Monday 21 May, 2018

6 mosquito-borne diseases plaguing the Caribbean

More deadly than sharks, snakes or plague-bearing fleas, the deadliest creature on earth is actually the mosquito.

According to the World Health Organisation (WHO), mosquitos carry diseases which cause several million deaths and hundreds of millions of cases every year. 

Malaria is endemic in 91 countries, with about 40% of the world's population at risk - up to 500 million cases occur every year, 90% of them in Africa, and there are up to 2.7 million deaths annually.

Dengue is the world's most important mosquito-borne virus disease, with 2500 million people worldwide at risk of infection and 20 million cases a year in more than 100 countries.

In 1995, the worst dengue epidemic in Latin America and the Caribbean for 15 years struck at least 14 countries, causing more than 200 000 cases of dengue fever and almost 6000 cases of the more serious dengue haemorrhagic fever.

Here are six diseases you can get from mosquitos in the Caribbean:

 

1. Dengue 

According to WHO, the incidence of dengue has grown dramatically around the world in recent decades from 2.2 million in 2010 to 3.2 million in 2015.

Severe dengue affects most Asian and Latin American countries and has become a leading cause of hospitalization and death among children and adults in these regions.

One recent estimate indicates 390 million dengue infections per year, of which 96 million (67–136 million) manifest clinically (with any severity of disease). 

Dengue is spread by the Aedes aegypti mosquito which is active in most tropical regions. It can cause Dengue Dengue Hemorrhagic Fever, a severe and sometimes fatal form of the disease. 

Measures can be taken to limit the spread of Dengue by keeping living spaces clean, reducing the chance for the mosquito to reproduce. 

 

2. Malaria

In 2016, 445,000 people died from malaria, a mosquito-borne disease.

There were an estimated 216 million cases of malaria in 91 countries, an increase of 5 million cases over 2015.

Although the African region carries a disproportionately high share of the total number of cases, the disease also exists in the Caribbean and Latin America. 

Malaria is caused by Plasmodium parasites, which is spread by the Anopheles mosquito, of which there are over 40 varieties. 

(Photo: Anopheles mosquito.)

Antimalarial medicines can also be used to prevent malaria, however WHO has noticed a growing resistance to anti-malarial medications. 

A vaccine was recently developed called Mosquirix (RTS,S). In November 2016, WHO announced that the vaccine would be rolled out in pilot projects in selected areas in 3 countries in sub-Saharan Africa: Ghana, Kenya and Malawi.

Measures can also be taken to limit the spread of Dengue by keeping living spaces clean, reducing the chance for the Anopheles mosquito to reproduce. 

 

3. Chikungunya

Chikungunya or ChickV mostly occurs in Africa, Asia and the Indian subcontinent. However a major outbreak in 2015 affected several countries in the Caribbean and Latin America. 

The virus is transmitted from human to human by the bites of infected mosquitoes, namely the Aedes aegypti and Aedes albopictus mosquitos.

(Photo: Aedes albopictus

ChickV Chikungunya is characterized by an abrupt onset of fever frequently accompanied by joint pain. Other common signs and symptoms include muscle pain, headache, nausea, fatigue and rash. 

Most patients recover but there the disease can be debilitating or even fatal for vulnerable groups such as the elderly and small children.

There is no specific antiviral drug treatment for chikungunya and most health control programmes focus on prevention measures. 

 

4. Zika

The Zika virus is also transmitted through the bite of an infected Aedes species mosquito, the same mosquitoes that spread dengue and chikungunya viruses.

An outbreak of the Zika virus was recorded in tropical Africa, Southeast Asia, and the Pacific Islands. Zika virus likely will continue to spread to new areas. In May 2015, the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika virus infections in Brazil.

If symptomatic, symptoms are generally mild–fever, rash, joint pain, or red eyes. Severe disease requiring hospitalization is uncommon and deaths have not been reported.

 

5. Yellow fever

Many major cities of the world, especially in the Americas, are at risk of potentially devastating epidemics of yellow fever because they are infested with Aedes aegypti mosquitos which can transmit the disease.

A small proportion of patients who contract the virus develop severe symptoms and approximately half of those die within 7 to 10 days.

Yellow fever is caused by the Flavivirus, which is spread by the Aedes aegypti mosquito.

Vaccination is the most important means of preventing yellow fever, followed by preventative measures to eradicate the mosquitos from living spaces.  

 

6. Lymphatic filariasis (elephantiasis)

According to WHO, 856 million people in 52 countries worldwide remain threatened by lymphatic filariasis and require preventive chemotherapy to stop the spread of this parasitic infection.

Lymphatic filariasis impairs the lymphatic system and can lead to the abnormal enlargement of body parts, causing pain, severe disability and social stigma.

Lymphatic filariasis is caused by infection with parasites classified as nematodes (roundworms) of the family Filariodidea.

Adult worms lodge in the lymphatic vessels and disrupt the normal function of the lymphatic system. The worms can live for approximately 6–8 years and, during their lifetime, produce millions of microfilariae (immature larvae) that circulate in the blood.

Mosquitoes are infected with microfilariae by ingesting blood when biting an infected host. Microfilariae mature into infective larvae within the mosquito. When infected mosquitoes bite people, mature parasite larvae are deposited on the skin from where they can enter the body. The larvae then migrate to the lymphatic vessels where they develop into adult worms, thus continuing a cycle of transmission.

The roundworms are transmitted by the  CulexAnopheles and Aedes mosquitos. 

The disease is treated using antiparasitic drugs, such as diethylcarbamazine (DEC), mectizan, and albendazole (Albenza).

Find out how you can prevent the spread of these mosquito-borne diseases: https://bit.ly/1xlCgnT

 

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