That's why on World Health Day today, the World Health Organisation is drawing attention to vector-bourne diseases like malaria and dengue fever.
In the past two decades, the WHO says many of these diseases have re-emerged and spread to new parts of the world... making them an increasing threat to global public health.
Presenter: Kate Arnott 2
Speaker: Professor James Beeson, Burnet Institute; Dr Freya Fowkes, Burnet Institute; Geoff Chan, International health officer, Burnet Institute;
Mosquitoes, flies, ticks, bugs and fleas are all responsible for speading life threatening illnesses in tropical environments and beyond.
The World Health Organisation estimates vector-borne diseases cause more than a million deaths every year.
Professor James Beeson from the Melbourne-based Burnet Institute says the burden of disease is a huge problem.
"About 50 per cent of the world's population is at high risk of vector bourne diseases - so that's an enourmous burden. Secondly obviosuly that carries a huge health burden - both in terms of lives lost, disability, repeated illness or chronic illness - that's obviously a big health burden. But there's also a big economic budren - these vector bourne diseases are huge barriers and impediments to economic development and growth in countries and really compund the poverty cycle."
Malaria is responsible for the most deaths and illness - and although the death rate for dengue fever is much lower, Professor Beeson says about half a million people end up in hospital with that virus every year.
"But what's also very alarming is that the rates of dengue are actually increasing - so it's not a problem that's going away - it's a problem that's getting more prevalent."
Another mosquito borne disease similar to dengue is chikungunya.
It's infected tens of thousands of people in Papua New Guinea and researchers fear it could spread to Australia.
Most of these vector-borne diseases are a long way from erradication because there are huge challenges in controlling and preventing them.
For many, there are no vaccines and some don't even have effective treatments.
As well, drug resistence is a growing and serious threat.
Malaria parasites, for example are constantly evolving and the Burnet Institute's Dr Freya Fowkes (folks) says they don't respond to medication as well as they used to.
"This can occur either through patients not adhering to their medication but also through counterfeit medication which is widespread in south-east Asia and Africa."
Dr Fowkes is involved in a major international project, which is tracking drug-resistant malaria in the regions between Cambodia and Thailand, and Thailand and Myanmar.
"Most of the studies are predominately around the Greater Mekong region which is where a majority of the resistence has been detected to date, and really what we need to know if how far that resistence has spread. So we've even gone further afield out to the west to Bangladesh and India and also into Africa as well."
The results are due to be released in the next few months... researchers then hope to be in a better position to form strategies to stop the spread of drug-resistant malaria.
Vector-borne diseases put a huge strain on health systems in developing countries.
Like in Papua New Guinea - where malaria is a big problem in the province of East New Britian.
That's why the early diagnosis and management of malaria at a community level is key.
International health officer, Geoff Chan has been involved in a project in the province to train health workers in the diagnosis and treatment of the disease.
Volunteers are trained as well, to provide health care in villages.
"After the training, they're given testing kits, they're given drugs for treatment, so artemisinin-based therapies and paracetomol and then our supervisors provide them with ongoing support and supervision."
Geoff Chan say one volunteer and her family, in particular, have embraced the project.
"She was finding it a bit hard to store everything and have a dedicated space for her medicines and her kits so her husband built her a hut where she could basically provide her servies out of and store her stuff. It was really, really lovely because it was a nice example of that support and commitment from the family and I think also so recognition in the community for the contribution she's making to her village."
The World Health Organisation says because many vector-borne diseases have re-emerged and spread to new parts of the world.. they're now an increasing threat to global health.
The W-H-O has called for more funding and political commitment to improve vector control and stop diseases outbreaks.
And it says renewed momentum from public health agencies, government sectors and communities is key.