Navy News :: Health & Fitness

Get mozzies to buzz off
Insects, particularly mosquitoes, aren’t just annoying – they can be deadly.

Blood sucker: Disease is transmitted when an infected mosquito bites a person, releasing microscopic blood parasites.

Photo courtesy of Department of Medical Entomology, ICPMR

Pills to kill parasites:
ADF personnel are required to take medications if deployed to a high-risk region.

Photos by CPL Craig Eager

THE RISK of mosquito-borne diseases is high in many areas of recent operation – East Timor, Solomon Islands and Aceh for example. Even in Australia’s north, mosquitoes can pose a threat because of the climate.

Certain types of mosquitoes are known to carry several diseases, which can appear within weeks or take months to show symptoms. The common diseases worldwide are malaria, dengue fever and, in Australia, Ross River fever. They are all hard to treat.

Malaria in its various forms is estimated to kill at least one million people throughout the world every year. Ross River fever is not fatal, but can make you very sick.

There are several thousand cases of Ross River fever every year in Australia. Of course, it is hard to tell which mosquitoes are which, so avoiding bites is best. For many mosquito-borne diseases, there is no treatment or cure, so taking precautions to reduce exposure is the best prevention.

Preventative action

On deployment
ADF Health advises to take these precautions when on deployment:

eliminate mosquito-breeding sites – anything that can hold static water, such as cans, tyres and potholes. Mosquitoes breed in the “wet season” in the tropics, which is from about November to March;
roll up bedding when not in use and shake out sleeping bags, clothing, webbing and boots before use;
apply insect repellant (DEET) to exposed skin in the evening and at night when most mosquitoes are biting, but avoid putting it on eyes, lips or broken skin;
ensure DPCUs and bednets are treated with Permethrin. Treat DPCUs regularly (every 3-4 washes);
keep sleeves rolled down, tuck trousers into boots, sleep under bednets and tuck bednets under bedding;
take medication/prophylaxis (malaria tablets) as prescribed. For most people, this will be a daily tablet of doxycycline. For many of the arboviruses, such as dengue fever and Ross River fever, there is no preventative medication so avoiding mosquito bites is the only form of defence; and
conduct “buddy” checks for ticks – get medical assistance to remove them.

Around home
At home, anywhere water collects is an ideal breeding ground. So objects such as bird baths, boats, discarded tyres, pot plants and pools need to be maintained. For example:

discard containers, tyres and other items no longer wanted that hold stagnant water;
cover containers that collect rainwater for gardens with screening;
treat pools and ponds with products – see a local business;
tip out excess water from saucers under outdoor pot plants;
keep rain gutters free of leaves and other debris that prevents water from draining;
flush out the water in bird baths regularly;
store boats in a place away from the weather and remove water collected in tarpaulins that cover equipment;
fix drainage problems in the yard where water collects in low-lying areas;
use insecticides and keep fly screens in doors and windows in good repair; and
avoid being outside in the late afternoon and at dusk. Mosquitoes are usually most active a few hours after sunset, during the night and again around dawn.

How the infection occurs
Malaria is transmitted by the bite of an infected Anopheles mosquito. When the infected mosquito bites a person, it releases microscopic parasites into the blood stream.

These parasites then travel to the person’s liver, enter the liver cells, grow and multiply, then leave the liver and invade blood cells. Parasites in the blood cause symptoms as early as eight days or as long as a year after the bite. There are different strains of malaria.

Our geographic region has some of the most drug-resistant strains of malaria in the world. The Army Malaria Institute is at the forefront of research to find drugs that will deal with these strains.

Although personnel have been or are in high-risk areas, very few have contracted malaria or other related diseases due to the preventative action they’ve action. About 30 to 50 per cent of Solomon Islanders have malaria, which makes the risk of cross-infection via mosquito bites very possible.

Yet no ADF members developed malaria in-country and just nine personnel developed malaria after their return to Australia.

The cause of their malaria has been traced to the inability of Primaquine to eradicate the dormant, liver stages of the non-lethal type of malaria.

Dengue fever is a viral disease transmitted by the container-breeding mosquito Aedes aegypti. Two ADF personnel among the 120 posted to East Timor on Operation Spire recently acquired this disease.

Symptoms of infection
With many of the arboviruses, such as Ross River fever, symptoms may be mild – sometimes people who are infected never develop symptoms – but they can equally develop into something serious.

Malaria symptoms include fever, flu-like illness, intense headaches and fatigue. Malaria is a serious, frequently fatal, disease. It is critical to take all malaria medication to be sure of killing the blood and liver stages of the infection.

ADF personnel have effective antimalarial drugs which will protect them if they are in a high-risk area. However, they can still become sick later when they return to Australia and stop taking their medication due to the dormant liver stages, which can cause relapses.

Symptoms for dengue fever are similar. They include sudden onset of high fever, severe headaches, joint and muscle pain, nausea/vomiting and rash. There are four subtypes of dengue fever, and getting a second or further infection increases the risk of serious illness or even death.

Ross River fever also causes people to have flu-like symptoms that include fever, chills and aches. Some joints can become swollen or stiff and sometimes a rash occurs for a few days that then disappears.

Personnel should medical attention and advise their MO of being in an area that is high-risk.

Treatment: before and after
ADF personnel who have deployed to a high-risk region are required to complete an eradication course. This starts on the day of departure from the area.

Continue taking doxycycline every day for 14 days after returning to Australia. Remember to take medication with food and a full glass of water. Begin Primaquine on the day of departure, take two tablets twice a day for 14 days with food. It is important to take Primaquine with food to minimise the potential side effects, such as nausea.

Doxycycline is used to continue to suppress infection, while Primaquine kills the parasite in blood and the liver. If you have been tested for G6PD and know you are deficient, you should not take Primaquine. There are a few people who cannot tolerate doxycycline.

These people can take either Mefloquine or Malarone as an alternative malaria medication. Mefloquine is taken weekly while Malarone is taken daily. These two medications, and Primaquine, should also be taken post-deployment.

Treatment of malaria depends on the type of malaria parasite and severity of symptoms. Chloroquine, Mefloquine and Malarone are currently the mainstay of uncomplicated malaria in the ADF.

There are no specific treatments for dengue fever or Ross River fever. However there are medications that doctors can prescribe to help ease the discomfort of symptoms.

Plenty of rest, along with moderate exercise after the acute phase, and healthy eating, can help recovery. Most people recover from symptoms quickly with no long-term complications. Treatment will always be tailored for the needs of individual patients.

Information sources: ADF Health web site and information booklets, NSW Health, the Department of Entomology North Carolina Cooperative Extension, Army Malaria Institute.