Haemophilus, Actinobacillus, Pasteurella Flashcards
HAEMOPHILUS (were haemophilus)
–> Characteristics
* Gram- _______, ______
* weakly ______
* Originally based on whether requires _____ or blood _____. Now based on genetic relatedness.
* Normally X factor (hemin) or V factor (NAD) coenzyme in electron transport chain for
respiration. Found in UPR, urogenital tract; will not be found in environment.
* obligate parasite of host mucosal surfaces
* each species is host specific
* taxonomy is in state of flux
negative, coccobacillus, fermentative, blood, factors
Haemophilus” spp and their host
* Avibacterium (H.) paragallinarum
* Glaesserella (H). parasuis
* Histophilus (H.) somni
Used to be haemophillus, now this.
things in red = important
What disease do you think these pigs have?
* A. Atrophic rhinitis
* B. Swine cholera
* C. Glässer’s disease
* D. Erysipelas
* E. I don’t have a clue
C
What is (H.) parasuis?
- specific for swine
- requires V (NAD) factor only.
- Nonhemolytic; does not produce an exotoxin
- More than 15 serotypes may occur, based on capsule or lipooligosaccharide
(LOS), or are untypable; usually a herd issue, which is why you want to know the serotypes.
Where do pigs with PRRS usually come from? What is the typical age of the pig? What can be seen clinically/ post mortem?
Pigs that have been infected with PRRS or are from SPF herds are particularly susceptible.
* Usually occurs in young pigs (important cause of nursery mortality; develop early on in development)
** fibrinous inflammation of serous surfaces (e.g. pleura or
joints)
“Purple ears are often a feature. Bacteria can readily be isolated from the blood and lesions at post-mortem examination. Chronic cases may be more difficult to
diagnose and may require P-M to look for joint and heart valve lesions.”
What can be seen in this image?
Glasser’s Disease (polyserositis)
What can be seen in this image?
Fibrin on paricardium and liver
What can be seen in this image?
Blood clot in trachea
What can be seen in this image?
Pericarditis;
Specific Diseases due to G. (H.) parasuis?
- Respiratory Disease
- Usually occurs in older pigs
following previous infection
(mycoplasma or virus) - Chronic pleurisy
- Differential:
- P. multocida, Bordetella,
Actinobacillus spp., others
What are the virulence factors of G. (H.) parasuis ?
Virulence Properties
* Capsule
* Lipooligosaccharide
* Adherence factors
* Membrane proteins, no known exotoxins
What are the Adherence Factors of G.(H) parasuis?
- required to colonize the host
- bacteria attach to mucosal epithelial cells
- Usually mediated through pili, LOS, or membrane proteins
What is important about the haemophilus species in terms of bacterial composition?
Lipooligosaccharide
There are no O side chains (polysaccharide) in the LPS of Haemophilus species examined, and therefore it can be called an LOS
* The Lipid A still has endotoxic properties
** Causes inflammation
* Core oligosaccharide is antigenic
What are the Compromising Factors?
* Viral Infection: associated with respiratory disease
* Stress: associated with Glasser’s disease, but not required as
newborn pigs are already compromised
The disease is predominately the result of HOST INFLAMMATION-trying to remove a pathogen it cannot
- Viral Infection: associated with respiratory disease
- Stress: associated with Glasser’s disease, but not required as
newborn pigs are already compromised
The disease is predominately the result of HOST INFLAMMATION-trying to remove a pathogen it cannot
How is Immunity to G. (H.) parasuis formed?
- Protection is usually mediated by antibodies to capsule; however,
there are at least 15 capsule types - Protective antibodies may also be made to LOS, membrane proteins,
and other somatic antigens. - Humoral immunity most important
What is the Vaccination, treatment and prevention of G. (H) parasuis ?
Make sure to get correct serotype.
Don’t necessarily need to be long lasting in the case of Glaccier’s disease
Vaccination, treatment and prevention
*Bacterins are effective against homologous serotype (and somewhat against
others), but may not be long lasting
* Attenuated live vaccine also available and effective
* Antimicrobials
* Intentional exposure at 3-5 days of age with low dose of less virulent
serotypes (RISKY)
* Protection also through maternal antibodies
What is Avibacterium (H). paragallinarum?
Avibacterium (H). paragallinarum
* Specific for avian species
* Requires V factor only
* Nonhemolytic
What diseases are Specific due to A. paragallinarum?
Fowl Coryza (acute rhinitis)
* inflammation of turbinates and sinus epithelium
* air sacculitis
* primarily a disease of chickens
What is seen here?
Depressed, discharge near beak, painful, hunched over
What is seen here?
High morbidity, but not
mortality
What is seen here?
Inflammation of air sacs
What is seen here?
Inflammation, pus
What is seen here?
Need CO2 and yellow = key characteristic
What is seen here?
TME
Eyes drooping, inflammed (key of TME)
Laying down; unwilling to get up
What is seen here?
Pneumonia
What is seen here?
Myocarditis
Acute, necrotizing myocarditis; bacteria are
in biofilm-like aggregates and adherent to venous
endothelium, with fibrin and neutrophils
What is seen here?
Filaments, fibirn material
polysa, protein, extracelluar dNA = components of biofilm.
What is seen here?
short chains; can phase vary. Can resist host defenses; host makes antibodey repsonse to Lipo, organisms cleared and those that have changed their oligo now persist.
What is seen in this image?
Third image on right = cell that does produce binding protein.
