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 42.2C (108F) prostration and finally death. Purple discoloration of the abdomen is not uncommon.


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.


Occasional cough, thumping and little or no fever. Generally affects pigs from 10-16 weeks of age (25-50 kg)

Resp weaners past 2


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.


Respiratory nose

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

Enzootic pneumonia detail

Respiratory  abscesses multiple

Pasteurella and streptococci are commonly isolated from cases of enzootic pneumonia

Streptococci are commonly associated with pulmonary abscessation



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.



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.



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


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