Morphological Characteristics of Skin Lesions in Cattle Naturally Infected with Lumpy Skin Disease Virus in Serbia

Cellular infiltration, cytokines, and histopathology of skin lesions associated with different clinical forms and stages of naturally occurring lumpy skin disease in cattle

Lumpy skin disease (LSD) caused by the Capripoxvirus LSD virus which infects cattle, leading to a serious disease characterized by fever and the eruption of skin nodules all over the surface of the body. Our understanding of the pathogenesis of this disease is still incomplete, particularly the immunopathological alterations occurring in the skin nodules of infected animals. Therefore, we collected skin nodules from naturally infected cattle with different forms of the disease, both in the early stage of clinical infection and after disease progression. The skin samples were examined both histopathologically and immunohistochemically using a variety of antibodies targeting immune cellular markers and cytokines. As a result, the dermatohistopathology revealed orthokeratotic hyperkeratosis, vasculitis, epidermal microvesicles, and cellules claveleuses of Borrel in the early stage of infection, with the severity of the lesions correlating with the severity of the clinical disease. Meanwhile, late-stage samples had epidermal hyperkeratosis as well as dermal lymphocytic and histiocytic infiltrations. The predominant cellular infiltrates in the cutaneous lesions of early-stage LSD samples were interferon (IFN)-γ⁺ cells and CD4⁺ T lymphocytes with few macrophage lineage cells. However, in the late-stage samples, numerous Iba-1⁺ macrophages, with few IFN-γ⁺ cells and CD4⁺ T lymphocytes, were detected. Our findings indicate that IFN-γ⁺ cells, CD4⁺ T lymphocytes, and macrophages play a key role in the immunity against natural LSD virus infection and imply that cutaneous vasculopathy associated with LSD virus infection is an immune-mediated lesion. The current study contributes to our understanding of the pathogenesis of LSD.

Seroprevalence of Bovine Viral Diarrhea on Smallholder Farms on the Territory of Belgrade City

Bovine viral diarrhea (BVD) is a viral disease of cattle with a high economic impact. To estimate the seroprevalence of Bovine viral diarrhea virus (BVDV) infection of cattle on smallholder farms we included 78 smallholder farms in the Belgrade epizootiological area where 318 blood serum samples from cattle were collected, and subsequently tested. The samples were analyzed using a commercially available competitive enzyme immunoassay (ELISA) for the detection of antibodies against BVDV. The obtained results showed an overall seroprevalence of 3.8% whereas the seroprevalence on herd level varied from 0% to 80%. The obtained results showed a relatively low seroprevalence of BVD infection on smallholder farms on the territory of Belgrade city.

Validation of TaqMan-Based Assays for Specific Detection and Differentiation of Wild-Type and Neethling Vaccine Strains of LSDV

Lumpy skin disease (LSD) is an important animal disease with significant health and economic impacts. It is considered a notifiable disease by the OIE. Attenuated strains of LSDV have been successfully used as vaccines (LAV) but can also produce mild or systemic reactions. Vaccination campaigns using LAVs are therefore only viable if accompanying DIVA assays are available. Two DIVA qPCR assays able to distinguish Neethling-based LAVs and wild-type LSDV were developed. Upon validation, both assays were shown to have high sensitivity and specificity with a diagnostic performance comparable to other published DIVA assays. This confirmed their potential as reliable tools to confirm infection in animals during vaccination campaigns based on Neethling vaccine strains.