Occurrence of infectious bronchitis in layer birds in Plateau state, north central Nigeria

Abstract

A flock of 54 wk-old layer birds exhibiting signs of respiratory distress, greenish diarrhea, and drop in egg production was investigated. A marked drop in egg production (55%) was recorded with eggs appearing white and soft-shelled. Mortality was in the range of 1%–2% with post-mortem lesions revealing cloudy air sacs, frothy, and congested lungs. Viral RNA was extracted from pooled tissue samples (trachea, lungs, spleen, and liver) and tested for Avian influenza virus (AIV), Newcastle disease virus (NDV), and infectious bronchitis virus (IBV) by reverse transcriptase-polymerase chain reaction (RT-PCR). In addition, virus isolation was attempted in 9–11 day-old embryonating chicken eggs (ECE). In order to determine the prevalence of IBV serotype(s) in the flock, serum samples were screened by hemagglutination-inhibition (HI) test using IBV antigens and antisera (Arkansas, Connecticut, and Massachusetts). Neither AIV nor NDV but IBV was detected in the tissue samples by RT-PCR. In addition, virus isolate obtained after four serial passages in ECE produced dwarfed, stunted, and hemorrhagic embryos, and the isolate was confirmed by RT-PCR to be IBV. The serum samples were 100% seropositive for three serotypes with HI titres ranging from 5 to 12 Log 2 . In this study, IBV was confirmed as the causative agent of the observed respiratory distress and drop in egg production. Also, the evidence of co-circulation of multiple IBV serotypes was established, this to the best of our knowledge is the first of such report in Nigeria. We recommend extensive molecular and sero-epidemiology of circulating IBV genotypes and serotypes in Nigeria with the aim of developing better control strategies, including vaccination.

Sero-prevalence and serotypes of infectious bronchitis virus in free-range chicken in Plateau state, Nigeria

“…The finding of high distribution of the Mass serotype with 89.3% across the four Local Government Area in this study supported that of Fellahi et al (2015) who showed that Mass seemed to be the highest in prevalence in a lot of countries when compared to other serotypes given that it was both the first detected and most frequently detected IBV genotype (Fellahi et al, 2015). In commercial poultry, Mass has been identified as the commonly used serotype for vaccination (Shittu et al, 2019). In North America, the commonly used serotypes in most vaccination programs are the Mass, Conn and the Ark (Butcher et al, 2014).…”

“…The findings of this present study revealed the first detection of Conn, Ark and De-072 strains of IBV in free-range chicken in Nigeria. Even though, they had been detected in commercial poultry (Shittu et al, 2019). The prevalence of Conn (5.0%) in Mangu LGA is comparable to the cumulative prevalence (13.4%) reported in the USA from field samples collected during 11 year period occurring throughout the South eastern USA states including North Carolina, Tennessee, Alabama and other Midwest and Western USA states (Jackwood et al, 2005).…”

“…The Ark prevalence in Bassa (45.7%) was similar to that found in the USA where the Ark (42.4%) was the most frequently identified type of IBV (Jackwood et al, 2005) Conn and Mass had a prevalence of 13.4% and 10.2% respectively (Jackwood et al, 2005). However, just as it might have taken QX (an Italian isolate of QX strain of IBV) to migrate to Europe from China in about 7 years (Toffan et al, 2011), it might be suggested that migration of birds, international trade, poultry importation (both legal and illegal) could be a possible explanation of the fact that the IBV Ark serotype which is found in the US, rarely in Africa; and not previously found in Nigeria can now be found in Plateau State and probably elsewhere (Worthington et al, 2008;Shittu et al, 2019). It is also possible that due to the importation of vaccines from several countries such as US, and other European countries into Nigeria, we now have the Ark strain from vaccine(s) (Worthington et al, 2008;Shittu et al, 2019).…”

“…In the northern part of Nigeria, studies showed that the overall prevalence of IBV for Sokoto and Borno State were 89% and 26.6% respectively (Mungadi et al, 2015;Shettima et al, 2016). Recently, an incidence of IBV in a commercial poultry was reported in Jos South Local Government Area of Plateau State (Shittu et al, 2019). In freerange rural poultry of Plateau State, little is however known about the sero-prevalence and serotype(s) of IBV in circulation.…”

Unique Variants of Avian Coronaviruses from Indigenous Chickens in Kenya

“…Molecular and serological surveys in the backyard and commercial poultry flocks have reported IBV variants in the Mediterranean basin and Western and Northern African countries [ 27 , 53 ], but epidemiological and genomic data on IB and its impact on the poultry industry in Africa are scarce. This is despite IBV being one of the most common and important viral agents associated with respiratory disease and severe reduction in egg production in chickens, with IB outbreaks occurring in commercial and backyard flocks regardless of their vaccination status [ 54 ]. Contributing factors to this situation include a lack of surveillance initiatives for poultry viruses and inadequate genomic sequence data of detected isolates, most of which remain uncharacterized.…”