Melioidosis

Melioidosis occurs through contact with contaminated water or soil (breaks in the skin, inhalation, or ingestion). Rice farmers in Thailand are at risk for this disease. The mortality rate ranges from 15 to 40%. Horses are the primary reservoir.

CASES/YEAR
5 (US); 60,000 (Global)
CATEGORY
Sapronoses
AGENT TYPE
Bacteria
OTHER NAMES
Whitmore disease; Burkholderia pseudomallei infection;
ACUITY
Subacute/Chronic
INCUBATION
1-21 days or as short as a few hours after high dose exposure; Latent foci may reactivate years after exposure; [CCDM, p. 399]
INITIAL SYMPTOMS
Pneumonia (from mild to fulminant septic shock); Chronic lung infection (mimicking tuberculosis); Skin ulcers & abscesses; Suppurative parotitis in children in Thailand; [PPID, p. 2709] Acute to chronic & localized to disseminated infections; [Guerrant]
PRECAUTIONS
Standard; "Not transmitted from person to person." [CDC 2007 Guideline for Isolation Precautions] Rare person-to-person transmission (direct or sexual contact in 3 reported cases); [CCDM, p. 399]
COMMENTS
EPIDEMIOLOGY:
Infection occurs through contact with contaminated water or soil through breaks in the skin, inhalation, or ingestion. Rice farmers in Thailand are at risk for this disease. Some chronic diseases (diabetes, cirrhosis, alcoholism, renal failure, COPD, thalassemia, malignancy) increase the risk of contracting the disease. The mortality rate ranges from 15 to 40%. Horses are the primary reservoir; also sheep, goats, swine, monkeys and rodents; [CCDM, p. 397-400] Risk factors include diabetes, alcoholism, chronic renal disease, COPD, thalassemia, and malignancy. [CDC Travel, p. 292]

FINDINGS
These saprophytic bacteria may infect humans and other animals. About 50% of patients present with acute pneumonia. Some patients develop rapidly fatal septicemia. The disease may be confused with typhoid fever or tuberculosis. Findings may include pulmonary cavitation, empyema, chronic abscesses, and osteomyelitis. In 5% of cases in northern Australia, patients have meningoencephalitis with paralysis and weakness. [CCDM, p. 397-8] A petechial or purpuric rash may occur. Jaundice may occur in septicemic melioidosis. Leukopenia, lack of fever, azotemia, and abnormal liver function tests are poor prognostic indicators. Empyema and purulent pericarditis are complications. [Guerrant, p. 220, 956]

The disease may present as sepsis and "overwhelming necrotizing pneumonia." Other findings may include pleuritic chest pain, normal or elevated WBC count, arthritis, meningitis, septic shock, abdominal pain, diarrhea, pharyngitis, skin pustules, lymphadenitis, cyanosis, myalgias, and abnormal liver function tests. Chest x-ray findings may include pleural effusions, nodular infiltrates, cavitation, and consolidation. [Merck Manual, p. 1588] Liver and spleen abscesses are common in patients with septicemic melioidosis. Unlike TB, hilar adenopathy is not usually found in pulmonary infections caused by B. pseudomallei. Acute suppurative parotitis caused by B. pseudomallei occurs in about 1/3 of pediatric cases of melioidosis in Thailand. [Guerrant, p. 220-1] Presentations of 363 cases in Northern Australia were pneumonia (81), genitourinary (21), skin abscesses (45), soft tissue abscesses (11), neurologic (12), and osteomyelitis/septic arthritis (5). Mortality was 5% in pneumonia cases and 25% in neurologic cases. Genitourinary diseases include prostate abscesses and orchitis. Neurologic diseases include encephalomyelitis, cranial nerve palsies, brain abscesses, motor weakness, and paralysis. 11% of patients presented with chronic symptoms similar to tuberculosis (fever, weight loss, and productive cough). [PPID, p. 2709-13, Table 221.2] 1/4 of Thai patients have urinary symptoms including hematuria. [Cohen, 3rd Ed, p. 1214] Chronic pulmonary disease may mimic tuberculosis. Regional lymphadenopathy may accompany skin lesions. [Harrison ID, p. 536]
DIAGNOSTIC
Indirect hemagglutination assay (IHA) and ELISA assays are useful for ill tourist returning from endemic area, but culture is definitive test. [PPID, p. 2713]
SCOPE
Highly endemic in NE Thailand, Malaysia, Singapore, & N. Australia; [CDC Travel, p. 292] Cases reported in tropical & subtropical Asia, Australia/Pacific Islands, India, & less in Middle East, Latin America, & Caribbean; Extent in Africa not known; [CCDM]
SIGNS & SYMPTOMS
  • >fatigue, weakness
  • >fever
  • >myalgia
  • E pharyngitis
  • G abdominal pain
  • G diarrhea
  • G jaundice
  • G liver function test, abnormal
  • H anemia
  • H leukocytosis
  • H leukopenia
  • H lymphadenopathy
  • N confusion, delirium
  • N headache
  • N muscle weakness
  • R chest pain
  • R cough
  • R dyspnea
  • R hemoptysis
  • R sputum production
  • S entry wound with lymph nodes
  • S lymphadenitis, acute
  • S lymphangitis
  • S nodular lymphangitis
  • S petechiae and ecchymoses
  • S pustule
  • S skin or subcutaneous nodule
  • S ulcer of skin
  • U hematuria
  • X cystic or cavitary lesions
  • X lung infiltrates
  • X pleural effusions
  • *arthritis
  • *brain abscess or lesion
  • *cranial neuropathy
  • *encephalitis
  • *epididymo-orchitis
  • *mediastinitis
  • *meningitis
  • *osteomyelitis
  • *paralysis
  • *parotitis
  • *pericarditis
  • *pneumonia
  • *sepsis
  • *shock
  • *stupor, coma
  • *weight loss
ANTIMICROBIC

Yes

VACCINE

No

ENTRY
Inhalation, Ingestion, Needle (Includes Drug Abuse), Scalpel or Transfusion, Skin or Mucous Membranes (Includes Conjunctiva), Sexual Contact
SOURCE
Person-to-Person, Soil or Dust (Ingesting or Inhaling), Waterborne (Ingesting, Inhaling, or Swimming)
RESERVOIR
Cattle, Goats and Sheep, Horses, Monkeys, Rodents, Swine, Human
RISK FACTORS
  • Cancer patients
  • Ingest infectious agents in food/water
  • Swim in contaminated water (skin)
  • Travel to endemic area
  • Victim--air release of infectious agents
  • Walk barefooted in contaminated soil
  • Work in a medical or research lab
DRUG LINK
Merck Manual: Melioidosis
REFERENCES FOR CASES/YEAR
1. (US) 0-5 cases per year in the US; [Gorbach, p. 328]
2. (Global) 49 cases identified in UK from 1997 to 2007, most in travelers to Thailand, Bangladesh, and Australia; [Public Health England website] As high as 50 cases per 100,000 in northeast Thailand and northern Australia; Considered a disease of rice farmers in Thailand; [CCDM, p. 398] About 2000 to 5000 cases per year occur in Thailand plus another 50 cases diagnosed in Singapore and Australia; Sporadic cases in other parts of the world--may be underreported; [Guerrant, p. 219] Guesstimate: 6000 cases/year; use correction factor of 10 for reported diseases;