Eimeria infections among commercial laying chickens in Nigeria: the prevalence and clinico-histopathological changes

Coccidiosis is known to affect a wide range of animals including chickens. This study was designed to determine the nation-wide prevalence and clinico-histopathological changes associated with Eimeria infections in commercial laying birds in Nigeria. One Thousand eight hundred and forty-three (1843) commercial laying chickens from 28 states and the Federal Capital Territory (FCT) of Nigeria, between 2007 and 2016 were examined for the presence of Eimeria parasites and for clinicopathological lesions. Simple flotation and the McMaster techniques were used to confirm the presence of Eimeria oocysts and estimate the oocyst load. Positive samples were sporulated for the purpose of species differentiation. Gross and histopathology were carried out accordingly. Two hundred and seven (207) faecal samples/carcasses were positive for Eimeria infections (11.23%; 95% CI = 9.87-12.75). Eimeria tenella and E. necatrix were the most prevalent species. The highest mean oocyst per gram (OPG) was recorded in E. acervulina (5260.87 (± 1838.35)). The prevalence of Eimeria infections in commercial laying birds within the states ranged between 4.4% (Kaduna State), and 33% (Ebonyi and Lagos States), and 21.1% in FCT. There was a higher prevalence of Eimeria infections in commercial laying birds that are less than 1 year compared to those above a year. Eimeria infections was 2.19 times more likely to occur during the wet season compared to the dry season (95% CI = 1.59-3.06; χ2 = 23.29; P = < 0.01). One hundred and eighty-five (185) carcasses showed moderate petechiae to ecchymotic intestinal/caecal mucosa, while 22 carcasses showed severe petechiae to ecchymotic intestinal/caecal mucosa with bloody intestinal lumen. This study appears to be the first nation-wide study on the prevalence and clinico-histopathological changes associated with Eimeria infections in commercial laying chickens in Nigeria.

Serological evaluation of Newcastle disease protection among broilers at a live bird market in Kano, Northwest Nigeria, and its epidemiological significance

Vaccination is a tool of Newcastle disease (ND) control among broilers. This study aimed at determining the immunity status of sampled broilers against ND at a live bird market in Kano, Northwest Nigeria, and its epidemiological implication. A cross-sectional study of antibodies against Newcastle disease virus (NDV) was carried out among broiler chicken in a live bird market in Kano State, Northwest Nigeria. A total of 471 samples was tested successfully. NDV antibody titer was assayed using hemagglutination-inhibition test (HI) and ND indirect enzyme-linked immunosorbent assay (ELISA). Serological levels of NDV antibodies were 67.9% (ELISA) and 78.1% (HI). Also, 67 (20.9%) samples tested positive for ELISA but negative for HI, whereas 115 (31.3%) samples tested negative for ELISA but positive for HI. There is strong association between the immune status obtained from both tests (P < .05), significant difference exists between the immune titer obtained from both tests (P < .05). Protective antibody titer among the test subjects suggests individual protection against virulent NDV (vNDV) strain; however, protective levels ≥85% that confers herd immunity were not attained. This report emphasizes the need for farmers to be more compliant to ND vaccination schedule and best practices in their poultry farm to enhance ND control in Live Bird Markets (LBMs).

Discriminant analysis of response to Newcastle disease and heat tolerance among chicken genotypes in hot humid tropical environment

Newcastle disease and heat stress reduce the productivity of local chickens of Nigeria (LCN). This study compared the antibody response to Newcastle disease and heat tolerance among different LCN genotypes in hot humid tropics using multivariate discriminant analysis. A total of 299 birds were used for the study. Geometric mean titre against Newcastle disease before vaccination (GMTB), geometric mean titre against Newcastle disease after vaccination (GMTA), rectal temperature at week 4 (RT4), pulse rate at week 4 (PR4), respiratory rate at week 4 (RR4), heat stress index at week 4 (H4), rectal temperature at week 13 (RT13), pulse rate at week 13 (PR13), respiratory rate at week 13 (RR13) and heat stress index at week 13 (H13) were measured. All the traits were significantly (p < 0.05) affected by the genotype while sex differences were only observed in GMTB, GMTA and RR13. The stepwise discriminant analysis revealed RR4, PR13, RT13, H4, GMTA, GMTB, H13 and RT4 to be effective in differentiating the three chicken genotypes. Two canonical variables that accounted for 60.21% and 39.79% of the total variation were revealed. Linear discriminant functions for differentiation of the three chicken genotypes were also developed. 87.39% of normal feather, 76.58% of naked neck and 100% of frizzle feather chickens were correctly assigned into their genotypes. The longest Mahalanobis distance was observed between normal feather and frizzle feather chickens. The discriminant functions developed in this study could be used to differentiate the three genotypes of LCN using antibody response to Newcastle disease and heat tolerance.

Participatory assessment of paid vaccination campaigns for village chickens against Newcastle disease in Kongo Central province

In the Democratic Republic of Congo (DRC), where state-driven animal vaccination campaigns are organized only in response to epidemics, the organization of a permanent animal vaccination service is urgently needed. A non-governmental organization has set up an experimental paid vaccination service for village chickens against Newcastle Disease (ND) in the Kongo Central province. This mixed-method study presents a participatory assessment of this experiment, identifying socio-economic factors that influence the decision of chicken keepers to adopt vaccination. The study was conducted in four territories of the province. Qualitative and quantitative data were collected through 12 focus group discussions (FGDs) with professionals of animal health and chicken keepers and 160 semi-structured interviews with chicken keepers, sampled by snowball technique. This participatory process has resulted in the design of a grid for assessing animal vaccination service's performance. Here translating the narratives into a preliminary structured assessment, this grid is an output of the study, to be mobilized for future rapid assessments of the vaccination service in a quantitative prospect. The grid consisted of nine criteria, further composed by 16 items, translated into questions to be asked to chicken keepers and vaccinators. In our study area, fieldworkers enumerated four animal vaccination campaigns during a period of 21 years (except those subject to the present assessment). Around 13% of chicken keepers of our sample had participated in ND vaccination programs. Almost 96% of interviewed chicken keepers expressed their willingness to pay for ND vaccination, and 87% of chicken keepers that vaccinated their chickens perceived the vaccine as effective. Vaccinators estimated that 56% of the chicken keepers who were contacted had actually paid for the vaccination of their chickens. The assessment grid highlighted four points in favor of the sustainability of this service, i.e. the general interest of chickens keepers, vaccine efficacy, vaccine availability and ease of use of the vaccine. Two weak points were identified, viz. the poor access of chicken keepers to information and the weak motivation of vaccinators. The vaccine coverage was calculated within the sample at 13.1%. Paid vaccination campaign for village chicken in Kongo Central obtained a performance score of 62.8%, with the highest score in Kwilu-Ngongo (73.1%) and the lowest in Kasangulu (52.4%). Two factors of adoption of vaccination were identified as statistically significant, i.e. chicken housing and territory. Significant differences appeared between territories in access to information for chicken keepers and in vaccinators motivation. The priorities for the improvement of this service appear to be awareness raising among chicken keepers and increasing vaccinators' motivation.

Cross-sectional study of Eimeria species of poultry in Kwara State, North-Central Nigeria

Coccidiosis is one of the biggest challenges faced by the global poultry industry as the protozoan is found anywhere poultry are reared. Before now, there have been no documents on the intensity and diversity of Eimeria species of poultry in Kwara State. This study aimed to determine the prevalence and intensity of Eimeria species and its species diversity among poultry in Kwara Central, North-Central Nigeria. Five hundred and two fecal samples (from four hundred and seventy two chickens and thirty turkeys) were collected from chickens and turkeys from 15 farms from December 2017 to May 2018. The samples were subjected to floatation technique. Positive samples were further subjected to the McMaster counting technique for determining the intensity of infection. Sporulation of unsporulated oocysts was carried out using 2.5% potassium dichromate (K₂Cr₂O₇), for the purpose of identifying the different Eimeria species. Ninety five (18.9%) of the sampled population, 10 (66.7%) of the 15 sampled farms were positive for Eimeria species. The total mean oocyst per gram was 6325.0. Eight Eimeria species were detected in the study: 7 in chickens and 1 in turkeys. Eimeria tenella was the most predominant among chickens, E. meleagrimitis was the only species detected in turkeys. Age, sex, bird type, physiological status, farm age, farm size (acres), management system, frequency of anthelmintic use, frequency of anticoccidial use, distance to dumping site (meters), level of biosecurity and frequency of cleaning the pen were significantly associated (P < 0.05) with the occurrence of Eimeria infection. It is envisaged that the information obtained in this study will contribute to a clearer understanding of the epidemiology of poultry coccidiosis, for better management protocol which will improve the productivity of the sector in Kwara State and Nigeria.

Assessment of antibody assay methods in determination of prevalence of infectious bursal disease among local chickens and guinea fowls in Kwara state, North Central Nigeria

Aim:

This study aimed to assess available assay methods for infectious bursal disease (IBD) diagnosis and seromonitoring in local birds. It also sought to know the prevalence of IBD antibodies among local chickens and guinea fowls in Kwara state, North Central Nigeria.

Materials and Methods:

Sera were obtained from local chickens and guinea fowls and IBD virus (IBDV) antibodies were assayed using enzyme-linked immunosorbent assay (ELISA), indirect hemagglutination (IHA) test, and agar gel immunodiffusion (AGID) test.

Results:

A total of 265 sera were obtained from local birds during dry and wet seasons. ELISA recorded the highest prevalence of 81.1% (215/265) while IHA and AGID detected IBDV antibodies in 183 (69.1%) and 122 (46%) birds, respectively. Significant differences were established for IBD-positive sera based on the assay method used, bird species, and seasons.

Conclusion:

This study indicated that ELISA is the most sensitive and reliable assay method while AGID is the least. It also showed that there is a high prevalence of IBDV antibodies among local birds which were not vaccinated, and this implies a high IBDV activity among these bird species in the study area. This may have significant epidemiological implications on the spread of the virus to exotic bird reared in the rural areas on a commercial scale. Thus, this study suggests continuous surveillance, awareness campaign, and advocacy for vaccination of indigenous birds against IBD.

Newcastle disease in Nigeria: epizootiology and current knowledge of circulating genotypes

Over the years, Newcastle disease (ND) has defied all available control measures. The disease has remained at the forefront of infectious diseases afflicting poultry production after avian influenza. Despite the continuous global use of million doses of ND vaccine annually, the causative pathogen, avian paramyxovirus type 1 also known as Newcastle disease virus (NDV) has continued to evolve causing, even more, a threat not only to the unvaccinated but the vaccinated flocks inclusive. The disease has been well studied in the developed countries where the virus is found in circulation. However, limited information exists on the epizootiology and circulating genotypes of the virus in developing countries where the majority of the flocks are raised on the extensive management system. Identification of virulent NDV in apparently healthy free-range ducks in this system calls for concern and pragmatic approach to investigate factor(s) that favour the virus inhabiting the ducks without clinical manifestation of the disease. Recently, novel genotypes (XIV, XVII, and XVIII) with peculiarity to West and Central African countries have been discovered and due to lack or poor surveillance system possibility of hitherto unreported genotypes are likely. This review elucidates and discusses available literature on the diversity of the circulating NDV genotypes across the West Africa countries and the epizootiology (molecular) of the disease in Nigeria with the view of identifying gaps in knowledge that can assist in the development of effective vaccines and control strategies to combat the peril of the disease.