Spatiotemporal pathogenesis and tissue tropism of a virulent goatpox virus Mukteshwar strain in the goats.

Detailed spatiotemporal pathogenesis data for virulent Indian Goatpox virus (GTPV) isolates in the natural host remain limited. This study characterized systemic dissemination and tissue tropism of the GTPV Mukteshwar strain following experimental intradermal inoculation (106 SRD50) in goats. Sixteen GTPV-seronegative goats (12-21 months) were monitored longitudinally, with replicated serial necropsies conducted from 3 to 35 days post-infection (dpi). Viral dissemination was quantified by real-time PCR targeting the RPO147 gene, and tissue lesions and antigen localization were evaluated by gross pathology, histopathology, immunohistochemistry, and special staining. Infected goats developed fever, lymphadenopathy, and characteristic cutaneous lesions after an incubation period of 3-11 days. Primary replication was detected at the inoculation site by 3 dpi, followed by viremia between 5 and 14 dpi, with peak blood viral loads of 1.64-3.55 log10 DNA copies/μL during 8-11 dpi. Systemic dissemination involved skin, lymphoid organs, respiratory and gastrointestinal tissues, urinary system, and male reproductive organs, while central nervous system tissues remained negative. Viral shedding occurred predominantly via conjunctival and nasal secretions between 8 and 21 dpi, peaking at 5.04 and 4.24 log10 DNA copies/μL, respectively, at 11 dpi, with intermittent urinary detection reaching 2.11 log10 DNA copies/μL at 14 dpi. Persistent antigen and/or viral DNA detection in respiratory and gastrointestinal tissues beyond clinical recovery indicates tissue-specific viral maintenance. Defined viremia peaks and persistence windows establish a kinetic framework for systemic dissemination and provide quantitative benchmarks for vaccine efficacy assessment, surveillance, and control strategies in endemic regions.