Obligate intracellular bacteria

Obligate intracellular bacteria of veterinary importance

genus

Chlamydia

Coxiella

Anaplasma

Lawsonia

developmental spores arthropod zoonosis cell target forms transmission

+ - - + epithelium & M

- + + + epithelium & M

- - + - M & PMNL

- - - + epithelium

Detection of intracellular bacteria

Microscopy:non-specific staining immunohistochemistry

(antigen detection)

Immune responses: antibody or CMI

Genomic detection:PCR

Culture: co-culture with eukaryotic cells

Chlamydiae as animal pathogens

Chlamydia spp.Chl. trachomatis human ocular and urogenital Chl. muridarum mouse respiratory infectionChl. suis porcine pneumonia, enteritis,

conjunctivitis

Chlamydophila spp.Cp. pneumoniae human, horse, koalaCp. pecorum ruminants, pigs, koalas - multisystemCp. caviae guinea pig conjunctivitis/pneumonitisCp. psittaci avian - multiple serovarsCp. abortus ruminant abortion Cp. felis cat conjunctivitis, rhinitis

Potential ZOONOSES

Chlamydia/Chlamydophiladevelopmental phases

Elementary Body (EB):300-500nm infective stagespore-likeresistant to environmental stresses

Reticulate Body (RB):~2000nmnon-infective replicative stagebinary fission

host cell lysis

Elementary Body (EB)

Chlamydia/Chlamydophila infection

adherence to cell membrane

entry by endocytosis

prevention of phagosome-lysosome fusion

transformation of EB to Reticulate Body (RB)

division - formation of "inclusion"

differentiation to EB

ingestion/ inhalation

localisation to tonsils/lymph nodes

dissemination

latent, persistent or intermittent infection

placentitis

foetal infection

abortionstillbirth

weak lambssubclinically infected lambs

Chlamydophila abortus

Chlamydophila abortus

Enzootic Abortion of Ewes (EAE) /

Ovine Enzootic Abortion (OEA)

Antibiotic treatment – tetracyclines Closed flocks / OEA-free accreditationVaccines: Mediavac,

Enzovax, Cevac Chlamydophila

ZOONOSIS: respiratory & abortion

1st exposure ~30% abort 2nd exposure ~5% abort

young/ stressed

- acute, generalised disease

- multisystemic inflammation

(air sacs, lung, intestine, pericardium)

- discharges, depression, inappetance, diarrhoea

- dissemination to spleen, liver, kidneys

- up to 90% mortality

convalescent carriers

Avian Chlamydiosis - Cp. psittaciPsittacosis, Ornithosiswidespread in birds

adult birds

- usu. asymptomatic, persistent

ZOONOSIS

Feline Chlamydiosis - Cp. felismucopurulent conjunctivitis & rhinitis

highly infectious

ZOONOSIS

Zoonotic ChlamydiosisFever Chills Headache Muscle aches Dry coughmalaisepneumoniaendocarditis/meningitisAbortion

Avian source: 1620 casesFeline source: rareOvine source: rare

A. phagocytophilum Tick-Borne Fever neutrophil

E. canis Canine Ehrlichiosis monocyte

E. chaffeensis Canine & Human Ehrlichiosis neutrophil

E. risticii Potomac Fever enterocyte

Anaplasmoses / Ehrlichioses

Anaplasma spp. & Ehrlichia spp.

ARTHROPOD-BORNE

GEOGRAPHICALLY RESTRICTED

Anaplasma phagocytophilum

Pathogenesis of Tick-borne fever - TBF

tick haemolymph

inoculation by tick bite

infection of PMN

tick pyaemia (S. aureus)louping ill

neutropaenia

fever, abortion

2° infections

Anaplasma phagocytophilum - morulae

asymptomatic in ruminants

Coxiella burnetti - Q Fever

?? occ. abortion

excreted in urine, faeces, milk, placenta

inhalation by human

infects respiratory epithelium, endothelium & phagocytes

influenza-like syndrome pneumonia endocarditis

ZOONOSIS

(previously Bacillus piliformis)

intracellular; Gram-negative; spore-forming; obligate anaerobe

phylogenetically Clostridium

mice; foals, cats, dogs 50-100% fatal

colonises enterocytes enteritis

relocalises to LN lymphadenitis

relocalises to liver necrosis

Tyzzer's Disease - Clostridium piliforme