Laboratory outbreak investigation of sudden death syndrome in broiler chicken in Kathmandu Valley, Nepal

The incidence of death of broiler birds above 40 days suddenly increased in the month of July to October 2008-2009 in Kathmandu Valley. Birds that were presented for post-mortem examination at the Central Veterinary Laboratory Tripureswor Kathmandu were usually found dead on their backs with wings out-stretched. Gross lesions recorded on post mortem examinations were muscle oedema, pulmonary, renal and liver congestion, dark black to pale yellow streaked liver bile filled gall bladder and congestive splenomegaly, blood clot in atrium haemorrhage in duodenal muscle, whitish yellow pasty fluid in proventriculus gland, greenish coloration marked intact feed particles in gizzard and swollen intestine with excessive mucous filled. Incidence rate was recorded between 1.5 to 2.5% of the flock. The mean mortality rate due to sudden death syndrome was 1.3 to 9.6%. Penicillium spp., Aspergillus spp., with colony-forming unit (CFU) ranging from 56*104-‑62*105, to uncountable mold count, Escherichia coli, Streptococcus spp. and Staphylococcus spp. were the usual organisms isolated from culture samples of liver, lung, spleen and proventriculus. The condition seems to be related to mycotoxicosis. Reduction of mortality was achieved by feed restriction, with 8 to 10% reduction in nutrient density. Supplementation of glucose containing electrolyte, liquid toxin binder, immunomodulator, acidifier and antibiotic therapy.   Key words: Sudden death syndrome, broilers, Kathmandu Valley, Penicillium, colony-forming unit, ranging from 56*104 to 62*105/g, uncountable mold count, Aspergillus, Escherichia coli, Streptococcus,Staphylococcus, liver, proventriculus.