When it comes to nasties transmitted by mosquitoes and other biting creepy crawlies, tropical diseases like Malaria, Yellow fever, Dengue fever and West Nile virus, not to mention tick-borne Lyme Disease often get top billing in the press.
But all that has changed in recent months with a mosquito-borne virus of a different kind hitting the headlines. Zika virus, spread by the Aedes species of mosquito, has been deemed a public health emergency of international concern (PHEIC) by the World Health Organisation (W.H.O). The US Centers for Disease Control (CDC) reports that Zika was first discovered in 1947 and is actually named after the Zika forest located in Uganda.
About Zika virus
What is Zika virus?
Zika virus is a disease which is spread to humans initially through bites from an infected species of mosquito. The nature and symptoms of the disease in healthy people means that people often don’t become ill enough to warrant a visit to their doctor or healthcare professional, so many people might not be aware they have been infected. It is rare for a person to die of Zika. Those with compromised immune systems such as the very old, very young and pregnant women are thought to be more at risk.
Zika virus and microcephaly
In May 2015 the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika infection in Brazil, and on Feb 1, 2016, The World Health Organization (WHO) declared Zika virus a public health emergency of international concern (PHEIC).
Until recently, experts believed there was a potential link between Zika and microcephaly, a birth defect causing abnormal smallness of the head, developmental problems in young children and other neurological disorders. However on April 13th 2016, scientists at the Centers for Disease Control and Prevention (CDC) confirmed, after careful review of existing evidence, that Zika virus is a cause of microcephaly and other severe fetal brain defects in babies, marking a turning point in the Zika outbreak.
The CDC is launching further studies to determine whether children who have microcephaly born to mothers infected by the Zika virus are just a small proportion seen, in terms of the damaging effects Zika could have on the brain and other developmental problems.
Official guidance remains that pregnant women, those looking to conceive, and their partners, should take steps to avoid Zika infection by meticulously practicing mosquito bite prevention.
The CDC also advises pregnant women to avoid travel to areas where Zika is actively spreading such as Brazil and more than 20 other global territories.
How is Zika virus transmitted?
Zika is primarily transmitted to humans through the bite of an infected Aedes species of mosquito. Once a person has been infected, he or she is likely to be protected from future infections.
Can Zika virus be passed from person to person?
More has become known about the virus transmission as the outbreak has unfolded and experts now firmly believe it can be transmitted from mother to child. Whilst there have been no reported cases of transmission via breastfeeding, it is believed a mother who is almost full term and becomes infected with the virus can pass it onto her newborn around the time of birth.
In reported cases of sexual transmission to date, and men who developed Zika symptoms, the virus has been spread in various circumstances when the man has symptoms, before symptoms start and after symptoms have resolved. In one case, the virus was spread a few days before symptoms developed. It is thought the virus is present in semen longer than it is in blood.
Ongoing investigations are underway into the possibility of transmission via blood transfusion. Up to February 2016 no cases via blood transfusion had been reported in the US or UK. Numerous cases however have been reported in Brazil. These reports are currently being investigated.
How many cases of Zika virus have been reported so far?
The very first cases reported in humans was recorded in 1952. From then on, cases have been recorded in tropical Africa, Southeast Asia and the Pacific Islands. Experts at the CDC believe that more Zika outbreaks have probably occurred in many locations over the years. However, as symptoms of Zika can be similar to those of a variety of other diseases, such as Dengue fever, many cases may not have been recognised.
In Brazil, cases of Zika have increased 20-fold since May 2015, and almost 4,000 cases of microcephaly in newborns have been reported since October 2015.
In the US Territories, 351 locally acquired cases of mosquito-borne Zika virus have been reported in the Commonwealth of Puerto Rico, the US Virgin Islands, and American Samoa, as of April 2016 (of which 37 were pregnant women and 1 had Guillain-Barré syndrome and 3 travel-associated cases).
In the US States, no local mosquito-borne Zika virus disease cases have been reported, however, there have been 346 travel-associated cases (as of April 2016) whereby people have been infected during travel to a Zika outbreak area and diagnosed on their return. The CDC estimates that travel-associated Zika cases among travelers visiting or returning to the United States will likely increase potentially resulting in the local spread of the virus in some areas of the United States.
Outbreaks of Zika have also been identified in Africa, Southeast Asia, the Caribbean and Pacific Islands. Three travellers returning to the United Kingdom from South America have also recently tested positive for Zika according to Public Health England.
Zika virus hotspots
Current Zika hotspots
- Cape Verde (West Africa)
- The Caribbean has been widely affected including:
- Outbreaks across Central America include:
- In the Pacific Islands:
- In South America outbreaks have been noted in:
Where are you most likely to find the types of mosquito that can transmit Zika virus?
Zika is spread primarily by bites from an infected Aedes mosquito. Both the Aedes aegypti (Yellow fever) and Aedes albopictus (Asian tiger) mosquitoes are carriers of several tropical diseases. They can be present in more temperate areas in summer months, including the southern and eastern US.
Whilst there is speculation about very small numbers of this species of mosquito arriving in shipments of water containers into the UK, this is yet to be proven.
The Aedes mosquito is a genus most commonly found in tropical and subtropical zones, but is now also found on all continents except Antarctica. They are opportunistic and aggressive biters, whose feeding peaks in the early morning and late afternoon. However, some types of Aedes (such as Aedes aegypti) are capable of breeding indoors and therefore bite throughout the day. This ability to breed indoors also makes them less susceptible to climatic variations and increases the mosquitoes’ longevity. Aedes mosquitoes have been able to expand their geographic distribution rather easily through the increase in international trade due to the fact that their eggs can withstand very dry conditions and remain viable for many months in the absence of water.
Members of the Aedes genus are known vectors of many diseases in addition to Zika, most notably Dengue fever, Yellow fever, West Nile virus, Chikungunya and Eastern Equine Encephalitis.
Zika virus symptoms, vaccinations and treatment
What are the symptoms of Zika Virus and how long do they last?
The incubation period from exposure to developing symptoms is typically a few days to a week after being bitten by an infected mosquito and normally lasts for around 4-7 days. Zika usually remains in the blood of an infected person for about a week but it can be found to be longer in some people.
Can you be vaccinated against Zika virus before you travel?
There is currently no vaccine to protect against Zika virus. Although research is underway to develop a vaccine it is likely to be some years before it is ready for use on the general population. This is why taking steps to prevent mosquito bites in high risk areas is key.
How is Zika virus treated?
There is no specific treatment for Zika virus. Always seek urgent advice from your doctor or healthcare professional if you feel unwell after travel to a country where malaria and other insect-borne diseases are present.
What should I do if I think I have been exposed to Zika virus?
Always seek urgent advice from your doctor or healthcare professional if you feel unwell after travelling to a country where malaria and other insect-borne diseases are present.
Zika virus travel concerns and protection
What should I do before I travel if I’m concerned about Zika virus?
Always, always be prepared and do your research well before you travel. At least six weeks before your trip, check the CDC or Fit For Travel websites to see if the area you are visiting is affected by an outbreak of Zika or other mosquito-borne diseases and always seek advice from your Doctor or travel clinic before you leave.
What can I do to protect myself and my family against Zika virus?
Take meticulous precautions against bites by covering exposed skin and using a repellent containing an active ingredient registered with the U.S. Environmental Protection Agency (EPA).
Bite prevention tips
- Being prepared is key in reducing the risk of being bitten
- In high risk areas, cover as much exposed skin as possible with lightweight long-sleeved tops and trousers
- Choose accommodation with air conditioning and screens on windows and doors
- Avoid areas of standing water such as lakes and reservoirs, where mosquitoes thrive
- Apply a thin, even layer of a mosquito repellent proven to be effective, to exposed skin
- Use insect repellents safely. Always read the label and product information before use
Is Mosi-guard Natural effective against the mosquitoes that transmit Zika virus?
Mosi-guard Natural is suitable for all the family, including children from six months of age and pregnant and breastfeeding women. The active ingredient in Mosi-guard Natural, Citriodiol® (also known as Oil of Lemon Eucalyptus and Eucalyptus citriodora oil hydrated, cyclized EC Oil (H/C) is EPA registered.
Derived from essential lemon eucalyptus oil, Citriodiol® is the only naturally sourced active ingredient recommended by the CDC for protection against mosquito borne disease.
Most-guard Natural is also free from DEET (N,N-diethyl-meta-toluamide) a man-made chemical which is known to damage plastics. To date it is worth noting that there are few published studies addressing the effects of DEET in mothers-to-be and their offspring and no studies involved pregnant women in the first trimester.