Southern Italy study reports first PHEV detection in wild boars

A new surveillance study from southern Italy reports the first detection of porcine hemagglutinating encephalomyelitis virus, or PHEV, in wild boars, widening the known ecology of a swine coronavirus that has mostly been discussed in domestic pig herds. The work was conducted in Basilicata, where dense wild boar populations overlap with a meaningful number of pig farms, including outdoor and free-range operations, creating the kind of wildlife-livestock interface that keeps veterinary epidemiologists on alert. (mdpi.com)

That backdrop matters. Italy’s wild boar population has expanded sharply over the past decade, with ISPRA estimating about 1.5 million wild boars nationally by 2021. At the same time, wild boars have become central to disease discussions in Europe because they can maintain or bridge a range of pathogens relevant to domestic swine and animal health programs. Separate work from southern Italy has already documented viral and parasitic surveillance findings in wild boars, underscoring that this isn’t an isolated concern but part of a broader monitoring effort around the wildlife-domestic animal interface. (isprambiente.gov.it)

PHEV itself is not a new virus, but it is an underrecognized one. It was first described in pigs in the 1950s and remains the only known neurotropic coronavirus affecting swine. Clinical disease is mainly a problem in piglets younger than 4 weeks, especially when they lack lactogenic immunity from exposed or immune sows. In those animals, infection can present as vomiting and wasting disease and/or encephalomyelitis, while infection in grower pigs and adults is often subclinical. Merck Veterinary Manual notes there is no specific treatment or licensed vaccine, so control depends largely on immunity in the sow herd and herd-level management. (pmc.ncbi.nlm.nih.gov)

The Italian study is especially relevant because Basilicata is not just wildlife habitat. It is also an area with thousands of pig farms, and prior regional research has highlighted how outdoor and semi-extensive production can increase opportunities for contact between wild boars and domestic pigs. That doesn’t prove transmission from wild boars to farmed pigs in this case, but it does strengthen the biological plausibility that wildlife surveillance could provide an early signal for pathogens that otherwise circulate quietly. This is particularly important for PHEV, which can be widespread in pig populations without causing obvious clinical outbreaks in older animals. (mdpi.com)

Recent literature has also started to frame swine coronaviruses in wild suids as a surveillance gap. A 2026 review in Animals noted that coronavirus antibodies and RNA have been identified in wild boars in several European countries, including Italy, and highlighted concern that wild populations may act as reservoirs or amplifiers. That doesn’t mean wild boars are now established as a major driver of PHEV outbreaks in commercial herds, but it does suggest the Italian detection fits a broader pattern of increasing scrutiny around wildlife reservoirs for swine coronaviruses. (mdpi.com)

Why it matters: For veterinarians, especially those serving swine operations, the practical takeaway is less about immediate alarm and more about sharper surveillance. PHEV should stay on the differential list when very young piglets show vomiting, wasting, tremors, paddling, or other neurologic signs, particularly in herds with naïve gilts or uncertain sow immunity. For mixed-practice and public health veterinarians, the study is another reminder that wildlife disease monitoring is increasingly relevant to production animal medicine, not only for headline pathogens like African swine fever, but also for quieter endemic agents that can cause losses under the right conditions. The finding may be most relevant for outdoor, free-range, and backyard systems, where fencing, feed protection, carcass handling, and separation from wild suids remain core biosecurity steps. (merckvetmanual.com)

What to watch: The next important questions are whether additional Italian or European surveys replicate the finding, whether sequencing shows close relationships between wild boar and domestic pig strains, and whether regulators or regional animal health authorities fold PHEV more explicitly into routine wild boar surveillance alongside other swine pathogens. (mdpi.com)