Pasteurella (Bontlong/Pneumonia)

PASTEURELLA   ‘Bont Long’ ‘Pneumonia’

Pasteurellosis is often used to describe the disease ‘pneumonia’ or ‘bontlong’ and occurs more commonly in late autumn and early winter.  Losses are usually 2-8% but 10-50% can show signs of the disease.

Pneumonia is a disease of complex aetiology, involving interactions between a range of micro-organisms and the immunological and physiological responses of the host. Pasteurella (Manneheimia) haemolytica is considered to be the main bacteria.

Pasteurella haemolytica is divided into 2 biotypes ( A and T) and 16 serotypes.

  • Biotype A: 1,2,5,6,7,8,9,,11,12,13,14,16
  • Biotype T: 3,4,10,15.

The dominant serotypes with pneumonia have been 6,2,1 (in that order)

Biotype T is has also now been called Pasteurella Trehalosi and further renamed Bibersteiniatrehalosi. More research  has been conducted in sheep where  Pasteurella ( Bibersteinia) multocida has 5 types A,B,D,E (type C was not a separate type so was removed).  Sheep are affected by type A or D.

Mycoplasma  ovipneumoniae, Mycoplasma arganini   and the viruses Parainfluenza virus type 3, Respiratory syncytial virus, Ovine adenovirus type 6 have also been implicated in sheep.

In goats Chlamydia psittaci  ‘Enzootic Abortion’   organisms have also been implicated as a predisposing cause.

In Angora goats less is known about the agents involved and more research needs to be done to isolate the causes of pneumonia. SAMGA will start to type cases of Pasteurella when diagnosed on Post Mortem to build up a database on pneumonia and Pasteurella in Angora goats.

The Pasteurella bacteria occurs in the normal environment of the respiratory tract and proliferation and disease consequences occur under certain predisposing factors. Not all infections result in pneumonia. At low levels of invasion a purulent lesion develops which may resolve if the body’s immune system is effective. When the antibacterial defences in the lung are overwhelmed, and bacterial proliferation occurs, the result will be pneumonia. The lesions never resolve completely and fibrous scars remain. High levels of infection may result in necrosis of the lung tissue which may lead to a septicaemia and death.

Predisposing factors:

  • Period of stress involving collection and kraaling often in dry dusty conditions
  • Panting and open mouthed breathing associated with collection and kraaling in hot conditions aids in the establishment and proliferation of the Pasteurella pathogens.
  • Shearing and stress from handling - particularly if animals are hungry.
  • Dipping (usually 4-7days later)
  • Mixing of goats from different sources
  • Young goats are more susceptible

Clinical signs:

  • Goats may just be found dead, deaths can occur within 12-24 hours of infection and  may occur for further 4-6 weeks
  • May cough especially if herded
  • Goats may lag behind flock
  • Show signs of respiratory distress and lie down
  • Fever with evidence of respiratory involvement ( dyspnoea)
  • Muco-purulent nasal discharge, lacrimation, froth at mouth
  • Some goats may become ‘poor doers’ due to fibrinous adhesions or lung abscess.

Pathology:

Acute cases:

Severe fibrinous pleurisy with adhesions between lung and thorasic wall may occur. Fibrinous exudate is often found on the pericardial sac. The lungs are dark red and solid and feel thick on palpation- mainly in the antero-ventral lobes of the lung. Haemorrhages on heart muscle wall may be seen. The liver and kidneys are congested and appear dark red.

If the head is split the nasal nasal passages are seen to be dark red to purple in colour

Chronic cases:

Grey hepatisation (‘bont long’) of the antero-ventral lobes with fibrinous adhesions

Consolidation of the anterior and ventral lobes of the lung can be seen (photo by Dr Swist).

Fibrinous adhesions between the lung and thorasic wall (photo vetnext)

Treatment:

 Long acting tetracyclines , sulphamezanthine and penicillin has helped  but treatment with antibiotics has often proven unsatisfactory. Research indicates that a follow up treatment 4-6 days later is advisable when using antibiotics to achieve better results.

Some farmers who had problems with pneumonia have found dosing ‘Pennville triple sulpha’ at a dose of 5g/litre (dosing kids 8ml and adults 24mls) during times of expected outbreaks has had an prophylactic effect.

Prevention

  • Reduce predisposing factors (kraaling, dusty conditions, chasing too hard resulting in open mouth breathing). Sprinklers have been used in kraals when working with goats to dampen and settle dust.
  • Vaccination: Has proven effective but there are studies where  limited difference in cases of pneumonia between vaccinated and unvaccinated small stock have occurred.
  • Multivax P is not liscenced for goats but probably the most widely used vaccine. Onderstepoort has a licenced vaccine with fewer serotypes.
  • It is clear that not all the Pasteurella biotypes are covered by the vaccines so research needs to be done on the Angora goat to determine the most common pathogens, biotypes and serotypes isolated to ensure the right vaccines are used or developed.

Where pasteurella is a problem on farms vaccination every 6 months after initial vaccines may be required and even then not all the Biotypes and serotypes are covered and so where deaths are still occurring due to ‘pneumonia’ identification of the pathogen needs to be done. 

VACCINE  COMPANY  COMPOSITION DOSE AGE
PASTEREURELLA VACCINE FOR SHEEP AND GOATS ONDERSTEPOORT
  • Mannheimia haemolyticatypes

               2, 5, 6, 9,

  • Bibersteinia trehalosi type 15

2ml s/c.

Repeat  after 4 weeks and again 6 months later. Then single injection yearly
From 2 week old
Multivax P  MSD
  • Mannheimia haemolyticaA and T serotypes (9 serotypes)

2ml s/c

Repeat after 4 wks

Then yearly booster 4-6 weeks before lambing 
If from vaccinated ewes then have colostrum cover for 4 weeks . If from unvaccinated ewes then can vaccinate in first week of life.
Multivax P Plus MSD
  • Mannheimia haemolyticaA and T serotypes
  • Pasteurella trehalosi

2ml s/c

Repeat after 4 weeks and then yearly booster 4-6 weeks before lambing. A booster vaccine can be given 2-3 weeks before expected  seasonal outbreak

Minimum age of 3 weeks

If from vaccinated ewes then lambs at 4 wks old
One shot Ultra 7 Pfizer
  • Mannhaemia haemolytica biotype A1
1ml s/c then repeat with  UltraChoice 7 four  weeks later and then yearly booster of one shot ultra

 

 

Other forms of Pasteurella disease:

  1. 1.       Systemic pasteurellosis

Systemic Pasteurellosis due to infection with P.haemolytica  biotype T can effect young goats between 5 months and a year. Prevalence is most common in autumn with the same predisposing causes.

The injured mucosa  of the alimentary tract (such as acidosis and brown stomach worm) can serve as an entry for the biotype T as emboli into the blood. Most emboli end up in the capillary beds of the lung. Death occurs as a result of endotoxeamia.

Clinical signs:

  • Unexpected deaths without any significant signs. The mortality rate rarely exceeds 5%

Post Mortem:

Petchiae and eccymoses in subcutis of pleura and peritoneum. Cranial, cervical and mesenteric lymph nodes are oedematous and haemorrhagic. Erosions and ulcerations of the pyloric region of the abomasum may be seen. Blood stained froth in the trachea and bronchi. The liver may show yellowish-white areas of necrosis 0.5-5mm diameter.

  1. 2.       Septicaemic  pasteurellosis

Kids under 2 months at greatest risk from P.haemolytica biotype A

Post Mortem:

Non-specific petechia on serosal surfaces, fibrinous pleuritis and pericarditis, congestion of the lungs

  1. 3.       Blue udder

Blue udder is predominantly caused by the bacteria Pateurella haemolytica but Staphlococcus aureus andCorynebacterium spp can also be implicated.  Environmental contamination is an important source of infection and distended udders are predisposed to as suckling kids cause trauma.   Kids can transmit the infection to other ewes when they try to suckle off them.   Up to 5% of ewes in a flock can be affected.    The affected udder becomes firm, swollen and reddish to bluish in colour.   Ewes can die after 2-3 days or the inflammation may subside, developing later into an abscess of the udder.  Treatment is with oxytetracycline injectable, intra-mammary treatments and stripping of the udder.   The affected part of the udder is unlikely to be saved unless treated very early in the disease course.

A Onderstepoort vaccine is availablefor use where a problem has been diagnosed.

 Dr Mackie Hobson

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