No abstract

Human cases of Crimean-Congo hemorrhagic fever (CCHF) were first detected in Spain in 2016. National human and animal health authorities organized a large, multidisciplinary study focusing on ticks as sentinels to determine the nationwide distribution of ticks with CCHF virus. Ticks were collected from animals and vegetation, samples pooled (12,584 ticks; 4,556 pools), and molecular methods used to look for the virus. We detected the virus in 135 pools from most of the regions studied, indicating that it is widespread in Spain. We found sequences of CCHF virus genotypes I, III, and IV in the tick species collected, most commonly in Hyalomma lusitanicum , suggesting this tick has a prominent role in the virus’s natural cycle. The red deer ( Cervus elaphus ) was the host that most frequently yielded positive ticks. Our study highlights the need for larger studies in Spain to ascertain the complete risk to public health.

The recent outbreak of Monkeypox displays novel transmission features. The circulating strain is a descendant of a lineage that had been circulating in Nigeria since 2017. The prognosis of monkeypox disease (MPX) with the circulating strain is generally good but the estimated primary reproduction number (R0) among men who have sex with men (MSM) was above 1 suggesting efficient person-to-person transmission. Different mechanisms of viral entry and egress, as well as virus-coded host factors, are the main biological determinants of poxvirus transmissibility. OPXV evolution is driven by gene loss of virus-host interacting genes and selective pressure from host species using unique adaptive strategies at the gene and nucleotide level. In this context, we evaluated the effects of genomic instability in low-complexity-regions, areas that are often neglected during sequencing, during the early stage of the outbreak in Madrid, Spain. We uncovered significant variation in short-tandem repeat areas of the MPXV genome that could be associated with changes in transmissibility. Expression, translation, stability, or function of OPG153 (VACV A26L), OPG204 (VACV B16R) and OPG208 (VACV B19R) could be affected by the changes, in a manner that is consistent with proven genomic accordion strategies of OPXV evolution. Intriguingly, while the changes observed in OPG153 stand out as they are located inside a region under high selective pressure for transmission, in a gene that is clearly considered a core gene involved in attachment and egress; the changes in OPG208, a serine protease inhibitor-like protein that has been identified as an apoptosis inhibitor, host-range factor and virulence factor; and OPG204, a known inhibitor of the Type I interferon system shown to act as a decoy receptor, could also explain phenotypic changes. Further functional studies to complement this comparative genomic study are urgently needed.

No abstract

Crimean–Congo haemorrhagic fever (CCHF) is a potentially lethal tick-borne viral disease with a wide distribution. In Spain, 12 human cases of CCHF have been confirmed, with four deaths. The diagnosis of CCHF is hampered by the nonspecific symptoms, the high genetic diversity of CCHFV, and the biosafety requirements to manage the virus. RT-qPCR and serological tests are used for diagnosis with limitations. Reverse-transcription loop-mediated isothermal amplification (RT-LAMP) could be an effective alternative in the diagnosis of the disease. However, none of the few RT-LAMP assays developed to date has detected different CCHFV genotypes. Here, we designed a RT-LAMP using a degenerate primer set to compensate for the variability of the CCHFV target sequence. RT-LAMP was performed in colorimetric and real-time tests on RT-qPCR-confirmed CCHF patient samples notified in Spain in 2020 and 2021. Urine from an inpatient was analysed by RT-LAMP for the first time and compared with RT-qPCR. The amplicons obtained by RT-qPCR were sequenced and African III and European V genotypes were identified. RT-LAMP amplified both genotypes and was more sensitive than RT-qPCR in urine samples. We have developed a novel, rapid, specific, and sensitive RT-LAMP test that allows the detection of different CCHFV genotypes in clinical samples. This pan-CCHFV RT-LAMP detected viral RNA for the first time in urine samples. It can be easily performed as a single-tube isothermal colorimetric method on a portable platform in real time and without the need for expensive equipment, thus bringing molecular diagnostics closer to rural or resource-poor areas, where CCHF usually occurs.