Vietnam: What is Melioidosis? Clinical and subclinical signs Melioidosis

Vietnam: What is Melioidosis? Clinical and subclinical signs Melioidosis (Image from Internet)

1. What is Melioidosis?

According to the Guidelines issued with Decision 6101/QD-BYT in 2019, Melioidosis is a human and animal infectious disease caused by the bacterium Burkholderia pseudomallei. The bacteria live in contaminated soil and water and primarily enter through the skin. The disease is common in Northern Australia and countries in Southeast Asia. In Vietnam, the first case was recorded in 1925, and the disease has since appeared in various localities nationwide and has been increasing in recent times.

The disease has very diverse clinical manifestations, is difficult to diagnose, and has a high mortality rate in severe pneumonia, septicemia, and septic shock cases. People with underlying conditions (diabetes, liver disease, kidney disease, chronic lung disease, etc.) are at high risk of contracting the disease.

2. Clinical and subclinical signs Melioidosis

The clinical and subclinical signs of Melioidosis according to the Guidelines issued with Decision 6101/QD-BYT in 2019 are as follows:

* Clinical

The incubation period ranges from 1 to 21 days, which can be prolonged and difficult to determine. B. pseudomallei infections can be latent and reactivated similar to tuberculosis.

- Acute form

+ Common clinical manifestations

++  Pneumonia  is  the  most  common  form,  with  clinical  manifestations  similar  to  community-acquired  pneumonia  caused  by  other  pathogens.  Patients  have  high  fever,  shaking  chills,  productive  cough  with  purulent  sputum.  Lesions  can  progress  to  necrotizing  pneumonia  leading  to  respiratory  failure,  septic  shock.

++  Septicemia  is  also  a  common  form,  which  may  not  have  an  identifiable  entry  point,  and  can  easily  progress  to  septic  shock,  multi-organ  failure  causing  death.

+ Less common clinical manifestations

++  Intra-abdominal  abscesses:  liver  abscess,  spleen  abscess,  psoas  abscess.

++  Skin  and  soft  tissue:  non-specific  diverse  lesions  such  as  skin  ulcers,  subcutaneous  abscesses,  scattered  pustules,  cellulitis,  fasciitis,  muscle  abscesses.

++  Genitourinary:  Pyelonephritis,  prostatitis,  prostate  abscess.

++  Bones  and  joints:  Osteomyelitis,  septic  arthritis.

++  Nervous  system:  purulent  meningitis,  brain  abscess,  meningoencephalitis.

++  Cardiovascular:  pericarditis,  aneurysm.

++  Parotid  gland  abscess  or  purulent  inflammation.

++  Lymphadenitis.

- Subacute and chronic forms

Clinical manifestations are often seen in the lungs and skin.

+ In the lungs, lesions create cavities. Patients have fever, productive cough with purulent or bloody sputum, weight loss, night sweats. The clinical presentation mimics pulmonary tuberculosis.

+ On the skin, lesions are granulomas, non-healing skin ulcers.

- Clinical manifestations in children

Clinical manifestations may differ from adults. Pneumonia, septicemia forms can occur but are not common. Instead, skin lesions or purulent inflammation, parotid gland abscesses are frequently seen.

* Subclinical

- Microbiological tests

+ Requires multiple cultures to find B. pseudomallei with appropriate specimens (blood, cerebrospinal fluid, abscess pus, skin lesions, pleural fluid, sputum, throat swabs, etc.).

+ PCR testing can be applied to sputum, pus, urine specimens.

- Other tests

+ Blood leukocyte test often shows increased neutrophil count.

+ Hematology, biochemistry tests: help detect organ dysfunction such as liver failure, kidney failure, respiratory failure, coagulation disorders, etc.

- Imaging diagnosis

+ Chest X-ray: pneumonia lesions are very diverse such as interstitial pneumonia, lobar pneumonia, bronchopneumonia, or lesions similar to tuberculosis.

+ Ultrasound, computed tomography, magnetic resonance imaging help detect and diagnose sites of infection and abscesses.

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