Zika virus is a mosquito-borne flavivirus that was first identified in Uganda in 1947 in monkeys through a network that monitored yellow fever. It was later identified in humans in 1952 in Uganda and the United Republic of Tanzania. Outbreaks of Zika virus disease have been recorded in Africa, the Americas, Asia and the Pacific. From the 1960s to 1980s, human infections were found across Africa and Asia, typically accompanied by mild illness. The first large outbreak of disease caused by Zika infection was reported from the Island of Yap (Federated States of Micronesia) in 2007. In July 2015 Brazil reported an association between Zika virus infection and Guillain-Barré syndrome. In October 2015 Brazil reported an association between Zika virus infection and microcephaly.
Signs and Symptoms
The incubation period (the time from exposure to symptoms) of Zika virus disease is not clear, but is likely to be a few days. The symptoms are similar to other arbovirus infections such as dengue, and include fever, skin rashes, conjunctivitis, muscle and joint pain, malaise, and headache. These symptoms are usually mild and last for 2-7 days.
Complications of Zika virus disease
After a comprehensive review of evidence, there is scientific consensus that Zika virus is a cause of microcephaly and Guillain-Barré syndrome. Intense efforts are continuing to investigate the link between Zika virus and a range of neurological disorders, within a rigorous research framework.
Zika virus is primarily transmitted to people through the bite of an infected mosquito from the Aedes genus, mainly Aedes aegypti in tropical regions. Aedes mosquitoes usually bite during the day, peaking during early morning and late afternoon/evening. This is the same mosquito that transmits dengue, chikungunya and yellow fever. Sexual transmission of Zika virus is also possible. Other modes of transmission such as blood transfusion are being investigated.
Zika virus disease is usually mild and requires no specific treatment. People sick with Zika virus should get plenty of rest, drink enough fluids, and treat pain and fever with common medicines. If symptoms worsen, they should seek medical care and advice. There is currently no vaccine available.
Protection against mosquito bites is a key measure to prevent Zika virus infection. This can be done by wearing clothes (preferably light-colored) that cover as much of the body as possible; using physical barriers such as window screens or closing doors and windows; sleeping under mosquito nets; and using insect repellent containing DEET, IR3535 or picaridin according to the product label instructions. Special attention and help should be given to those who may not be able to protect themselves adequately, such as young children, the sick or elderly. Travelers and those living in affected areas should take the basic precautions described above to protect themselves from mosquito bites.
It is important to cover, empty or clean potential mosquito breeding sites in and around houses such as buckets, drums, pots, gutters, and used tyres. Communities should support local government efforts to reduce mosquitoes in their locality.
Dengue Fever & Dengue Haemorrhagic Fever (also known as break bone fever)
- Currently the most rapidly spreading vector borne disease affecting 50 million people worldwide annually. Half the world’s population live at risk from this disease.
- Cases in the Caribbean have increased from 29,000 cases annually in the non-Hispanic Caribbean in the 1980’s and 1990’s to in the region of 89,000 cases annually between 2000-2007*
- Dengue fever is caused by a virus.
- Symptoms include: fever, headache, muscle and joint pains.
- Transmission is by the Aedes aegypti and Aedes albopictus mosquitoes, Aedes aegypti is currently rife on Grand Cayman.
- We see a number of cases of Dengue each year in the Cayman Islands, mostly in travellers returning from endemic regions.
- There is no vaccine or cure for Dengue so the only answer is through mosquito control
- Chikungunya virus (CHIKV) is transmitted by Aedes aegypti and albopictus mosquitoes
- The geographic range of chikungunya virus has extended from Africa and Asia and it is now endemic in the Caribbean. There have been a number of introduced cases of chikungunya in the Cayman Islands and 4 cases of local transmission have been reported.
- Chikungunya is mostly characterised by acute fever, headache, fatigue, nausea, vomiting, muscle pain, rash, and joint pain symptoms appearing within 48 hours of an infectious bite and lasting up to 10 days
- Chikungunya” means “that which bends up”, and in some cases can cause a debilitating and disabling illness with some persons (particularly the very young and old, and those who are unwell) at risk of severe complications
- There is no vaccine or cure for chikungunya, but health care practitioners can help manage symptoms
- Avoiding mosquito bites is the best method of prevention. So, stay indoors at dawn & dusk, cover up, use insect repellant, and screen your doors and windows.
- There are approximately 225 million cases worldwide per year. 90% of malaria deaths occur in Sub-Saharan Africa mostly in children.
- Malaria is present in many parts of the Caribbean including Belize, Columbia, Costa Rica, The Dominican Republic, Guatemala, Haiti, Honduras, Mexico, Nicaragua, Panama and Venezuela**
- Malaria is caused by a parasite called Plasmodium.
- Symptoms include: Fever, shivering, joint pain, severe headache, vomiting, anaemia, convulsions and coma.
- Transmitted by Anopheles mosquitoes (in Cayman the likely vector for malaria is Anopheles albimanus which can be recognized by its white back feet !).
- Cases of malaria are rarely seen in the Cayman Islands despite there being many cases across the region as well as having the right mosquito to carry it.
- There are a number of drug regimes for the prevention and treatment of malaria, but resistance to these drugs can be seen in some areas.
- Heartworm is a debilitating, sometimes fatal disease caused by a nematode (round worm) parasite called Dirofilaria immitis.
- It can affect not just dogs, but cats and humans also.
- Symptoms include: coughing, vomiting, lethargy, anorexia, difficulty breathing, collapse, convulsions and blindness.
- Heartworm is transmitted by many different species of mosquito and is endemic in the Cayman Islands.
- Heartworm can be prevented by regular medication; contact your vet for further details.
*(San Martin et al. (2010) The Epidemiology of Dengue in the Americas Over the Last Three Decades: A Worrisome Reality. The American Journal of Tropical Medicine & Hygiene. 82, 128-135).
**(PAHO. (2008) Malaria in the Americas: Time series Epidemiological Data from 2000-2007).
Dengue map from wwwnc.cdc.gov