Know your tropical diseases

Dengue, Malaria, Lyme and Zika are all tropical diseases that spread mainly through insects. However, their effects on the human body vary. Although many may have heard of these diseases, it is important to know their differences.


Dengue is a mosquito borne viral disease that is mainly prevalent in the tropical and subtropical climates of the Americas, Africa, the Middle East, and the Pacific Islands. It is a leading infection and cause of death in some Asian and Latin American countries.

Symptoms of the disease show up after 4 to 10 days after a mosquito bite infection, and include headaches, muscle and joint pain, vomiting, and swelling of glands. More serious dengue complications include bleeding, abdominal pain, and organ impairment.

No specific treatment exists for dengue, however many disease cases can be self-managed. Severe dengue involving the listed complications require medical care.

Photo: The Aedes aegypti mosquito which is capable of spreading the dengue and zika viruses


Malaria is a mosquito borne illness caused by a parasite that is prevalent in Africa, South Asia, South America, and the Eastern Mediterranean region. The transmission of malaria through mosquitoes can occur during and after rainy seasons.   

Symptoms of malaria infection appear 10 days to 4 weeks after an infecting bite, and include fevers, chills, headaches, muscle fatigue, and nausea. If left untreated, malaria can cause complications like organ failure and breathing problems which can lead to death. Pregnant women and children are more likely to experience these malaria complications. 

The current treatment for malaria includes a combination of antimalarial medications that can fight and sometimes prevent an infection. No vaccine has been developed for malaria.


Lyme disease is a bacterial infection spread to humans through bites of infected ticks. The disease is common in the United States and Europe.

Symptoms become evident about 7 days after being bit by an infected tick, especially by nymphs which are smaller immature ticks. These symptoms include fever, chills, headache, fatigue, and swollen lymph nodes. Some, but not all cases, yield an expanding ring rash at the site of the tick bite.

Months after an infecting bite, a person may experience nerve pain, facial palsy, swollen joints, and inflammation of the brain. If diagnosed and treated early with antibiotics, patients usually have rapid and complete recovery. More aggressive antibiotic treatment is needed for late stage lyme


Zika is a mosquito borne virus documented in Africa, the Americas, Asia, and the Pacific with the most recent outbreak occurring in Brazil in 2015. A person can also be infected by an infected person via sexual contact or contact with blood. 

Symptoms of Zika can appear from 3 to 14 days after infection, and can include fevers, rashes, muscle and joint pains, headaches, and conjunctivitis (also known as pink eye). While typically not fatal, Zika can cause complications in pregnant women and their fetuses. A newborn of an infected mother can have abnormally small heads (microcephaly). 

While there is no medical treatment to combat the infection, drinking fluids and seeking clinical care when needed can reduce complications. Avoiding areas of outbreaks or physical barriers like nets and clothing can also be protective.

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