Diversity Of Pathogens Research Articles

Pathotype determination of sorghum anthracnose (Colletotrichum sublineola) isolates from Ethiopia using sorghum differentials.

Sorghum anthracnose, caused by Colletotrichum sublineola, is the most destructive disease of sorghum, which causes up to 80% grain yield loss in susceptible varieties. The use of resistance varieties is an effective, durable, and eco-friendly strategy for anthracnose control. Knowledge of the phenotypic and genetic variation in C. sublineola is vital for designing appropriate anthracnose management strategies. The present study examined the morphology and virulence of 25 C. sublineola isolates recovered from various sorghum-producing regions of Ethiopia against 18 known sorghum anthracnose differentials, 6 Ethiopian sorghum landraces, and a variety of Bonsa. Analysis of variance (ANOVA) revealed significant differences among sorghum genotypes, C. sublineola isolates, and their interactions. There was a significant difference between the isolates in virulence, with each isolate exhibiting virulence in 8-72% of the sorghum genotypes tested. Among the 25 tested isolates, the top four most virulent isolates were from Pawe, suggesting that this area is suitable for pathogen diversity studies and host plant resistance screening. The sorghum genotypes IS_18760, Brandes, and Bonsa showed resistance to all tested isolates. Consequently, they may provide potential sources of resistance genes for sorghum breeding programs to develop cultivars resistant to different C. sublineola pathotypes. However, the resistant check SC748-5 was susceptible to isolates NK73_F37, while another resistant check SC112-14 was susceptible to isolates PW123_F47 and PW122_F47. Cluster analysis grouped 22 isolates into seven clusters based on their morphological characters, whereas 24 pathotypes were identified among 25 isolates that were tested on 25 sorghum genotypes. Hence, this study revealed high variation in C. sublineola in Ethiopia suggesting the need for broad-spectrum resistance to control the disease. Sorghum genotypes resistant to various C. sublineola isolates were identified in this study, which can be used in sorghum breeding programs aiming to develop resistant cultivars to anthracnose. Highly virulent C. sublineola isolates were also identified which could be used in sorghum germplasm resistance screening. The report is the first to show the existence of C. sublineola pathotypes in Ethiopia.

Evolutionary origin and population diversity of a cryptic hybrid pathogen

Cryptic fungal pathogens pose disease management challenges due to their morphological resemblance to known pathogens. Here, we investigated the genomes and phenotypes of 53 globally distributed isolates of Aspergillus section Nidulantes fungi and found 30 clinical isolates—including four isolated from COVID-19 patients—were A. latus, a cryptic pathogen that originated via allodiploid hybridization. Notably, all A. latus isolates were misidentified. A. latus hybrids likely originated via a single hybridization event during the Miocene and harbor substantial genetic diversity. Transcriptome profiling of a clinical isolate revealed that both parental subgenomes are actively expressed and respond to environmental stimuli. Characterizing infection-relevant traits—such as drug resistance and growth under oxidative stress—revealed distinct phenotypic profiles among A. latus hybrids compared to parental and closely related species. Moreover, we identified four features that could aid A. latus taxonomic identification. Together, these findings deepen our understanding of the origin of cryptic pathogens.

Phylogenetic analyses and pathogenic diversity of Meloidogyne graminicola of rice (cv. BRRI Dhan28) from different agro-ecological zones of Bangladesh

Rice root-knot caused by Meloidogyne graminicola is a major yield-limiting factor in all rice growing countries around the world, which is often ignored in Bangladesh due to its subtle and obscure above ground symptoms. The current study proposes a comprehensive diagnosis of rice root-knot nematode at the molecular level and analyzes the pathogenic diversity of M. graminicola population of different AEZs. Rice seedlings of a popular variety (BRRI Dhan28) showing galls in the roots were collected from thirty Agro-Ecological-Zones (AEZs) of Bangladesh. For molecular identification, nuclear DNA was collected from single second-stage juvenile and internal transcribed spacer (ITS) was used as a universal primer. Molecular identification and phylogenetic analyses revealed that all nematode populations of galled rice seedlings from different locations belong to M. graminicola. The nematode populations constitute six phylogenetic clades. Nematode population of phylogenetic clade II showed the highest no. of galls (178 ± 1.67), although galling index was higher and similar in clade I, clade-II, clade-III and clade-VI. The highest percent reduction in both vegetative and yield-contributing traits were recorded in clade-II. A negative correlation was found in galling incidence and all growth and yield parameters. Comparative hatching of M. graminicola from different locations reveals that the pathogenicity of M. graminicola depends on the genetic variability of the nematode population, but not on the hatched juveniles. It might be concluded that the rice root-knot nematodes (M. graminicola) are prevalent in all agro-ecological zones of Bangladesh, despite the most pathogenic groups being frequent in AEZ- 1, 6, 7, 10, 18, 19, 21 and appropriate management initiatives are therefore crucial for maximizing rice yield.

Colletotrichum species associated with anthracnose disease on mango (Mangifera indica L.) cv. Azúcar in Colombia

The role of some Colletotrichum species is uncertain in crops of economic importance for Colombia such as mango (Mangifera indica L.) cv. Azúcar. Eight Colletotrichum isolates from asymptomatic plant tissues were characterized by their pathogenicity on fruits and identified by phylogenetic analysis of the sequences of the ITS, GADPH, Tub2, CHs-1 and Act genomic regions. Colletotrichum asianum, C. gloeosporioides and C. tropicale of the C. gloeosporioides species complex and C. karstii of the C. boninense species complex were identified. The highest virulence was observed for isolates of C. asianum, that was the most prevalent species, and for C. tropicale, that showed high and intermediate virulence levels, indicating diversity in pathogenicity within the same species. The isolate of C. karstii, which displayed intermediate virulence, is the first report on mango in Colombia. Colletotrichum gloeosporioides presented intermediate virulence and was isolated at a low frequency in the present research. The mycelial growth rate did not show differences between species and ranged between 6.1 and 8.3 mm per day. Colletotrichum asianum recorded higher values of conidia germination and appressoria formation than other species, at 77% and 79%, respectively (p < 0.001). The shape and size of conidia did not vary between species. Appressoria exhibited different shapes between isolates and the largest average diameter was for C. karstii with 7.6 µm (p < 0.001). There was a diversity of Colletotrichum species associated with mango cv. Azúcar in Colombia, with differential virulence among isolates of the same species.

Strain-level multidrug-resistant pathogenic bacteria in urban wastewater treatment plants: Transmission, source tracking and evolution

Wastewater treatment plants (WWTPs) serve as reservoirs for various pathogens and play a pivotal role in safeguarding environmental safety and public health by mitigating pathogen release. Pathogenic bacteria, known for their potential to cause fatal infections, present a significant and emerging threat to global health and remain poorly understood regarding their origins and transmission in the environment. Using metagenomic approaches, we identified a total of 299 pathogens from three full-scale WWTPs. We comprehensively elucidated the occurrence, dissemination, and source tracking of the pathogens across the WWTPs, addressing deficiencies in traditional detection strategies. While indicator pathogens in current wastewater treatment systems such as Escherichia coli are effectively removed, specific drug-resistant pathogens, including Pseudomonas aeruginosa, Pseudomonas putida, and Aeromonas caviae, persist throughout the treatment process, challenging complete eradication efforts. The anoxic section plays a predominant role in controlling abundance but significantly contributes to downstream pathogen diversity. Additionally, evolution throughout the treatment process enhances pathogen diversity, except for upstream transmission, such as A. caviae str. WP8-S18-ESBL-04 and P. aeruginosa PAO1. Our findings highlight the necessity of expanding current biomonitoring indicators for wastewater treatment to optimize treatment strategies and mitigate the potential health risks posed by emerging pathogens. By addressing these research priorities, we can effectively mitigate risks and safeguard environmental safety and public health.

Zoonotic outbreak risk prediction with long short-term memory models: a case study with schistosomiasis, echinococcosis, and leptospirosis

BackgroundZoonotic infections, characterized with huge pathogen diversity, wide affecting area and great society harm, have become a major global public health problem. Early and accurate prediction of their outbreaks is crucial for disease control. The aim of this study was to develop zoonotic diseases risk predictive models based on time-series incidence data and three zoonotic diseases in mainland China were employed as cases.MethodsThe incidence data for schistosomiasis, echinococcosis, and leptospirosis were downloaded from the Scientific Data Centre of the National Ministry of Health of China, and were processed by interpolation, dynamic curve reconstruction and time series decomposition. Data were decomposed into three distinct components: the trend component, the seasonal component, and the residual component. The trend component was used as input to construct the Long Short-Term Memory (LSTM) prediction model, while the seasonal component was used in the comparison of the periods and amplitudes. Finaly, the accuracy of the hybrid LSTM prediction model was comprehensive evaluated.ResultsThis study employed trend series of incidence numbers and incidence rates of three zoonotic diseases for modeling. The prediction results of the model showed that the predicted incidence number and incidence rate were very close to the real incidence data. Model evaluation revealed that the prediction error of the hybrid LSTM model was smaller than that of the single LSTM. Thus, these results demonstrate that using trending sequences as input sequences for the model leads to better-fitting predictive models.ConclusionsOur study successfully developed LSTM hybrid models for disease outbreak risk prediction using three zoonotic diseases as case studies. We demonstrate that the LSTM, when combined with time series decomposition, delivers more accurate results compared to conventional LSTM models using the raw data series. Disease outbreak trends can be predicted more accurately using hybrid models.

Pathogenic diversity, ecology, epidemiology, and management practices of the potato bacterial wilt ( Ralstonia solanacearum ) disease

Pathogenic diversity, ecology, epidemiology, and management practices of the potato bacterial wilt ( <i>Ralstonia solanacearum</i> ) disease

Diagnostic Value of Metagenomic next-generation sequencing and X-pert in Bronchoalveolar lavage fluid for pneumonia in HIV-infected and HIV-uninfected patients

BackgroundThe pathogens causing unexplained pneumonia in both HIV-infected or HIV-unfected patients are likely to be complex. This retrospective study aimed to characterize the etiology of pneumonia in HIV-infected and HIV-uninfected patients using bronchoalveolar lavage fluid (BALF) analysis with metagenomic next-generation sequencing (mNGS) and X-pert MTB/RIF. MethodsBetween January 2022 and May2024, 141 HIV-infected and 104 HIV-uninfected patients admitted to Nanjing Second Hospital with pneumonia were included. BALF samples were collected and analyzed using mNGS to detect bacteria, fungi, viruses, tuberculosis (TB) and non-tuberculous mycobacteria (NTM), and X-pert for TB detection. Clinical data including CD4 T-cell counts, comorbidities, and ART status were collected and analyzed. ResultsHIV-uninfected patients were found to be older and exhibited a higher prevalence of comorbidities compared to HIV-infected patients. Despite higher median CD4 T-cell counts in HIV-uninfected individuals (412 cells/μL vs. 31 cells/μL in HIV-infected), TB detection rates using X-pert and mNGS were lower than anticipated, particularly in HIV-infected patients. Mixed-pathogen infections were significantly more prevalent in HIV-infected patients, especially those with lower CD4 T-cell counts. ART use showed variable impacts on pathogen diversity, with longer treatment durations associated with reduced infection complexity but persistent immunodeficiency in some cases.In patients with pneumonia, whether HIV-infected or HIV-uninfected, pathogens often exhibit complexity, underscoring the critical role of timely mNGS and X-pert analysis of BALF for early pathogen detection.

Diversity and Distribution of Fungal Infections in Rwanda: High Risk and Gaps in Knowledge, Policy, and Interventions.

Fungal infections (FIs) are spreading globally, raising a significant public health concern. However, its documentation remains sparse in Africa, particularly in Rwanda. This report provides a comprehensive review of FIs in Rwanda based on a systematic review of reports published between 1972 and 2022. The findings reveal a rich diversity of fungal pathogens, including Blastomyces, Candida, Cryptococcus, Histoplasma, Microsporum, Pneumocystis, Rhinosporidium, and Trichophyton caused human infections. Candida infections predominantly affect the vagina mucosa, while Histoplasma duboisi was linked to disseminated infections. Other pathogens, such as Blastomyces dermatitidis and Rhinosporidium seeberi, were associated with cerebellar and nasal mucosa infections, respectively. The widespread observation of soilborne fungi affecting bean crops highlights the pathogens' threat to agricultural productivity, food security, and socioeconomic stability, as well as potential health impacts on humans, animals, and the environment. Of particular importance is that there is no information about FIs among animals in the country. Moreover, the analysis underscores significant limitations in the detection, reporting, and healthcare services related to FIs in the country, indicating gaps in diagnostic capacity and surveillance systems. This is underscored by the predominant use of traditional diagnostic techniques, including culture, cytology, and histopathology in the absence of integrating more sensitive and specific molecular tools in investigating FIs. Developing the diagnostic capacities and national surveillance systems are urgently needed to improve the health of crops, animals, and humans, as well as food security and socioeconomic stability in Rwanda. Also, it is important to indicate severe gaps in the evidence to inform policymaking, guide strategic planning, and improve healthcare and public health services, underscoring the urgent need to build national capacity in fungal diagnosis, surveillance, and research. Raising awareness among the public, scientific community, healthcare providers, and policymakers remains crucial. Furthermore, this report reveals the threats of FIs on public health and food insecurity in Rwanda. A multisectoral one health strategy is essential in research and intervention to determine and reduce the health and safety impacts of fungal pathogens on humans, animals, and the environment.

Constitutive innate immune defenses in relation to urbanization and population density in an urban bird, the feral pigeon Columba livia domestica.

Urbanization processes modulate the immunological challenges faced by animals. Urban habitat transformations reshape pathogen diversity and abundance, while high population density-common in urban exploiter species-promotes disease transmission. Responses to urbanization may include adaptive adjustments of constitutive innate immune defenses (e.g. complement system and natural antibodies [NAbs]), which serve as first-line protection against infections. Here, we investigated associations of habitat urbanization and host population density with complement and NAbs in an urban bird, the feral pigeon Columba livia domestica. To do so, we employed the hemolysis-hemagglutination assay to analyze nearly 200 plasma samples collected across urbanization and pigeon population density gradients in five major cities in Poland. We found a negative association between urbanization score and hemagglutination (i.e. NAbs activity), but not hemolysis (i.e. complement activity), indicating either immunosuppression or adaptive downregulation of this immune defense in highly transformed urban landscape. Population density was not significantly related to either immune parameter, providing no evidence for density-dependent modulation of immune defenses. At the same time, there was a negative association of hemolysis with condition (scaled mass index), suggesting resource allocation trade-offs or contrasting effects of the urban environment on immune defenses and body condition. The results demonstrate that habitat structure can be an important factor shaping the immune defenses of the feral pigeon, although these associations were not mediated by variation in population density. Our study highlights the complexity of the links between immune defenses in wildlife and urbanization and reinforces the need for comprehensive ecoimmunological studies on urban animals.

Demographic and zoological drivers of infectome diversity in companion cats with ascites.

Frequent studies reported the risks of cats as an intermediate host of zoonotic pathogens (e.g., SARS-CoV-2). Cats have a physically close interaction with their owners through activities like petting, kissing, and being licked on the cheek and hands. However, there are still limited studies that systematically investigate the infectome structure of cats. In this study, we employed a meta-transcriptomics approach to characterize 15 species of pathogens in cats, with Candidatus Rickettsia tarasevichiae first characterizing infection in diseased cats. Most feline diseases were better explained by the presence of virus-bacteria or virus-virus coinfection. The increase in infectome diversity could be influenced by a variety of predictors including age growth, temperature increase, and a higher proportion of females. A higher diversity of pathogens was harbored in young cats rather than adults. Importantly, we showed the value of linking the modern influx of meta-transcriptomics with comparative ecology and demography and of utilizing it to affirm that ecological and demographic variations impact the total infectome.

Virulence variation and pathotypes of Zymoseptoria tritici isolates causing wheat leaf blotch in Oromia, Ethiopia

Leaf blotch, caused by Zymoseptoria tritici, is a fungal disease that poses a severe threat to wheat production worldwide. Knowledge of virulence variability is crucial in choosing effective control measures. However, there have only been a few studies of the pathogenic variability and pathotypes within Ethiopian isolates. Hence, the objective of this study was to assess the virulence spectrum and variability of Z. tritici isolates. Forty-three isolates were tested for their virulence and pathotype against 7 wheat differential lines that have different resistance genes. A pathogenicity assay detected 41 differential line-specific virulent isolates among 301 interactions between a host and pathogen based on the percentage coverage of the leaf area by pycnidia. Some isolates were virulent against 50 %–60 % of the resistant genes, but most of them were virulent against some differential lines. Isolates such as EtA-11, EtSh-1, EtSh-2, EtSh-4, and EtA-19 expressed broad-spectrum virulence, highlighting that such isolates are useful for germplasm screening. The isolates were classified into 25 pathotypes, defined by their differential virulence responses. They were also assigned to two clusters according to their mean pycnidia percent. Pathotypes and principal component analysis detected 58.1 % and 62.2 % pathogenic diversity in Ethiopian isolates, respectively. The current findings provide information that breeders can use to identify and select more resistant varieties for farmers.

Pathogenicity, phylogenomic, and comparative genomic study of Pseudomonas syringae sensu lato affecting sweet cherry in California.

Comprehensive identification of phytopathogens and an in-depth understanding of their genomic architecture, particularly virulence determinants and antibiotic-resistant genes, are critical for several practical reasons. These include disease diagnosis, improved knowledge of disease epidemiology, pathogen diversity, and determination of the best possible management strategies. In this study, we provide the first report of the presence and pathogenicity of genomospecies Pseudomonas cerasi and Pseudomonas viridiflava in California sweet cherry. More importantly, we report a relatively high level of resistance to copper among the population of Pseudomonas syringae pv. syringae (47.5%). This implies copper cannot be effectively used to control bacterial blast and bacterial canker of sweet cherries. On the other hand, no isolates were resistant to kasugamycin, an indication that kasugamycin could be effectively used for the control of bacterial blast and bacterial canker. Our findings are important to improve the management of bacterial blast and bacterial canker of sweet cherries in California.

Detection of Gastrointestinal Pathogens with Zoonotic Potential in Horses Used in Free-Riding Activities during a Countrywide Study in Greece.

The objectives of this study were (a) to detect zoonotic gastrointestinal pathogens in faecal samples of horses using the FilmArray® GI Panel and (b) to identify variables potentially associated with their presence. Faecal samples collected from 224 horses obtained during a countrywide study in Greece were tested by means of the BioFire® FilmArray® Gastrointestinal (GI) Panel, which uses multiplex-PCR technology for the detection of 22 pathogens. Gastrointestinal pathogens were detected in the faecal samples obtained from 97 horses (43.3%). Zoonotic pathogens were detected more frequently in samples from horses in courtyard housing (56.0%) than in samples from horses in other housing types (39.7%) (p = 0.040). The most frequently detected zoonotic pathogens were enteropathogenic Escherichia coli (19.2% of horses) and Shiga-like toxin-producing E. coli stx1/stx2 (13.8%). During multivariable analysis, two variables emerged as significant predictors for the outcome 'detection of at least one zoonotic pathogen in the faecal sample from an animal': (a) the decreasing age of horses (p = 0.0001) and (b) the presence of livestock at the same premises as the horses (p = 0.013). As a significant predictor for the outcome 'detection of two zoonotic pathogens concurrently in the faecal sample from an animal', only the season of sampling of animals (autumn) emerged as significant in the multivariable analysis (p = 0.049). The results indicated a diversity of gastrointestinal pathogens with zoonotic potential in horses and provided evidence for predictors for the infections; also, they can serve to inform horse owners and handlers regarding the possible risk of transmission of pathogens with zoonotic potential. In addition, our findings highlight the importance of continuous surveillance for zoonotic pathogens in domestic animals.

Regional survey, isolation, and morphotypes diversity of Fusarium Wilt pathogen in chilli from Andhra Pradesh and Tamil Nadu

Regional survey, isolation, and morphotypes diversity of Fusarium Wilt pathogen in chilli from Andhra Pradesh and Tamil Nadu

Detection of Iturin A from Bacillus atrophaeus by HPLC and Mass Spectrometry Analysis and Evaluation of its Antifungal Activity

Background: Bacillus species create several kinds of metabolites, which contain cyclic lipopeptide-type antibiotics, consisting of three major families: fengycin, surfactin, and iturin. Iturin demonstrates powerful biocontrol characteristics and can restrain the growth of a diversity of plant fungal pathogens. Objective: The current study investigates the identification of iturin A from Bacillus atrophaeus using HPLC and Mass spectrometry analysis and evaluate its antifungal effects. Materials and Methods: In this study, the lipopeptide antibiotics were isolated by HPLC and characterized by MS. Then, the lipopeptides were examined for their ability to antagonize the growth of different pathogenic fungi. Antifungal performance of the lipopeptides was determined against Fusarium oxysporum, Aspergillus niger, Penicillium chrysogenum, and Mucor hiemalis according to well diffusion and percentage of growth inhibition. Results: Bacillus atrophaeus HNSQJYH170, isolated from Isfahan soil, offered strong fungicidal activity by producing cyclic lipopeptide-type antibiotics. Inhibition zones were 17.55, 17, 18.50, and 20.99 mm, and the percentages of growth inhibition were 78.54, 62.55, 83.11, and 84/95 for Fusarium oxysporum, Penicillium chrysogenum, Mucor hiemalis and Aspergillus niger, respectively. The spectrum represented the iturins family in retention times of 32.423–33.893 min. MS demonstrated molecular ion peaks (M+H) + for iturin at m/z 1029.55, 1043.60, 1051.55, 1065.60, 1079.60 and 1093.65. The inhibition rate against all fungi on the seventh day of incubation was higher than 80%. Among them, Aspergillus niger was the most sensitive fungal species with an average of 84.95% inhibition. Conclusion: According to the results, Bacillus atrophaeus HNSQJYH170 could operate as a biocontrol agent against a wide spectrum of pathogenic fungi.

Genetic diversity of tick-borne zoonotic pathogens in ixodid ticks collected from small ruminants in Northern Pakistan

Mapping tick distribution and pathogens in unexplored areas sheds light on their importance in zoonotic and veterinary contexts. In this study, we performed a comprehensive investigation of the genetic diversity of tick and tick-borne pathogens (TBPs) detection infesting/infecting small ruminants across northern Pakistan. We collected 1587 ixodid ticks from 600 goats and sheep, an overall tick infestation rate of 50.2 %. Notably, gender-based infestation rates were higher in female goats and sheep compared to their male counterparts. Age-wise analysis showed that the tick infestation rate was higher in older animals. This study identified 11 ixodid tick species within three genera: Hyalomma, Haemaphysalis, and Rhipicephalus, which were taxonomically classified using 16S rRNA and cytochrome oxidase I (cox1) molecular markers. Sequence analysis indicated that reported ticks are similar to ixodid species found across various Asian and African countries. Tick-borne pathogens were detected by amplifying 16S rRNA and citrate synthase (gltA) for bacterial pathogens and 18S rRNA for apicomplexan parasites. The present study reported a diverse array of TBPs in ticks from the study area, with Rickettsia massiliae (24.5 %) and Theleria ovis (16.4 %) as the most prevalent bacterial and apicomplexan pathogens. Phylogenetically, detected TBPs shared evolutionary relatedness with identical TBPs from old and new world countries. These findings highlight the presence of zoonotic TBPs in ixodid ticks from Pakistan. In addition, it also provides a foundation for future epidemiological research on ticks and TBPs, emphasizing their relevance in both zoonotic and veterinary contexts.

Complete genome of the Medicago anthracnose fungus, Colletotrichum destructivum, reveals a mini-chromosome-like region within a core chromosome.

Colletotrichum destructivum (Cd) is a phytopathogenic fungus causing significant economic losses on forage legume crops (Medicago and Trifolium species) worldwide. To gain insights into the genetic basis of fungal virulence and host specificity, we sequenced the genome of an isolate from Medicago sativa using long-read (PacBio) technology. The resulting genome assembly has a total length of 51.7 Mb and comprises ten core chromosomes and two accessory chromosomes, all of which were sequenced from telomere to telomere. A total of 15, 631 gene models were predicted, including genes encoding potentially pathogenicity-related proteins such as candidate-secreted effectors (484), secondary metabolism key enzymes (110) and carbohydrate-active enzymes (619). Synteny analysis revealed extensive structural rearrangements in the genome of Cd relative to the closely related Brassicaceae pathogen, Colletotrichum higginsianum. In addition, a 1.2 Mb species-specific region was detected within the largest core chromosome of Cd that has all the characteristics of fungal accessory chromosomes (transposon-rich, gene-poor, distinct codon usage), providing evidence for exchange between these two genomic compartments. This region was also unique in having undergone extensive intra-chromosomal segmental duplications. Our findings provide insights into the evolution of accessory regions and possible mechanisms for generating genetic diversity in this asexual fungal pathogen.

Tick-Borne Diseases in Sub-Saharan Africa: A Systematic Review of Pathogens, Research Focus, and Implications for Public Health.

Sub-Saharan Africa, with its hot and humid climate, is a conducive zone for tick proliferation. These vectors pose a major challenge to both animal and human health in the region. However, despite the relevance of emerging diseases and evidence of tick-borne disease emergence, very few studies have been dedicated to investigating zoonotic pathogens transmitted by ticks in this area. To raise awareness of the risks of tick-borne zoonotic diseases in sub-Saharan Africa, and to define a direction for future research, this systematic review considers the trends of research on tick-borne bacteria, parasites, and viruses from 2012 to 2023, aiming to highlight the circulation of these pathogens in ticks, cattle, sheep, goats, and humans. For this purpose, three international databases were screened to select 159 papers fitting designed inclusion criteria and used for qualitative analyses. Analysis of these studies revealed a high diversity of tick-borne pathogens in sub-Saharan Africa, with a total of 37 bacterial species, 27 parasite species, and 14 viruses identified. Among these, 27% were zoonotic pathogens, yet only 11 studies investigated their presence in humans. Furthermore, there is growing interest in the investigation of bacteria and parasites in both ticks and ruminants. However, research into viruses is limited and has only received notable interest from 2021 onwards. While studies on the detection of bacteria, including those of medical interest, have focused on ticks, little consideration has been given to these vectors in studies of parasites circulation. Regarding the limited focus on zoonotic pathogens transmitted by ticks, particularly in humans, despite documented cases of emerging zoonoses and the notable 27% proportion reported, further efforts should be made to fill these gaps. Future studies should prioritize the investigation of zoonotic pathogens, especially viruses, which represent the primary emerging threats, by adopting a One Health approach. This will enhance the understanding of their circulation and impact on both human and animal health. In addition, more attention should be given to the risk factors/drivers associated to their emergence as well as the perception of the population at risk of infection from these zoonotic pathogens.

Genomic characterization of Volzhskoe tick virus (Bunyaviricetes) from a Hyalomma marginatum tick, Hungary

Hyalomma marginatum, a vector for the high-consequence pathogen, the Crimean–Congo hemorrhagic fever virus (CCHFV), needs particular attention due to its impact on public health. Although it is a known vector for CCHFV, its general virome is largely unexplored. Here, we report findings from a citizen science monitoring program aimed to understand the prevalence and diversity of tick-borne pathogens, particularly focusing on Hyalomma ticks in Hungary. In 2021, we identified one adult specimen of Hyalomma marginatum and subjected it to Illumina-based viral metagenomic sequencing. Our analysis revealed sequences of the uncharacterized Volzhskoe tick virus, an unclassified member of the class Bunyaviricetes. The in silico analysis uncovered key genetic regions, including the glycoprotein and the RNA-dependent RNA polymerase (RdRp) coding regions. Phylogenetic analysis indicated a close relationship between our Volzhskoe tick virus sequences and other unclassified Bunyaviricetes species. These related species of unclassified Bunyaviricetes were detected in vastly different geolocations. These findings highlight the remarkable diversity of tick specific viruses and emphasize the need for further research to understand the transmissibility, seroreactivity or the potential pathogenicity of Volzhskoe tick virus and related species.