Crimean-Congo hemorrhagic fever (CCHF) seroprevalence: A systematic review and meta-analysis

Serological Evidence of Crimean-Congo Haemorrhagic Fever in Livestock in the Omaheke Region of Namibia

This research examined the positivity ratio of Crimean-Congo haemorrhagic fever (CCHF) antibodies in cattle and sheep within Namibia's Omaheke region after a human disease outbreak in the same geographical area. A total of 200 samples (100 cattle and 100 sheep) were randomly collected from animals brought to two regional auction sites, and then tested using the ID Screen® CCHF Double Antigen Multi-Species Enzyme-Linked Immunosorbent Assay kit. Of the cattle samples, 36% tested positive, while 22% of the sheep samples were seropositive. The cattle had a significantly higher positivity ratio than sheep at the individual animal level (p = 0.0291). At the herd level, 62.5% of cattle herds and 45.5% of sheep flocks had at least one positive animal, but this difference was statistically insignificant (p = 0.2475). The fourteen cattle farms with at least one seropositive animal were dispersed across the Omaheke region. In contrast, the ten sheep farms with seropositive cases were predominantly situated in the southern half of the region. The study concluded that the CCHF is endemic in the Omaheke region and likely in most of Namibia, underscoring the importance of continued surveillance and preventive measures to mitigate the impact of CCHFV on animal health and potential spillover into human populations.

Animal Exposure Model for Mapping Crimean-Congo Hemorrhagic Fever Virus Emergence Risk

To estimate the determinants of spatial variation in Crimean-Congo hemorrhagic fever virus (CCHFV) transmission and to create a risk map as a preventive public health tool, we designed a survey of small domestic ruminants in Andalusia, Spain. To assess CCHFV exposure spatial distribution, we analyzed serum from 2,440 sheep and goats by using a double-antigen ELISA and modeled exposure probability with environmental predictors by using generalized linear mixed models. CCHFV antibodies detected in 84 samples confirmed low CCHFV prevalence in small domestic ruminants in the region. The best-fitted statistical model indicated that the most significant predictors of virus exposure risk were cattle/horse density and the normalized difference vegetation index. Model validation showed 99.7% specificity and 10.2% sensitivity for identifying CCHFV circulation areas. To map CCHFV exposure risk, we projected the model at a 1 × 1-km spatial resolution. Our study provides insight into CCHFV ecology that is useful for preventing virus transmission.

Analysis of liver fibrosis equations as a potential role of predictive models in Crimean-Congo hemorrhagic fever

Crimean-Congo Hemorrhagic Fever (CCHF) is a formidable global health concern, characterized by its rapid onset and high fatality rate. Distinguishing between patients at different stages remains challenging because of overlapping clinical features. This study aimed to evaluate the diagnostic efficacy of 14 hepatic fibrosis indices for distinguishing fatal cases and intensive care unit requirement (ICU) in CCHF. This study enrolled 194 patients with confirmed CCHF. Laboratory measurements were performed using auto analyzers. Indirect indicators of fibrosis were calculated for each patient based on previously described formulas. Time-dependent receiver operating characteristic (tdROC) curve analyses were employed to evaluate the predictive effects of hepatic fibrosis indices on both intensive care unit requirement and overall survival among patients. Regarding the tdROC analyses results, the highest area under the curve statistics were obtained for the baseline S-INDEX, KING, and GPRI scores (0.920, 0.913, and 0.909 respectively) in the estimation of ten-day survival, and the baseline KING, Goteborg University cirrhosis index (GUCI), and gamma-glutamyl transferase to platelet ratio index (GPRI) scores (0.783, 0.773, and 0.769 respectively) in the estimation of intensive care requirements for up to ten days. S-index and KING index emerged as early predictors of ten-day survival, while KING, GUCI, and GPRI indices demonstrated predictive capabilities for ICU admission on the first day. The identified indices have the potential to assist healthcare providers in making timely and informed decisions regarding patient management and treatment strategies. Further research and validation are warranted to solidify the role of these hepatic fibrosis indices in the clinical setting and enhance their broader applicability in the management of CCHF.

Emergence of Crimean-Congo Hemorrhagic Fever Virus in Eastern Senegal in 2022

Crimean-Congo hemorrhagic fever (CCHF), the most widespread tick-borne viral human infection, poses a threat to global health. In this study, clinical samples collected through national surveillance systems were screened for acute CCHF virus (CCHFV) infection using RT-PCR and for exposure using ELISA. For any CCHF-positive sample, livestock and tick samples were also collected in the neighborhood of the confirmed case and tested using ELISA and RT-PCR, respectively. Genome sequencing and phylogenetic analyses were also performed on samples with positive RT-PCR results. In Eastern Senegal, two human cases and one Hyalomma tick positive for CCHF were identified and a seroprevalence in livestock ranging from 9.33% to 45.26% was detected. Phylogenetic analyses revealed that the human strain belonged to genotype I based on the available L segment. However, the tick strain showed a reassortant profile, with the L and M segments belonging to genotype I and the S segment belonging to genotype III. Our data also showed that our strains clustered with strains isolated in different countries, including Mauritania. Therefore, our findings confirmed the high genetic variability inside the CCHF genotypes and their introduction to Senegal from other countries. They also indicate an increasing CCHF threat in Senegal and emphasize the need to reinforce surveillance using a one-health approach.

Knowledge, attitudes, and practices regarding Crimean-Congo hemorrhagic fever in a high-prevalence suburban community, southeast of Iran

Crimean Congo Hemorrhagic Fever (CCHF) is a zoonotic viral disease with a high mortality rate. The World Health Organization has classified it as a high-priority pathogen due to its severity. To manage this disease, knowledge, attitude, and practices (KAP) of the community play an important role. This study was conducted in a suburban area in southeastern Iran, an endemic region with a high occurrence of CCHF. A cross-sectional study was performed among 176 livestock farmers in Zahedan suburb, and data were collected through an interviewer-administered questionnaire. Single-factor and multi-factor analysis of variance was used to identify factors related to participants' knowledge, attitude, and risk of CCHF. All statistical analyses were conducted using SPSS 24, and a significance level of p ≤ 0.05 was adopted to determine statistical significance. Overall, the knowledge level about CCHF was moderate. Participants demonstrated a better understanding of high-risk occupations compared to the transmission routes and symptoms of CCHF. Conversely, their knowledge about the prevention and treatment of CCHF was found to be inadequate. The participants exhibited a good attitude towards CCHF prevention; most considered it a dangerous disease, believed in the effectiveness of preventive measures, and demonstrated the ability to address perceived obstacles. High-frequency engagement in high-risk behaviors related to CCHF was observed among the study participants. In the multi-factor model, the most critical factors associated with knowledge were age (p = 0.044), CCHF infection (p = 0.047), and CCHF education (p = 0.004). Income (p = 0.001), keeping livestock at home (p = 0.028), and receiving CCHF education (p = 0.012) were the most critical factors associated with attitude toward the risk of CCHF. The most important factors related to CCHF high-risk behavior were age (p = 0.045), gender (p = 0.028), and handling livestock (p < 0.001). These findings emphasize the need for maintaining health educational efforts on CCHF.

Seroprevalence of Crimean-Congo hemorrhagic fever virus among people living with HIV in Brazzaville, Congo and among blood donors in Bamako, Mali

Crimean-Congo hemorrhagic fever virus (CCHFV) is the causative agent of Crimean-Congo hemorrhagic fever (CCHF), a highly contagious and potentially fatal emerging disease. We assessed CCHFV seroprevalence by conducting a serological survey of two cohorts from Brazzaville, Congo and Bamako, Mali. We retrospectively screened 581 sera samples, including 352 from monitoring centers for people living with HIV (PLWH) in Brazzaville and 229 provided by the Blood Transfusion Center at Gabriel Touré Hospital in Bamako. An ELISA kit (ID Screen® CCHF Double Antigen Multi-species, Innovative Diagnostics) was used to detect total anti-CCHFV antibodies in serum. CCHFV seroprevalence was 0.6% in the PLWH cohort in Brazzaville, all in a peri‑urban area near livestock/agriculture, and 1.75% in a cohort of blood donors in Bamako, half living in a peri‑urban area near livestock/agriculture and the others performing risk-exposure activities, such as working as a butcher or with frequent rural travels. PLWH from Brazzaville were mostly female, older, and more highly educated, with a tertiary sector activity and living in an urban biotope without livestock/agricultural activities in the surroundings, in contrast to the blood donors of Bamako, who were younger and more likely to live in peri‑urban/rural areas with livestock/agricultural activities in the surroundings. Despite a low CCHFV seroprevalence, our study indicates human contact with CCHFV in sub-urban areas of the capital cities of Congo and Mali associated with previously described CCHFV risk factors.

Tick-borne pathogens in camels: A systematic review and meta-analysis of the prevalence in dromedaries

Published data on tick-borne pathogens (TBPs) in camels worldwide have been collected to provide an overview of the global prevalence and species diversity of camelid TBPs. Several TBPs have been detected in dromedary camels, raising concerns regarding their role as natural or maintenance hosts for tick-borne pathogens. Insubstantial evidence exists regarding the natural infection of camels with Babesia spp., Theileria spp., Anaplasma spp., and Ehrlichia spp., particularly because most of the camels were considered healthy at the time of sampling. Based on polymerase chain reaction (PCR) testing, a pooled prevalence of 35.3% (95% CI: 22.6-48.1%) was estimated for Anaplasma, which was the most frequently tested TBP in dromedaries, and DNA of Anaplasma marginale, Anaplasma centrale, Anaplasma ovis, Anaplasma platys, and A. platys-like were isolated, of which ruminants and dogs are reservoirs. Similarly, the estimated pooled prevalence for the two piroplasmid genera; Babesia and Theileria was approximately equal (10-12%) regardless of the detection method (microscopy or PCR testing). Nevertheless, Babesia caballi, Theileria equi, and Theileria annulata DNA have frequently been detected in camels but they have not yet been proven to be natural hosts. Scarce data detected Babesia microti, Anaplasma phagocytophilum, and Borrelia burgdorferi sensu lato (s.l.) DNA in blood of dromedaries, although ticks of the genus Ixodes are distributed in limited areas where dromedaries are raised. Interestingly, a pooled seroprevalence of 47.7% (26.3-69.2%) was estimated for Crimean-Congo hemorrhagic fever virus, and viral RNA was detected in dromedary blood; however, their contribution to maintain the viral transmission cycles requires further experimental investigation. The substantially low incidence and scarcity of data on Rickettsia and Ehrlichia species could imply that camels were accidentally infected. In contrast, camels may play a role in the spread of Coxiella burnetii, which is primarily transmitted through the inhalation of aerosols emitted by diseased animals and contaminated environments. Bactrian camels showed no symptoms due to the examined TBPs, meanwhile, clinical disease was seen in alpacas infected with A. phagocytophilum. Similar to dromedaries, accidental tick bites may be the cause of TBP DNA found in the blood of Bactrian camels.

Quantifying the influence of climate, host and change in land-use patterns on occurrence of Crimean Congo Hemorrhagic Fever (CCHF) and development of spatial risk map for India

Crimean Congo Hemorrhagic Fever (CCHF), is an emerging zoonosis globally and in India. The present study focused on identifying the risk factors for occurrence of CCHF in the Indian state of Gujarat and development of risk map for India. The past CCHF outbreaks in India were collated for the analyses. Influence of land use change and climatic factors in determining the occurrence of CCHF in Gujarat was assessed using Bayesian spatial models. Change in maximum temperature in affected districts was analysed to identify the significant change points over 110 years. Risk map was developed for Gujarat using Bayesian Additive Regression Trees (BART) model with remotely sensed environmental variables and host (livestock and human) factors. We found the change in land use patterns and maximum temperature in affected districts to be contributing to the occurrence of CCHF in Gujarat. Spatial risk map developed using CCHF occurrence data for Gujarat identified density of buffalo, minimum land surface temperature and elevation as risk determinants. Further, spatial risk map for the occurrence of CCHF in India was developed using selected variables. Overall, we found that combination of factors such as change in land-use patterns, maximum temperature, buffalo density, day time minimum land surface temperature and elevation led to the emergence and further spread of the disease in India. Mitigation measures for CCHF in India could be designed considering disease epidemiology and initiation of surveillance strategies based on the risk map developed in this study.

A social-ecological systems approach to tick bite and tick-borne disease risk management: Exploring collective action in the Occitanie region in southern France

Ticks are amongst the most important zoonotic disease vectors affecting human and animal health worldwide. Tick-borne diseases (TBDs) are rapidly expanding geographically and in incidence, most notably in temperate regions of Europe where ticks are considered the principal zoonotic vector of Public Health relevance, as well as a major health and economic preoccupation in agriculture and equine industries. Tick-borne pathogen (TBP) transmission is contingent on complex, interlinked vector-pathogen-host dynamics, environmental and ecological conditions and human behavior. Tackling TBD therefore requires a better understanding of the interconnected social and ecological variables (i.e., the social-ecological system) that favor disease (re)-emergence. The One Health paradigm recognizes the interdependence of human, animal and environmental health and proposes an integrated approach to manage TBD. However, One Health interventions are limited by significant gaps in our understanding of the complex, systemic nature of TBD risk, in addition to a lack of effective, universally accepted and environmentally conscious tick control measures. Today individual prevention gestures are the most effective strategy to manage TBDs in humans and animals, making local communities important actors in TBD detection, prevention and management. Yet, how they engage and collaborate within a multi-actor TBD network has not yet been explored. Here, we argue that transdisciplinary collaborations that go beyond research, political and medical stakeholders, and extend to local community actors can aid in identifying relevant social-ecological risk indicators key for informing multi-level TBD detection, prevention and management measures. This article proposes a transdisciplinary social-ecological systems framework, based on participatory research approaches, to better understand the necessary conditions for local actor engagement to improve TBD risk. We conclude with perspectives for implementing this methodological framework in a case study in the south of France (Occitanie region), where multi-actor collaborations are mobilized to stimulate multi-actor collective action and identify relevant social-ecological indicators of TBD risk.

Seroepidemiological investigation of Crimean Congo hemorrhagic fever virus in livestock in Uganda, 2017

Crimean-Congo Hemorrhagic fever (CCHF) is an important zoonotic disease transmitted to humans both by tick vectors and contact with fluids from an infected animal or human. Although animals are not symptomatic when infected, they are the main source of human infection. Uganda has reported sporadic human outbreaks of CCHF in various parts of the country since 2013. We designed a nationwide epidemiological study to investigate the burden of CCHF in livestock. A total of 3181 animals were sampled; 1732 cattle (54.4%), 1091 goats (34.3%), and 358 sheep (11.3%) resulting in overall livestock seropositivity of IgG antibodies against CCHF virus (CCHFV) of 31.4% (999/3181). Seropositivity in cattle was 16.9% and in sheep and goats was 48.8%. Adult and juvenile animals had higher seropositivity compared to recently born animals, and seropositivity was higher in female animals (33.5%) compared to male animals (24.1%). Local breeds had higher (36.8%) compared to exotic (2.8%) and cross breeds (19.3%). Animals that had a history of abortion or stillbirth had higher seropositivity compared to those without a history of abortion or stillbirth. CCHFV seropositivity appeared to be generally higher in northern districts of the country, though spatial trends among sampled districts were not examined. A multivariate regression analysis using a generalized linear mixed model showed that animal species, age, sex, region, and elevation were all significantly associated with CCHFV seropositivity after adjusting for the effects of other model predictors. This study shows that CCHFV is actively circulating in Uganda, posing a serious risk for human infection. The results from this study can be used to help target surveillance efforts for early case detection in animals and limit subsequent spillover into humans.

Risk factors associated with Crimean-Congo hemorrhagic fever virus circulation among human, livestock and ticks in Mauritania through a one health retrospective study

BACKGROUND

Crimean Congo hemorrhagic fever (CCHF) is endemic in Southern Mauritania where recurrent outbreaks have been constantly observed since the 1980's. The present study is the first to assess CCHFV antibodies and RNA in humans.

METHODS

A retrospective study was conducted using 263 humans and 1380 domestic animals serum samples, and 282 tick specimens of Hyalomma genus collected from 54 settings in 12 provinces across Mauritania. Antibodies targeting CCHF viral nucleoprotein were detected in animal and human sera using double-antigen ELISA. CCHFV specific RNA was detected in human and animal sera as well as tick supernatants using a CCHFV real time RT-PCR kit. Individual characteristics of sampled hosts were collected at the same time and data were geo-referenced. Satellite data of several environmental and climatic factors, were downloaded from publicly available datasets, and combined with data on livestock mobility, animal and human density, road accessibility and individual characteristics to identify possible risk factors for CCHFV spatial distribution. To this end, multivariate logistic models were developed for each host category (human, small and large ruminants).

RESULTS

The overall CCHFV antibody prevalence was 11.8% [95% CI: 8.4-16.3] in humans (17.9% in 2020 and 5.4% in 2021; p = 0.0017) and 33.1% (95% CI: 30.1-36.3) in livestock. CCHFV-specific antibodies were detected in 91 (18.1%) out of 502 sheep, 43 (9.0%) out of 477 goats, 144 (90.5%) out of 161 dromedaries and 179 (74.6%) out of 240 cattle. CCHFV RNA was detected in only 2 (0.7%) sera out of 263 animals herders samples from Hodh El Gharbi province and in 32 (11.3%) out of 282 Hyalomma ticks. In humans as well as in animals, seropositivity was not associated with sex or age groups. The multivariate analysis determined the role of different environmental, climatic and anthropic factors in the spatial distribution of the disease with animal mobility and age being identified as risk factors.

CONCLUSION

Results of the present study demonstrate the potential risk of CCHF for human population in Mauritania primarily those living in rural areas in close vicinity with animals. Future studies should prioritize an integrative human and veterinary approach for better understanding and managing Crimean-Congo hemorrhagic fever.

Monitoring of hard tick parasitism in domestic ruminants: A scale evidence for policymakers

Domestic ruminants such as camels, cattle, goats, and sheep represent a substantial part of the global world economy. Hard ticks are well-known as obligatory bloodsucking ectoparasites of domestic ruminants. Policymakers need to get results that show the global distribution of tick genera and species, their parasitic levels, and their roles as disease vectors in camels, cattle, goats, and sheep. Iran is endemic to a broad range of hard tick-borne diseases. A study that reviews the tick genera and species, life stage, seasonal and attachment site parasitism levels, the global mean ranks of tick species parasitism rates and records, and their distribution in target animals would be of particular importance. Accordingly, this review aims to summarize the above objectives. After evaluating the identified articles, 147 were selected to be part of the survey based on the study objectives. Globally, tick parasitism levels were 28.7, 29.9, 36.0 and 47.6% for goats, cattle, sheep, and camels, respectively. The tick parasitism trends have exhibited an increasing trend for camels and sheep over the years while remaining constant for cattle and goats, indicating that current tick control measures are not being properly followed. Ticks tend to parasitize females more than males because males are more resistant to certain pests than females. The distribution of tick genera and species, their parasitism levels, and their roles as disease vectors provided. This information addresses the needs of decision-makers to make decisions.

Serological Prevalence of Crimean-Congo Hemorrhagic Fever Virus Infection in Small Ruminants and Cattle in The Gambia

Crimean-Congo hemorrhagic fever virus (CCHFV) is a widely distributed tickborne zoonotic agent that infects a variety of host species. There is a lack of information on the true geographic distribution of the prevalence and risk of CCHFV in West Africa. A countrywide cross-sectional study involving 1413 extensively managed indigenous small ruminants and cattle at livestock sales markets and in village herds, respectively, was carried out in The Gambia. In sheep, an overall anti-CCHFV antibody prevalence of 18.9% (95% CI: 15.5-22.8%), goats 9.0% (95% CI: 6.7-11.7%), and cattle 59.9% (95% CI: 54.9-64.7%) was detected. Significant variation (p < 0.05) in the prevalence of anti-CCHFV antibodies at sites in the five administrative regions (sheep: 4.8-25.9%; goats: 1.8-17.1%) and three agroecological zones (sheep: 8.9-32.9%; goats: 4.1-18.0%) was also observed. Comparatively, higher anti-CCHFV antibody prevalence was detected in cattle (33.3-84.0%) compared to small ruminants (1.8-8.1%). This study represents the first countrywide investigation of the seroprevalence of CCHFV in The Gambia, and the results suggest potential circulation and endemicity of the virus in the country. These data provide critical information vital to the development of informed policies for the surveillance, diagnosis, and control of CCFHV infection in The Gambia and the region.

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.

Global prevalence and species diversity of tick-borne pathogens in buffaloes worldwide: a systematic review and meta-analysis

BACKGROUND

Buffaloes are important contributors to the livestock economy in many countries, particularly in Asia, and tick-borne pathogens (TBPs) commonly infect buffaloes, giving rise to serious pathologies other than their zoonotic potential.

METHODS

The present investigation focuses on the prevalence of TBPs infecting buffaloes worldwide. All published global data on TBPs in buffaloes were collected from different databases (e.g., PubMed, Scopus, ScienceDirect, and Google Scholar) and subjected to various meta-analyses using OpenMeta[Analyst] software, and all analyses were conducted based on a 95% confidence interval.

RESULTS

Over 100 articles discussing the prevalence and species diversity of TBPs in buffaloes were retrieved. Most of these reports focused on water buffaloes (Bubalus bubalis), whereas a few reports on TBPs in African buffaloes (Syncerus caffer) had been published. The pooled global prevalence of the apicomplexan parasites Babesia and Theileria, as well as the bacterial pathogens Anaplasma, Coxiella burnetii, Borrelia, Bartonella, and Ehrlichia in addition to Crimean-Congo hemorrhagic fever virus, were all evaluated based on the detection methods and 95% confidence intervals. Interestingly, no Rickettsia spp. were detected in buffaloes with scarce data. TBPs of buffaloes displayed a fairly high species diversity, which underlines the high infection risk to other animals, especially cattle. Babesia bovis, B. bigemina, B. orientalis, B. occultans and B. naoakii, Theileria annulata, T. orientalis complex (orientalis/sergenti/buffeli), T. parva, T. mutans, T. sinensis, T. velifera, T. lestoquardi-like, T. taurotragi, T. sp. (buffalo) and T. ovis, and Anaplasma marginale, A. centrale, A. platys, A. platys-like and "Candidatus Anaplasma boleense" were all were identified from naturally infected buffaloes.

CONCLUSIONS

Several important aspects were highlighted for the status of TBPs, which have serious economic implications for the buffalo as well as cattle industries, particularly in Asian and African countries, which should aid in the development and implementation of prevention and control methods for veterinary care practitioners, and animal owners.

Risk factors for Crimean-Congo Haemorrhagic Fever (CCHF) virus exposure in farming communities in Uganda

BACKGROUND

Crimean-Congo Haemorrhagic Fever (CCHF) is an emerging human-health threat causing sporadic outbreaks in livestock farming communities. However, the full extent and the risks associated with exposure of such communities has not previously been well-described.

METHODS

We collected blood samples from 800 humans, 666 cattle, 549 goats and 32 dogs in districts within and outside Ugandan cattle corridor in a cross-sectional survey, and tested for CCHFV-specific IgG antibodies using Enzyme-Linked Immunosorbent Assays. Sociodemographic and epidemiological data were recorded using structured questionnaire. Ticks were collected to identify circulating nairoviruses by metagenomic sequencing.

RESULTS

CCHFV seropositivity was in 221/800 (27·6%) in humans, 612/666 (91·8%) in cattle, 413/549 (75·2%) in goats and 18/32 (56·2%) in dogs. Human seropositivity was associated with livestock farming (AOR=5·68, p<0·0001), age (AOR=2·99, p=0·002) and collecting/eating engorged ticks (AOR=2·13, p=0·004). In animals, seropositivity was higher in cattle versus goats (AOR=2·58, p<0·0001), female sex (AOR=2·13, p=0·002) and heavy tick infestation (>50 ticks: AOR=3·52, p=0·004). CCHFV was identified in multiple tick pools of Rhipicephalus appendiculatus.

INTERPRETATION

The very high CCHF seropositivity especially among livestock farmers and multiple regional risk factors associated exposures, including collecting/eating engorged ticks previously unrecognised, highlights need for further surveillance and sensitisation and control policies against the disease.

Widespread exposure to Crimean-Congo haemorrhagic fever in Uganda might be driven by transmission from Rhipicephalus ticks: Evidence from cross-sectional and modelling studies

BACKGROUND

Crimean-Congo haemorrhagic fever (CCHF) is a widespread tick-borne viral infection, present across Africa and Eurasia, which might pose a cryptic public health problem in Uganda. We aimed to understand the magnitude and distribution of CCHF risk in humans, livestock and ticks across Uganda by synthesising epidemiological (cross-sectional) and ecological (modelling) studies.

METHODS

We conducted a cross-sectional study at three urban abattoirs receiving cattle from across Uganda. We sampled humans (n = 478), livestock (n = 419) and ticks (n = 1065) and used commercially-available kits to detect human and livestock CCHF virus (CCHFV) antibodies and antigen in tick pools. We developed boosted regression tree models to evaluate the correlates and geographical distribution of expected tick and wildlife hosts, and of human CCHF exposures, drawing on continent-wide data.

FINDINGS

The cross-sectional study found CCHFV IgG/IgM seroprevalence in humans of 10·3% (7·8-13·3), with antibody detection positively associated with reported history of tick bite (age-adjusted odds ratio = 2·09 (1·09-3·98)). Cattle had a seroprevalence of 69·7% (65·1-73·4). Only one Hyalomma tick (CCHFV-negative) was found. However, CCHFV antigen was detected in Rhipicephalus (5·9% of 304 pools) and Amblyomma (2·9% of 34 pools) species. Modelling predicted high human CCHF risk across much of Uganda, low environmental suitability for Hyalomma, and high suitability for Rhipicephalus and Amblyomma.

INTERPRETATION

Our epidemiological and ecological studies provide complementary evidence that CCHF exposure risk is widespread across Uganda. We challenge the idea that Hyalomma ticks are consistently the principal reservoir and vector for CCHFV, and postulate that Rhipicephalus might be important for CCHFV transmission in Uganda, due to high frequency of infected ticks and predicted environmental suitability.

FUNDING

UCL Global Challenges Research Fund (GCRF) and Pan-African Network on Emerging and Re-Emerging Infections (PANDORA-ID-NET) funded by the European and Developing Countries Clinical Trials Partnership (EDCTP) under the EU Horizon 2020 Framework Programme for Research and Innovation.

Crimean–Congo hemorrhagic fever in the Arab world: A systematic review

Crimean-Congo hemorrhagic fever (CCHF) is an important tick-borne viral infection with a fatality rate of up to 50% during outbreaks. Crimean-Congo hemorrhagic fever virus (CCHFV) is sustained in the ecosystem in benign form through vertical and horizontal transmission cycles involving tick vectors, wildlife, and livestock. Hyalomma ticks are considered the major source of human infection. CCHF occurs most often among butchers, slaughterhouse workers, and farmworkers through infected tick bites or/and contact with blood and tissues of infected livestock. The nosocomial transmission can occur in auxiliary nurses and physicians through contact with the infected patients. The widespread distribution of CCHFV most probably occurred by ticks on migratory birds, or through international travel and trade of livestock and wildlife. During co-infections of ticks and vertebrates, reassortment among genome segments could play a significant role in generating diversity, and hence, a potential risk for the emergence of novel variants. In this systematic review, we aimed to determine the epidemiology, transmission, distribution, mortality, and clinical features of CCHF in 22 Arab countries, comprising the Arab world. Based on the analysis of 57 studies published from 1978 to 2021, we found 20 tick species that could be associated with CCHFV transmission. During the 43-year period, 321 cases of CCHF were reported from 9/22 Arab countries, Iraq, Kuwait, UAE, Saudi Arabia, Oman, Sudan, Egypt, Tunisia, and Mauritania. The mean case fatality rate was 29% during various outbreaks. Individuals working in abattoirs/slaughter houses, livestock farms, and healthcare were most at risk. Contact with blood or body secretions from infected animals and patients was the most common mode of transmission. A number of different animals, including cattle, goats, sheep, and camels were reported to be seropositive for CCHFV. The highest seroprevalence was observed in camels (29%), followed by cattle (21%), goats (15%), and sheep (14%). We discuss these results in the context of policy-making and potential preventative measures that can be implemented to reduce the burden of CCHF in the Arab world.

Systematic Review on Crimean–Congo Hemorrhagic Fever Enzootic Cycle and Factors Favoring Virus Transmission: Special Focus on France, an Apparently Free-Disease Area in Europe

Crimean–Congo hemorrhagic fever (CCHF) is a viral zoonotic disease resulting in hemorrhagic syndrome in humans. Its causative agent is naturally transmitted by ticks to non-human vertebrate hosts within an enzootic sylvatic cycle. Ticks are considered biological vectors, as well as reservoirs for CCHF virus (CCHFV), as they are able to maintain the virus for several months or even years and to transmit CCHFV to other ticks. Although animals are not symptomatic, some of them can sufficiently replicate the virus, becoming a source of infection for ticks as well as humans through direct contact with contaminated body fluids. The recent emergence of CCHF in Spain indicates that tick–human interaction rates promoting virus transmission are changing and lead to the emergence of CCHF. In other European countries such as France, the presence of one of its main tick vectors and the detection of antibodies targeting CCHFV in animals, at least in Corsica and in the absence of human cases, suggest that CCHFV could be spreading silently. In this review, we study the CCHFV epidemiological cycle as hypothesized in the French local context and select the most likely parameters that may influence virus transmission among tick vectors and non-human vertebrate hosts. For this, a total of 1,035 articles dating from 1957 to 2021 were selected for data extraction. This study made it possible to identify the tick species that seem to be the best candidate vectors of CCHFV in France, but also to highlight the importance of the abundance and composition of local host communities on vectors' infection prevalence. Regarding the presumed transmission cycle involving Hyalomma marginatum, as it might exist in France, at least in Corsica, it is assumed that tick vectors are still weakly infected and the probability of disease emergence in humans remains low. The likelihood of factors that may modify this equilibrium is discussed.

Recent advances in treatment Crimean-Congo hemorrhagic fever virus: A concise overview

The Crimean Congo Hemorrhagic Fever Virus (CCHFV) is widespread in Africa, Asia, and Europe, among other places. The disease was initially discovered in the Crimean cities of the Soviet Union and the Congo, and it was given the name Crimean Congo because it induces hemorrhagic fever. According to studies, when the virus enters the body, it settles in immune cells such as macrophages and dendritic cells, causing them to malfunction and secrete inflammatory cytokines such as TNF-alpha, IL1, and IL6, resulting in cytokine storms that induces shock via endothelial activation and vascular leakage, while on the other hand, clots and disseminated intravascular coagulation (DIC) formation causes massive defects in various organs such as the liver and kidneys, as well as fatal bleeding. Disease prevention and treatment are crucial since no other effective vaccination against the disease has yet been developed. Immunotherapy is utilized as a consequence. One of the most effective treatments, when combined with compensatory therapies such as blood and platelet replacement, water, electrolytes, Fresh Frozen Plasma (FFP) replacement, and other compensatory therapies, is one of the most effective treatments. Studies; show that immunotherapy using IVIG and neutralizing and non-neutralizing monoclonal antibodies; cytokine therapy, and anti-inflammatory therapy using corticosteroids are effective ways to treat the disease.

Current and Future Molecular Diagnostics of Tick-Borne Diseases in Cattle

Ticks and tick-borne diseases such as babesiosis, anaplasmosis, ehrlichiosis, Lyme disease, Crimean Congo hemorrhagic fever, and Rocky Mountain spotted fever pose a significant threat to animal and human health. Tick-borne diseases cause billions of dollars of losses to livestock farmers annually. These losses are partially attributed to the lack of sensitive, robust, cost effective and efficient diagnostic approaches that could detect the infectious pathogen at the early stages of illness. The modern nucleic acid-based multiplex diagnostic approaches have been developed in human medicine but are still absent in veterinary medicine. These powerful assays can screen 384 patient samples at one time, simultaneously detect numerous infectious pathogens in each test sample and provide the diagnostic answer in a few hours. Development, commercialization, and wide use of such high throughput multiplex molecular assays in the cattle tick-borne disease surveillance will help in early detection and control of infectious pathogens in the animal reservoir before community spread and spillover to humans. Such approaches in veterinary medicine will save animal life, prevent billions of dollars of economic loss to cattle herders and reduce unwanted stress to both human and animal health care systems. This literature review provides recent updates on molecular diagnostics of tick-borne pathogens and discusses the importance of modern nucleic acid high throughput multiplex diagnostic approaches in the prevention of tick-borne infection to livestock.

Seroprevalence and Risk Factors of Crimean-Congo Hemorrhagic Fever in Cattle of Smallholder Farmers in Central Malawi

Crimean-Congo hemorrhagic fever virus (CCHFV) is endemic in Africa, Asia, and Eastern Europe where it circulates among animals and ticks causing sporadic outbreaks in humans. Although CCHF is endemic in sub-Saharan Africa, epidemiological information is lacking in many countries, including Malawi. To assess the risk of CCHF in Malawi, we conducted an epidemiological study in cattle reared by smallholder livestock farmers in central Malawi. A cross-sectional study was conducted in April 2020 involving seven districts, four from Kasungu and three from Lilongwe Agriculture Development Divisions. A structured questionnaire was administered to farmers to obtain demographic, animal management, and ecological risk factors data. Sera were collected from randomly selected cattle and screened for CCHF virus (CCHFV) specific antibodies using a commercial ELISA kit. Ticks were collected from cattle and classified morphologically to species level. An overall CCHFV seropositivity rate of 46.9% (n = 416; 95% CI: 42.0–51.8%) was observed. The seropositivity was significantly associated with the age of cattle (p < 0.001), sex (p < 0.001), presence of ticks in herds (p = 0.01), district (p = 0.025), and type of grazing lands (p = 0.013). Five species of ticks were identified, including Hyalomma truncatum, a known vector of CCHFV. Ticks of the species Hyalomma truncatum were not detected in two districts with the highest seroprevalence for CCHF and vector competency must be further explored in the study area. To our knowledge, this is the first report of serologic evidence of the presence of CCHV among smallholder cattle in central Malawi. This study emphasizes the need for continued monitoring of CCHFV infection among livestock, ticks, and humans for the development of data-based risk mitigation strategies.

Detailed Infestation Spectrums About Biological Stages of Hard Ticks (Acari: Ixodida: Ixodidae) in Humans: A Systematic Review and Meta-Analysis

PURPOSE

A comprehensive systematic meta-analysis review which deals with the degrees and trends of human infestation by biological stages of ticks, the degrees and trends of human infestation by biological stages of ticks in rural and urban areas, the infestation scale of tick attachment sites in body parts of humans, and the degrees of tick infestation in human age groups is critical. Therefore, this systematic meta-analysis review summarizes the above-detailed human infestation spectrums about biological stages of hard ticks.

METHODS

After a preliminary review from 605 papers representing areas of the study objectives, 96 were selected for detailed human infestation spectrums of biological stages of hard ticks.

RESULTS

In general, the results suggest that the adult ticks, and mostly females attack humans more than larval and nymphalid ones, and adult males, respectively. Unlike the trends of human infestation by larval and nymphalid stages of ticks, and the adult, male and female ticks which exhibited approximately a sharply decreasing trend, the global trend of human infestation by hard ticks exhibited approximately a sharply increasing trend over time. Ticks attack humans more in rural area than urban area. Also, the trends of human tick infestation in rural and urban areas exhibit, respectively, a sharp increase and decrease trends over time.

CONCLUSIONS

The majority of ticks mostly attach to human body trunk and extremity than head and neck, and genital area. Ticks attack human age groups of 0-9, 20-39, and 40-59 years more than those aged between 10 and 19 or older than 60 years.

Risk of Crimean Congo haemorrhagic fever virus (CCHFV) introduction and spread in CCHF-free countries in southern and Western Europe: A semi-quantitative risk assessment

Crimean-Congo hemorrhagic fever (CCHF) is a severe tick-borne viral zoonotic disease caused by Crimean-Congo hemorrhagic fever virus (CCHFV). The disease is usually asymptomatic in domestic and wild animals, both of which may act as reservoirs of the virus. CCHF is endemic in parts of Africa, Asia, the Middle East and Eastern Europe. During the last decade, the emergence or re-emergence of CCHF was described in several countries in the Eastern Mediterranean Region, with an increasing risk of extension into new areas. Given the public health importance, this study undertakes a semi-quantitative risk assessment to analyse the likelihood of entry and exposure of CCHFV into 9 CCHF-free countries in Southern and Western Europe. Based on a framework outlining the probability of the virus entry and exposure, the risk estimates were assessed for each individual country. The risk assessment was performed using information from public databases and the available scientific literature. The likelihood of entry was conducted considering 3 main pathways: infected tick vectors, wildlife and livestock. The likelihood of exposure was assessed considering the probability of survival of the infected ticks once introduced in CCHF-free countries (depending on abiotic and biotic factors), and the exposure of resident uninfected susceptible ticks to infected imported wildlife and livestock. The risk estimates (combined CCHFV introduction and exposure) were low for the majority of the countries (Austria, Belgium, Germany, Luxembourg, Netherlands, Slovenia and Switzerland) and medium for France and Italy, if accounting only for animal health consequences. Considering the public health consequences only, the risks were rated low for all the countries, except for Italy where it was assessed to be medium.

Commercially available rapid diagnostic tests for the detection of high priority pathogens: status and challenges

The ongoing COVID-19 pandemic has shown the importance of having analytical devices that allow a simple, fast, and robust detection of pathogens which cause epidemics and pandemics. The information these devices can collect is crucial for health authorities to make effective decisions to contain the disease's advance. The World Health Organization published a list of primary pathogens that have raised concern as potential causes of future pandemics. Unfortunately, there are no rapid diagnostic tests commercially available and approved by the regulatory bodies to detect most of the pathogens listed by the WHO. This report describes these pathogens, the available detection methods, and highlights areas where more attention is needed to produce rapid diagnostic tests for future pandemic surveillance.

Determination of Seroprevalence and Risk Factors of Crimean-Congo Haemorrhagic Fever (CCHF) in the Endemic Region in Turkey: A Population-Based Cross-Sectional Study

Objectives

Turkey is one of the countries that has the most cases of CCHF in recent years among the endemic countries. The disease also poses an important health threat with high mortality rate. The aim of the study was to determine the seroprevalence and risk factors of CCHF in adults aged ≥20 years in Tokat in the endemic region, Turkey.

Methods

In this population-based cross-sectional study, a total of 85 Family Medicine Units (FMUs), from over 170 in Tokat, were randomly selected using 50% sampling. The sample size was determined among the subjects aged ≥20 who registered with the FMUs, due to gender, age group, and the urban/rural population size of Tokat using the stratified cluster sampling method. Subjects were invited to the FMUs. A questionnaire was performed face to face. The blood samples were taken, and anti-CCHFV IgG antibodies were measured with ELISA method.

Results

1272 (54.9%) out of 2319 participants were female, and the mean age was 47.3 ± 15.3. Anti-CCHFV IgG seropositivity was 5.6% (n = 130). Seropositivity rates in terms of adjusted odds ratios (AOR) were higher 2.53 times (95% CI: 1.57–4.08; p=0.001) in males; 4.05 (95% CI: 2.14–7.65; p < 0.001) in age group ≥65; 0.33 (95% CI: 0.14–0.76; p < 0.001) in graduates of high school and above; 0.71 (95%CI: 0.33–1.52; p < 0.001) in ones with good income; 1.84 (95%CI: 1.18–2.86; p < 0.001) in farmers; 1.64 (95% CI: 1.04–2.27; p < 0.001) in people dealing with animal husbandry; and 1.02 (95% CI: 1.03–2.29; p < 0.001) in those with history of tick contact.

Conclusions

CCHF seroprevalence is still a common public health problem in Tokat, Turkey. Male gender, advanced age group, low-educated, low-income, farmers, animal husbandry, and history of tick contact were found to be risk factors for CCHF. The importance of this kind of community-based studies to identify the seroprevalence in regional and national level increases even more.

Crimean-Congo Haemorrhagic Fever (CCHF) in animals: Global characterization and evolution from 2006 to 2019

This study describes the global distribution and temporal evolution of Crimean-Congo haemorrhagic fever (CCHF) during the period 2006-2019, using the information officially reported to the World Organisation for Animal Health (OIE) by the National Veterinary Services of 210 countries. Eight per cent (CI 95% 4-12) of the countries reported the disease as present at least once during the study period, whereas 82% (CI 95% 77-87) as absent. Information on CCHF status lacked for 10% (CI 95% 6-13) of the countries. The majority of the countries (46%, CI 95% 39-53) never declared CCHF as notifiable, whereas only 27% (CI 95% 21-33) reported the disease as notifiable during the large majority (≥76%) of the study period. The percentage of countries that routinely applied some CCHF control measures were as following: 14% (CI 95% 9-18) passive surveillance, 3% (CI 95% 0.9-5) active surveillance and 1% (CI 95% -0.2-3) control of vector. The time series analysis indicates a significant decreasing trend in the percentage of countries reporting no information, whereas the percentage of countries applying disease control measures significantly increase. This finding may reflect the increased awareness on the importance of the disease and the increased efforts to monitor virus circulation in animals through the application of surveillance programmes. Out of 25 countries reporting cases in humans since 2006, only 12 report cases in animals, pointing out the lack of surveillance capacity in animal populations for some countries. The paucity of CCHF notifications in animals may also reflect the difficulty in identifying the infection due to absent or mild clinical signs. Given that the implementation of surveillance programmes by the Veterinary Services is an essential tool for monitoring the virus circulation and prevent its further spread, National Veterinary Services should keep monitoring and reporting information on CCHF, and at the same time, they should improve the quality and accuracy of the information provided.

Worldwide epidemiology of Crimean-Congo Hemorrhagic Fever Virus in humans, ticks and other animal species, a systematic review and meta-analysis

There are uncertainties about the global epidemiological data of infections due to Crimean-Congo hemorrhagic fever virus (CCHFV). We estimated the global case fatality rate (CFR) of CCHFV infections and the prevalence of CCHFV in humans, ticks and other animal species. We also explored the socio-demographic and clinical factors that influence these parameters. In this systematic review with meta-analyses we searched publications from database inception to 03rd February 2020 in Pubmed, Scopus, and Global Index Medicus. Studies included in this review provided cross-sectional data on the CFR and/or prevalence of one or more targets used for the detection of CCHFV. Two independent investigators selected studies to be included. Data extraction and risk of bias assessment were conducted independently by all authors. Data collected were analysed using a random effect meta-analysis. In all, 2345 records were found and a total of 312 articles (802 prevalence and/or CFR data) that met the inclusion criteria were retained. The overall CFR was 11.7% (95% CI = 9.1-14.5), 8.0% (95% CI = 1.0-18.9), and 4.7% (95% CI = 0.0-37.6) in humans with acute, recent, and past CCHFV infections respectively. The overall CCHFV acute infections prevalence was 22.5% (95% CI = 15.7-30.1) in humans, 2.1% (95% CI = 1.3-2.9) in ticks, and 4.5% (95% CI = 1.9-7.9) in other animal species. The overall CCHFV recent infections seroprevalence was 11.6% (95% CI = 7.9-16.4) in humans and 0.4% (95% CI = 0.0-2.9) in other animal species. The overall CCHFV past infections seroprevalence was 4.3% (95% CI = 3.3-5.4) in humans and 12.0% (95% CI = 9.9-14.3) in other animal species. CFR was higher in low-income countries, countries in the WHO African, South-East Asia and Eastern Mediterranean regions, in adult and ambulatory patients. CCHFV detection rate in humans were higher in CCHFV suspected cases, healthcare workers, adult and hospitalized patients, ticks of the genus Ornithodoros and Amblyomma and in animals of the orders Perissodactyla and Bucerotiformes. This review highlights a significant disease burden due to CCHFV with a strong disparity according to country income levels, geographic regions, various human categories and tick and other animal species. Preventive measures in the light of these findings are expected.

New insights about human tick infestation features: a systematic review and meta-analysis

There are many studies that provide information regarding ticks infesting humans. However, there is no a meta-analysis about the global ranks of tick infestation rates and records, global monthly tick bites and annually and periodically trends of tick infestation rates, and the global tick infestation rates among years, mounts, regions, and countries. The study provides new insights about the above objectives in a global context and therefore performed. After a preliminary review of the 610 papers representing objective areas, 241 were selected for detailed meta-analysis. In general, the global ranks of tick species were, respectively, between 0.01-85.4% and 1-53 for human infestation rates and records. Twenty-six and sixteen tick species have more than 10% and 10 records of human tick infestation rates and records, respectively. It seems these tick species tend to be more blood-feeding on humans and as a result can be more dangerous to humans. The outcome of study demonstrated that there is no difference between seasonal human tick infestation patterns in the northern and southern hemispheres. The most global monthly mean tick bites in humans were observed in June then followed in July, August, May, and September. The global annually and periodically trends of tick infestation rates in humans exhibited decreasing trends over the past decades suggesting the preventive measure to prohibit human tick infestation have been successful. It seems that the ranks of tick infestation rates and records in humans may be as two indexes to illustrate the degree of importance of tick infesting humans.

The Integration of Human and Veterinary Studies for Better Understanding and Management of Crimean-Congo Haemorrhagic Fever

Outbreaks that occur as a result of zoonotic spillover from an animal reservoir continue to highlight the importance of studying the disease interface between species. One Health approaches recognise the interdependence of human and animal health and the environmental interplay. Improving the understanding and prevention of zoonotic diseases may be achieved through greater consideration of these relationships, potentially leading to better health outcomes across species. In this review, special emphasis is given on the emerging and outbreak pathogen Crimean-Congo Haemorrhagic Fever virus (CCHFV) that can cause severe disease in humans. We discuss the efforts undertaken to better understand CCHF and the importance of integrating veterinary and human research for this pathogen. Furthermore, we consider the use of closely related nairoviruses to model human disease caused by CCHFV. We discuss intervention approaches with potential application for managing CCHFV spread, and how this concept may benefit both animal and human health.

The electrochemical detection of bioterrorism agents: a review of the detection, diagnostics, and implementation of sensors in biosafety programs for Class A bioweapons

During the past year, disease has shown us the iron grip it can hold over a population of people. Health systems can be overwhelmed, economies can be brought into recession, and many people can be harmed or killed. When weaponized, diseases can be manipulated to create a detriment to health while becoming an economic burden on any society. It is consequently prudent that easy detection of bioweapons is available to governments for protecting their people. Electrochemical sensing displays many distinct advantages, such as its low limit of detection, low cost to run, rapid generation of results, and in many instances portability. We therefore present a wide array of electrochemical sensing platforms currently being fabricated, a brief summary of Class A bioweapons, and the potential future of bioweapon detection and biosafety.

Epidemiological investigation of Crimean-Congo haemorrhagic fever virus infection among the one-humped camels (Camelus dromedarius) in southern Tunisia

Crimean-Congo haemorrhagic fever is a viral tick-borne zoonotic disease caused by a Nairovirus, Crimean-Congo haemorrhagic fever virus (CCHFV). The present survey aimed to determine the exposure of one-humped camels (Camelus dromedarius) from southern Tunisia to CCHFV. A total of 273 sera from extensively reared camels were collected from Tataouine district, Tunisia, and tested by CCHFV-specific enzyme linked immunosorbent assays. By combining the results of three serological tests, the overall seroprevalence of CCHFV was estimated as 89.7% (245/273). No viral RNA was detected from camel sera using quantitative real-time PCR (RT-qPCR). A total of 165 ticks were collected from camels and tested with RT-qPCR, and only one Hyalomma impeltatum tick was positive for virus RNA.

The emerging tick-borne Crimean-Congo haemorrhagic fever virus: A narrative review

Crimean-Congo Haemorrhagic Fever (CCHF) is an increasingly relevant viral zoonosis caused by the negative-sense single-stranded (ss) RNA Crimean-Congo Haemorrhagic Fever Orthonairovirus (CCHFV) (Nairoviridae family, Bunyavirales order). The viral genome is divided into three segments (L-M-S) of distinct size and functions. The infection is generally mediated by a tick vector, in particular belonging to the Hyalomma genus, and the transmission follows a tick-vertebrate-tick ecologic cycle, with asymptomatic infected animals functioning as reservoirs and amplifiers for CCHFV. Human hosts could be infected primarily through infected ticks or by contact with infected hosts or their body fluids and tissues, also in a nosocomial way and in occupational contexts. Infected symptomatic patients generally manifest a nonspecific illness, which progresses across four stages, with possibly lethal outcomes. Disease outbreaks show a widespread geographic diffusion and a highly variable mortality rate, dramatically peaking in untreated patients. The lack of an adequate animal model and the elevated virus biological risk (only manageable under biosafety level 4 conditions) represent strongly limiting factors for a better characterization of the disease and for the development of specific therapies and vaccines. The present review discusses updated information on CCHFV-related disease, including details about the virus (taxonomy, structure, life cycle, transmission modalities) and considering CCHF pathogenesis, epidemiology and current strategies (diagnostic, therapeutic and preventive).

Towards a Sustainable One Health Approach to Crimean-Congo Hemorrhagic Fever Prevention: Focus Areas and Gaps in Knowledge

Crimean–Congo hemorrhagic fever virus (CCHFV) infection is identified in the 2018 World Health Organization Research and Development Blueprint and the National Institute of Allergy and Infectious Diseases (NIH/NIAID) priority A list due to its high risk to public health and national security. Tick-borne CCHFV is widespread, found in Europe, Asia, Africa, the Middle East, and the Indian subcontinent. It circulates between ticks and several vertebrate hosts without causing overt disease, and thus can be present in areas without being noticed by the public. As a result, the potential for zoonotic spillover from ticks and animals to humans is high. In contrast to other emerging viruses, human-to-human transmission of CCHFV is typically limited; therefore, prevention of spillover events should be prioritized when considering countermeasures. Several factors in the transmission dynamics of CCHFV, including a complex transmission cycle that involves both ticks and vertebrate hosts, lend themselves to a One Health approach for the prevention and control of the disease that are often overlooked by current strategies. Here, we examine critical focus areas to help mitigate CCHFV spillover, including surveillance, risk assessment, and risk reduction strategies concentrated on humans, animals, and ticks; highlight gaps in knowledge; and discuss considerations for a more sustainable One Health approach to disease control.

Seroprevalence of Crimean-Congo Hemorrhagic Fever in Domesticated Animals in Northwestern Senegal

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne disease that can be contracted by direct contact with viremic animals or humans. In West Africa, recurrent CCHF outbreaks have been constantly observed in Mauritania and Senegal. Moreover, acquisition and epidemiology of the infection in humans are correlated with the occurrence and the seroprevalence of the virus in livestock. The main objective of this study is to provide updated information on the local spread of CCHF in animals in the northern region of Senegal. Out of a total of 283 animal sera collected, CCHF-specific antibodies were identified in 92 (32.5%; confidence interval [CI]_95% 27.1-38.3) sera by double antigen sandwich enzyme-linked immunosorbent assay (ELISA) test. The prevalence of CCHF virus (CCHFV) infection among horses, cattle, sheep, dogs, donkeys, and goats was 70.3% (45/64), 57.1% (8/14), 22.1% (30/136), 18.2% (2/11), 17.2% (5/29), and 6.9% (2/29), respectively. The antibody titers were found significantly affected by age (p < 0.0001) and gender (p < 0.05). High tick infestation by Rhipicephalus spp. and Hyalomma spp. was recorded on horses. The high seroprevalence to CCHFV among animals in the northern region of Senegal observed in this study indicates the permanent presence of the infection in the northern region of the country suggesting the need to strengthen surveillance plans for CCHF in Senegal.

Diagnostic Testing for Crimean-Congo Hemorrhagic Fever

Crimean-Congo hemorrhagic fever is the most geographically widespread tick-borne virus, with infection resulting in mortality in up to 30% of cases. Clinical diagnosis alone is difficult due to the nonspecific nature of symptoms; therefore, laboratory diagnostics should be utilized for patients with residence in or travel to regions of endemicity in whom the disease is suspected. This minireview provides an overview of laboratory tests available for Crimean-Congo hemorrhagic fever (CCHF) and their utility in diagnosis with a focus on diagnosing CCHF in humans.

Seroprevalence of Crimean-Congo hemorrhagic fever in humans in the World Health Organization European region: A systematic review

BACKGROUND

Crimean-Congo hemorrhagic fever (CCHF) is an emerging infectious disease caused by a Nairovirus. CCHF is a tick-borne disease that is predominantly associated with Hyalomma ticks and have a widespread distribution in Africa, Asia and Europe. CCHF usually presents as a subclinical disease, but in some cases, it may present as a hemorrhagic fever with a high mortality rate. This systematic review of the literature was performed to identify the available evidence on the prevalence of CCHF in the European Region of the World Health Organization, based on seroprevalence (IgG antibodies).

METHODOLOGY

A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement protocol. PubMed, Embase, and the Web of Science were used for the search (up to January 31, 2019), combining the following MeSH terms: ["Crimean-Congo haemorrhagic fever" OR "Crimean-Congo hemorrhagic fever virus" OR "Congo-Crimea" OR "Crimea-Congo"] AND ["Europe"] AND ["epidemiology" OR "seroprevalence"]. The abstracts were screened. Subsequently, full-text articles were selected and reviewed based on the PICOS (Population-Intervention-Comparison-Outcomes-Study type) criteria by two independent reviewers for inclusion in the final analysis. The data were qualitatively synthesized without quantitative pooling due to the heterogeneity in the study populations and methodologies.

PRINCIPAL FINDINGS

Thirty articles (9 from western Europe, 18 from central Europe and 3 from eastern Europe) were included in the analysis. All articles were cross-sectional studies (descriptive studies).

CONCLUSIONS

The highest seroprevalence of CCHF is found in central and eastern European countries. Southern and western Europe countries, such as Greece and Spain, have low levels of endemicity, but the spread of the infection, which is associated with climate change, is a possibility that we should keep in mind. Further studies, especially larger seroprevalence studies in humans and animals, are needed to establish the current status of the CCHF epidemiology and to generate standardized guidelines for action in the region.

New aspects about Crimean-Congo hemorrhagic fever (CCHF) cases and associated fatality trends: A global systematic review and meta-analysis

Crimean-Congo hemorrhagic fever (CCHF) is the most popular tick-borne disease causing by Crimean-Congo hemorrhagic fever virus (CCHFV). There are several valuable reviews considering some fields of the CCHF aspects. While there is no a systematic review about means and trends of CCHF cases and fatality rate, means and trends of CCHF cases and fatality rates of human occupations involved in CCHF. Therefore, this meta-analysis review performed to highlight and provide a global detailed of the above CCHF aspects. Among 398 collected papers, 173 papers were become this meta-analysis review. The study results confirm that an apparent increasing CCHF cases occurred through the past decades. The trends of annually and periodically CCHF cases and fatality rates were also increased. The means of annually and periodically CCHF cases and fatality rates were 57 and 432 cases, and 10 cases and 32.2 % and 49 cases and 28.8 %, respectively. The means of annually and periodically CCHF fatality rates are about one-tenth of CCHF human cases. The mean of CCHF fatality rates in Africa (22.0 %) is lower than Asia (33.5 %) and Europe (33.8 %). Among occupations involved in CCHF, agricultural (28.9 %), health-care (19.2 %) and slaughterhouse (16.7 %) workers, and farmers (13.9 %) had the maximum CCHF fatality rates in order. Based on literature review of CCHFV S-segment aspects, several clades and genotypes are reported to distribute in Africa, Asia and Europe regions. There are very wide fields to investigate the epidemiology characteristics of CCHFV clades, genotypes and their distribution in the future.

The cytotoxicity of malathion and essential oil of Nepeta crispa (lamiales: lamiaceae) against vertebrate and invertebrate cell lines

Introduction

Pesticides are used as essential tools to control vector-borne diseases and agricultural pests and maintain quality and quantity crop production. Scientists attempt to use derived plant natural products due to environmental safety and low mammalian toxicity. Therefore, the cytotoxicity of malathion and Nepeta crispa essential oil against vertebrate L929 and invertebrate Sf9 cell lines were investigated.

Methods

About 2×10³ cells were placed into the wells of a 96-well plate experiments. Then appropriate concentrations of malathion and N. crispa essential oil added to the wells. The cells were allowed to grow for 3-5 days and estimated the cell numbers. Control cell wells contained only cells with DMSO. All treatments and controls repeated at least four replicates.

Results

About 2×10³ cells were placed into the wells of a 96-well plate experiments. Then appropriate concentrations of malathion and N. crispa essential oil added to the wells. The cells were allowed to grow for 3-5 days and estimated the cell numbers. Control cell wells contained only cells with DMSO. All treatments and controls repeated at least four replicates.

Conclusion

Plant essential oil not only had no negative effects but also had boosting effects on the L929 cell viability. Nepeta crispa essential oil had negative effects on the Sf9 cell viability with the differences that derived plant natural products containing environmentally friendly and readily biodegradable derivatives, hydrolyzing rapidly in nature and nearly having no destructive effects on mammals and environment.

Comparing cytotoxicity of propoxur and Nepeta crispa (Lamiales: Lamiaceae) essential oil against invertebrate (Sf9) and vertebrate (L929) cell lines

Background and Aim:

Attempts to use the plant products are to be an appropriate option due to substantial concerns about human health and environmental problems of using synthetic pesticides. Therefore, the cytotoxicity of Nepeta crispa essential oil was compared with propoxur against invertebrate (Sf9) and vertebrate (L929) cell lines.

Materials and Methods:

The cell lines of Sf9 and L929 which were derived from the ovary glands of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) and mouse fibroblast cells, respectively, were obtained from the National Cell Bank of Pasteur Institute of Iran. About a number of 2 × 10³ cells were placed into the wells of 96-well plate experiments. Then, appropriate concentrations of essential oil of N. crispa plant and propoxur added to the wells. The cells were allowed to grow for 3-5 days and estimated the numbers of cells. The cells of control experiment wells contained only cells with dimethyl sulfoxide. All control and treatment experiments repeated at least four replicates.

Results:

Propoxur had negative effects on the viability of both invertebrate (Sf9) and vertebrate (L929) cell lines. The cytotoxicity of propoxur against invertebrate (Sf9) and vertebrate (L929) cell lines was gradually increased in accordance with propoxur concentrations. The cytotoxicity of N. crispa essential oil against vertebrate (L929) cell line was gradually decreased in accordance with plant concentrations, while the cytotoxicity of N. crispa essential oil against invertebrate (Sf9) cell line was strongly increased in accordance with plant concentrations.

Conclusion:

Plant essential oil not only had no negative effects but also had boosting effects on vertebrate cell viability. Essential oil of N. crispa plant had negative effects on invertebrate cell viability with the differences that the products derived from plants possessing of biodegradable and environmentally friendly derivatives, hydrolyzing rapidly in nature, and nearly having no destructive effects on environment, humans, or the mammals.