loads at early time points it was ultimately unable to prevent development of terminal disease in mice infected with either strain of CCHFV. In contrast, favipiravir showed clinical benefit even when administered late in the clinical progression of CCHF. Interestingly, in a small subset of mice, late-onset of CCHF was observed after favipiravir treatment was stopped and persistence of viral RNA in favipiravir treated survivors was also seen. Nevertheless, favipiravir showed significant clinical benefit against two distinct strains of CCHFV suggesting it may be a potent antiviral for treatment of human CCHFV infections.

Ribavirin Had Demonstrable Effects on the Crimean-Congo Hemorrhagic Fever Virus (CCHFV) Population and Load in a Patient With CCHF Infection.

The use of ribavirin to treat Crimean-Congo hemorrhagic fever virus (CCHFV) infection has been controversial, based on uncertainties about its antiviral efficacy in clinical case studies. We studied the effect of ribavirin treatment on viral populations in a recent case by deep-sequencing analysis of plasma samples obtained from a CCHFV-infected patient before, during, and after a 5-day regimen of ribavirin treatment. The CCHFV load dropped during ribavirin treatment, and subclonal diversity (transitions) and indels increased in viral genomes during treatment. Although the results are based on a single case, these data demonstrate the mutagenic effect of ribavirin on CCHFV in vivo.

Identification of 2'-deoxy-2'-fluorocytidine as a potent inhibitor of Crimean-Congo hemorrhagic fever virus replication using a recombinant fluorescent reporter virus.

Crimean-Congo hemorrhagic fever virus (CCHFV), a tick-borne orthonairovirus, causes a severe hemorrhagic disease in humans (Crimean-Congo hemorrhagic fever, CCHF). Currently, no vaccines are approved to prevent CCHF; treatment is limited to supportive care and the use of ribavirin, the therapeutic benefits of which remain unclear. CCHF is part of WHO's priority list of infectious diseases warranting further research and development. To aid in the identification of new antiviral compounds, we generated a recombinant CCHFV expressing a reporter protein, allowing us to quantify virus inhibition by measuring the reduction in fluorescence in infected cells treated with candidate compounds. The screening assay was readily adaptable to high-throughput screening (HTS) of compounds using Huh7 cells, with a signal-to-noise ratio of 50:1, and Z'-factors > 0.6 in both 96- and 384-well formats. A screen of candidate nucleoside analog compounds identified 2'-deoxy-2'-fluorocytidine (EC50 = 61 ± 18 nM) as having 200 × the potency of ribavirin (EC50 = 12.5 ± 2.6 µM), as well as 17 × the potency of T-705 (favipiravir), another compound with reported anti-CCHFV activity (EC50 = 1.03 ± 0.16 µM). Furthermore, we also determined that 2'-deoxy-2'-fluorocytidine acts synergistically with T-705 to inhibit CCHFV replication without causing cytotoxicity. The incorporation of this reporter virus into the high-throughput screening assay described here will allow more rapid identification of effective therapeutic options to combat this emerging human pathogen.

Tetracyclines as a potential antiviral therapy against Crimean Congo hemorrhagic fever virus: Docking and molecular dynamic studies.

Crimean-Congo Hemorrhagic Fever Virus (CCHFV) is one of the deadliest human diseases with mortality rate near 50%. Special attention should be paid to this virus since there is no approved treatment for it. On the other hand, the recent outbreak of Ebola virus which is a member of hemorrhagic fever viruses shows this group of viruses can be extremely dangerous. Previous studies have indicated that nucleoprotein of CCHFV, a pivotal protein in virus replication, is an appropriate target for antiviral drug development. The aim of this study is finding inhibitor(s) of this protein. Herein, a virtual screening procedure employing docking followed by molecular dynamic was used to identify small molecule inhibitors of the nucleoprotein from FDA-approved drugs. Regarding CCHFV, using in-silico method is a safe way to achieve its inhibitor(s) since this virus is categorized as a World Health Organization (WHO) biosafety level 4 pathogen and therefore investigation in general laboratories is restricted. In conclusion, considering docking and molecular dynamic results alongside with bioavailability of FDA-approved drugs, doxycycline and minocycline are proposed as potential inhibitors of CCHFV nucleoprotein. There is hope, this study encourage other research groups for in-vitro and in-vivo studies about the efficacy of those two medicines in CCHFV treatment.

Potent and selective inhibition of pathogenic viruses by engineered ubiquitin variants.

The recent Middle East respiratory syndrome coronavirus (MERS-CoV), Ebola and Zika virus outbreaks exemplify the continued threat of (re-)emerging viruses to human health, and our inability to rapidly develop effective therapeutic countermeasures. Many viruses, including MERS-CoV and the Crimean-Congo hemorrhagic fever virus (CCHFV) encode deubiquitinating (DUB) enzymes that are critical for viral replication and pathogenicity. They bind and remove ubiquitin (Ub) and interferon stimulated gene 15 (ISG15) from cellular proteins to suppress host antiviral innate immune responses. A variety of viral DUBs (vDUBs), including the MERS-CoV papain-like protease, are responsible for cleaving the viral replicase polyproteins during replication, and are thereby critical components of the viral replication cycle. Together, this makes vDUBs highly attractive antiviral drug targets. However, structural similarity between the catalytic cores of vDUBs and human DUBs complicates the development of selective small molecule vDUB inhibitors. We have thus developed an alternative strategy to target the vDUB activity through a rational protein design approach. Here, we report the use of phage-displayed ubiquitin variant (UbV) libraries to rapidly identify potent and highly selective protein-based inhibitors targeting the DUB domains of MERS-CoV and CCHFV. UbVs bound the vDUBs with high affinity and specificity to inhibit deubiquitination, deISGylation and in the case of MERS-CoV also viral replicative polyprotein processing. Co-crystallization studies further revealed critical molecular interactions between UbVs and MERS-CoV or CCHFV vDUBs, accounting for the observed binding specificity and high affinity. Finally, expression of UbVs during MERS-CoV infection reduced infectious progeny titers by more than four orders of magnitude, demonstrating the remarkable potency of UbVs as antiviral agents. Our results thereby establish a strategy to produce protein-based inhibitors that could protect against a diverse range of viruses by providing UbVs via mRNA or protein delivery technologies or through transgenic techniques.

Low-dose ribavirin potentiates the antiviral activity of favipiravir against hemorrhagic fever viruses.

Favipiravir is approved in Japan to treat novel or re-emerging influenza viruses, and is active against a broad spectrum of RNA viruses, including Ebola. Ribavirin is the only other licensed drug with activity against multiple RNA viruses. Recent studies show that ribavirin and favipiravir act synergistically to inhibit bunyavirus infections in cultured cells and laboratory mice, likely due to their different mechanisms of action. Convalescent immune globulin is the only approved treatment for Argentine hemorrhagic fever caused by the rodent-borne Junin arenavirus. We previously reported that favipiravir is highly effective in a number of small animal models of Argentine hemorrhagic fever. We now report that addition of low dose of ribavirin synergistically potentiates the activity of favipiravir against Junin virus infection of guinea pigs and another arenavirus, Pichinde virus infection of hamsters. This suggests that the efficacy of favipiravir against hemorrhagic fever viruses can be further enhanced through the addition of low-dose ribavirin.

Evaluation of Crimean-Congo hemorrhagic fever virus in vitro inhibition by chloroquine and chlorpromazine, two FDA approved molecules.

Crimean-Congo hemorrhagic virus (CCHFV) causes hemorrhagic fever with high case mortality rates and is endemic in south-eastern Europe, Africa, and Asia. The limited catalog of specific treatment, highlight the necessity to look for additional therapeutic solutions. Previous experiments suggested that CCHFV enters the cells via a clathrin dependent pathway. Therefore, we have evaluated the potential anti-CCHFV activity of several molecules targeting this entry possibility. We identified two molecules chloroquine and chlorpromazine. Neutralization and virus yield reduction assays were tested in Vero E6 and Huh7 cells on two different CCHFV strains. Several combinations, including ribavirin, were assayed to test a potential synergistic effect. The two molecules inhibited CCHFV, and depending on the virus and the cell lines, the 50% inhibitory concentration (IC50) values for chloroquine and chlorpromazine ranged from 28 to 43 and 10.8-15.7 µM, respectively. Time-of-addition studies demonstrated that these molecules had a direct effect on CCHFV infectivity and spread. The antiviral activity of the two molecules was still effective even when added up to 6h post-infection and up to 24h. The selectivity index ranging from 3 to 35 lead us to evaluate combinations with ribavirin. Combinations of ribavirin and chloroquine or chlorpromazine were synergistic against CCHFV. Though the low chlorpromazine selectivity index suggests the need for a chemical improvement, our present study highlights chloroquine as the main drug having the potential for drug repurposing.

Antagonistic antiviral activity between IFN-lambda and IFN-alpha against lethal Crimean-Congo hemorrhagic fever virus in vitro.

BACKGROUND AND AIMS: Crimean Congo Hemorrhagic fever virus (CCHFV) is the causative agent of Crimean-Congo hemorrhagic fever, a severe disease with a mortality rate of around 30% in humans. Previous studies demonstrate that pre-treatment with type I IFNs have an antiviral effect against CCHFV, while established CCHFV infection is almost insensitive to subsequent IFN-α treatment. No data concerning type III IFNs antiviral activity against CCHFV are available so far. The aim of the present study was to explore the capability of IFN-λ1 to inhibit the replication of CCHFV and the possible synergism/antagonism between IFN-α and IFN-λ1 both in the inhibition of CCHFV replication and in the activation of intracellular pathways of IFN response. METHODS: Human A549 and HuH7 cells were treated with increasing amounts of IFN-λ1, or IFN-α or a combination of them, infected with CCHF; the extent of virus yield inhibition and the induction of MxA and 2'-5'OAS mRNA was measured. RESULTS AND CONCLUSIONS: Our study pointed out that type III IFN possess an antiviral activity against CCHFV, even if lower than type I IFN. Moreover, a clear antagonism between IFN-λ and IFN-α was observed in both cell lines (A549 and HuH7 cells), in terms of antiviral effect and activation of pivotal ISGs, i.e. MxA and 2'-5'OAS. Elucidating the interplay between type I and III IFNs will help to better understand innate defence mechanisms against viral infections and may provide novel scientific evidence for a more rational planning of available and future treatments, particularly against human diseases caused by high concern viruses.

Evaluation of antiviral efficacy of ribavirin, arbidol, and T-705 (favipiravir) in a mouse model for Crimean-Congo hemorrhagic fever.

BACKGROUND: Mice lacking the type I interferon receptor (IFNAR-/- mice) reproduce relevant aspects of Crimean-Congo hemorrhagic fever (CCHF) in humans, including liver damage. We aimed at characterizing the liver pathology in CCHF virus-infected IFNAR-/- mice by immunohistochemistry and employed the model to evaluate the antiviral efficacy of ribavirin, arbidol, and T-705 against CCHF virus. METHODOLOGY/PRINCIPAL FINDINGS: CCHF virus-infected IFNAR-/- mice died 2-6 days post infection with elevated aminotransferase levels and high virus titers in blood and organs. Main pathological alteration was acute hepatitis with extensive bridging necrosis, reactive hepatocyte proliferation, and mild to moderate inflammatory response with monocyte/macrophage activation. Virus-infected and apoptotic hepatocytes clustered in the necrotic areas. Ribavirin, arbidol, and T-705 suppressed virus replication in vitro by ≥3 log units (IC50 0.6-2.8 µg/ml; IC90 1.2-4.7 µg/ml). Ribavirin [100 mg/(kg×d)] did not increase the survival rate of IFNAR-/- mice, but prolonged the time to death (p<0.001) and reduced the aminotransferase levels and the virus titers. Arbidol [150 mg/(kg×d)] had no efficacy in vivo. Animals treated with T-705 at 1 h [15, 30, and 300 mg/(kg×d)] or up to 2 days [300 mg/(kg×d)] post infection survived, showed no signs of disease, and had no virus in blood and organs. Co-administration of ribavirin and T-705 yielded beneficial rather than adverse effects. CONCLUSIONS/SIGNIFICANCE: Activated hepatic macrophages and monocyte-derived cells may play a role in the proinflammatory cytokine response in CCHF. Clustering of infected hepatocytes in necrotic areas without marked inflammation suggests viral cytopathic effects. T-705 is highly potent against CCHF virus in vitro and in vivo. Its in vivo efficacy exceeds that of the current standard drug for treatment of CCHF, ribavirin.

Early use of ribavirin is beneficial in Crimean-Congo hemorrhagic fever.

We evaluated the effect of early use of ribavirin on outcomes of patients at a secondary care hospital. The study included patients who were hospitalized between 2005 and 2010 at the Infectious Diseases Department of Kastamonu Dr. Münif Islamoglu Hospital in the Kastamonu Province of Turkey. In total, 342 confirmed cases of Crimean-Congo hemorrhagic fever (CCHF) were included in the study. The overall case fatality rate was 2.9%. In multivariate analysis, the patients that were admitted to the hospital within 2 days after onset of symptoms (odds ratio [OR]=5, confidence interval [CI] 0.31-0.86) and received oral ribavirin (OR=0.12, CI 0.05-0.26) were less likely to become more severe cases and less likely to be transferred to the tertiary care centers. Having vaginal bleeding was a significant parameter for transfer.

Emergence of Crimean-Congo hemorrhagic fever in Amreli District of Gujarat State, India, June to July 2013.

Crimean-Congo hemorrhagic fever virus (CCHFV) etiology was detected in a family cluster (nine cases, including two deaths) in the village of Karyana, Amreli District, and also a fatal case in the village of Undra, Patan District, in Gujarat State, India. Anti-CCHFV IgG antibodies were detected in domestic animals from Karyana and adjoining villages. Hyalomma ticks from households were found to be positive for CCHF viral RNA. This confirms the emergence of CCHFV in new areas and the wide spread of this disease in Gujarat State.

Re-evaluation of 400 Crimean-Congo hemorrhagic fever cases in an endemic area: is ribavirin treatment suitable?

BACKGROUND: Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral disease, seen in various regions around the world, leading to death following a clinical syndrome of hemorrhagic fever. METHODS: This trial was conducted in Tokat State Hospital that is located in an endemic area. Four hundred patients referring to hospital between 2007 and 2009 and diagnosed as having CCHF with RT-PCR were enrolled in this trial. Ribavirin was not administered to any patient. Epidemiological, clinical, and laboratory findings of CCHF and factors affecting mortality were evaluated. RESULTS: Twenty patients (5%) died and 380 patients recovered (95%). It was found that mean age, white blood cells (WBC), active tromboplastine time (aPTT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) values were significantly higher in patients who died, as compared with recovered cases and the difference was significant. Platelet values were significantly lower in patients who died, as compared with recovered cases. CONCLUSIONS: Age, male gender, high levels of ALT, AST, WBC aPTT values, platelet levels, and decrease in these values during follow-up are indicative of a poor prognosis. Use of ribavirin is not required in treatment of CCHF.