Epidemiological background
During PREPARE-TID webinar series Episode 4, Prof. Zati Vatansever, expert parasitologist at Kafkas University in Turkye, provided a data-rich overview of Crimean-Congo hemorrhagic fever (CCHF) in Turkey, which currently hosts the largest recognized endemic focus worldwide with 17131 laboratory-confirmed human cases between 2002 and 2024, mean case-fatality rate of 4.8% and annual incidence in some rural Anatolian districts exceeding 20 cases per 100,000 inhabitants, with a seasonal peak in May–July.
Despite this substantial burden, Turkey does not have a comprehensive, active national tick-surveillance program. Most surveillance remains passive and clinically driven.
Ecology and behaviour of Hyalomma marginatum
Key ecological and biological features of Hyalomma marginatum include an active host-seeking behaviour, with adults capable of moving tens of meters toward visual, thermal or CO₂ cues and a two-host life cycle. Larvae and nymphs feed on small wild mammals and ground-feeding birds. Adults predominantly feed on large ungulates (cattle, horses, wild boar), with incidental human feeding.
A single cow can feed up to 36 female ticks in a grazing season. An engorged adult female can lay ≈ 7,000 eggs, translating to ~250,000 larvae per cattle host per grazing season and creating high potential for local population amplification under favourable conditions.
Land use, livestock, and host systems
Prof. Vatansever presented data showing that rotational agriculture (e.g. wheat–fallow cycles) can inadvertently create optimal habitats for hosts of immature ticks in fallow periods and shift adult tick feeding patterns when cattle are excluded from cultivated plots. Rural depopulation and land abandonment promote bush encroachment, increasing habitat suitability for wildlife reservoirs.
Serological screening indicates 90% anti-CCHF antibody prevalence in cattle in endemic provinces. Additional roles for wild boar and hares as seasonal amplifiers.
These findings position cattle as central to virus maintenance in endemic landscapes.
Molecular surveillance: sampling and detection
Standard flagging or dragging methods are insufficient for Hyalomma; researchers often act as live bait to collect host-seeking adults.
Methodological priorities include maintaining live or cold-stored specimens to prevent RNA degradation at >25 °C and testing individual ticks rather than large pools, due to strong inhibition from engorged blood.
Reported CCHFV prevalence in ticks varies markedly by region and context:
- Central Anatolia: 16–18% in host-seeking adults (RT-PCR).
- Eastern Anatolia: <5% in mixed adults (nested PCR).
- Thrace: ≈50% in host-seeking adults (qPCR), despite few human cases, indicating possible decoupling between vector infection and human exposure.
Sequencing confirms circulation of lineage V CCHFV, with emerging micro-variants and indications of S-segment rearrangements whose phenotypic relevance remains under investigation. Viral load appears to correlate with disease severity in humans.
Wildlife and long-distance dispersal
Ticks collected from wildlife further clarify the system. Ticks from hares that have 17% CCHFV positivity and ticks from partridges: ≈10% CCHFV positivity.
While most birds are likely non-viremic, they disseminate infected ticks along migratory routes. Wild boar sustain early summer adult tick populations before extreme temperatures limit activity.
System-level gaps and One Health requirements
Prof. Vatansever emphasised several structural gaps. Human CCHF cases are monitored by the Ministry of Health. Livestock are monitored by the Ministry of Agriculture and there is limited integration of human, animal, and vector data.
Nationally, there is no standardised protocol for vector sampling and site selection, estimating sample sizes and vector density, ensuring consistent cold-chain transport and species identification and parallel reporting of infection rates and ecological context.
These gaps limit the development of robust early-warning models.
Climate trends and future risk
Hyalomma adults typically become active at temperatures above 10 °C and remain active until late September. The 2024–2025 season recorded mean January temperatures 2.3 °C above historical averages, effectively extending the vector-active season by nearly a month. Under such conditions, even low numbers of infected adult females can sustain local CCHFV circulation.
Similar signals are now visible elsewhere in Europe, including the recent flagging-based detection of Hyalomma lusitanicum in Spain, indicating niche expansion beyond historical climatic envelopes.
Toward integrated, proactive vector-borne surveillance (Part I, Part II, Part III - PREPARE-TID Ep. 4)
Across these contributions, several consistent principles emerged:
- Emergence is contact-driven, not purely mutation-driven.
- Ecological intelligence (microclimate, host–vector networks, land-use change) is necessary for anticipating where and when pathogen circulation will intensify.
- Molecular workflows, including inhibitor-resistant extraction, isothermal amplification, and NGS, are critical for converting ecological signals into actionable data.
- One Health integration, linking human, livestock, wildlife, and environmental data streams, remains the limiting step in many high-burden regions.
Robust, inhibitor-free nucleic-acid extraction is a foundational step across all these layers.
Workflows such as reverse-purification–based SwiftX™ DNA and RNA extraction support consistent, field-adapted recovery of nucleic acids from arthropods, animal material, and environmental samples, enabling reliable PCR, LAMP/RPA, and sequencing-based surveillance.
Next steps
The next steps for prof. Vatansever are collaborating with ecologists to identify high-priority habitats and host species, standardise field and laboratory protocols for tick and pathogen detection and integrate ecological and molecular datasets into shared analytic platforms.
These measures collectively shift vector-borne disease programs from reactive outbreak response to evidence-based early warning and prevention.
Bring your diagnostics to the field
We work with ecologists, surveillance programs, and molecular laboratories to integrate ecological forecasts into diagnostic strategies.
- Contact us to integrate SwiftX toolbox and SwiftX Grinding tools for your virus detection and analysis in ticks and beyond
- Watch the full PREPARE-TID Ep. 4 webinar