There is no specific treatment for viral infections.
These include: Coryza (Haemophilus paragalinarum) I.coryza, Mycoplasma/CRD, Pasteurella multocida- F cholera, E. coli, Streptococcosis, Chlamydiosis, Ornithobacterium rhinotracheale.
-some species were more susceptible than others (e.g. F cholera - turkeys).
-Some aspects like the age of the bird are useful in differential diagnosis (F cholera rarely in birds younger than 16 weeks of age).
It is almost impossible to arrive at a presumptive diagnosis of any of the above bacterial diseases on the basis of respiratory signs. mortality, % morbidity, presence of other clinical signs and clinical history are important for diagnosis.
Gross pathology like perihepatitis and pericarditis usually associated with E.coli are also encountered in Pastuerellosis, Streptococcosis, Chlamydiosis, CRD and Ornithobacterium rhinotracheale. Gross pathology may not be present in acute cases especially when the organism excretes endotoxins or its presence may actually be a result of secondary infection.
Clinical signs: respiratory signs ranging from runny eyes and nostrils to wheezing, sneezing, gasping, and mortality may be encountered. However, for example, the presence of significant mortality among chickens would suggest that Infectious Coryza, CRD, and possibly Chlamydiosis or Ornithobacterium rhinotrachelis are not serious contenders on the differential diagnosis list.
While a unilateral swelling of the face in chickens may indeed indicate presence of Haemophilus paragallinarum, the absence of such a swelling but presence of runny nostrils does not indicate that it is CRD or other bacterial infection in preference to Coryza.