Written by:
- Dr Tanya Melillo, Consultant in Public Health Medicine and Head of Malta’s Infectious Disease Prevention and Control Unit (IDCU)
- Dr Matthew Sacco, Basic Specialist Trainee in Public Health Medicine
What Are Infectious Diseases?
Infectious diseases are caused by harmful microorganisms like bacteria, viruses, fungi, and parasites. These lead to mild infections that clear up on their own, but can also lead to serious life-threatening illness.
Infectious diseases spread in several ways – through droplets in the air, contaminated food or water, insect bites, sexual contact, or the environment.
The good news? Most infections can be prevented with simple everyday actions! Understanding how each infection spreads helps you choose the right preventive steps.
Foodborne Disease
Foodborne illness happens food or water becomes contaminated with harmful bacteria, viruses, or parasites such as Salmonella, Escherichia coli, campylobacter, norovirus and cryptosporidium. Common symptoms include: nausea, vomiting, diarrhoea, tiredness, and fever. Severe cases can lead to dehydration or kidney failure.
Prevention:
1. Separate raw and ready-to-eat foods
2. Wash your hands well before preparing foods and after handling raw meat
3. Refrigerate leftovers within two hours of cooking (or within one hour in summer)
4. Keep your fridge below 4°C and freezer below –18°C
5. Keep meats on the lowest fridge shelves
6. Cook food thoroughly: eggs should be hard-boiled, and meats should be well-done throughout
Vector-borne Disease
Vectors are organisms – mostly insects such as mosquitoes, ticks and mites – can transmit when they feed on blood. During feeding they can pick up microbes and pass them on to others.
Although these diseases were once limited to tropical regions, increased international travel and climate change are expanding their reach. In Malta, the current main locally-transmitted vector-borne diseases are rickettsia, leishmaniasis and sandfly fever.
No locally transmitted cases of malaria, dengue, chikungunya, or Zika have ever been recorded, though imported cases from returning travellers occur. The mosquito species capable of spreading dengue, chikungunya and Zika is now locally endemic, meaning these infections could eventually become established, as has happened in other Mediterranean countries.
Prevention focuses on avoiding contact with vectors:
1. Wear long sleeves and trousers
2. Use DEET-containing insect repellent on exposed skin
3. Avoid being outdoors at dawn and dusk, when mosquitoes are most active
4. Stay away from stagnant water, which serves as mosquito breeding sites
5. Take preventive medication (prophylaxis) when traveling to malaria-endemic countries if advised
Sexually Transmitted Diseases
Sexually transmitted diseases (STDs) spread through vaginal, anal or oral sex and can pass from mother-to-child during pregnancy, childbirth or breastfeeding.
Common STDs include syphilis, chlamydia, gonorrhoea, trichomoniasis, herpes simplex virus, HIV, hepatitis B, human papilloma virus (HPV), and mpox.
Symptoms vary and may include: genital discharge, itching, skin rashes and painful sexual intercourse. However, many can show no symptoms. Untreated infections may lead to serious long-lasting complications such as infertility, increased cancer risk (HPV and hepatitis B), and severe neonatal outcomes including stillbirth, premature birth, sepsis or congenital deformities.
Prevention:
1. Use condoms correctly and consistently
2. Get vaccinated against Hepatitis B and HPV (these are available on the National Immunisation Schedule)
3. Attend regular screening and check-ups for timely detection and treatment
Respiratory Diseases and Legionnaires’ Disease
Respiratory infections affect the upper or lower airwards and are commonly caused by bacteria, viruses, or fungi. Infections such as influenza, COVID19 and respiratory syncytial virus (RSV), spread through tiny droplets released when a person talks, coughs, or sneezes.
Symptoms range from a mild cough or nasal congestion to serious illness with chest pain or shortness of breath. They can affect any individual, however those under the 5 years of age or over 70 years of age and those who suffer from any underlying respiratory conditions are more affected.
Prevention:
1. Practice hand hygiene (wash your hands well), especially when sick
2. Cover your mouth and nose when sneezing or coughing
3. Stay home when sick
4. Wear a facemark when unwell
5. Keep up-to-date with yearly vaccinations targeting these diseases
Legionnaires’ disease is caused by Legionella bacteria and spreads through inhaling contaminated water vapour rather than person-to -person contact.
Legionella thrives in warm stagnant water, especially in poorly maintained domestic water tanks pipes, taps, and showerheads.
Reduce the risk of harm:
1. Clean and maintain water storage tanks at least once a year to prevent build-up of biofilm
2. Set water heaters above 60°C and avoid switching them off for long periods
3. Clean and descale shower heads and taps every few months
4. Remove rarely-used taps or “dead legs” in your water system
5. Flush taps and showers with cold and then hot water after returning from holidays or long absences
A Word about Vaccination
Vaccination prepares the immune system to respond to infections safely and effectively. High uptake reduces illness and protects vulnerable groups.
In Malta, all vaccines on the national immunisation schedule are free of charge for those under the age of 17, and influenza, COVID19 and PCV vaccines are offered free of charge to individuals over the age of 65.
Conclusion
Infectious diseases remain an important public health challenge. Althrough these infections may feel distant from everyday life, prevention starts with simple actions we can all take. Good hygiene, safe food handling, protecting ourselves from insect bites, keeping vaccinations up-to-date, responsible sexual practices, and maintaining clean home systems all play a crucial role in reducing disease spread.
If this article was helpful, sharing it is another easy way to support community health!
References
- Nair, P. (2025, August 19). Contaminated Food: Understanding Foodborne Illnesses & Prevention. Wellri. https://wellri.com/contaminated-food-understanding-foodborne-illnesses-prevention
- Todd, E. (2020). Food-Borne Disease Prevention and Risk Assessment. International Journal of Environmental Research and Public Health, 17(14), 5129. https://doi.org/10.3390/ijerph17145129
- World Health Organization. (2024, September 26). Vector-borne Diseases. Who.int; World Health Organization: WHO. https://www.who.int/news-room/fact-sheets/detail/vector-borne-disease
- WHO. (2025, May 29). Sexually Transmitted Infections (STIs). World Health Organization; World Health Organization: WHO. https://www.who.int/news-room/fact-sheets/detail/sexually-transmitted-infections- (stis)
- Zhou, F., et al. (2024). Health and economic benefits of routine childhood immunization — United States, 1994–2013 (MMWR/summary review). Centers for Disease Control and Prevention.