Myanmar lies in the western region of mainland Southeast Asia. Agriculture is the backbone of the Myanmar economy, and poultry farming is one of the country’s major industries. In association with the recent economic development of Myanmar, the total number of raised chickens has increased over the last decade [1]. In order to provide a stable supply of poultry products, the development of farm biosecurity measures is required, and it is important that farmers and veterinarians are aware of these measures. Infectious respiratory diseases have severe impacts on the poultry industry. Avian influenza and Newcastle disease are major threats to the poultry industry, and these diseases have been reported in Myanmar [2,3,4]. Other respiratory pathogens, such as mycoplasmas and infectious bronchitis virus (IBV), have not been investigated in Myanmar, although clinical signs suggesting contagious respiratory diseases have been detected, according to local veterinarians’ observations. These diseases cause considerable economic losses worldwide, and vaccines for their prevention have been developed. It is important to determine the genotypes and/or serotypes of each pathogen circulating in Myanmar to inform vaccination programs.
Avian mycoplasmosis is caused by several pathogenic mycoplasmas. Among them, Mycoplasma gallisepticum (MG) and M. synoviae (MS) are the most impactful to the poultry industry. MG infections usually cause chronic respiratory disorders and are characterized by sneezing, coughing, and snicks as well as nasal and ocular discharges [5, 6]. MS infections most frequently occur as subclinical upper respiratory tract infections and may cause air sac disease. MS results in infectious synovitis, an acute to chronic infectious disease of chickens [5]. The co-infection by MG or MS with respiratory virus infections, such as IBV and Newcastle disease, can exacerbate the disease conditions [5]. Both MG and MS infections cause considerable economic losses in the poultry industry by reducing weight gains and meat quality in broilers, causing severe drops in egg production in layers, and increasing embryo mortality in breeders [7].
Infectious bronchitis (IB) is a severe acute disease of poultry caused by IBV, which primarily infects the respiratory tracts, with respiratory disease being the most frequent sign. In addition, IBV can infect the kidneys and reproductive tracts and consequently cause kidney damage and decrease in egg production [8]. Generally, IB is controlled by serotype-specific vaccines [9]. The identification of field isolates is necessary for appropriate vaccinations because these vaccines exhibit little cross-reactivity among different serotypes [10, 11].
In this study, we performed molecular detection of MG, MS, and IBV in chickens from poultry farms at the outskirts of three large cities in Myanmar: Mandalay and Pyin Oo Lwin in February 2018 and Yangon in May 2018. In addition, by analyzing genetic characteristics, we detected at least three genotypes of IBV existing in Myanmar. To our knowledge, this is the first report using molecular analysis to detect MG, MS, and IBV in Myanmar.