Occurrence: Mainly southern US states and in third world countries (multi-age farms).
Species affected: Chickens in cages.
Age affected: 5-30 weeks.
Causes: Gram negative, non-motile bacterium- Hemophilus gallinarum.
Effects: The organism gives off a strong odour of rotten eggs. Symptoms include watery eyes, facial oedema, diarrhoea, anorexia, and there may be a high cull rate (20%). Nasal discharge, swollen infraorbital sinus, laboured breathing, drop in egg production and poor shell quality can also occur.
Special note: It is found more commonly in developing countries on multi-age farms)and backyard flocks. Several serotypes (A-C) make successful vaccination difficult.