Water-borne and vector-borne disease
With increased rainfall and flooding in many parts of Australia in 2022, the threat of both waterborne illnesses and vector-borne viruses will increase over the summer months, including in areas not known for vector-borne presentations (eg in southern states). The RACGP has developed a fact sheet to help practices prepare for and respond to water and vector-borne illnesses. GPs are encouraged to watch for public health alerts on unfamiliar diseases via their state and territory health departments.
Water-borne diseases caused by contaminated drinking water during and after floods include hepatitis A, gastroenteritis, leptospirosis and melioidosis. Practices can prevent patient and staff exposure to these diseases by ensuring an adequate supply of clean drinking water and by wearing protective clothing when assisting with clean-up efforts 43.
There is an increased likelihood of vector-borne viruses following flooding, as standing water can provide a breeding ground for mosquitoes. Vector-borne viruses include Barmah Forest Virus, Ross River virus, Dengue fever 43 and Japanese encephalitis.
Contraction of mosquito-borne viruses can be mitigated by using insect repellants, wearing light coloured protective clothing, avoiding the outdoors during times where mosquito infestation may be higher (eg in evenings during warmer months), using screens and checking your practice for areas where mosquitoes are more likely to breed (eg emptying uncovered water containers) 43.
Ross River virus
Ross River virus, also known as Ross River fever and epidemic polyarthritis, is spread to humans via mosquitoes. Symptoms include joint pain and swelling, fever headache, fatigue, swollen lymph nodes and rash. While most people recover within a few weeks, others may continue to experience symptoms for months after infection 44.
Japanese encephalitis virus
Japanese encephalitis is a mosquito borne virus which has been found throughout the eastern states of Australia in 2022, particularly in piggeries. While incidence rates have been quite low to date, the warming climate and extreme floods of 2022 are likely to increase transmission, frequency and severity of outbreaks 45.
Most cases will be asymptomatic, however, for people who develop symptoms, the fatality rate is estimated to be 30%. Approximately 50% of symptomatic people who survive the virus go on to develop long-term neurological damage 45
The following resources may be useful when preparing for possible vector-borne virus outbreaks and informing patients about what they can do to protect themselves: