Malaria, the most widespread mosquito-borne disease, affects 350-500 million people each year. Dengue Fever infects between 50-100 million, causing an estimated 25,000 deaths and an enormous economic cost in affected countries which rivals that of Malaria. Other serious illnesses transmitted by mosquitoes are on the rise. Chikungunya, Yellow Fever and Eastern Equine Encephalitis are painful and debilitating diseases which can in some cases prove fatal; all are increasing in prevalence.
Although Malaria is transmitted by several different types of mosquito, Dengue Fever is primarily passed on by just two related species, called Aedes aegypti (the Yellow Fever Mosquito) and Aedes albopictus (the Asian Tiger Mosquito). Both of these mosquitoes also transmit Chikungunya, Yellow Fever as well as several other viruses, making these tiny insects some of the most dangerous creatures on the planet.
Dengue Fever is the fastest-growing mosquito-borne disease. It is a serious and sometimes fatal condition, which affects over 50 million people every year. Read more about this dangerous illness, and how Oxitec is working to control it, in the Dengue Information Centre.
Chikungunya is a rapidly emerging viral disease that is also spread by the Aedes mosquitoes. According to the Centers for Disease Control and Prevention (CDC), symptoms of chikungunya infection include fever, headache, fatigue, nausea, vomiting, muscle pain, rash and joint pain. The joint pain can last for months. On rare occasions, infection may lead to viral encephalitis and death. Because there is no vaccine or specific treatment available, the best way to avoid chikungunya infection is to minimise the likelihood of contact with an infected mosquito.
There have been recent large outbreaks in India and South East Asia but the geographical spread is increasing and is of growing concern to health officials. On the island of La Réunion in 2006, over 20% of the population was estimated to have been infected. There was also an outbreak in Europe in 2007 in Northern Italy. The virus is believed to have been introduced into Italy by a vacationer from India and then transmitted by local mosquitoes. During the outbreak, there were 254 suspected and 78 laboratory-confirmed cases including one death. Because only a small percentage of infected individuals present for diagnosis, the actual number of cases may be higher. This outbreak has forced global public health experts to re-evaluate the geographic threat of this mosquito-borne virus.
Yellow fever occurs in Africa and Latin America and used to be known as ‘Yellow Jack’ among European sailors who visited the tropics. Once in a community it can spread rapidly. It is characterised by fever, muscle pain, headache, nausea and vomiting. Most patients improve and the symptoms will disappear but in some the disease becomes ‘toxic’. There is high mortality once the disease has entered the toxic phase.
There is no cure for yellow fever but there is a vaccine making monitoring and rapid vaccination critical in stopping the disease once an outbreak occurs. However it is expensive and availability is not sufficient to protect other parts of the world if the disease should move there from Latin America.