A deadly bug that wears many veils

By Carol Aloysius

It goes by many names and hides under many cloaks. In Sri Lanka it is sometimes referred to as Whitmore’s disease after the first case of Melioidosis was reported in 1927 in a sixteen-year-old European tea broker resident in Sri Lanka, by well known pathologist Alfred Whitmore and his assistant C. S. Krishnaswami. The case made history as it was not only Sri Lanka’s first published case of the disease: it was the first in the entire sub continent.

Since then the disease has regularly manifested itself especially after heavy rains and landslides such as we are now experiencing. However of late, the deadly bug that takes cover under many identities has appears to have surged to alarming levels, as Government Epidemiology Unit (GEU) figures prove. It has also claimed a shockingly high number of lives despite interventions being put in place. A glance at the confirmed figures for just the past five years will show you just how high that jump has been; In 2011 there were six confirmed cases islandwide, with a marginal reduction of one the following year. However by 2013, the confirmed cases doubled at ten and in 2014 more than doubled to 23. By 2015, 65 persons had been confirmed as having Melioidosis, with the stage set for a further spike this year judging from the current figure of 28 for the first five months from January to May 2016.

The bacteria also carry with it a sinister threat that can harm mankind. It could be a potential agent for biological warfare and biological terrorism, scientists have warned.

What is this bug that can change its identity to the extent that it can mislead clinicians in their diagnosis and so prevent early correct diagnosis and treatment to cure the patient? Is it infectious? What causes it in the first place?

Epidemiologists responded to questions by the Sunday Observer on this little known disease, with data sourced from the Epidemiology Unit, Health Ministry.

Excerpts …

The disease, they explained, was caused by a bacterium known by a j tongue twisting medical term: Burkholderia pseudomallei-Gramnegatgive oxidase positive bacillus. And Yes, it is infectious and appears in the list of notifiable and commiunicable diseases, they said and is similar to glanders disease, which is passed to humans from infected domestic animals. Melioidosis is most frequently reported in Southeast Asia and Northern Australia. It also occurs in South Pacific, Africa, India, and the Middle East. Although Sri Lanka is not considered as a country where melioidosis is endemic, an increasing number of cases have been reported recently,” they said.

So how is the disease transmitted? Where is the bacteria usually found and at what specific times of the year does it spike, we asked.

The bacteria, they explained, are found in contaminated water and soil and spread to humans and animals through direct contact with the contaminated source. The bacterium that causes the disease is found in the soil, rice paddies, and stagnant waters of the area.

Can people acquire it? If so how?

“ People acquire the disease by inhaling dust contaminated by the bacteria and when the contaminated soil comes in contact with abraded (scraped) area of the skin. Infection most commonly occurs during the rainy season”, they said.

Where does it hide? What are the places that it thrives most?

“In contaminated water and muddy soil, after heavy floods and landslides”.

Symptoms?

“Melioidosis symptoms most commonly stem from lung disease where the infection can form a cavity of pus (abscess). The effects can range from mild bronchitis to severe pneumonia. As a result, patients also may experience fever, headache, loss of appetite, cough, chest pain, and general muscle soreness. The effects can also be localized to infection on the skin (cellulitis) with associated fever and muscle aches. It can spread from the skin through the blood to become a chronic form of melioidosis affecting the heart, brain, liver, kidneys, joints, and eyes”.

To our question, “Are persons with pre-disposed illnesses like diabetes more vulnerable to the disease?

People with Diabetes mellitus, renal disease, liver disease or alcoholism are most likely to get the severe form of the infection. Melioidosis can be spread from person to person as well, they added.

Diagnosed

How is the disease diagnosed?

“A diagnosis of B. pseudomallei infection requires both clinical suspicion and supporting laboratory evidence. The variety of clinical manifestations of infection makes melioidosis difficult to

diagnose clinically. The definitive diagnosis depends on the isolation and identification of B. pseudomallei from clinical specimens. (blood, urine, sputum, or skin-lesion sample. )”

What happens when there is a delay in diagnosis ?

“A delay in diagnosis can be fatal, since empirical antibiotic regimens used for suspected bacterial sepsis often do not provide adequate coverage for B. pseudomallei. Guidelines for empirical treatment of community-acquired pneumonia in endemic regions recommend the administration of antibiotic agents with activity against B. pseudomallei in patients with risk factors for melioidosis. Laboratory procedures for maximizing the culture and identification of B. pseudomallei have been developed, but a delay in the identification of B. pseudomallei or a misidentification as another species is not uncommon in laboratories that are unfamiliar with this organism.

A direct polymerase-chain-reaction assay of a clinical sample may provide a more rapid test result than culture, but the assay is less sensitive, especially when performed on blood. Serologic testing alone is inadequate for confirming the diagnosis, especially in endemic regions where the background seropositivity rate can be more than 50%.”

How long is the treatment procedure usually?

The treatment of melioidosis consists of an intensive phase of at least 10 to 14 days of ceftazidime, meropenem or imipenem administered intravenously, followed by oral eradication therapy, usually with trimethoprim–sulfamethoxazole (TMP-SMX) for 3 to 6 months. Carbapenems, such as meropenem and imipenem, have lower minimum inhibitory concentrations and superior results in in vitro time-kill studies than ceftazidime, but a randomized comparative study in Thailand did not show a survival advantage of imipenem over ceftazidime. The current recommendation for the oral phase of therapy is TMP-SMX, which replaces the previous recommendation to give this medicationin conjunction with doxycycline. A careful search for internal-organ abscesses is recommended, such as with the use of computed tomography or ultrasonography of the abdomen and pelvis. Adjunctive therapy for abscesses includes drainage of collections and aspiration and washout of septic joints.

Prevention

An important question on everyone’s lips at present is how it can be prevented. Are there certain guidelines as in other diseases like Rat fever which it mimics?

Melioidosis is potentially preventable, but there is no evidence base for the development of guidelines for prevention.

Although it has been recommended that people with cystic fibrosis be warned about traveling to areas where melioidosis is endemic, no advice is given to tourists in general, despite the steadily increasing number of cases in returning travelers, many of whom have diabetes.

It is recommended that people with risk factors such as diabetes or immunosuppressive therapy stay indoors during periods of heavy wind and rain, when aerosolization of B. pseudomallei is possible.

Since the disease also mimics TB and other respiratory diseases, can it be transmitted from human to human through respiratory spread?

There is no evidence to support direct human-to-human transmission through respiratory spread.

Is there a vaccine against it?

“A human vaccine is currently not available for melioidosis, But this is an active area of research in animal models involving the use of live attenuated, subunit, plasmidbased

DNA and killed whole-cell vaccine candidates. No vaccine candidates have been associated with sterilizing immunity.”

What Microbiologists had to say…

The Sunday Observer also spoke to two Microbiologists to find out more about the microbiological aspect of the disease.

Microbilogist General Hospital Dr Mrs G. Patabendige said patients with Meliodiosis were often detected at the General Hospital . “ We have had quite a number of patients who have been positively diagnosed with the disease, both microbiologically and clinically. Many of them have recovered . The disease is curable if detected early and treated early.”

She stressed microbiological diagnosis and a high clinical suspicion must be present for a correct early diagnosis, “The patient’s compliance is also very important because this is a long term therapy”,, she noted. She agreed that diabetes and other predisposed conditions were also risk factors due to the lowered immunity of the patient.

Consultant Microbiologist at the Central Hospital, Dr. Maya Atapattu said,

“The task of a Microbiologist is to isolate the organism responsible for the disease. Any qualified microbiologist can do this in a hospital setting. But the problem is that most people don’t suspect they have the disease and often can miss it.

It is thus important that everyone especially persons in high risk jobs like cleaning drains, or paddy farmers, or living in landslide prone areas which get muddy after rains, need to have is a high index of suspicion. And be constantly alert for possible symptoms. If they have any suspicious symptoms, they must not waste any time but immediately seek a qualified Western doctor’s advice or go to the nearest hospital..

They must also take with them their full medical history so that the physician examining them will have the complete picture before prescribing any medications”