Infectious Bursal disease in indigenous village chickens, ducks and turkeys in Embu county, Kenya: status; knowledge, attitudes and practices of value chain actors

Abstract

Indigenous village chickens are mainly raised in rural settings under free range systems alone or as mixed flocks with ducks and turkeys. They are routinely exposed to overwhelming number of microorganisms, some of which are highly pathogenic such as infectious bursal disease (IBD) virus. The IBD infected ducks and turkeys do not show overt (IBD) clinical signs and they may act as a source of infection to naive chickens kept in such mixed flocks. It is not clear what poultry value chain actors know on IBD maintenance and spread and the status of the disease in Embu County, in chickens, ducks and turkeys, is also not known. The objectives of this study were to determine knowledge, attitudes and practices of value chain actors on IBD in indigenous village chicken, ducks and turkeys and status of the disease in these birds in Embu County. Structured questionnaires, direct observation, sero-survey and reactive Bursa of Fabricius homogenates were used to collect the respective data. The questionnaire study involved a total of 93 poultry value chain actors including: 47 farmers, 39 traders and slaughter personnel and 7 animal health providers. As the disease status sera were collected from 97 indigenous village chickens, 32 ducks and 13 turkeys; Indirect enzyme linked immunosorbent assay (ELISA; IDEXX IBD-XR from IDEXX laboratories USA) was used to screen for IBD virus (IBDV) antibodies in the birds' sera; Agar gel precipitation test (AGPT) was used to detect presence of IBDV in reactive homogenised bursae, collected from chicken during post-mortem. Fisher's and Chi-square tested for association between the risk factors and transmission of IBD. Odds ratio greater than one (OR ˃1) and p-value less than 0.05 (p ˂0.05) were taken to be significant. The risk factors for IBD endemicity identified among the poultry value chain actors were: sourcing birds from other farmers and traders with no known disease or vaccination history (68.1% farmers and 100% traders); moving with gathered chickens from one farm to another during procurement (46.15% traders); lack of disinfection between farms (89.74% traders; xvi 57.1% animal health providers); low use of vaccines against diseases (8.5% farmers); feeding dogs on sick and dead birds (farmer 25.3%; traders 35.89%; slaughter personnel 12.82%); disposal of manure (without making compost) in the farm (95.7%); direct mixing of new and unsold birds from the market with home flocks (55.3% farmers; 21.51% traders) and mixed rearing of different species of birds by farmers (38.3%). There was a significant association (p˂0.05) between traders sourcing of chickens from local farmers (p= 0.0107), feeding sick and dead birds to dogs (O.R=2.75), low IBD vaccine use by farmers (O.R=3.07) and maintenance and spread of IBD in indigenous chickens. The seroprevalence rates were 65% in chicken, 6% in ducks and 92% in turkeys and there was significant difference (P>0.05) between age groups of individual species of bird (indigenous village chickens, ducks and turkeys). Agar gel precipitation test results were all negative for IBDV antigen. In conclusion: presence of IBDV antibodies in the named birds suggested an on-going viral circulation in chickens with ducks and turkeys possibly acting as virus reservoirs for the primary source of new IBD outbreaks in chickens. Some practices undertaken by poultry value chain actors because of their attitudes and due to lack of knowledge have promoted maintenance and spread of IBD in indigenous village poultry. There is therefore a need for awareness-creating campaigns and training on biosecurity to build prevention capacity at community level and routine surveillance coupled with vaccination against IBD in indigenous village chickens, ducks and turkeys in order to control the disease.