156. Glanders and melioidosis (Zoon.).

Question 1

Glanders Occurence aetiology and epidemiology?

Answer 1

_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

Question 2

Pathogenesis of glanders?

Answer 2

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

Question 3

Clinical signs of Glanders?

Answer 3

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

Question 4

Pathology of Glanders?

Answer 4

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

Question 5

Diagnosis of Glanders?

Answer 5

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

Question 6

Differential diagnosis, treatment , Prevention , Control eradication public health aspects of glanders?

Answer 6

Differential diagnosis:

1. strangles (enlarged LNs can be moved),
2. ulcerative lymphangitis (C. pseudotuberculosis no resp CS/lesions in nose),
3. 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

Question 7

Melioidosis Occurence

Answer 7

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

Question 8

Pathogenesis, clinical signs and diagnosis?

Answer 8

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

Question 9

treatment prevention and public health aspects of meloidiosis?

Answer 9

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