Ten-day-old chicken embryos were inoculated with isolates of myeloblastosis-associated virus that induced osteopetrosis of slow or rapid onset. Bursa of Fabricius, thymus, spleen, bone marrow, kidney, liver, and lung were examined at 15, 17, and 19 days in ovo and at 7 and 25 days after hatching by histologic and immunoperoxidase techniques. Tissues from 19-day-old in ovo embryos also were examined by electron microscopy. The lymphoid organs of embryos inoculated with all isolates manifested changes suggesting inhibited development. Virus was most often associated with macrophages, heterophils, and non-lymphoid stromal cells in these organs. Viral particles and antigen were abundant in tissues from embryos inoculated with slow-onset isolates, but cell necrosis was infrequent. The kidney and bursa had especially abundant viral particles and antigen. Conversely, viral particles and antigen were minimal in tissues from embryos inoculated with the rapid-onset isolate, yet intravascular cellular thrombi, substantial cell necrosis, and increased heterophils and hemocytoblasts were found.

A mixed viral infection of Newcastle Disease (ND), Marek’s Disease (MD) and Avian Leukosis (AL) was reported in village chickens. Analysis of the deduced amino acid sequences of the F protein cleavage site of ND virus showed that the isolate was virulent with sequence KRRKR for the C-terminus of the F2 protein and phenylanine (F) at residue 117, the N-terminus of the F1 protein. Basic Local Alignment Search Tool (BLAST) analysis showed the isolate was ND which was 96% similar identity with Indonesia Sukorejo genotype VII, MD 99% similar identity with China very virulent strain and ALV 100% similar identity with Taiwan ALV strain. Due to the free ranging type of management, causes of the diseases in the poultry were uncertain as many factors can contribute to the disease occurrence. However, good hygiene practices can help to improve the farm’s sanitary. Basic biosecurity system can be applied although the success may be limited. Vaccination is another alternative that can be considered to prevent the diseases with the help from certain parties.