Avian Infectious Bronchitis Virus: Molecular Detection in Southwestern Ethiopia Chickens

Infectious bronchitis virus (IBV) is a significant threat to poultry worldwide, but its status in Ethiopia remains understudied. Thus, this study aimed to detect the virus and associated risk factors in South West Ethiopia. Ninety oropharyngeal swab samples were purposively collected from symptomatic chickens located in Jimma town, Seqa Chekorsa, and Tiro Afeta woredas of the Jimma zone between November 2021 and April 2022 to detect IBV virus by using RT-PCR. A side-by-side questionnaire was administered to assess risk factors. Total RNA was extracted, reverse transcription polymerase chain reaction (RT-PCR) was conducted, and products were visualized under UV light. The overall proportion of IBV was 16.6% (15/90). No statistical association was observed between any of the animal risk factors and the detection of the virus (P=0.57, 0.586, and 1). However, the proportion of birds infected by the virus was higher in males, exotic breeds, and adults compared to females, local breeds, and young birds. Similarly, none of the management risk factors had a significantly different effect on virus detection (P=0.25, 0.09, 0.088, and 0.726). However, improper carcass disposal (OR = 0.43, 95% CI: 0.13-1.4), lack of veterinary services (OR = 2.7, 95% CI: 0.8-8.3), and the presence of wild birds/rodents (OR = 4.4, 95% CI: 0.88-22.3) were associated with increased IBV risk but not cleaning of feeders/drinkers (OR = 1.1, 95% CI: 0.2-4.8). These findings underscore the need for enhanced biosecurity practices and further research to implement informed IBV control strategies in Ethiopia.

Evaluating Disease Threats to Sustainable Poultry Production in Africa: Newcastle Disease, Infectious Bursal Disease, and Avian Infectious Bronchitis in Commercial Poultry Flocks in Kano and Oyo States, Nigeria

The growth of the poultry industry in Nigeria is constrained by major poultry diseases, despite the implementation of vaccination programs. This study aimed to assess the level of protection against Newcastle disease (ND), infectious bursal disease (IBD), and avian infectious bronchitis (IB) afforded by current vaccination schedules and characterize the circulating virus strains in commercial poultry flocks in Nigeria. A cross-sectional study was conducted on 44 commercial poultry farms in Oyo and Kano states of Nigeria. Serum and tissue samples and data on flock, clinical and vaccination records were collected on each farm. Farms were classified as being protected or not protected against ND, IBD and IB based on a defined criterion. Real-time reverse transcription polymerase chain reaction (rRT-PCR) testing was performed for each target virus on tissue samples and positive samples were sequenced. A total of 15/44 (34.1%), 35/44 (79.5%), and 1/44 (2.3%) farms were considered to be protected against ND, IBD, and IB, respectively, at the time of sampling. NDV RNA was detected on 7/44 (15.9%) farms and sequences obtained from 3/7 farms were characterized as the lentogenic strain. Infectious bursal disease virus (IBDV) RNA was detected on 16/44 (36.4%) farms tested; very virulent (vv) IBDV and non-virulent (nv) IBDV strains were both detected in 3/16 (18.8%) positive samples. Sequences of IBDV isolates were either clustered with a group of genotype 3 virulent IBDV strains or were related to vaccine strains MB and D78 strains. IBV RNA was detected on 36/44 (81.8%) farms, with variant02, Massachusetts, 4/91, and Q1 variants detected. Sequences of IBV isolates were either clustered with the vaccines strains Massachusetts M41 and H120 or were most closely related to the D274-like strains or a clade of sequences reported in Nigeria and Niger in 2006 and 2007. This study revealed that most study farms in Oyo and Kano states did not have adequate protective antibody titers against IBV and NDV and were therefore at risk of field challenge. Infectious bursal disease virus and IBV RNA were detected on farms with a history of vaccination suggesting potential vaccination failure, or that the vaccine strains used mismatch with the circulating strains and are therefore not protective.

An overview of health challenges in alternative poultry production systems

Due to consumer demand and changing welfare standards on health, ecology, equity, and safety concepts, poultry production has changed markedly over the past 20 y. One of the greatest changes to poultry production standards is now offering poultry limited access to the outdoors in alternative and organic poultry production operations. Although operations allowing access to the outdoors are still only a small portion of commercial poultry production, it may impact the gastrointestinal (GIT) health of the bird in different ways than birds raised under conventional management systems. The present review describes current research results in alternative systems by identifying how different poultry production operations (diet, environmental disruptive factors, diseases) impact the ecology and health of the GIT. Various research efforts will be discussed that illustrate the nutritional value of free-range forages and how forages could be beneficial to animal health and production of both meat and eggs. The review also highlights the need for potential interventions to limit diseases without using antibiotics. These alternatives could enhance both economics and sustainability in organic and free-range poultry production.

Detection of Newcastle Disease Virus (NDV) in Laughing Doves and the Risk of Spread to Backyard Poultry

Newcastle disease (ND) is a highly infectious viral disease of birds caused by the Newcastle disease virus (NDV) and doves have been incriminated in previous outbreaks of the disease that have discouraged backyard poultry productions. This survey was done to detect and characterize the NDV from 184 swabs from the cloacae and pharynxes of 67 trapped laughing doves and 25 backyard poultry birds. The study utilized haemagglutination assay (HA) followed by haemagglutination inhibition (HI) tests on HA positive samples to screen field samples. Conventional reverse transcriptase polymerase chain reaction (RT-PCR) was conducted on the HI positives to characterize the NDV. This study revealed that of 134 dove samples screened, 88 (65.7 %) were HA positive. Of these HA positives subjected to HI testing, 37 (42.1 %) were HI positive. Interestingly, 21 (56.8 %) of the HI positives were also RT-PCR positive: 8 lentogenic, 12 velogenic, while one had both lentogenic and velogenic NDV. Comparatively, of the 50 chicken samples screened, 23 (46 %) were HA positive; and of these, HA positives subjected to HI testing, 16 (69.6 %) were HI positive. Only 4 (25 %) of the HI positives were RTPCR positive: 3 lentogenic and a velogenic NDV. From this study it was concluded that laughing doves were demonstrated to be infected with either lentogenic or velogenic NDV or both. The use of red blood adsorption-de-adsorption concentration of NDV enhanced the RT-PCR detection using the fusion gene primers NDV-F 4829 and NDV-R 5031. The detection of not only lentogenic but velogenic NDV in laughing doves poses a great risk to backyard poultry production.

Serological and Molecular Surveillance of Infectious Bronchitis Virus Infection in Free-Range Chickens and Guinea Fowls in the Ga-East District of Ghana

Infectious bronchitis is an economically important disease with worldwide distribution. Information is available on the presence of infectious bronchitis virus in commercial chicken in parts of Ghana but there is no information on free-range poultry and guinea fowls in the country. Possible IBV infections among free-range chickens and guinea fowls in Abokobi and Frafraha communities in the Ga-East district of the Greater Accra Region of Ghana were investigated using serology and PCR. Blood, tracheal, and cloacal swabs were obtained from 219 free-range chickens and guinea fowls with no respiratory symptoms and no history of IBV vaccination. Sera were evaluated for IBV antibodies by ELISA using commercial IBV test kit from IDEXX, Inc., USA. Swab samples were evaluated for S1 glycoprotein gene by one-step RT PCR. All the swab samples tested negative for IBV. 16% of all tested sera were positive for IBV. IBV seroprevalence in guinea fowls was 0%. 21.2% of sera from local chickens were positive for IBV. The seroprevalence of IBV among local chickens from Frafraha was 30% and that of Abokobi was 7.7%. This study shows exposure of local chickens in the study communities to IBV.