Search Results (1,585)

Ticks of the genus Hyalomma are major ectoparasites of dromedary camels and serve as important vectors for diverse tick-borne pathogens (TBPs) affecting both animals and humans. In this study, we determined the tick species diversity and distribution and estimated the prevalence of TBPs in those ticks. A total of 780 ticks collected from camels in Bol, Chad, were identified into four species: Hyalomma dromedarii (49.0%), H. rufipes (22.6%), H. impeltatum (19.1%), and H. truncatum (9.4%). Sixty ticks were selected proportionally across the four Hyalomma species and screened for TBPs using PCR. Coxiella burnetii was detected in 11.7% of the ticks, and Rickettsia aeschlimannii in 1.7%. Anaplasmataceae-specific 16S rRNA primers detected Candidatus Midichloria mitochondrii, a tick endosymbiont, in 10% of the ticks. No protozoan pathogens (Theileria or Babesia) were detected. This study highlights the need for integrated surveillance of ticks and their associated microorganisms in Chadian camels to mitigate zoonotic and veterinary risks. Strengthening such efforts will support camel health and pastoral livelihoods in the region. Full article

The livestock sector underpins food security, employment, and rural livelihoods across the Southern African Development Community (SADC), contributing up to 50% of agricultural GDP and supporting more than 60% of rural households. Yet climate change poses escalating threats through heat stress, declining pasture productivity, water scarcity, and vector-borne diseases that compromise productivity and economic resilience. This review identifies and locates effective climate change mitigation strategies along the livestock value chain, spanning production, processing, transport, and consumption, to promote sustainable, low-emission, and inclusive growth in the SADC region. A broad review of 46 peer-reviewed and institutional sources (2000–2024) was undertaken, focusing on livestock-related mitigation within SADC and comparable agro-ecological systems. Strategies were thematically categorized by value-chain stage and assessed for their emission-reduction and livelihood-enhancement potential. Local strategies include genetic improvement for low-methane and heat-tolerant breeds, adaptive rangeland and feed management, renewable-energy adoption in processing, climate-resilient transport infrastructure, and consumer awareness of low-emission products. Evidence suggests potential GHG-emission reductions of 18–30%, coupled with productivity gains and improved smallholder incomes. Coordinated implementation through the SADC Regional Agricultural Investment Plan (2021–2030) and national policies can transform the livestock sector into a climate-resilient driver of inclusive growth. Further research should quantify the socioeconomic feasibility and scaling potential of these strategies across production systems. Successful integration of climate change mitigation imperatives must be tailored to local biophysical conditions (e.g., rainfall, soil type) and socioeconomic contexts (e.g., market access, cultural practices). Full article

Bats are recognized reservoirs for a vast array of viral diversity, including members of the Hepadnaviridae family. Within a One Health framework, genomic surveillance of these animals is fundamental to understanding viral diversity and the potential risks of zoonotic spillover in high-density human population areas. This study describes the detection of a bat hepadnavirus through agnostic viral metagenomics in samples from passive surveillance collected in urban and peri-urban areas in Brazil. Sequencing was performed using the Oxford Nanopore Technologies (MinION) platform, and the bioinformatics pipeline involved de novo assembly and taxonomic identification against viral databases. We identified several contigs with similarity to the Tent-making bat hepatitis B virus (TBHBV) in a single liver sample. The largest contig (3182 bp) represents the complete genome, exhibiting a nucleotide identity of 80.93% with the original reference isolate. Our findings document the circulation of this viral lineage in a new epidemiological setting (the Brazilian urban interface), underscoring the importance of continuous surveillance to monitor the evolution and geographic distribution of bat orthohepadnaviruses and their relevance to public health. Full article

Dengue Hemorrhagic Fever (DHF) is a tropical infectious disease transmitted by the Aedes aegypti mosquito and exhibits seasonal patterns with periodic increases in cases throughout the year. The control of vector-borne diseases such as DHF is very important for strengthening public health resilience against climate change, in line with the Sustainable Development Goals (SDGs) for Good Health, Well-being, and Climate Action. Therefore, this study was focused on Bogor city, which experiences high rainfall and continues to face an elevated risk of DHF. The objective was to develop a time series forecasting model to predict DHF outbreaks using Singular Spectrum Analysis (SSA). This is a statistical method for identifying patterns in time series data. Lunar and Solar calendars were adopted to capture seasonal patterns and determine the optimal window length for prediction. The results showed that the Lunar calendar more accurately captured local seasonal variation related to DHF risk. Moreover, the SSA model with one component and a window length of 7 achieved the best performance with a Mean Absolute Percentage Error (MAPE) of 0.0757. The forecast accuracy decreased with longer horizons, but the model provided reliable predictions for short-term periods (approximately 1 month, i.e., up to 4 weeks ahead), which were considered useful for planning DHF mitigation. The results emphasized that the combination of SSA with appropriate calendar systems could improve the accuracy of epidemiological predictions and support vector control policymaking in tropical regions. Full article

Ticks harbor complex microbial communities composed of symbionts, commensals, and tick-borne pathogens (TBPs). Together, these microorganisms form the tick holobiont. Within this system, the tick’s physiological architecture structures microbial communities by distributing microorganisms across distinct tissues. This compartmentalization creates spatially distinct ecological niches, which in turn shape how microbial communities assemble and interact. In this review, we integrate ecological theory with current knowledge of tick microbiome research to examine how pathogen–pathogen and pathogen–microbiome interactions emerge within these tissue-structured microbial communities. We first outline how baseline ecological filters, including tick species, developmental stage, tissue identity, vertical transmission, and environmental context, shape the microbiome configuration through community assembly processes. We then examined how TBPs, as high-impact colonizers, can further modify microbial networks by altering host-mediated selective pressures, influencing interaction topology, and reshaping community stability. Based on these observations, we propose a dual selective pressure framework in which (i) baseline ecological structuring processes and (ii) pathogen-associated selective pressures interact to determine the microbial network configuration and functional outcomes within the tick holobiont. These interacting forces may drive shifts in diversity, modularity, keystone taxa emergence, and network resilience, ultimately influencing vector competence. This review frames the microbial communities within the tick holobiont as spatially structured ecological systems shaped by multilevel selective pressures. This conceptual foundation provides a coherent framework for understanding microbial interactions in arthropod vectors and highlights avenues for mechanistic research and microbiome-based strategies to mitigate tick-borne diseases. Full article

Lyme disease is the most common reported vector-borne disease in North America and is also highly prevalent across Europe. Although tick-borne diseases are uncommon in Singapore, there remains a risk of imported tick-borne diseases among travelers from endemic regions. We present a case series of three pediatric patients with imported Lyme disease managed at a tertiary children’s hospital in Singapore, illustrating the varied clinical presentations of Lyme disease in children. One child developed meningitis following prior antibiotic therapy for Lyme disease, although causality cannot be definitively established. This series aims to highlight key diagnostic considerations and management principles relevant to clinicians practicing in non-endemic regions. Full article

Background: Bovine tuberculosis (bTB) caused by Mycobacterium bovis is a major zoonotic disease in West Africa. In Africa, bTB is endemic in cattle with a prevalence ranging from 2% up to 18%. The disease causes significant public health risks due to unpasteurized milk and milk product consumption. In the context of the EU-PRISMA project, which promotes research and innovation for productive, resilient, and healthy agropastoral systems in West Africa, a cross-sectional survey was conducted in dairy herds from Mali and Niger to assess animal, herd, and within-herd bTB prevalence, as well as to identify animal risk factors and predictors of bTB herd status. Method and principal findings: A random cross-sectional survey on dairy cattle farms using comparative intradermal tuberculin test and epidemiological inquiry was performed in four regions of Mali (Bamako, Koulikoro, Mopti, and Sikasso) and three regions of Niger (Tahoua, Dosso, and Tillabéry). Herd and animal prevalence of bTB and within-herd prevalence were significantly higher in Mali (especially in Bamako and Koulikoro) than in Niger. Several risk factors were significantly associated with animals positive to bTB, i.e., the region where animals live, the age range from 3 to 7 years old, and female animals. In addition, in regions with higher bTB prevalence, the herd with slaughtering of animals in the farm and the herd with the presence of an animal assembly area were associated with the most unfavorable status of a herd with regards to bTB. Moreover, the average and the median annual economic losses of bTB at animal level were estimated at €262 and €137 respectively, with large variability depending on the farm (between €46 and €838). Conclusion and significance: This survey provides useful data on bTB epidemiology and economical losses in Mali and Niger and urges for improvement of surveillance systems and prevention and control strategies. Cost-benefit, return of investment, or similar analyses are strongly recommended to help with decision making. Full article

Chikungunya virus (CHIKV) pathogenesis research has long been constrained by the lack of suitable immunocompetent rodent models. Through serial passaging in A129 and C57BL/6 mice, we obtained an adapted strain (CHIKV-Adapt) harboring an E2-K200R substitution along with non-structural protein mutations. Phenotypic analysis in C57BL/6 mice, BALB/c mice, and hamster models demonstrated that compared to the wild-type virus CHIKV-Adapt induced significantly higher and more prolonged viremia, broader tissue tropism, and more severe internal joint inflammation, without exacerbating external swelling. Notably, the K200R mutation did not alter the viral replication kinetics in vitro and was predicted not to affect its binding pattern to the MXRA8 receptor. Furthermore, mice challenged 160 days after primary infection exhibited nearly complete protective immunity. These findings indicate that E2-K200R is a critical adaptive mutation that, together with accompanying non-structural mutations, significantly enhances CHIKV replication capacity and pathogenicity in immunocompetent rodents without changing its in vitro replication ability or predicted receptor-binding mode. The acquisition of this adapted strain provides a new tool for CHIKV pathogenesis research and vaccine evaluation. Full article

Human astroviruses are small, non-enveloped RNA viruses belonging to the family Astroviridae. Among the four species known to infect humans, the species Mamastrovirus hominis (the classical human astroviruses, formerly MAstV1) is associated with gastrointestinal illness worldwide, while three more recently identified species have been linked to lethal central nervous system infections. High substitution rates and recombination drive their rapid evolution, yet recombination patterns in classical human astroviruses remain poorly characterized. This study systematically analyzes patterns and temporal dynamics of natural recombination in classical human astroviruses. Publicly available genomes of classical human astroviruses were analyzed to identify recombination hotspots. Recombinant forms were defined as stable phylogenetic lineages unaffected by recombination, and their half-lives were estimated based on time-scaled phylogenies (BEAST2v2.7.7). Recombination in classical human astroviruses occurred most frequently at the ORF1b/ORF2 junction, but also within ORF1a, at the ORF1a/ORF1b junction, and within ORF2. Only the 3′-part of ORF1a and a fragment of ORF1b exhibited robust temporal signal, yielding substitution rates of 2.35 × 10⁻³ and 2.14 × 10⁻³ s/s/y, respectively. The half-lives of recombinant forms varied considerably by genomic region: longest for exchanges between the parts of ORF1a (21 years), intermediate for ORF1a/ORF1b recombinants (7–9 years), and shortest for ORF1ab/ORF2 recombinants (2.5–3.6 years). The estimated half-lives for recombinants align with those reported for human enteroviruses and noroviruses. These findings highlight the dynamics of the generation of astrovirus diversity and may inform advanced surveillance of emerging strains. Full article

Yellow fever (YF) remains a re-emerging vector-borne zoonotic disease in tropical regions of the Americas despite the availability of an effective vaccine. In South America, the virus is maintained through a jungle transmission cycle involving Haemagogus and Sabethes mosquitoes and non-human primates (NHPs), which act as amplifying hosts and key epidemiological sentinels. This narrative review examines the current status of YF epizootics in South America, with a focus on the role of NHPs in viral circulation, early detection, and spillover risk to human populations. We synthesize recent evidence on epizootic patterns across endemic countries, the differential susceptibility of neotropical primates, and the ecological and environmental drivers influencing transmission, including deforestation, habitat fragmentation, and human encroachment into forested areas. In addition, we analyze current surveillance strategies, including wildlife monitoring, entomological and genomic surveillance, and their integration within a One Health framework. This review highlights that YF epizootics are expanding geographically and are closely linked to environmental change and human–ecosystem interactions. Strengthening integrated, multidisciplinary surveillance systems is essential to improve early detection, guide vaccination strategies, and prevent human outbreaks. These findings underscore the critical importance of operationalizing the One Health approach to enhance preparedness and response to YF in South America. Full article

In 2024 Kenya had a population of 4.78 million camels that contributed to the livelihoods of pastoralist communities in northern Kenya. Previous studies in Kenya, Saudi Arabia and eastern Africa demonstrated high seroprevalence of Middle East respiratory syndrome coronavirus (MERS-CoV)-specific antibodies in dromedary camels, as well as sporadic transmission of MERS-CoV from camels to humans. Based on the MERS-CoV data and the very close contact between owners and their camels in northern Kenya, we speculated that camels may also transmit other zoonotic viruses, such as Rift Valley fever virus (RVFV). In this study, 493 camel and 197 human sera were collected in Marsabit, Kenya, through a cross-sectional survey in 2018 and analyzed for the presence of RVFV IgG antibodies using a laboratory-developed indirect enzyme-linked immunosorbent assay (ELISA). Overall, 15.6% of camels and 7.6% of humans were RVFV IgG-positive; IgG-positive camels were predominantly females in large population herds and IgG-positive humans were engaged in farming-related activities and were greater than 18 years old. Of the eight location groups sampled, two had high camel (site 2 and site 6) and two had high human (site 5 and site 6) RVFV seropositivity rates. These data suggest that camelids, such as dromedary camels, may serve as amplifying hosts for vector-borne zoonotic diseases, such as RVFV, and that humans with frequent farming and camel meat, milk, or camel product contact may have increased risk for RVFV exposure or infection. Full article

The increasing burden of dengue represents a growing global public health concern. Among the factors associated with rising dengue incidence, climate change, particularly increasing temperatures, has been frequently highlighted, alongside other environmental, biological, and social determinants. The emergence of dengue in previously non-endemic areas and its sustained increase in incidence have become increasingly common in recent decades. Objective: The aim of this study was to describe national dengue case trends in Mexico from 1990 to 2023 and to assess their association with temperature over the same period using a descriptive, retrospective analysis of epidemiological surveillance and temperature data. Methods: Epidemiological data on confirmed dengue cases and incidence were obtained from the Morbidity Yearbook of the General Directorate of Epidemiology (DGE) of the Mexican Ministry of Health. These data were used to construct epidemic curves and to analyze the geographic distribution of incidence using quartiles. Temperature data were derived from the national annual mean calculated from monthly reports issued by the National Water Commission (CONAGUA). Associations between temperature and dengue cases and incidence were explored over the study period. Results: Temporal analysis revealed a significant increase in both dengue cases and incidence in Mexico, with a positive association with temperature during the same period. Quartile-based geographic analysis showed that state-level classifications remained relatively stable across periods, with several states clustering within or tending toward the group considered endemic. Conclusions: The results of this study show an increase in cases and incidence of dengue over time, as well as a positive association between cases/incidence of dengue in Mexico and the increase in the national average temperature during the study period; however, due to its descriptive and retrospective design, causal inference is not possible. Dengue transmission is inherently multifactorial, and the observed trends likely reflect the combined influence of climatic conditions, historical expansion of transmission cycles, vector establishment, and unmeasured socio-epidemiological factors. The absence of entomological indicators, additional climatic variables, and spatially or seasonally disaggregated analyses limits the ability to capture localized dynamics. Overall, temperature should be interpreted as a contributing factor within a complex system rather than as the sole driver of dengue trends, underscoring the need for integrated surveillance and control strategies in both endemic and non-endemic regions. Full article

Infections caused by arboviruses, a diverse group of viral pathogens transmitted by biting arthropod vectors, mainly mosquitoes, ticks, and midges, can cause a range of illnesses in humans, from mild, influenza-like symptoms to severe neurological complications including encephalitis and viral hemorrhagic fever. According to 2024 World Health Organization statistics, vector-borne diseases collectively account for over 700,000 human deaths annually, with mosquito-borne infections such as dengue, chikungunya, Zika, and yellow fever constituting a growing and significant proportion of this burden. What was once considered a problem localized to poorly resourced settings in tropical and subtropical regions is now becoming a pervasive global challenge. This is due largely to a combination of factors including climate change, transcontinental travel, and urbanization, with the geographical spread and intensity of arboviral outbreaks reaching unprecedented levels during the current century. In much the same way that the escalating global burden of bacterial infections resistant to antibiotics has been described as a silent pandemic, the insidious rise of arboviruses begs questions regarding outbreak preparedness, prevention and control. Here, we highlight the pressing need for comprehensive strategies that incorporate various health sectors to mitigate the emergence and resurgence of arboviral diseases. Future directives that should be prioritized are outlined. As demonstrated by epidemiological trends and historical outbreak data, an orchestrated global response is critical not only for managing current threats but also for preventing future epidemics. Full article

Ticks serve as primary vectors for a wide array of RNA viruses, yet the diversity and distribution of tick-associated RNA viruses remain incompletely characterized in Hebei province. To address this gap, we conducted a systematic metatranscriptomic investigation of 986 ticks representing six species, collected from the diverse ecological landscapes of Hebei Province in northern China. Our analysis recovered 25 complete or near-complete viral genomes spanning 12 families, including Phenuiviridae, Flaviviridae, and Nairoviridae. Of critical public health significance, we identified Severe Fever with Thrombocytopenia Syndrome Virus (SFTSV) in both Haemaphysalis longicornis and Dermacentor nuttalli. Phylogenetic reconstruction revealed marked geographic stratification where strains from the coastal plains clustered with the dominant Genotype F, while those from the mountainous north formed a characteristic and divergent lineage phylogenetically linked to isolates from Inner Mongolia. Furthermore, a novel viral agent provisionally named Zhangjiakou Hepacivirus was discovered in Haemaphysalis japonica. This virus shared less than 80% nucleotide identity with the rodent-associated Hepacivirus P, consistent with a rodent origin and possible cross-species transmission. Collectively, these findings reveal descriptive variation associated with vector identity, physiological status, and ecological context in shaping viral evolution and underscore the need for continuous metagenomic surveillance to mitigate emerging tick-borne disease risks within a One Health framework. Full article

Lyme disease is the most common vector-borne disease in North America. Predicting Lyme disease incidence is a key component of public health preparedness. Previously, we demonstrated that the volume of data searches on Google Trends for terms related to Lyme disease, such as “Lyme” and “tick bite”, can be used as a tool to predict monthly human Lyme disease incidence at the state level. The objective of this project was to build upon our previous work by adding environmental and canine data to our predictive models for the prediction of state-level human and canine Lyme disease incidence. Human data were acquired from state health departments. Canine data were acquired from IDEXX Laboratories. We hypothesized that incorporating a One Health approach with human, animal, and environmental data would improve the predictive ability of the models. The One Health model performed significantly better (Mean Absolute Error [MAE] = 12.1) in predicting human disease incidence in 6 out of 16 states compared to the environmental data model (MAE = 16.5), human search terms model (MAE = 21.4), canine data (search terms + case count) model (MAE = 31.1), and the canine case data model (MAE = 32.0). For canine Lyme disease incidence, the One Health model performed worse (MAE = 330.5) compared to the canine search data model (MAE = 282.3), the human data (search terms + cases) model (MAE = 248.4), and the environmental data (MAE = 221.5) model. However, even the best-performing models had large prediction errors, which limit practical utility. Future studies should incorporate alternative data streams, such as electronic health records and insurance claims, to test predictive ability. Full article