Detection of Chicken Respiratory Pathogens in Live Markets of Addis Ababa, Ethiopia, and Epidemiological Implications

Abstract

A moderate to high seroprevalence of exposure to Newcastle disease (NDV), avian metapneumovirus (aMPV), infectious laryngotracheitis virus (ILTV), infectious bronchitis virus (IBV) and Mycoplasma gallisepticum (MG) has recently been reported in Ethiopia, but it is unclear to what extent these contribute to clinical cases of respiratory disease. This study investigated the presence of these pathogens in chickens exhibiting respiratory disease in two live markets in Addis Ababa. Markets were visited weekly for three months, and 18 chickens displaying respiratory clinical signs were acquired. Swab samples were taken from the choana, trachea, air sac and larynx for bacteriology and PCR tests targeting these five pathogens. PCR-positive samples were sequenced. All 18 chickens were PCR-positive for aMPV, 50% for each of Mg and NDV, 39% for IBV and 11% for ILTV. Infections with >3 pathogens were detected in 17 of 18 chickens. Potentially pathogenic bacteria such as Escherichia coli, Klebsiella spp., Streptococcus spp. and Staphylococcus were found in 16 to 44% of chickens. IBV-positive samples were of the 793B genotype. The results associate the presence of these organisms with clinical respiratory disease and are consistent with recent serological investigations, indicating a high level of exposure to multiple respiratory pathogens.

Molecular Detection and Serological Investigation of Newcastle Disease in Intensive, Semi-Intensive, and Backyard Production Systems in Central and Southwestern Areas of Ethiopia

“…21 Likewise, a significant proportion of the virus was detected from collected samples targeting the F gene in a study conducted in two open markets of Addis Ababa in 2022. 22 In two states of India, it was also reported that it was possible to determine the prevalence of the disease by detecting the M gene of the virus. 23,24 In this study, antibody against ND was detected in a higher proportion of the samples (68%) even though the sampled birds were not vaccinated (Table 1).…”

Intranasally Delivered Adenoviral Vector Protects Chickens against Newcastle Disease Virus: Vaccine Manufacturing and Stability Assessments for Liquid and Lyophilized Formulations

“…Even short-term stability at a high temperature, such as 37 °C, is considered important for manufacturing, handling, and distribution of vaccines in less developed areas, such as rural locations and home-based producers’ properties. These ones are the main source of poultry production in sub-Saharan countries [ 4 , 5 , 6 ]. Moreover, the functional or infectious titer was stable after storage for 16 weeks at 21.5 °C and after 24 weeks at 4 °C.…”

“…Even short-term stability at a high temperature, such as 37 • C, is considered important for manufacturing, handling, and distribution of vaccines in less developed areas, such as rural locations and home-based producers' properties. These ones are the main source of poultry production in sub-Saharan countries [4][5][6]. Moreover, the functional or infectious titer was stable after storage for 16 weeks at 21.5 • C and after 24 weeks at 4 • C. Linear regression analyses of the formulation L2 data indicated that the t1/2 for Ad-CMV-F functional titer loss at 4 • C is 94.7 months, i.e., 7.9 years, a slightly longer half-life than previous findings with the A195 formulation [27].…”

“…In sub-Saharan Africa, chickens are also farmed in small villages and rural settings by women, which are the main work force in the agricultural sector. In these settings, ND Vaccines 2024, 12, 41 2 of 21 can have devastating effects for small-scale producers, affecting their economic independence [5,6]. Immunizing poultry with inactivated or live-attenuated ND vaccines is the current prevention method; however, there are critical limitations with the supply chain of pathogen-free embryonated eggs and other disadvantages, such as possible virus shedding [7].…”

Isolation, Identification, and Whole Genome Analysis of Chicken Infectious Anemia Virus in an Outbreak of Disease in Adult Layer Hens

“…Samples were collected and processed for routine Polymerase Chain Reaction (PCR) testing, following the pooling of every 5 samples. The PCR analysis aimed to identify common poultry viruses, including Marek’s disease virus (MDV), avian influenza virus (AIV), infectious bursal disease virus (IBDV), infectious bronchitis virus (IBV), reticuloendotheliosis virus (REV), chicken infectious anemia virus (CIAV) [ 32 , 33 , 34 , 35 ]. Bacterial isolation was also conducted using a Luria–Bertani agar plate, MacConkey agar plate, and Blood agar plate.…”