A study published in April 2016 in Frontiers in Cellular and Infection Microbiology provides new serological evidence of exposure to Crimean-Congo hemorrhagic fever virus (CCHFV) or closely related orthonairoviruses in free-range cattle in southern Italy.
The results reinforce the need to maintain One Health surveillance in a country that, to date, has not reported any autochthonous human cases of this disease. Crimean-Congo Hemorrhagic Fever: A Tick-Borne Zoonosis: Crimean-Congo hemorrhagic fever (CCHF) is a serious zoonosis transmitted primarily by ticks of the genus Hyalomma. Domestic and wild animals can become infected without developing apparent disease and may exhibit transient viremia, playing a significant role in maintaining the virus cycle and infecting new ticks. Domestic ruminants, especially cattle, sheep, and goats, are also useful as sentinel animals, since antibody detection can provide signs of viral circulation before human cases appear. Italy is currently considered a non-endemic territory with no reported human cases, although findings in recent years have warranted increased surveillance.
These include the prior detection of CCHFV RNA in Hyalomma rufipes ticks and serological evidence in cattle from southern regions of the country. The study: 670 cattle from 59 farms in Gargano National Park. Researchers analyzed 670 bovine serum samples collected between 2024 and 2025 from 59 farms in Gargano National Park, in Apulia, southeastern Italy. The animals were Podolica cattle raised extensively in areas where Hyalomma ticks are present. In the initial screening using a commercial ELISA, 105 of the 670 samples were positive, corresponding to an individual seroprevalence of 15.7%. At the farm level, positive animals were detected in 23 of the 59 farms studied, representing 39%.
These initial results, however, required confirmation with additional techniques. Significant differences depending on the test used: To study the results in greater depth, the researchers selected 20 samples—18 initially positive and two negative—from ten different farms and used three serological approaches: a commercial ELISA; an indirect ELISA developed to detect antibodies against the CCHFV nucleoprotein; and a viral neutralization test. Of the 18 samples initially reactive with the commercial ELISA, 13 were also positive with the second ELISA. Subsequently, 16 could be analyzed by neutralization, and only three showed neutralizing antibodies against CCHFV, with low titers of 1:10 in two samples and 1:16 in another. This discrepancy is one of the most important messages of the study: a single positive serological result does not automatically allow for the assumption of confirmed CCHFV circulation. CCHFV or a related virus?
The authors propose several explanations for the weak neutralizing activity observed. One possibility is that the animals were exposed to a CCHFV variant antigenically different from the genotype used in the neutralization test. Another possibility is exposure to another closely related orthonairovirus, such as the Aigai virus, capable of producing antibodies with some cross-reactivity. The progressive decline of antibodies after a previous infection could also play a role, as there is still limited information on the duration of the immune response to CCHFV in cattle.
Therefore, the researchers themselves emphasize the need to interpret the results with caution and use several complementary diagnostic techniques. Evidence of exposure, but not of an established enzootic cycle. The study concludes that there is serological evidence of contact between cattle from the Gargano area and CCHFV or an antigenically related orthonairovirus. However, this finding does not demonstrate the current existence of a stable cycle of enzootic transmission of CCHFV in Italy. The authors point out that further molecular studies, particularly direct detection of the viral genome in ticks, are necessary to confirm that CCHFV is actively circulating in the territory.
This distinction is especially important to avoid interpreting the seropositivity found in cattle as equivalent to an outbreak of Crimean-Congo hemorrhagic fever. A relevant signal from a One Health perspective. Despite these limitations, the results are of epidemiological interest. The expansion of certain Hyalomma species towards more northerly latitudes, favored by environmental factors and the transport of ticks by migratory birds, is progressively modifying the potential distribution of various vector-borne diseases in Europe. In this context, surveillance of domestic animals can serve as an early warning system.
The area studied also has relevant characteristics: extensive livestock farming, frequent contact with ticks, and a natural environment conducive to interaction between vectors, wildlife, and domestic animals. From the perspective of the Global Risk Atlas, these data should not be interpreted as evidence of a high risk for the average traveler in Italy, but rather as an epidemiological signal that justifies maintaining and strengthening integrated animal-vector-human surveillance. What does this mean for travelers and rural activities? The article does not directly assess the risk for travelers nor does it propose specific recommendations for them. Its results focus on animal serological surveillance. However, the information is of particular interest to people who engage in rural or outdoor activities in areas where Hyalomma is present, as it confirms the need to continue studying the circulation of orthonairovirus in southern Italy.
Prevention of tick-borne diseases continues to rely primarily on reducing exposure to bites and detecting and removing attached ticks early. In summary, the study conducted on podolic cattle in the Gargano National Park contributes a new piece to the epidemiological understanding of Crimean-Congo hemorrhagic fever in Italy: 670 cattle studied, 59 farms, 105 positive results in the initial screening, an apparent seroprevalence of 15.7%, and three samples with neutralizing antibodies. However, the discrepancy between the different tests necessitates a cautious interpretation of these data. The most appropriate conclusion is not that the CCHF virus is definitively established in Italy, but rather that there is serological evidence of exposure to CCHFV or a related orthonairovirus that requires confirmation through molecular surveillance of animals and ticks.
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