Colistin is a polymyxin antibiotic that has been used in veterinary medicine for decades, as a treatment for enterobacterial digestive infections as well as a prophylactic treatment and growth promoter in livestock animals, leading to the emergence and spread of colistin-resistant Gram-negative bacteria and to a great public health concern, considering that colistin is one of the last-resort antibiotics against multidrug-resistant deadly infections in clinical practice. Previous studies performed on livestock animals in Tunisia using culture-dependent methods highlighted the presence of colistin-resistant Gram-negative bacteria. In the present survey, DNA extracted from cloacal swabs from 195 broiler chickens from six farms in Tunisia was tested via molecular methods for the ten mobilized colistin resistance (mcr) genes known so far. Of the 195 animals tested, 81 (41.5%) were mcr-1 positive. All the farms tested were positive, with a prevalence ranging from 13% to 93%. These results confirm the spread of colistin resistance in livestock animals in Tunisia and suggest that the investigation of antibiotic resistance genes by culture-independent methods could be a useful means of conducting epidemiological studies on the spread of antimicrobial resistance.

Livestock farming represents a key economic activity in the Tataouine Governorate of southern Tunisia, where cattle and dromedary camels coexist. Varicellovirus bovinealpha1 (BoAHV-1), the etiological agent of infectious bovine rhinotracheitis (IBR), primarily affects cattle, while its circulation in camelids remains poorly understood. Following recent European Union regulations requiring BoAHV-1 surveillance in multiple animal species, this short communication reports serological findings from dairy cattle and dromedary herds in southern Tunisia. In March 2024, serum samples were collected from four non-vaccinated farms, including two intensive Friesian dairy cattle herds and two extensive dromedary herds (50 animals each). Serum samples from all animals were tested for BoAHV-1 antibodies using competitive commercial gB- and gE-based enzyme-linked immunosorbent assays (c-ELISA) and confirmed by virus neutralization test (VNT). Antibodies against BoAHV-1 were detected in cattle from both dairy farms, with low seroprevalence and neutralizing antibody titers, indicating past or ongoing exposure. In contrast, all dromedary samples tested seronegative by both c-ELISA and VNT. These findings confirm BoAHV-1 circulation in cattle in the Tataouine region and its absence in dromedaries at sampling. Further studies involving larger sample sizes and molecular investigations are required to clarify the potential role of camelids in BoAHV-1 epidemiology in southern Tunisia.

Lumpy Skin Disease (LSD) is an economically significant viral disease of cattle, widely prevalent across Africa, particularly in sub-Saharan regions. In 2024, Tunisia reported its first outbreak. Understanding the genetic characteristics of lumpy skin disease virus (LSDV) and related poxviruses is critical for surveillance and control. Twenty-nine samples from 26 suspected cases were screened for LSDV using qPCR, followed by a High-Resolution Multiplex Melting (HRM) assay. Three representative samples, two LSDV-positive and one bovine papular stomatitis virus (BPSV)-positive, were subjected to whole-genome sequencing using Pacific Biosciences (PacBio) HiFi long-read technology. Phylogenetic analyses of the LSDV-marker gene RPO30 and complete genomes were performed alongside SNP and InDel profiling. The Tunisian LSDV isolates clustered with Clade 1.2.2 field strains and were 100% identical to each other and to the Italian isolate LSDV_Italy_Sardinia_2025, sharing 99.99% nucleotide identity with LSDV_V281_Nigeria. Although only two LSDV isolates were sequenced which showed no genetic differences, these findings suggest genomic stability within Clade 1.2.2. The Tunisian BPSV isolate showed high similarity (98.15–98.59%) to strains reported in Germany and Switzerland. This study presents the first genetic characterization of LSDV and BPSV in Tunisia, highlighting the importance of accurate differential diagnosis among poxviruses and continuous genomic surveillance to inform control strategies.