156. Glanders and melioidosis (Zoon.). Flashcards
Glanders Occurence aetiology and epidemiology?
_1) Glanders (Malleus, Farcy, Rotzkrankheit) ʹ *NOTIFIABLE* - Zoonotic!_
Occurrence:
- Susceptible: Equidae, Felidae, dog, camel (donkeys, mules more susceptible than horses)
- Asia, Africa, South America, Hungary is free from 1956
Aetiology:
- Burkholderia mallei (used to be Pseudomonas mallei)
- Close relationship to B. pseudomallei
- Low resistance (lower than Pseudomonas) ʹ kill with disinfectants & heattreatment
- Discharges contain lots of water: prevents dehydration of the bacterium ʹ survive in environment for long time
Epidemiology
- Introduced by carrier animals
- Infection: discharge (nasal, ruptured nodules), feed, water, contact, shared trough, utensils, poorhygiene
- Discharge drops into the water : consumed by other animals
- High animal density helps spreading
Pathogenesis of glanders?
Pathogenesis
- Mainly PO (aerogenic) infection
- -> colonise and replicate in the pharynx
- -> lymph vessels
- -> Lns-> blood
- Spread to organs: lung, nose, skin (lymphatic vessels, LNs)
- Granulomas: necrosis, suppuration, demarcation with CT, ulceration, star-shaped cicatrices
- (CT fibres contracted -scar)
- Remain carriers
Clinical signs of Glanders?
Clinical signs
- Horse (least susceptible species)
- Chronic disease (can be asymptomatic),
- incubation at least 2 weeks- several months
- Sometimes general CS: Anorexia, fever, weakness
- Nose:
- Serous, sticky mucous-purulent discharge, blood
- Nodules, ulcers (like crater), star-shaped cicatrices
- Lung: cough, nasal discharge
- Skin:
- Nodules, ulcers, mucoid nasal discharge
- Enlarged lymph nodes (cannot be moved ʹ due to prolif of CT)
- Donkey, mule (more susceptible):
- acute disease - septicaemia, Pneumonia -> death
- Camel: mucous nasal discharge, ulcer (not as fast as donkey/mule, faster than horse)
- Cats: Infected when eat meat of horses that died of glanders
- Acute septicaemia
- Pneumonia, enteritis, conjunctivitis
- Purulent-haemorrhagic nasal discharge
- Nose: granulomas, ulcers
Pathology of Glanders?
Pathology
- Nose: granuloma, ulcer, cicatrices
- Pneumonia:
- Proliferative: granulomas isolated by CT surrounding (less susceptible animals e.g. horse, cat)
- Exsudative: necrosis, cavern (more aggressive ʹ more susceptible sp. e.g. donkey)
- Generalised malleus: Parenchymal organs, LNs - focal inflammation, necrosis, purulent granulomas
Diagnosis of Glanders?
Diagnosis
ͻ Diagnosis of the disease
- Epidemiology ʹ clinical signs - pathology
- Detection of the agent: bacterium isolation (no special demands),
- PCR, IF, Western Blot, (animaltrial now replaced by PCR)
- confirm diagnosis using 2 methods e.g. isolation + PCR
- Detection of antibodies (in case of horse ʹ chronic disease) - serology: complement fixation test, ELISA,
- immunoblot
- Diagnosis of infection ʹ cross reaction with B pseudomallei
- Allergic tests: mallein tests (PPD) ʹ extract from bacterium
- A) Eye: 0.2 ml drop on conjunctiva of 1 eye (compare with other), 8-12h, 16-24h(repeating!)
- x +ve case = purulent conjunctivitis
- B) Skin (intradermal): 0.1 ml: neck/lower eyelid, 24h- 48hr 5mm > increase of thickness
- Serology: CFT, ELISA, immunoblot
Differential diagnosis, treatment , Prevention , Control eradication public health aspects of glanders?
Differential diagnosis:
- strangles (enlarged LNs can be moved),
- ulcerative lymphangitis (C. pseudotuberculosis no resp CS/lesions in nose),
- epizootic lymphangitis (Histoplasma farciminosum ʹ tropical areas, recognise fungi in smear)
Treatment
- Glanders free area: stamping out (no treatment!)
- Endemic area
- Wide spectrum antibiotics: doxycycline, gentamicin, ceftazidime (thick cell wall)
- long and high dose
- Remain carriers
Prevention
- Control of animal import from infected countries
- Import of animals from infected countries (horse race, exhibition):
- quarantine, laboratory diagnostics
- There are no vaccines
Control
- Killing ill and infected animals
- Regular serological examinations (moving animals ʹ yearly; non-moving animals ʹ every 3rd year)
Eradication: selection (test and slaughter)
Public health aspects
- Humans are moderately susceptible
- Occupational disease: veterinarian, farmer, slaughter house worker
- Infection: aerogen, PO (raw horse meat), conjunctiva, wound
- Local suppuration
- Generalisation: fever, depression, pneumonia, dyspnoea
- Antibiotics are effective: doxycycline, fluoroquinolones (if diagnosed at right time)
- Personal protective methods ʹ use a mask to examine animals
- Biological weapon, bioterrorism
Melioidosis Occurence
Melioidosis - Zoonosis
Occurrence:
- tropical/warm areas - diagnosed in S.E Asia, sporadic importation to Europe
Aetiology: B. pseudomallei
- Habitat: wet soli (mud), water
- Susceptible: swine, cattle, sheep, goat, horse, camel (pigs carry infection frequently), human
- Facultative pathogen
- Epidemiology
- Predisposing factors:
- stress, rainy season, warm weather
- Doesn’t spread from animal to animals
Pathogenesis, clinical signs and diagnosis?
Pathogenesis
Infection:
- soil
- aerogenic, PO, skin
- Septicaemia
- Abscesses: parenchymal organs, brain
Clinical signs:
- Acute: variable, fever, depression, purulent nasal discharge, cough, dyspnoea
- Chronic: variable, respiratory signs, dyspnoea, diarrhoea, CNS: ataxia, circling
- Pathology:
- abscesses (lung, spleen, liver, kidney, brain, nose), purulent inflammation
Diagnosis
- Epidemiology ʹ clinical signs ʹ PM lesions
- Detection of the agent: isolation of the bacterium, PCR
- Detection of antibodies: CFT, ELISA ʹ cross with B. mallei
treatment prevention and public health aspects of meloidiosis?
Treatment:
- antibiotics - wide spectrum (thick cell wall of bacteria),
- large doses,
- long lasting treatment (need time for
- the AB to diffuse into the lesions)
Prevention
- Endemic area: prevention of soil infection
- Disease-free area: stamping out
Public health aspects
- zoonosis (diagnosed in the Vietnam war)
- Infection from: soil, water, infected animals, wound, PO, aerogen, skin
- Subclinical infection can occur (asymptomatic carriage)
- Predisposing factors: exhausting work, stress, chronic diseases
- Acute septicaemia: fever, depression, anorexia
- Different clinical signs: fever, pneumonia, dyspnoea, diarrhoea
- Antibiotic treatment: large doses, long treatment