Infectious diseases — sometimes out of sight, never out of mind

Created 4 years before the first issue of the MJA, de Trye-Maison’s lithograph (front cover) captures the sense of fear and desperation that infectious disease provoked then and still does today — consider society’s response to HIV/AIDS or the recrudescence of polio in war-torn Syria. As the Australasian Society for Infectious Diseases will soon hold its annual conference, this issue of the Journal includes articles on this theme.

While its remoteness may have spared Australia from northern hemisphere outbreaks of Clostridium difficile infection (CDI), it was inevitable that serious strains would reach our shores. But, as Johnson and Stuart note, our surveillance has paid dividends. Slimings and colleagues report that CDI, once considered mostly hospital-acquired, is becoming more common in the community, a finding similar to overseas trends.

Surveillance and vigilance are essential, although not always successful. Worth and colleagues show that continuous surveillance for Staphylococcus aureus bloodstream infection in Victorian hospitals has been effective, whereas Gunaratnam and colleagues found that screening for pandemic (H1N1) 2009 influenza at Sydney International Airport was not effective in detecting cases.

The association between risky behaviour, such as sharing needles, and bloodborne infections is well established. Reekie and colleagues report encouragingly on new prison entrants participating in the National Prison Entrants’ Bloodborne Virus Survey. Although half the participants reported injecting drug use, there was a very low prevalence of HIV, which may be due to harm minimisation programs such as access to clean needles and methadone. The most prevalent bloodborne virus was hepatitis C, but a third of those testing positive for this were unaware of their infection status.

Weakened human defences open the gate for unpleasant organisms such as Listeria monocytogenes, named after the pioneer of sterile surgery, Joseph Lister. L. monocytogenes meningitis accounts for 5%–10% of bacterial meningitis and has high mortality, perhaps due to concomitant encephalitis. Its appetite is not confined to those with poor immunity; Otome and colleagues report a case in an immunocompetent person.

We welcome reports of improvements in Indigenous health. Crowe and colleagues, working predominantly in Indigenous communities in the Northern Territory, found a decrease over 11 years in microbiologically confirmed cases of infection with Trichuris trichiura, a soil-transmitted helminth associated with poor living conditions. Deworming campaigns may have led to a reduction in the helminth egg burden. This change, when linked with better living conditions, improved sanitation and less poverty, offers hope.

In Australia, Mycobacterium ulcerans, the causative organism associated with indolent skin ulcers that complicate cuts and scratches among people living in wet conditions, was first seen in Bairnsdale, Victoria. Now, with an expanded evidence base, O’Brien and colleagues update the guidelines for its management, the main change being antibiotics as first-line therapy and a shorter duration of antibiotic treatment.

After initial infection with varicella zoster virus, T cell immunity is boosted by subsequent exposure to chicken pox. However, this natural boost has been lost since 2005, as vaccination has markedly diminished the number of childhood cases. Cunningham and colleagues discuss mechanisms and present recent evidence about the effectiveness of vaccines in preventing shingles in older age groups.

As molecular science progresses, we learn more about the intricate adaptations underpinning antimicrobial resistance. In the Asia–Pacific region, an epidemic of drug-resistant tuberculosis threatens, warn Majumdar and colleagues. They advocate for an international collaboration to bring this problem under control.

Craig Venter, known for his involvement with sequencing the human genome, wrote about molecular biological approaches to preparing for the next influenza pandemic in his recent book, Life at the speed of light. The interplay of biological and informational sciences and computing is opening doors hitherto closed. But the more we learn, and to some extent the more control we gain over infections, the greater our respect for them grows.