Prevalence and occupational exposure to zoonotic diseases in high-risk populations in the Free State Province, South Africa.

Introduction: Zoonotic diseases are responsible for 2.5 billion human cases globally and approximately 2.7 million deaths annually. Surveillance of animal handlers and livestock for zoonotic pathogens contributes to understanding the true disease burden and risk factors within a community. This study investigated the prevalence of selected zoonoses in cattle, farm workers and occupational exposure to endemic zoonotic diseases and their associated risk factors. Methods: Sputum samples from farmworkers were screened for Mycobacterium bovis. Blood specimens from farmworkers and archived sera were tested for serological evidence of Brucella sp., hantaviruses, and Leptospira sp. Communal and commercial cattle herds were tested for bovine tuberculosis and brucellosis. Results: Mycobacterium bovis was not isolated from human samples. A total of 327 human sera were screened, and 35/327 (10.7%) were Brucella sp. IgG positive, 17/327 (5.2%) Leptospira sp. IgM positive, and 38/327 (11.6%) hantavirus IgG positive (95% CI). A higher proportion of Brucella sp. IgG-positive samples were detected among veterinarians (value of p = 0.0006). Additionally, two cattle from a commercial dairy farm were bovine tuberculosis (bTB) positive using the bTB skin test and confirmatory interferon-gamma assay. A higher percentage of confirmed brucellosis-positive animals were from communal herds (8.7%) compared to commercial herds (1.1%). Discussion: These findings highlight the brucellosis and M. bovis prevalence in commercial and communal herds, the zoonotic disease risk in commercial and subsistence farming in developing countries, and the occupational and rural exposure risk to zoonotic pathogens.

Factors affecting the use of biosecurity measures for the protection of ruminant livestock and farm workers against infectious diseases in central South Africa.

Biosecurity measures have been introduced to limit economic losses and zoonotic exposures to humans by preventing and controlling animal diseases. However, they are implemented on individual farms with varying frequency. The goal of this study was to evaluate which biosecurity measures were used by farmers to prevent infectious diseases in ruminant livestock and to identify factors that influenced these decisions. We conducted a survey in 264 ruminant livestock farmers in a 40,000 km2 area in the Free State and Northern Cape provinces of South Africa. We used descriptive statistics, to characterize biosecurity measures and farm attributes, then multivariable binomial regression to assess the strength of the association between the attributes and the implementation of biosecurity measures including property fencing, separate equipment use on different species, separate rearing of species, isolation of sick animals, isolation of pregnant animals, quarantine of new animals, animal transport cleaning, vaccination, tick control and insect control. Ninety-nine percent of farmers reported using at least one of the 10 biosecurity measures investigated (median [M]: 6; range: 0-10). The most frequently used biosecurity measures were tick control (81%, 214 out of 264), vaccination (80%, 211 out of 264) and isolation of sick animals (72%, 190 out of 264). More biosecurity measures were used on farms with 65-282 animals (M: 6; odds ratio [OR]: 1.52) or farms with 283-12,030 animals (M: 7; OR: 1.87) than on farms with fewer than 65 animals (M: 4). Furthermore, farmers who kept two animal species (M: 7; OR: 1.41) or three or more species (M: 7) used more biosecurity measures than single-species operations (M: 4). Farmers with privately owned land used more biosecurity measures (M: 6; OR: 1.51) than those grazing their animals on communal land (M: 3.5). Farms that reported previous Rift Valley fever (RVF) outbreaks used more biosecurity measures (M: 7; OR: 1.25) compared with farms without RVF reports (M: 6) and those that purchased animals in the 12 months prior to the survey (M: 7; OR: 1.19) compared with those that did not (M: 6). When introducing new animals into their herds (n = 122), most farmers used fewer biosecurity measures than they did for their existing herd: 34% (41 out of 122) used multiple biosecurity measures like those of vaccination, tick control, quarantine or antibiotic use, whereas 36% (44 out of 122) used only one and 30% (37 out of 122) used none. Certain farm features, primarily those related to size and commercialization, were associated with more frequent use of biosecurity measures. Given the variation in the application of biosecurity measures, more awareness and technical assistance are needed to support the implementation of a biosecurity management plan appropriate for the type of farm operation and available resources.

A systematic review and meta-analysis of the sensitivity of antibody tests for the laboratory confirmation of COVID-19.

Aim: The aim of this study was to investigate the utility of serological tests for the diagnosis of COVID-19 during the first week of symptom onset in patients confirmed with the real-time RT-PCR. Materials & methods: A systematic review and meta-analysis of 58 publications were performed using data obtained from Academic Search Ultimate, Africa-wide, Scopus, Web of Science and MEDLINE. Results: We found that the highest pooled sensitivities were obtained with ELISA IgM-IgG and chemiluminescence immunoassay IgM tests. Conclusion: Serological tests have low sensitivity within the first week of symptom onset and cannot replace nucleic acid amplification tests. However, serological assays can be used to support nucleic acid amplification tests.

Mammarenaviruses of Rodents, South Africa and Zimbabwe.

We conducted a survey for group-specific indirect immunofluorescence antibody to mammarenaviruses by using Lassa fever and Mopeia virus antigens on serum specimens of 5,363 rodents of 33 species collected in South Africa and Zimbabwe during 1964-1994. Rodents were collected for unrelated purposes or for this study and stored at -70°C. We found antibody to be widely distributed in the 2 countries; antibody was detected in serum specimens of 1.2%-31.8% of 14 species of myomorph rodents, whereas 19 mammarenavirus isolates were obtained from serum specimens and viscera of 4 seropositive species. Phylogenetic analysis on the basis of partial nucleoprotein sequences indicates that 14 isolates from Mastomys natalensis, the Natal multimammate mouse, were Mopeia virus, whereas Merino Walk virus was characterized as a novel virus in a separate study. The remaining 4 isolates from 3 rodent species potentially constitute novel viruses pending full characterization.

Whole-Genome Sequence and Comparative Analysis of Human Papillomavirus Type 18 Isolated from a Nasopharyngeal Carcinoma from South Africa.

We report the complete genome sequence of human papillomavirus type 18 isolated from a nasopharyngeal carcinoma in South Africa.

Complete genome sequence of a HPV31 isolate from laryngeal squamous cell carcinoma and biological consequences for p97 promoter activity.

Human papillomavirus type 31, although detected less frequently than HPV types 16 and 18, is associated with head and neck squamous cell carcinomas. Previous studies suggest that polymorphisms in the long control region (LCR) may alter the oncogenic potential of the virus. This study reports the first complete genome of a South African HPV31 isolate from a laryngeal squamous cell carcinoma. Sequence variations relative to the HPV31 prototype sequence were identified. The pBlue-Topo® vector, a reporter gene system was used to investigate the possible influence of these variations on the LCR promoter activity in vitro. Using mutagenesis to create two different fragments, ß-galactosidase assays were used to monitor the effect of nucleotide variations on the p97 promoter. Increased ß-galactosidase expression was observed in mutants when compared to the South African HPV31 LCR isolate. Enhanced transcriptional activity was observed with the mutant that possessed a single nucleotide change within the YY1 transcription factor binding site. In conclusion, sequence variation within the LCR of HPV31 isolates may have a functional effect on viral p97 promoter activity.

Risk factors associated with exposure to Crimean-Congo haemorrhagic fever virus in animal workers and cattle, and molecular detection in ticks, South Africa.

Crimean-Congo haemorrhagic fever (CCHF) is a severe tick-borne viral zoonosis endemic to parts of Africa, Europe, the Middle East and Central Asia. Human cases are reported annually in South Africa, with a 25% case fatality rate since the first case was recognized in 1981. We investigated CCHF virus (CCHFV) seroprevalence and risk factors associated with infection in cattle and humans, and the presence of CCHFV in Hyalomma spp. ticks in central South Africa in 2017-18. CCHFV IgG seroprevalence was 74.2% (95%CI: 64.2-82.1%) in 700 cattle and 3.9% (95%CI: 2.6-5.8%) in 541 farm and wildlife workers. No veterinary personnel (117) or abattoir workers (382) were seropositive. The prevalence of CCHFV RNA was significantly higher in Hyalomma truncatum (1.6%) than in H. rufipes (0.2%) (P = 0.002). Seroprevalence in cattle increased with age and was greater in animals on which ticks were found. Seroprevalence in cattle also showed significant geographic variation. Seroprevalence in humans increased with age and was greater in workers who handled livestock for injection and collection of samples. Our findings support previous evidence of widespread high CCHFV seroprevalence in cattle and show significant occupational exposure amongst farm and wildlife workers. Our seroprevalence estimate suggests that CCHFV infections are five times more frequent than the 215 confirmed CCHF cases diagnosed in South Africa in the last four decades (1981-2019). With many cases undiagnosed, the potential seriousness of CCHF in people, and the lack of an effective vaccine or treatment, there is a need to improve public health awareness, prevention and disease control.

Comorbidities in SARS-CoV-2 Patients: a Systematic Review and Meta-Analysis.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread across the globe at unprecedented speed and is showing no signs of slowing down. The outbreak of coronavirus disease 2019 (COVID-19) has led to significant health burden in infected patients especially in those with underlying comorbidities. The aim of this study was to evaluate the correlation between comorbidities and their role in the exacerbation of disease in COVID-19 patients leading to fatal outcomes. A systematic review was conducted using data from MEDLINE, Scopus, Web of Science, and EMBASE databases published from 1 December 2019 to 15 September 2020. Fifty-three articles were included in the systematic review. Of those 53 articles, 8 articles were eligible for meta-analysis. Hypertension, obesity, and diabetes mellitus were identified to be the most prevalent comorbidities in COVID-19 patients. Our meta-analysis showed that cancer, chronic kidney diseases, diabetes mellitus, and hypertension were independently associated with mortality in COVID-19 patients. Chronic kidney disease was statistically the most prominent comorbidity leading to death. However, despite having high prevalence, obesity was not associated with mortality in COVID-19 patients.IMPORTANCE COVID-19 has plagued the world since it was first identified in December 2019. Previous systematic reviews and meta-analysis were limited by various factors such as the usage of non-peer reviewed data and were also limited by the lack of clinical data on a global scale. Comorbidities are frequently cited as risk factors for severe COVID-19 outcomes. However, the degree to which specific comorbidities impact the disease is debatable. Our study selection involves a global reach and covers all comorbidities that were reported to be involved in the exacerbation of COVID-19 leading to fatal outcomes, which allows us to identify the specific comorbidities that have higher risk in patients. The study highlights COVID-19 high-risk groups. However, further research should focus on the status of comorbidities and prognosis in COVID-19 patients.

Arthritogenic alphaviruses: epidemiological and clinical perspective on emerging arboviruses.

Mosquito-borne viruses, or arboviruses, have been part of the infectious disease landscape for centuries, and are often, but not exclusively, endemic to equatorial and subtropical regions of the world. The past two decades saw the re-emergence of arthritogenic alphaviruses, a genus of arboviruses that includes several members that cause severe arthritic disease. Recent outbreaks further highlight the substantial public health burden caused by these viruses. Arthritogenic alphaviruses are often reported in the context of focused outbreaks in specific regions (eg, Caribbean, southeast Asia, and Indian Ocean) and cause debilitating acute disease that can extend to chronic manifestations for years after infection. These viruses are classified among several antigenic complexes, span a range of hosts and mosquito vectors, and can be distributed along specific geographical locations. In this Review, we highlight key features of alphaviruses that are known to cause arthritic disease in humans and outline the present findings pertaining to classification, immunogenicity, pathogenesis, and experimental approaches aimed at limiting disease manifestations. Although the most prominent alphavirus outbreaks in the past 15 years featured chikungunya virus, and a large body of work has been dedicated to understanding chikungunya disease mechanisms, this Review will instead focus on other arthritogenic alphaviruses that have been identified globally and provide a comprehensive appraisal of present and future research directions.

Basic insights into Zika virus infection of neuroglial and brain endothelial cells.

Zika virus (ZIKV) has recently emerged as an important human pathogen due to the strong evidence that it causes disease of the central nervous system, particularly microcephaly and Guillain-Barré syndrome. The pathogenesis of disease, including mechanisms of neuroinvasion, may include both invasion via the blood-brain barrier and via peripheral (including cranial) nerves. Cellular responses to infection are also poorly understood. This study characterizes the in vitro infection of laboratory-adapted ZIKV African MR766 and two Asian strains of (1) brain endothelial cells (hCMEC/D3 cell line) and (2) olfactory ensheathing cells (OECs) (the neuroglia populating cranial nerve I and the olfactory bulb; both human and mouse OEC lines) in comparison to kidney epithelial cells (Vero cells, in which ZIKV infection is well characterized). Readouts included infection kinetics, intracellular virus localization, viral persistence and cytokine responses. Although not as high as in Vero cells, viral titres exceeded 104 plaque-forming units (p.f.u.) ml-1 in the endothelial/neuroglial cell types, except hOECs. Despite these substantial titres, a relatively small proportion of neuroglial cells were primarily infected. Immunolabelling of infected cells revealed localization of the ZIKV envelope and NS3 proteins in the cytoplasm; NS3 staining overlapped with that of dsRNA replication intermediate and the endoplasmic reticulum (ER). Infected OECs and endothelial cells produced high levels of pro-inflammatory chemokines. Nevertheless, ZIKV was also able to establish persistent infection in hOEC and hCMEC/D3 cells. Taken together, these results provide basic insights into ZIKV infection of endothelial and neuroglial cells and will form the basis for further study of ZIKV disease mechanisms.

Persistence of Crimean-Congo Hemorrhagic Fever Virus RNA.

Crimean-Congo hemorrhagic fever virus (CCHFV) causes severe disease with fatalities. Awareness of potential sources of infection is important to reduce risk to healthcare workers and contacts. We detected CCHFV RNA in formalin-fixed, paraffin-embedded tissues from a spontaneous abortion that were submitted for histology 9 weeks after a suspected CCHFV infection in the mother.

A simple and rapid approach to prepare Sindbis and West Nile viral RNA controls for differentiation between positive samples and laboratory contamination.

Reverse transcription-polymerase chain reaction (RT-PCR) is frequently used for surveillance and diagnosis of arboviruses and emerging viruses. A disadvantage of RT-PCR assays, especially nested assays, is the potential for false-positive results caused by laboratory contamination from either positive controls or positive samples. Positive reactors usually require sequence determination for confirmation which delay timeous reporting of a result. Thus, the aim of the study was to use a simple technique to prepare a positive control allowing true positives to be differentiated from laboratory contamination based on size differentiation for conventional PCR, or melt temperatures for real time assays. A flavivirus positive control and an alphavirus positive control were prepared for two RT-PCR assays that we are currently using for arbovirus surveillance in South Africa. Primers targeting a region of the partial genes of interest cloned in pGEM®T-easy were modified at the 5' ends with non-viral nucleotides. The resulting amplicons were circularised, resulting in pGEM®T-easy constructs with 51 and 65 non-viral bases inserted into the partial flaviviral and alphaviral genes respectively and used as template for transcribing RNA. Sequence analysis was used to confirm the manipulation of the partial genes. Using virus specific primer pairs, viral RNA could be readily differentiated from the modified positive controls either by size differentiation, or melt temperature in a SYBR®Green real time RT-PCR. This study demonstrates how simple recombinant technology can be used to produce a positive control that has application in the laboratory for surveillance studies or as a diagnostic tool using synthetic genes to abrogate the requirement for handling infectious virus.

Taxonomy of the order Bunyavirales: update 2019.

In February 2019, following the annual taxon ratification vote, the order Bunyavirales was amended by creation of two new families, four new subfamilies, 11 new genera and 77 new species, merging of two species, and deletion of one species. This article presents the updated taxonomy of the order Bunyavirales now accepted by the International Committee on Taxonomy of Viruses (ICTV).

Rift Valley Fever Virus Exposure amongst Farmers, Farm Workers, and Veterinary Professionals in Central South Africa.

Rift Valley fever (RVF) is a re-emerging arboviral disease of public health and veterinary importance in Africa and the Arabian Peninsula. Major RVF epidemics were documented in South Africa in 1950⁻1951, 1974⁻1975, and 2010⁻2011. The number of individuals infected during these outbreaks has, however, not been accurately estimated. A total of 823 people in close occupational contact with livestock were interviewed and sampled over a six-month period in 2015⁻2016 within a 40,000 km² study area encompassing parts of the Free State and Northern Cape provinces that were affected during the 2010⁻2011 outbreak. Seroprevalence of RVF virus (RVFV) was 9.1% (95% Confidence Interval (CI95%): 7.2⁻11.5%) in people working or residing on livestock or game farms and 8.0% in veterinary professionals. The highest seroprevalence (SP = 15.4%; CI95%: 11.4⁻20.3%) was detected in older age groups (≥40 years old) that had experienced more than one known large epidemic compared to the younger participants (SP = 4.3%; CI95%: 2.6⁻7.3%). The highest seroprevalence was in addition found in people who injected animals, collected blood samples (Odds ratio (OR) = 2.3; CI95%: 1.0⁻5.3), slaughtered animals (OR = 3.9; CI95%: 1.2⁻12.9) and consumed meat from an animal found dead (OR = 3.1; CI95%: 1.5⁻6.6), or worked on farms with dams for water storage (OR = 2.7; CI95%: 1.0⁻6.9). We estimated the number of historical RVFV infections of farm staff in the study area to be most likely 3849 and 95% credible interval between 2635 and 5374 based on seroprevalence of 9.1% and national census data. We conclude that human RVF cases were highly underdiagnosed and heterogeneously distributed. Improving precautions during injection, sample collection, slaughtering, and meat processing for consumption, and using personal protective equipment during outbreaks, could lower the risk of RVFV infection.

Taxonomy of the order Bunyavirales: second update 2018.

In October 2018, the order Bunyavirales was amended by inclusion of the family Arenaviridae, abolishment of three families, creation of three new families, 19 new genera, and 14 new species, and renaming of three genera and 22 species. This article presents the updated taxonomy of the order Bunyavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV).

Human papillomavirus in head and neck squamous cell carcinomas in a South African cohort.

BACKGROUND: Most tumours of the head and neck are attributable to smoking and alcohol use, but an increasing proportion of head and neck tumours are caused by human papillomaviruses (HPVs). The aim of this study was to use in house molecular assays to detect and genotype HPV in biopsies from patients with histologically confirmed head and neck squamous cell carcinomas. In addition, the results were compared with p16 immunohistochemistry staining, which has been described as a potential marker for HPV infection. METHODS: Biopsies of squamous cell carcinomas of the oropharynx, nasopharynx, larynx and hypopharynx from 112 South African patients were screened using three PCR assays targeting the L1 and E6 regions of HPV and p16 immunohistochemical staining. RESULTS AND CONCLUSION: HPV was identified in 7 (6.3%) tumours, while 22 (19.6%) had positive p16 immunohistochemical staining. There was concordance between the results obtained using the three PCR assays. There was substantial agreement between the results of molecular tests and p16 immunohistochemistry for hypopharyngeal carcinomas, but only fair agreement for laryngeal and oropharyngeal carcinomas.

Long-lived CD8+ T cell responses following Crimean-Congo haemorrhagic fever virus infection.

Crimean-Congo haemorrhagic fever virus (CCHFV) is a member of the Orthonairovirus genus of the Nairoviridae family and is associated with haemorrhagic fever in humans. Although T lymphocyte responses are known to play a role in protection from and clearance of viral infections, specific T cell epitopes have yet to be identified for CCHFV following infection. A panel of overlapping peptides covering the CCHFV nucleoprotein and the structural glycoproteins, GN and GC, were screened by ELISpot assay to detect interferon gamma (IFN-γ) production in vitro by peripheral blood mononuclear cells from eleven survivors with previous laboratory confirmed CCHFV infection. Reactive peptides were located predominantly on the nucleoprotein, with only one survivor reacting to two peptides from the glycoprotein GC. No single epitope was immunodominant, however all but one survivor showed reactivity to at least one T cell epitope. The responses were present at high frequency and detectable several years after the acute infection despite the absence of continued antigenic stimulation. T cell depletion studies confirmed that IFN-γ production as detected using the ELISpot assay was mediated chiefly by CD8+ T cells. This is the first description of CD8+ T cell epitopic regions for CCHFV and provides confirmation of long-lived T cell responses in survivors of CCHFV infection.

Chikungunya virus: an update on the biology and pathogenesis of this emerging pathogen.

Re-emergence of chikungunya virus, a mosquito-transmitted pathogen, is of serious public health concern. In the past 15 years, after decades of infrequent, sporadic outbreaks, the virus has caused major epidemic outbreaks in Africa, Asia, the Indian Ocean, and more recently the Caribbean and the Americas. Chikungunya virus is mainly transmitted by Aedes aegypti mosquitoes in tropical and subtropical regions, but the potential exists for further spread because of genetic adaptation of the virus to Aedes albopictus, a species that thrives in temperate regions. Chikungunya virus represents a substantial health burden to affected populations, with symptoms that include severe joint and muscle pain, rashes, and fever, as well as prolonged periods of disability in some patients. The inflammatory response coincides with raised levels of immune mediators and infiltration of immune cells into infected joints and surrounding tissues. Animal models have provided insights into disease pathology and immune responses. Although host innate and adaptive responses have a role in viral clearance and protection, they can also contribute to virus-induced immune pathology. Understanding the mechanisms of host immune responses is essential for the development of treatments and vaccines. Inhibitory compounds targeting key inflammatory pathways, as well as attenuated virus vaccines, have shown some success in animal models, including an attenuated vaccine strain based on an isolate from La Reunion incorporating an internal ribosome entry sequence that prevents the virus from infecting mosquitoes and a vaccine based on virus-like particles expressing envelope proteins. However, immune correlates of protection, as well as the safety of prophylactic and therapeutic candidates, are important to consider for their application in chikungunya infections. In this Review, we provide an update on chikungunya virus with regard to its epidemiology, molecular virology, virus-host interactions, immunological responses, animal models, and potential antiviral therapies and vaccines.

Global Genomic Diversity of Human Papillomavirus 11 Based on 433 Isolates and 78 Complete Genome Sequences.

UNLABELLED: Human papillomavirus 11 (HPV11) is an etiological agent of anogenital warts and laryngeal papillomas and is included in the 4-valent and 9-valent prophylactic HPV vaccines. We established the largest collection of globally circulating HPV11 isolates to date and examined the genomic diversity of 433 isolates and 78 complete genomes (CGs) from six continents. The genomic variation within the 2,800-bp E5a-E5b-L1-upstream regulatory region was initially studied in 181/207 (87.4%) HPV11 isolates collected for this study. Of these, the CGs of 30 HPV11 variants containing unique single nucleotide polymorphisms (SNPs), indels (insertions or deletions), or amino acid changes were fully sequenced. A maximum likelihood tree based on the global alignment of 78 HPV11 CGs (30 CGs from our study and 48 CGs from GenBank) revealed two HPV11 lineages (lineages A and B) and four sublineages (sublineages A1, A2, A3, and A4). HPV11 (sub)lineage-specific SNPs within the CG were identified, as well as the 208-bp representative region for CG-based phylogenetic clustering within the partial E2 open reading frame and noncoding region 2. Globally, sublineage A2 was the most prevalent, followed by sublineages A1, A3, and A4 and lineage B. IMPORTANCE: This collaborative international study defined the global heterogeneity of HPV11 and established the largest collection of globally circulating HPV11 genomic variants to date. Thirty novel complete HPV11 genomes were determined and submitted to the available sequence repositories. Global phylogenetic analysis revealed two HPV11 variant lineages and four sublineages. The HPV11 (sub)lineage-specific SNPs and the representative region identified within the partial genomic region E2/noncoding region 2 (NCR2) will enable the simpler identification and comparison of HPV11 variants worldwide. This study provides an important knowledge base for HPV11 for future studies in HPV epidemiology, evolution, pathogenicity, prevention, and molecular assay development.

Comparative analysis of the L, M, and S RNA segments of Crimean-Congo haemorrhagic fever virus isolates from southern Africa.

Crimean-Congo haemorrhagic fever virus (CCHFV) is a member of the Bunyaviridae family with a tripartite, negative sense RNA genome. This study used predictive software to analyse the L (large), M (medium), and S (small) segments of 14 southern African CCHFV isolates. The OTU-like cysteine protease domain and the RdRp domain of the L segment are highly conserved among southern African CCHFV isolates. The M segment encodes the structural glycoproteins, GN and GC, and the non-structural glycoproteins which are post-translationally cleaved at highly conserved furin and subtilase SKI-1 cleavage sites. All of the sites previously identified were shown to be conserved among southern African CCHFV isolates. The heavily O-glycosylated N-terminal variable mucin-like domain of the M segment shows the highest sequence variability of the CCHFV proteins. Five transmembrane domains are predicted in the M segment polyprotein resulting in three regions internal to and three regions external to the membrane across the G(N), NS(M) and G(C) glycoproteins. The corroboration of conserved genome domains and sequence identity among geographically diverse isolates may assist in the identification of protein function and pathogenic mechanisms, as well as the identification of potential targets for antiviral therapy and vaccine design. As detailed functional studies are lacking for many of the CCHFV proteins, identification of functional domains by prediction of protein structure, and identification of amino acid level similarity to functionally characterised proteins of related viruses or viruses with similar pathogenic mechanisms are a necessary step for selection of areas for further study.