Seroprevalence of Bluetongue Virus in small ruminants in Balochistan province, Pakistan

Abstract

Bluetongue (BT), caused by bluetongue virus (BTV), is a vector-borne disease of small ruminants that has the potential to spread across international borders. Despite large populations of susceptible animals and borders with BTV endemic countries, little is known of the disease burden and prevalent serotypes in the province of Balochistan in Pakistan. We conducted a cross-sectional study to determine seroconversion and prevalent serotypes in selected districts of the province using a competitive enzyme-linked immunosorbent assay (cELISA) and real-time polymerase chain reaction (RT-PCR). Sera (n = 876) were collected from clinically healthy sheep and goats originating from the districts of Quetta (n = 300), Mastung (n = 201), Killa Saifullah (n = 75) and Kech (n = 300). None of the study herds (n = 97) were seronegative for BTV, and at the individual level, the overall prevalence of BTV seroconversion was 47.26% (n = 414/876, 95% CI = 43.92%-50.63%). A higher percentage of goats (50.87%, 95% CI = 45.99%-55.73%) were seropositive for anti-VP7 immunoglobulins (IgG) than sheep (44.21%, 95% CI = 39.81%-48.70%). Odds ratios of seroconversion for goats were associated with breed type (χ = 16.84, p = .01), parity (χ = 23.66, p = .00) and presence of vector (χ = 2.63, p = .10), whereas for sheep, it was associated with breed type (χ = 13.80, p = .01) and parity (χ = 53.40, p = .00). Serotype 8 was the most prevalent (26.82%, 95% CI = 14.75%-43.21%) followed by an equal prevalence of serotypes 2 and 9 (7.31%, 95% CI = 1.91%-21.01%). To the best of our knowledge, this is the first study conducted in Balochistan province and the results indicate that there is a necessity to initiate intervention strategies to control BT disease burden not only in this region of Pakistan but also in adjacent areas of the neighbouring countries, Iran and Afghanistan.

Serological Evidence of Bluetongue in Iran: A Meta-Analysis Study

“…Besides, C. imicola continues to be the foremost prevalent vector in Turkey (Ertürk et al, 2004). In Pakistan, the BTV seroprevalence was reported in sheep (47.3%) and goat (50.9%) and Serotype 8 was the most prevalent followed by an equal prevalence of serotypes 2 and 9 (Sohail et al, 2018). Up to date, seroprevalence rates of BTV in sheep (68.6%) and goats (71.8%) from Afghanistan and 22.3-60-1% and 21.4-100 % of sheep and goat in Iraq was reported (Ali et al, 2014;Shlash et al, 2012).…”

An updated review on bluetongue virus: epidemiology, pathobiology, and advances in diagnosis and control with special reference to India

“…The seroprevalence of BTV in Pakistan was 18%–57% in sheep, 41%–51% in goat, 18% in cattle, and 29% in buffalo (Sohail et al. 2018 ). In China, at least 14 BTV serotypes (BTV-1–5, -7, -9, -11, -12, -15, -16, -21, -23, and -24) have been reported by serological testing and VI.…”

Pathogenic Potential and Global Epidemiology of Bluetongue Virus that Cause Infection in Ruminants

“…Seroprevalence was more in goats than sheep. The Serotype 8 was again the most prevalent serotype in the Balochistan province followed by an equal prevalence of the serotypes 2 and 9 (Sohail et al, 2018).…”