Pneumonic Pasteurellosis and Streptococci

Causal agent	Pasteurella multocida and various species of streptococci, typically Strep. suis. Both are bacteria. Note toxigenic forms of P. multocida are associated with Infectious Progressive Atrophic Rhinitis.
Age group	Clinically affects the growing and finishing pig
Clinical signs
	Generally represents the final stage of the post-weaning respiratory syndrome
Acute form	This is most commonly associated with P. multocida serotype B. The animal presents with dyspnoea, laboured breathing, thumping, high fever 42.2•C (108•F) prostration and finally death. Purple discoloration of the abdomen is not uncommon.
Subacute	Pleuritis, coughing, difficulty in breathing. In chronic cases the pig can lose a lot of weight. The pigs may have only poor or no growth with serious consequences in pig flow.
Chronic	Occasional cough, thumping and little or no fever. Generally affects pigs from 10-16 weeks of age (25-50 kg)
A pig with chronic pneumonia, where pasteurella and streptococci were playing a role in killing the pig.		Nearly all of these pigs will be carrying pasteurella and streptococci in their noses.
Infectivity
	Piglets are infected with streptococci from the sow within hours of birth, some may be infected intrauterine. Pasteurella may be acquired within 5 days of birth.
	The bacteria are very common and probably a normal inhabitant of the pig's nasal flora
	Nose to nose contact most common route of infection
	Aerosol infection is possible.
	Rodents may carry or transmit pasteurella
	The disease may be spread around the body via the blood stream after tail biting or feet damage.
Stress factors
	All the normal stress factors involved in the post-weaning respiratory complex with draughts, chilling, damp environment, overstocking, mixed age groups and moving pigs are classic stressors.
Incubation period
	The disease can be very quick as the organisms may be already established in the pig.

Post-mortem Lesions
	Generally part of the enzootic pneumonia complex with and superimposed on, the lesions resulting in cranial consolidation. Severe cases may also present with pleurisy and abscessation. Note pasteurellosis in association with other viral agents in particular PRRSv or Swine Influenza virus can produce lesions closely resembling Mycoplasma hyopneumoniae (Enzootic pneumonia) even on M. hyopneumoniae negative herds. Note similar lesions may also occur associated with lower water availability and high ammonia concentrations. Also note any foot lesions or evidence of vice where haematogenous spread may occur.
Post-mortem findings
	Pasteurella and streptococci are commonly isolated from cases of enzootic pneumonia	Streptococci are commonly associated with pulmonary abscessation
Diagnosis
	Isolation of the organism. Note this can be complicated by the fact that both pasteurella and streptococci are very common in the respiratory tract. Also isolation can be complicated by concurrent antibiotic therapies. The isolation of pasteurella and streptococci does not mean they were the causes of the problem. However, they would have been significant in the animal's death.
Treatment
Individual	Antimicrobial agents, however, combinations are often required as the pathogens are rarely a primary agents and may be multiple types
	Vaccination against Mycoplasma hyopneumoniae has significantly reduced the effects of pasteurellosis.
Control	All-in/all-out
	Ventilation – avoid draughts and high ammonia concentrations
	Avoidance of temperature fluctuations
	Stocking rate controls
	Reducing other causes of pneumonia and other respiratory conditions
	Minimal mixing and sorting
	Reducing building and pen size
	Enhance drinking water supplies
Vaccination	Generally disappointing
Common differentials
	Actinobacillus pleuropneumonia, Salmonella choleraesuis. Enzootic pneumonia. Most other respiratory diseases. Water limitations and high ammonia concentrations. Note foot lesions and vices.
Zoonotic implications
	None specifically, although both Pasteurella spp. and streptococci spp. may be pathogenic to man