Pathology of porcine peripheral white blood cells during infection with African swine fever virus

Abstract

BackgroundAfrican swine fever virus (ASFV) is the causative agent of African swine fever (ASF) that is the significant disease of domestic pigs. Several studies showed that ASFV can influence on porcine blood cells in vitro. Thus, we asked ourselves whether ASFV infection results in changes in porcine blood cells in vivo. A series of experiments were performed in order to investigate the effects of ASFV infection on porcine peripheral white blood cells. Nine pigs were inoculated by intramuscular injection with 104 50% hemadsorbing doses of virus (genotype II) distributed in Armenia and Georgia. The total number of fifteen cell types was calculated during experimental infection.ResultsAlthough band-to-segmented neutrophils ratio became much higher (3.5) in infected pigs than in control group (0.3), marked neutropenia and lymphopenia were detected from 2 to 3 days post-infection. In addition to band neutrophils, the high number of other immature white blood cells, such as metamyelocytes, was observed during the course of infection. From the beginning of infection, atypical lymphocytes, with altered nuclear shape, arose and became 15% of total cells in the final phase of infection. Image scanning cytometry revealed hyperdiploid DNA content in atypical lymphocytes only from 5 days post-infection, indicating that DNA synthesis in pathological lymphocytes occurred in the later stages of infection.ConclusionFrom this study, it can be concluded that ASFV infection leads to serious changes in composition of white blood cells. Particularly, acute ASFV infection in vivo is accompanied with the emergence of immature cells and atypical lymphocytes in the host blood. The mechanisms underlying atypical cell formation remain to be elucidated.

Evidence of hemolysis in pigs infected with highly virulent African swine fever virus

“…The clinical signs of experimental infection have some differences from those in cited researches with Malawi’ 83 ASFV isolate [9] and our previous study [10]. …”

Comparison of African Swine Fever Virus Prevalence in Nigerian Indigenous Pig, Its Hybrid and Backcross in an Environment Prone to African Swine Fever

“…WBC of NIP (18.16 ± 3.01 × 10 3 /µl) was within the normal range (7 to 20 × 10 3 /µl) for domestic pigs while WBC of hybrid and backcross values of 31.27 ± 1.79 × 10 3 /µl and 27.71 ± 2.01 × 10 3 /µl were higher than the normal range (7 to 20 × 10 3 /µl) ( Table A1 in Appendix). This deviation from normal range for domestic pig was also observed to be in agreement with Karalyan (2012) [17], Anderson (1998) [18] and Eze et al (2010) [19] where the WBC (25.92 ± 8.08 × 10 3 /μl) of the pigs from South-East of Nigeria were higher than the normal or physiological values (7 to 20 × 10 3 /µl). The observed increase in WBC of Hybrid and backcross was adduced to a probable virus inducement of mass-scale mortality of lymphocytes and neutrophils causing the presence of additional nucleus as reported by Karalyan (2012) [17] and Anderson (1998) [18].…”

“…The observed increase in WBC of Hybrid and backcross was adduced to a probable virus inducement of mass-scale mortality of lymphocytes and neutrophils causing the presence of additional nucleus as reported by Karalyan (2012) [17] and Anderson (1998) [18]. Karalyan (2012) [19] also reported that ASFV infection leads to serious changes in composition of WBC. Stress effects induced due to the presence of pathogen was also presented as a possible cause of increase in WBC [17] [18].…”

“…Karalyan (2012) [19] also reported that ASFV infection leads to serious changes in composition of WBC. Stress effects induced due to the presence of pathogen was also presented as a possible cause of increase in WBC [17] [18]. The same trend as observed in WBC was observed in neutrophil and Eosinophil of male and female pigs ( Table 2).…”

Development of a Rapid and Sensitive Method for Detection of African Swine Fever Virus Using Loop-Mediated Isothermal Amplification

“…It causes acute hemorrhagic fever and leads to high morbidity and mortality with consequent economic losses. There is no available vaccine for ASF (Karalyan et al, 2012). Montgomery was the first to describe ASF, found in Kenya in 1921 (Gil et al, 2008).…”