Iranian Journal of Veterinary Medicine

Iranian Journal of Veterinary Medicine

Ecozone and Altitude-Associated Evidence of Bluetongue Virus Exposure in Domestic Ruminants and South American Camelids from the Heterogeneous Andean Region of Peru, 2020: A Cross-Sectional Study

Articles in Press

Document Type : Original Articles

Authors
Walter Guillermo Vergar Abarca 1
Edgar Alberto Valdez Gutierrez 1
Santos Wilton Calderon Ruiz 1
Fiorela Guzman Figuera 1
Hermelinda Rivera 2
Abel Eleazar Quispe 2
Dennis Alexander Navarro-Mamani 2
1 Laboratorio Institucional de Investigación de “Sanidad Animal M.V. Atilio Pacheco Pacheco”, Facultad de Agronomía y Zootecnia, Universidad Nacional de San Antonio Abad del Cusco, Cusco, Peru
2 Laboratorio de Virología, Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima, Peru
10.22059/ijvm.2026.415766.1006124
Abstract
Background: Bluetongue virus (BTV) is a vector-borne orbivirus of major veterinary importance in domestic and wild ruminants. In Peru, BTV presence has been reported in livestock species, but information from the Andean region remains limited, particularly across contrasting ecozones and different altitudes.
Objectives: To estimate serological and molecular evidence of BTV exposure in cattle, sheep, alpacas and llamas from the Cusco region of Peru, and to assess ecological factors associated with viral presence.
Methods: A cross-sectional study was conducted from March to July 2020 in the Cusco region of southeastern Peru. A total of 1060 apparently healthy, unvaccinated animals older than six months were sampled, including cattle (n = 449), sheep (n = 204), alpacas (n = 204), and llamas (n = 203). Animals were sampled from 22 locations distributed across ecozones- specifically the sierra and the accessible high forest (AHF)- ranging from below 1000 to 3000 meters above sea level. Antibodies against BTV were detected by cELISA, and viral RNA was detected by real-time RT-PCR. Descriptive analyses were performed for all species, and statistical associations were restricted to cattle because only cattle were represented across all ecological strata.
Results: Overall, 13.58% of animals (95% CI: 11.58 - 15.78; n = 144) were seropositive for antibodies and 10.66% (95% CI: 8.87 - 12.68; n = 113) were RT-PCR-positive. Seropositivity was detected in cattle (29.84%) and sheep (4.90%), but not in alpacas or llamas. Positivity was concentrated in the AHF ecozone and at lower altitudes. Among cattle, seropositivity and RT-PCR positivity were significantly higher in the AHF and below 1000 masl than in the sierra and at higher altitudes (P< 0.001). No significant statistical associations were identified between BTV positivity and age or sex in cattle.
Conclusions: The study provides serological and molecular evidence of BTV presence in the Cusco region of Peru, with detection concentrated in cattle from lower-altitude AHF locations and minimal detection in the sampled high-Andean sierra populations. The findings indicate an ecological influence on BTV occurrence and support the need for geographically targeted surveillance in heterogeneous Andean environments.
Keywords
Andes
Bluetongue virus
ecozone
RT-PCR
South American camelids
Iranian Journal of Veterinary Medicine

Articles in Press, Accepted Manuscript
Available Online from 19 September 2026