With border restrictions easing, travel within Australia at Christmas will be popular. We cannot predict COVID transmission, but vigilance and ongoing community engagement will hopefully control outbreaks. It is interesting that widespread hand hygiene and social distancing have reduced other respiratory viruses and gastroenteritis presentations to extremely low levels.

The lack of overseas travel makes Australians safer from ‘Bali-belly’, but Australia is the country where seemingly every bush critter either bites, stings or wants to eat you.

Dr Astrid Arellano, Infectious Disease Physician, Subiaco

Crocodiles hunt any animal within their territory, humans included, and although attacks are uncommon, they’re frequently fatal. In one non-fatal case, an attempt to ‘ride’ an adult saltwater crocodile resulted in a bite with a femoral compound fracture and a poly-microbial infection (Aeromonas, Clostridium, Enterococcus, Proteus and Pseudomonas species). This case is a warning not to ‘mess’ with saltwater crocs and a reminder of the dangers of excessive alcohol consumption.

Fig.2 Arthropod bite. Day 1, day 14 and day 25 after an arthropod bite (confirmed on histopathology). Culture negative resolved without treatment. (Photography courtesy of Mr. Craig Cooper).

Fig.1 Australian climatic zones, the predominant endemic arboviruses of human health significance that occur in those regions. http://www.bom.gov.au/climate/averages/maps.shtml (accessed 9 February 2018)

In the top end we find an endemic, gram negative, spore-forming and dry-resistant organism: Burkholderia pseudomallei. It causes Melioidosis, a cause of community acquired pneumonia, septicaemia and muscle abscesses reaching peak levels after monsoonal rains. Broad spectrum antimicrobials with IV ceftazidime or IV meropenem are the preferred empiric agents for these presentations in the north
of Australia.

Mosquito-borne infections such as RRV and Barmah Forest occur throughout Australia while Murray Valley encephalitis (MVE) is common in tropical and subtropical regions (fig.1). MVE is endemic in the Kimberley and largely asymptomatic but 1/1000 develop encephalitis (24% mortality, 50% neurological sequelae).

Far North Queensland has frequent outbreaks of Dengue fever due to mosquitos that blow across the Torres Strait. The only effective prevention for arboviral diseases is vector control or mosquito avoidance (DEET repellent and mosquito nets).

Arthropod bites and stings are common, and infection is caused by skin staphylococci or streptococci rather than bacteria injected with the bite or sting. Ticks typically cause an eschar at the site of the bite and less commonly a Rickettsial illness characterised by a maculopapular rash (‘spotted fever’), myalgia, fever and lymphopoenia. It responds to doxycycline therapy.

In the tropical North-West ocean, wearing a stinger-suit or wetsuit is worthwhile to avoid envenomation from Irukandji jelly fish stings (Carukia barnesi), which cause increased catecholamine release explaining the hyper-adrenergic state in the victim. Blue-ringed octopus inject tetrodotoxin, a potent sodium channel blocking neurotoxin, resulting in rapid paralysis. Less deadly but equally painful are coral injuries, which often become infected (S.aureus, Vibrio spp. and Pseudomonas aeruginosa).

Table 1. Common holiday-related infections and envenomations

We ought to get used to Australian holidays because skiing trips to Japan, Alaskan dog-sled holidays and trips to visit Santa’s Village in Finland are a long way off. Preparedness for ‘bush-bashing’, related infections, stings and bites are important in order to enjoy the holiday season and to understand illness presentations of holiday makers within Australia.

Key messages

  • Holidays in Australia carry their own risks
  • Mosquito-borne viruses are common
  • Being prepared is the key.

Questions? Contact the editor.

Author competing interests: Nil.

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