Diseases with bite

by  Sam Chivers, Global Health Campaigns Manager

Reflecting on World Health Day , that falls on 7th of April, I thought it a perfect time to talk about a few of my favourite subjects.

First up is worms. Worms that enter your skin as eggs through a bite from a fly, and make their home in the vessels under your armpits. Worms that burrow into your blood vessels and block the flow of your lymphatic system, slowly causing the liquid to permanently build up in one of your legs. Far from a Crichton-esque fantasy, lymphatic filariasis (LF) is a daily threat for over a billion people around the world. Although the infection itself is easily treatable, the physical disability elephantiasis is permanent, and many patients suffer daily discrimination in their communities.

Figure 1: Elephantiasis in Haitian patients

Now, let’s talk about parasites. A tiny parasite is injected into your bloodstream by the bite of a brown mosquito, and swims into your liver to set up a colony. When they’re mature enough, the parasites re-invade your bloodstream and take up residence of your red blood cells. They grow and multiply so fast inside your blood cells that they quickly burst, releasing thousands of baby parasites back into your blood stream. Every time your blood cells explode, your fever spikes to an extreme level, and your energy plummets. This is especially dangerous to small children, as they cannot regulate their body like adults can, and much more easily develop the brain infection that kills most sufferers of this condition.

This disease is malaria. Still causing more than 200 million illnesses around the world, malaria has been the cause of more than half of all human deaths since the Stone Age.

Malaria remains a major health problem in our region, especially in Myanmar. While there has been a very effective cure available for a decade, careless use of the treatment means that drug-resistant parasites have cropped up in Myanmar and Cambodia three years ago, and, as of last week, Angola. If the drug-resistant form spreads across to Africa as it did in the fifties, the only effective cure against malaria will be useless.

 Figure 2: Malaria bursting through a red blood cell

Thirdly, let’s talk about bacteria. A bacteria that spends some of its life in the warm squishy gut of a sandfly, before invading the soft warm squishiness of your skin. As it invades your soft tissue, it causes a large open sores in its the softest parts, including your nose, lips and cheeks. Other variants of the disease cause your skin to blacken and develop lesions, and weaken your ability to fight opportunistic infections such as pneumonia, TB and diarrhoea. Another horrifying dystopian nightmare, leishmaniasis is a scourge making a recurrence in India, as risk factors include poverty, malnutrition, deforestation and urbanisation. Some types of leishmaniasis make their home in areas of drought, famine, and high population density, such as Sudan and Somalia. Around 12 million people are infected with leishmaniasis right now, and another two million are infected every year.

Figure 3: Cutaneous leishmaniasis

Now for the last infectious agent, the virus. A disease that used to be known as breakbone fever for its excruciating joint pain, you catch this agonising disease through the bite of a huge black-and-white-striped tiger mosquito. The virus breaks micro-holes in your blood vessels, and you bleed into your skin, causing it to itch like nothing else. Your mouth is bone dry, and you feel like you can’t drink enough; I’ve seen people drink two-litre jugs of water in ten minutes and then ask for more. This disease is known as dengue haemorrhagic fever. Dengue has swept around the globe in an extreme outbreak over the past five years Malaysia alone has experienced triple the amount of deaths this year than it did last year. Without cure, treatment, or vaccine, people just have to suffer through it.

Figure 4: The tiger mosquito, Aedes spp.

What do all these diseases have in common?

They are all transmitted by insects, known as vectors. A vector is an organism that transmits a disease or parasite from one animal to another. Unlike diseases like influenza, diarrhoea or polio, one must be bitten by an insect to contract the disease; you can’t catch it from another person.

This World Health Day brings attention to the often-neglected vector-borne disease. More than half the world’s population is at risk of a vector-borne disease. They kill more than a million people each year, and disproportionately kill children. For most of them, there is no cure. For most, there is no vaccine. Prevention takes the form of long sleeves, insecticides, and bed nets.

The Senate recently released the results of its enquiry into Australian aid effectiveness. For me, one of crucial parts was the recognition that Australia must contribute more to research and development in diseases that affect our region. A vaccine against dengue haemorrhagic fever is one of the most crucial. The epidemic is close to doubling every year in Asia. Dengue also seriously threatens Australia’s health security (dengue outbreaks occur constantly in Queensland).

These diseases cause massive suffering and unnecessary death. Now is the time to invest, and finally the time to end it.


For the story of my experience with dengue, check out our latest media release!

Check out the World Health Organisation’s World Health Day video!