A traveller’s guide to dengue fever
Dengue fever is a serious (potentially life-threatening) viral, mosquito-borne illness that medicine today has little to offer for treatment, apart from symptom relief. There is a vaccine but, due to its potential side effects and toxicity, there is a list of clinical criteria (in Australia) that must be complied with, before it is considered.
It was of interest that a healthy and fit 51-year-old woman consulted me before visiting dengue-endemic Southeast Asia (40 per cent of the population was infected at the time) for a preventive program against the virus. Her lack of prior infection was an advantage.
Dengue fever is spread by the Aedes aegypti mosquitoes — a known vector of several viruses including Zika, Chikungunya and yellow fever, as well as dengue fever. Dengue fever is not contagious by human-to-human contact, as its transmission is reliant on the mosquito vector.
As such, we discussed various aspects of prevention initially with a focus on reducing the risk of being bitten. These mosquitoes thrive in densely populated areas lacking reliable water, waste management and sanitation. They inhabit human buildings as these are protected and provide a major food source — humans. They are attracted by the chemical scents secreted by the human body. They also like stagnant water to breed in and are active during the day, as well as at dawn and dusk.
Personal protective measures are therefore critical. Wearing loose, light-coloured clothing that covers the whole body — reducing skin exposure — and utilising an effective mosquito repellent is important. Lemon eucalyptus spray is less toxic to the person than pharmaceutical repellents containing the chemical DEET (research indicates it is generally as effective). Spraying clothing is also effective. A non-toxic mosquito-repellent bracelet was also suggested.
Research shows daily use of coconut oil as a moisturiser may help deter Aedes aegypti mosquitoes, as it masks the human scent. Essential oils mixed in coconut oil for dilution can be used topically, research recommending neem, clove and lemongrass as being the most effective. Burning these oils in rooms along with citronella may also help.
Indoors should be mosquito-proof. Using a mosquito net preferably also sprayed with a repellent (lemon eucalyptus) was suggested. She could also purchase insecticide-treated mosquito nets. Well-screened and air-conditioned rooms are safer.
Thiamine (vitamin B1) is an old remedy to prevent being bitten by mosquitoes (and other insects).
Research suggests that it changes the human scent to one that repels mosquitoes. The standard dose is 100mg of B1 along with a high-dose activated multi-B vitamin — to be taken daily for a few days before leaving and every day while away (which was about a month in this patient’s case).
Certain foods are known to help prevent viral damage and to increase platelets (the dengue virus can cause hemorrhagic (severe bleeding) conditions and can trigger a sudden drop in blood pressure by significantly lowering platelet and white cell counts). Foods that will help increase platelets are (primarily) papaya leaf — which is more effective as a juice rather than the fruit — pomegranate, beetroot, spinach, aloe vera juice, vitamin C-rich foods (citrus, kiwi fruit, capsicums) and fenugreek seeds (as tea) consumed daily. Curries containing turmeric and fenugreek were recommended. Ensuring she was well hydrated and drinking filtered or fresh coconut water was also essential.
Glucosamine and chondroitin sulphate were recommended as these have been shown to reduce vital entry into the cells. These supplements are also taken to reduce inflammation of arthritis, so they have multiple applications. Quercetin also reduces the inflammation associated with the dengue virus, and zinc and vitamin C are important antivirals.
There is also some interesting research on several herbal medicines that strengthen various pathways that reduce the risk of dengue fever infection. They work by inhibiting viral entry by blocking receptors, inhibiting viral maturation, reducing the inflammatory response to the virus, maintaining platelet levels and blood profiles and supporting the immune system and liver.
A herbal mixture was therefore prescribed (from this research) that included baical skullcap, cats claw, houttynia, eurphorbia, holy basil, schisandra and pawpaw leaf extracts, to be taken three times a day. A herbal tablet with andrographis and olive leaf was
also prescribed. It was also suggested she maintain this program for three weeks after arriving home (it can take two to three weeks to manifest symptoms of dengue fever after being infected).
Although the program seemed extensive, she was pleased with it, recognising the significant risk and need for thorough precautions. Several weeks later, she rang with good news and was impressed. Despite usually being a mosquito magnet, she received only three bites (treated with clove oil) while others nearby were heavily bitten. She also felt extremely well, with no health issues since starting the program, deeming it a great success.
