Apoptosis and its relation with clinical course in patients with Crimean-Congo hemorrhagic fever

Evaluation of the role of serum DcR3 levels in the early clinical prognosis of patients with Crimean-Congo hemorrhagic fever

BACKGROUND

Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic disease that is transmitted by Hyalomma ticks and is endemic in many parts of the world. This study aimed to determine the relationship between early serum Decoy receptor-3 (DcR3) level and clinical severity in patients with CCHF.

METHODS

The study included 88 patients hospitalized for CCHF between April and August 2022 and a control group of 40 healthy individuals. The patients were divided according to clinical course as those with mild/moderate (group 1, n=55) and severe (group 2, n=33) CCHF. DcR3 levels were measured by enzyme-linked immunosorbent assay of serum obtained at the time of diagnosis.

RESULTS

Fever, hemorrhage, nausea, headache, diarrhea, and hypoxia were significantly more common among patients with severe CCHF than patients with mild/moderate CCHF (p<0.001, <0.001, 0.02, 0.01, <0.001, and <0.001, respectively). Group 2 had higher serum DcR3 levels than both group 1 and the control group (p<0.001 for both). Serum DcR3 levels were also significantly higher in group 1 than in the control group (p<0.001). Using 98.4 ng/mL as the cut-off value, serum DcR3 had 99% sensitivity and 88% specificity in differentiating patients with severe CCHF from those with mild/moderate CCHF.

CONCLUSION

During the high season in our endemic region, CCHF can present with a severe clinical course independent of age and comorbidities, unlike other infectious diseases. Elevated DcR3 observed early in the disease may allow additional immunomodulatory therapies to be tried in addition to antiviral therapy in CCHF, for which treatment options are limited.

Crimean-Congo haemorrhagic fever virus

Crimean-Congo haemorrhagic fever (CCHF) is a severe tick-borne illness with a wide geographical distribution and case fatality rates of 30% or higher. Caused by infection with the CCHF virus (CCHFV), cases are reported throughout Africa, the Middle East, Asia and southern and eastern Europe. The expanding range of the Hyalomma tick vector is placing new populations at risk for CCHF, and no licensed vaccines or specific antivirals exist to treat CCHF. Furthermore, despite cases of CCHF being reported annually, the host and viral determinants of CCHFV pathogenesis are poorly understood. CCHFV can productively infect a multitude of animal species, yet only humans develop a severe illness. Within human populations, subclinical infections are underappreciated and may represent a substantial proportion of clinical outcomes. Compared with other members of the Bunyavirales order, CCHFV has a more complex genomic organization, with many viral proteins having unclear functions in viral pathogenesis. In recent years, improved animal models have led to increased insights into CCHFV pathogenesis, and several antivirals and vaccines for CCHFV have shown robust efficacy in preclinical models. Translation of these insights and candidate therapeutics to the clinic will hopefully reduce the morbidity and mortality caused by CCHFV.

An Experimental and Theoretical Approach to Understand Fever, DENF & its Cure

Fever is a response of a human body, due to an increase in the temperature, against certain stimuli. It may be associated with several reasons and one of the major causes of fever is a mosquito bite. Fever due to dengue virus (DENV) infection is being paid most attention out of several other fever types because of a large number of deaths reported worldwide. Dengue virus is transmitted by biting of the mosquitoes, Aedes aegypti and Aedes albopictus. DENV1, DENV2, DENV3 and DENV4 are the four serotypes of dengue virus and these serotypes have 65% similarities in their genomic structure. The genome of DENV is composed of single-stranded RNA and it encodes for the polyprotein. Structural and non-structural proteins (nsP) are the two major parts of polyprotein. Researchers have paid high attention to the non-structural protease (nsP) of DENV like nsP1, nsP2A, nsP2B, nsP3, nsP4A, nsP4B and nsP5. The NS2B-NS3 protease of DENV is the prime target of the researchers as it is responsible for the catalytic activity. In the present time, Dengvaxia (vaccine) is being recommended to patients suffering severely from DENV infection in few countries only. Till date, neither a vaccine nor an effective medicine is available to combat all four serotypes. This review describes the fever, its causes, and studies to cure the infection due to DENV using theoretical and experimental approaches.

Granzyme A in Chikungunya and Other Arboviral Infections

Granzyme A (GzmA) is secreted by cytotoxic lymphocytes and has traditionally been viewed as a mediator of cell death. However, a growing body of data suggests the physiological role of GzmA is promotion of inflammation. Here, we show that GzmA is significantly elevated in the sera of chikungunya virus (CHIKV) patients and that GzmA levels correlated with viral loads and disease scores in these patients. Serum GzmA levels were also elevated in CHIKV mouse models, with NK cells the likely source. Infection of mice deficient in type I interferon responses with CHIKV, Zika virus, or dengue virus resulted in high levels of circulating GzmA. We also show that subcutaneous injection of enzymically active recombinant mouse GzmA was able to mediate inflammation, both locally at the injection site as well as at a distant site. Protease activated receptors (PARs) may represent targets for GzmA, and we show that treatment with PAR antagonist ameliorated GzmA- and CHIKV-mediated inflammation.