Serological evidence of avian HEV antibodies in apparently healthy chickens in southwest Nigeria

Abstract

Avian hepatitis E virus (aHEV) is associated with hepatitis-splenomegaly syndrome, big liver and spleen disease and hepatic rupture haemorrhage syndrome. However, the knowledge about aHEV in commercial layer chickens in Nigeria is scarce. In this study, 460 serum samples obtained from 36 apparently healthy commercial layer chicken flocks in three states (Ogun, Osun and Oyo States) of southwestern Nigeria were analysed by enzyme linked immunosorbent assay for the presence of anti-aHEV immunoglobulin Y (IgY) antibodies. In total, the overall seroprevalence of anti-aHEV antibodies was 14.6%. The serological analysis revealed that 75% of the flocks examined were positive for anti-aHEV IgY antibodies from chickens of various ages in all three states. The percentage of the seropositive chickens in the three states varied from flock to flock ranging from 60% to 88.8% and seropositive chickens were detected at any age (24–52 weeks of age) without significant differences between the age groups. This is the first report assessing the presence of aHEV antibodies in chickens from Nigeria. The detection of anti-aHEV antibodies in commercial layer chickens in this study emphasizes the importance of serosurveillance in disease monitoring due to the economic threat posed by aHEV as a result of decreased egg production and increased mortality in affected commercial layer chicken farms. However, further studies are essential to reveal the clinical implications and to assess the real burden of aHEV in Nigeria.

Hepatitis E virus causes apoptosis of ovarian cells in hens and resulting in a decrease in egg production

“…In the field, avian HEV is often isolated from broiler breeders and laying hens with clinical symptoms, such as increased mortality and decreased egg production ( Haqshenas et al, 2001 ; Billam et al, 2005 ; Agunos et al, 2006 ; Troxler et al, 2014 ). Decreased egg production has also been reported under experimental conditions ( Sun et al, 2020 ; Osamudiamen et al, 2021 ; Zhao et al, 2017 ). Therefore, there is an urgent need to elucidate the mechanism underlying avian HEV-induced reduction in egg production.…”

Molecular detection of avian hepatitis E virus (Orthohepevirus B) in chickens, ducks, geese, and western capercaillies in Poland

“…This could be simply due to the type of material studied, as in Nigeria apparently healthy chickens were examined, while in our study we had samples obtained from flocks with diminished performance. In a recent study, we reported that the seroprevalence of aHEV in chicken flocks was much higher in Poland (56.1%) compared to China (35.9%), whereas in southwest Nigeria 75% examined chicken flocks were positive for aHEV antibodies [ 13 , 18 , 24 ].…”

“…This indicates that aHEV is capable of causing subclinical infections [ 11 , 17 ]. Recent study from apparently healthy layer flocks from Nigeria indicate approximately 10% aHEV RNA prevalence, while 75% of the examined flocks show antibodies against aHEV [ 18 , 19 ]. This study assessed the prevalence of aHEV among Polish flocks.…”

Identification of a Putative Novel Genotype of Avian Hepatitis E Virus from Apparently Healthy Chickens in Southwestern Nigeria

“…In Nigeria, cases of human HEV outbreaks have been reported [ 30 , 31 ]. Further, serological evidence of HEV is known from swine, rabbits, goats, sheep, cattle [ 32 , 34 , 35 ], and a 14.6% seroprevalence of aHEV was recently reported in layer chickens in Nigeria [ 36 ]. Only one study conducted in Ogun and Lagos Statesfound aHEV RNA in chicken feces samples.…”

“…In Nigeria, HEV is associated with sporadic cases and outbreaks in humans [ 30 , 31 ] and serological evidence has been reported from swine, rabbits, goats, hares, sheep, cattle, and layer chickens [ 32 , 33 , 34 , 35 ]. Until recently, when aHEV seroprevalence of 14.6% was reported in commercial layer chickens in Southwestern Nigeria [ 36 ], there was no report of the detection of aHEV antibodies among the chicken population in Nigeria. Although Ogbolu and Obi [ 37 ] reported the presence of aHEV RNA from chicken fecal samples collected in a study conducted in Lagos and Ogun States, Nigeria, only a small number of samples were tested in that study and no information on the virus genotype was provided.…”