Malaria may soon be detected with a simple breath test

Source: CSIRO. Tests such
as this one, which captures
exhaled breath for chemical
analysis, may soon be used to
detect malaria.

Australian scientists at CSIRO, QIMR Berghofer Medical Research Institute and the Australian National University have made a significant discovery that could lead to a simple and quick "breath test" for malaria. Current malaria diagnosis techniques focus on using microscopes to look for parasites in blood, using a method discovered in 1880. 

The researchers looked at the breath of volunteers who had been given a controlled malaria infection as part of existing studies to develop new treatments, and found that the levels of some normally almost undetectable chemicals increased markedly in the breath of the volunteers during the malaria infection.

"What is exciting is that the increase in these chemicals were present at very early stages of infection, when many other methods would have been unable to detect the parasite in the body of people infected with malaria," Dr Stephen Trowell, Research Group Leader at CSIRO said.

"In addition to its potentially better sensitivity, human breath offers an attractive alternative to blood tests for diagnosing malaria."

The study, published in the Journal of Infectious Diseases, was conducted in two independent studies where experimental drug treatments were being tested in volunteers who had been given a very small dose of infection.

Using a sophisticated analytical instrument, the researchers identified four sulphur-containing compounds whose levels varied across the time course of the malaria infection.

"The sulphur-containing chemicals had not previously been associated with any disease and their concentrations changed in a consistent pattern over the course of the malaria infection," Professor James McCarthy, Senior Scientist in Clinical Tropical Medicine at QIMR Berghofer said. "Their levels were correlated with the severity of the infection and effectively disappeared after they were cured."

"Now we are collaborating with researchers in regions where malaria is endemic, to test whether the same chemicals can be found in the breath of patients," Dr Trowell said.

"We are also working with colleagues to develop very specific, sensitive and cheap 'biosensors' that could be used in the clinic and the field to test breath for malaria."
In 2013, according to the WHO, there were almost 200 million cases and over half a million deaths due to this disease.

What we now know about ebola

Source: WHO.

Update: As of October 20, two nurses who had cared for the index patient have caught ebola. There are allegations that the hospital was not properly prepared for the case, and they did not have proper equipment while they looked after him.

Update: The news broke on October 11 and 12 that a nurse who had cared for the first (index) case of ebola in the US had caught ebola herself. It is worrying because she had worn the full hazmat gear in caring for the patient, and that she cannot remember committing any breach of security, unlike a nurse in Spain who said she had accidentally touched her face with a gloved hand. The US Centers for Disease Control and Prevention is firm that some breach of 'protocol' did occur; the question is where, or whether ebola is not well-understood enough.

The World Health Organization shared a list of ways in which the ebola virus may be transmitted on 6 October. While it's known that the virus is transmitted among humans through close and direct physical contact with infected bodily fluids, the most infectious are blood, faeces and vomit, the WHO said.

The virus has also been detected in breast milk, urine and semen. In a convalescent (recovering) male, the virus can persist in semen for at least 70 days; one study suggests persistence for more than 90 days. This implies that the virus can remain in semen for a longer period, but it remains unclear whether the virus can be transmitted through this method.

WHO also says that saliva and tears may also carry some risk of infection. However, the studies implicating these additional bodily fluids were extremely limited in sample size and the science is inconclusive. In studies of saliva, the virus was found most frequently in patients at a severe stage of illness. 

The whole live virus has never been isolated from sweat. This implies that sweat from a victim cannot transmit the virus.

The ebola virus can also be transmitted indirectly, by contact with previously contaminated surfaces and objects. The risk of transmission from these surfaces is low and can be reduced even further by appropriate cleaning and disinfection procedures.

Ebola virus disease is not an airborne infection. Airborne spread among humans implies that you can catch the virus from inhaling a suspended cloud of small dried droplets. This mode of transmission has not been observed during extensive studies of the ebola virus over several decades.

Theoretically, bigger droplets from a heavily infected individual, who has respiratory symptoms caused by other conditions or who vomits violently, could transmit the virus – over a short distance – to another nearby person. This could happen when virus-laden droplets are directly propelled, by coughing or sneezing (which does not mean airborne transmission) onto the mucus membranes or skin with cuts or abrasions of another person.

However, observation to date is that the spread of the virus via coughing or sneezing is rare, if it happens at all. Epidemiological data emerging from the outbreak are simply not consistent with the pattern of spread seen with airborne viruses, like those that cause measles and chickenpox, or the airborne bacterium that causes tuberculosis.

WHO is not aware of any studies that actually document this mode of transmission. On the contrary, good quality studies from previous ebola outbreaks show that all cases were infected by direct close contact with symptomatic patients.

There are also fears that the disease could change its mode of transmission. The WHO says scientists are unaware of any virus that has dramatically changed its mode of transmission. Speculation that ebola virus disease might mutate into a form that could easily spread among humans through the air is just that: speculation, unsubstantiated by any evidence.

For example, the H5N1 avian influenza virus, which has caused sporadic human cases since 1997, is now endemic in chickens and ducks in large parts of Asia. That virus has probably circulated through many billions of birds for at least two decades. Its mode of transmission remains basically unchanged.

The WHO is calling for more to be done to implement – on a much larger scale – well-known protective and preventive measures. Abundant evidence has documented their effectiveness, it says.

WHO downplays possibility of global ebola epidemic

The World Health Organization (WHO) provided an overview of the spread of Ebola virus disease (EVD) in West Africa on 11 August and stressed that in countries with well-developed health systems, an epidemic is highly unlikely "given the epidemiology of the Ebola virus and experiences in past outbreaks".

The organisation noted that fear has led to a very high level of vigilance and clinical suspicion worldwide, stating that "such a high level of alert further increases the likelihood that any imported case will be quickly detected and properly managed, limiting onward transmission."

On the downside, the WHO observes that the same fear is compromising outbreak control when it causes airlines to refuse to transport personal protective equipment and courier services to refuse to transport properly and securely packaged patient samples to a WHO-approved laboratory.

Facts about Ebola

• The Ebola virus is highly contagious, but is not airborne. 
• Transmission requires close contact with the bodily fluids of an infected person, as can occur during health-care procedures, home care, or traditional burial practices. 
• The incubation period ranges from two to 21 days, but patients become contagious only after the onset of symptoms. As symptoms worsen, the ability to transmit the virus increases. As a result, patients are usually most likely to infect others at a severe stage of the disease, when they are visibly, and physically, too ill to travel. 
• There is no cure. 
• Early detection and supportive care greatly improve prospects for survival. 

Read about the WHO announcement of the gravity of the EVD situation here, and how India and Singapore have prepared for the disease.