Increase in imported malaria cases

14 January 2019

An increase in malaria notifications occurred in 2018 with a total of 34 cases, including 10 in December, compared with 8 in 2017 and 10 in 2016. To date, there have been 5 cases notified in 2019. All cases were acquired overseas. Travel to or immigration from Africa accounted for the majority of cases, while others were associated with south east Asia, south Asia and Papua New Guinea.

Malaria is caused by Plasmodium spp., arthropod-borne parasites transmitted through the bite of female Anopheles mosquitoes. These mosquitoes are not present in South Australia so there is currently no risk of malaria transmission in South Australia.

The incubation period is typically 9-40 days depending on species. Symptoms may be mild and non-specific but typically include fever which may be cyclical. Other symptoms may include headache, nausea, vomiting, chills, sweating, diarrhoea and malaise. P. vivax and P. ovale can persist in the liver as hypnozoites and cause relapsing illness over several years. P. malariae may persist asymptomatically for several decades.

Doctors should request malaria testing in:

  • People who have travelled to countries where malaria is known to be endemic who present with fever or other symptoms suggestive of malaria.
  • People who have immigrated to Australia
    • if asymptomatic should be tested for malaria if they have travelled from/through an endemic malaria area within 3 months of arrival, or
    • if symptoms suggestive of malaria are present, at any time, regardless of previous malaria testing or treatment.

Management of cases:

  • Arrange laboratory testing of suspected cases. If testing is indicated, take blood (EDTA purple top tube) for thick and thin films and malaria antigen testing. If clinical suspicion remains for malaria and initial testing is negative, consider repeat testing.
  • Exclude other clinically similar diseases which may also occur in areas where the patient has travelled. Consider seeking advice from an infectious disease physician or clinical microbiologist.
  • Recommend treatment in consultation with an infectious disease physician or clinical microbiologist.
  • Notify confirmed cases to the Communicable Disease Control Branch on 1300 232 272. Malaria is a notifiable condition in South Australia.

 Doctors should advise people travelling to areas with ongoing malaria transmission to:

  • Avoid mosquito bites, particularly at night, by using insect repellent, wearing long-sleeve clothing if outdoors at night, and sleeping under insecticide-treated bed nets.
  • Take malaria prophylaxis as prescribed and complete the full course.
  • See a travel medicine expert, if required, prior to travel for specific advice relating to the areas where travel is occurring.

 Dr Louise Flood - Director, Communicable Disease Control Branch

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