Molecular characterization and phylogenetic analysis of lumpy skin disease virus detected in Tanzania between 2023 and 2024
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Date
2026-06-05
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Open Veterinary Journal
Abstract
Background: Lumpy skin disease virus (LSDV), a double-stranded DNA virus of the genus Capripoxvirus, causes Lumpy
skin disease in cattle, leading to significant economic and production losses. In Tanzania, information on the molecular
epidemiology of LSDV is limited, as its circulation has only been investigated in the Tanga, Pwani, and Rukwa regions.
Aim: This study aimed to characterize circulating LSDV strains in Dodoma, Arusha, Manyara, Kigoma, Mwanza,
and Mara regions, which are densely populated with cattle in Tanzania, to understand genetic diversity in these areas.
Methods: Blood and skin biopsy samples (n = 33 each) were collected from nine districts in Tanzania. Molecular
detection was performed by targeting the P32 gene, and genetic variability was assessed by amplifying and sequencing
the G protein-coupled chemokine receptor (GPCR) gene. Nucleotide sequences were translated into amino acid
sequences using the ExPASy Translate tool, and then both nucleotide and amino acid sequences were aligned, followed
by phylogenetic analysis.
Results: Of the 33 blood and 33 skin biopsy samples tested, 20 skin biopsy and 3 blood samples were polymerase chain
reaction-positive for LSDV based on the GPCR gene. Multiple sequence alignment revealed nucleotide substitutions
(A→C) at positions 10 and 34 and an amino acid substitution (T→P) at position 12 in some Tanzania field isolates,
while others exhibited unique amino acid signatures at positions A11, T12, T34, S99, and P199. Phylogenetic analysis
demonstrated that the LSDV isolates obtained from Tanzania clustered closely with one another, as well as with
reference strains from Africa, Asia, Europe, and Eurasia. Additionally, the Tanzania field isolates formed a different
cluster from most reference vaccine strains, suggesting notable genetic variation between circulating field viruses
and vaccine-derived strains. However, an exception was observed with the Kenya vaccine strains (KP663708 and
KJ818282), which clustered closely with the Tanzania field isolates, indicating a close genetic relationship with these
particular vaccine strains.
Conclusion: Tanzanian LSDV isolates are genetically similar to the reference strains but distinct from most vaccine
strains, confirming the circulation of wild-type viruses and highlighting the need for targeted control measures,
including monitoring emerging variants and regulating animal movement.
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Keywords
Lumpy skin disease virus, Molecular detection, Phylogenetic analysis, Tanzania