Mosquito-borne diseases have been around for many years. These diseases are transmitted through infected mosquitoes which are called vectors. From the perspective of infectious diseases, vectors are the transmitters of disease-causing organisms, that is, they carry pathogens from one host to another. Historically, these are the diseases that caused the epidemics of yellow fever which plagued the development of the New World.

It is believed by some scholars that mosquitoes cause more human suffering than any other organism — over one million people worldwide die from mosquito-borne diseases every year. Not only can mosquitoes carry diseases that afflict humans, they also transmit several diseases and parasites to which dogs and horses are very susceptible. These include dog heartworm, West Nile virus (WNV) and Eastern equine encephalitis (EEE). In addition, mosquito bites can cause severe skin irritation through an allergic reaction to the mosquito’s saliva — this is what causes the red bump and itching. Mosquito-vectored diseases include protozoan diseases such as malaria, filarial diseases such as dog heartworm, and viruses such as dengue, encephalitis, yellow fever, chikungunya and more recently, Zika virus.

Although early scholars recognised a relationship between certain insects and illness in humans and animals, the concept of disease transmission by mosquitoes was first recognised in 1877. Sir Patrick Manson first demonstrated that a parasite of humans was transmitted among humans by the Culex mosquito. In 1898, malaria was shown to be transmitted by the Anopheles mosquitoes. Since that time, many important disease pathogens of humans and animals have been shown to depend on bloodsucking mosquitoes to complete their transmission cycles.

Malaria is an ancient disease that has been described by the Chinese as far back as 2700 BC and the Sumerians from 1700 BC. The malaria parasite (plasmodium) is transmitted by female Anopheles mosquitoes.

The Aedes mosquito has emerged as one of the most dangerous vectors as it is able to transmit yellow fever, dengue, chikungunya and Zika. Yellow fever, which has a 400-year history, occurs only in tropical areas of Africa and the Americas. Every year, about 200,000 yellow fever cases occur with 30,000 deaths in 33 countries. Dengue is a serious arboviral disease of the Americas, Asia and Africa. The spread of dengue throughout the world can be directly attributed to the proliferation and adaptation of these Aedes mosquitoes that prefer to lay their eggs in containers close to human habitations.

The chikungunya virus was discovered in Africa in 1952. The disease occurs in Africa, Asia and the Indian subcontinent. In recent decades, mosquito vectors of chikungunya have spread to Europe and the Americas. Zika virus has emerged from its origins in Uganda in Africa in 1947, and has rapidly spread to the South Pacific and western hemisphere.

Since its discovery in 2014 off the coast of South America, Zika cases have been found in 35 countries in the Americas. Although in rare cases Zika can be spread through sexual contact with an infected person, it is usually transmitted through the bite of an infected Aedes aegypti mosquito. The illness features symptoms of fever, rash, conjunctivitis and joint pain lasting a few days to several weeks or months.

Zika becomes even more dangerous as cases of microcephaly — a congenital defect of cranium and brain size resulting in profound neurological defects in newborns that can result in death — have been positively identified as being caused by Zika infection. An autoimmune condition called Guillain-Barré syndrome — causing damage to nerve cells, resulting in muscle weakness and, on occasion, paralysis and death — has been linked to Zika infection as well.

Visit the nearest health centre or your physician if you start to experience any of the symptoms associated with Zika and for more information on mosquito-borne diseases, please visit the Ministry of Health’s website at www.moh.gov.jm or call 1888-ONE LOVE.