Pigs | April 2026
African swine fever (ASF) situation remains a continuing threat Given the potential for rapid spread of African swine fever (ASF) among wild boar and domestic pigs, the following provides an update on the ASF situation at the time of writing. The information therefore extends beyond the first quarter of 2026. A total of 4,988 ASF outbreaks in wild boar had been reported in 2026 up to and including 27 May. In domestic pigs, 155 outbreaks were reported. In Germany, 519 ASF-positive wild boar were reported, while no outbreaks were detected in domestic pigs. A new outbreak has recently emerged in the federal state of Saxony, bordering Poland. The outbreak in Hesse has not yet been completely eradicated, although the number of ASF-positive wild boar continues to decline. This is partly attributed to control measures, including increased hunting pressure, which effectively reduces the wild boar population. In the first five months of 2026, Poland reported 1,275 ASF cases in wild boar and one outbreak in domestic pigs. Most infections occurred in the north-western part of the country. The Baltic States continue to experience large numbers of ASF outbreaks in wild boar, reflecting the situation seen throughout 2025. The situation in north-western Italy remains particularly concerning. The number of ASF notifications in wild boar during the first five months of 2026 (660) has already nearly equalled the total number reported throughout 2025 (690). Controlling wild boar populations, and thereby ASF, remains a significant challenge. Furthermore, domestic pigs on farms with strict biosecurity measures are not always protected from ASF introduction. For example, an outdoor pig farm in the Piedmont region became infected despite double fencing and the use of personal protective equipment by visitors and staff. Natural environmental factors, such as water flowing onto the farm from surrounding hills, may have contributed to the outbreak and are currently under investigation.
Animal health monitoring Royal GD has been responsible for animal health monitoring in the Netherlands since 2002, in close collaboration with the veterinary sectors, the business community, the Ministry of Agriculture, Fisheries, Food Security and Nature, veterinarians and farmers. The information used for the surveillance programme is gathered in various ways, whereby the initiative comes in part from vets and farmers, and partly from GD. This information is fully interpreted to achieve the objectives of the surveillance programme – rapid identification of health issues on the one hand and monitoring trends and developments on the other. Together, we team up for animal health, in the interests of animals, their owners and society at large.
Specific findings Mandibular abscesses and residual feed contamination A veterinarian from a medium-sized farrow-to-finish farm contacted the Veekijker hotline regarding an unusual finding. During repeated farm visits, approximately five pigs weighing around 75 kg were consistently observed with unilateral mandibular abscesses, some reaching the size of a melon. Although the animals did not lose condition, the lesions appeared to cause a degree of discomfort. No mortality was associated with the condition and the pigs recovered following drainage of the abscesses. The veterinarian wondered whether there could be a relationship with Fox parvovirus, as other associated clinical signs had previously been observed on the farm. The Veekijker did not consider these findings consistent with Fox parvovirus infection. In cases of unilateral abscesses near the mandible, trauma and dental root infections should be considered the most likely differential diagnoses. Although submission of an affected pig for pathological examination was advised, no further diagnostic investigations were performed. The clinical problem subsequently resolved. Following a severe outbreak of tail biting, an extensive evaluation of water supply, feed, management practices and housing conditions was conducted. During cleaning of the feed delivery system, large quantities of caked and mould-contaminated feed residues were discovered. In retrospect, reduced feed intake had also been noted during this period. Following removal of the feed residues, neither tail biting nor mandibular abscesses were observed again. Although a direct causal relationship cannot be conclusively demonstrated, it is plausible that feed was repeatedly contaminated by residual material within the feed lines. This may have reduced feed palatability, leading to decreased feed intake. Reduced feed intake despite continued hunger may cause discomfort and frustration, both of which are recognised risk factors for the development of abnormal behaviour. Although no external evidence of trauma was identified, trauma remains one of the most plausible explanations for the mandibular abscesses.
Congenital abnormalities in neonatal piglets A sow farm reported an increasing number of congenital abnormalities in newborn piglets over recent weeks. Multiple litters were affected, and several piglets were submitted for pathological examination. Two distinct abnormalities were observed clinically: a soft swelling on the forehead and a flattened forehead. Pathological examination revealed two cranial malformations: cranioschisis and meningocele. In cases of cranioschisis, incomplete closure of the skull bones allows fluid to reach the developing brain, resulting in brain degeneration and anencephaly. In piglets with meningocele, incomplete closure of the vertebral column, similar to spina bifida, allows protrusion of the meninges and brain tissue through a defect in the skull. No abnormalities were identified in other organ systems. The causes of these congenital abnormalities may be either infectious or non-infectious. Although infectious agents such as PPV1, PRRS virus and PCV3 are known to be associated with congenital abnormalities, they are not specifically linked to the lesions observed in these piglets. Genetic factors should therefore be considered, as cranioschisis has previously been described as a hereditary condition in pigs, potentially inherited through either the sow or the boar line. In addition to genetic causes, nutritional deficiencies, particularly vitamin A deficiency, have been associated with congenital abnormalities. Although uncommon in modern pig production systems, formulation or feed-mixing errors may occasionally result in nutritional deficiencies. When congenital abnormalities are identified in piglets, veterinarians should evaluate both genetic and nutritional factors. Close collaboration with feed suppliers and breeding organisations is essential to minimise recurrence of potentially hereditary defects.
Royal GD P.O. Box 9, 7400 AA Deventer The Netherlands
T. +31 (0)88 20 25 575 info@gdanimalhealth.com www.gdanimalhealth.com
Pig Health in the Netherlands, First Quarter of 2026 Disease/disorder/health characteristic
Situation in the Netherlands/Europe
Category A, B, and C diseases (notifiable and controlled) Foot and Mouth Disease (FMD)
The Netherlands has been disease-free since 2001. Outbreaks occurred in Greece, Cyprus and Türkiye during the first quarter of 2026.
Classical swine fever (CSF)
The Netherlands has been disease-free since 1998. No outbreaks have been reported in Europe since 2015.
African swine fever (ASF)
The Netherlands has been disease-free since 1986.
Brucellosis
The Netherlands has been disease-free since 1973.
Aujeszky’s disease (ADV)
The Netherlands has been disease-free since 2007. Outbreaks were reported in France and Hungary during the first quarter of 2026.
Category C, D, and E diseases (notifiable) Salmonella
Detected four times in pathological examinations.
Monitoring: Veekijker Fox parvovirus
Fox parvovirus continues to be reported in the field.
Rotavirus/Coronavirus
Increase in the number of questions during the first quarter.
Monitoring: pathological examinations Sows and boars
More sows and boars were submitted for pathological examination during the first quarter of 2026 compared with previous quarters.
Meningitis
The most frequently reported diagnosis is meningitis caused by Streptococcus suis, particularly in suckling and weaned piglets.
Online Monitoring Absence of health complaints
In 78 per cent of Online Monitor reports, no health complaints were recorded.
Respiratory disorders
Where health complaints were reported in the Online Monitor, they were most frequently associated with the respiratory tract.
GD3630/09-26