Dengue Fever.

Question

Doc, My Cousin is admitted in ….Hospital in Mombasa with severe Malaria-like fever. We were sure it was Malaria or Typhoid. These are very common at the Coast. But he is not improving. The Doctors now say it is something called Dengue Fever. He is in kidney failure. As a family we are very worried. What is this “animal” called Dengue? It’s a new one for us. Please shed light on this condition. What causes it? Any treatment available? Is it infectious? Does one develop immunity? We visited him and stayed for quite some time. Will I get it now? Please help. We are very worried…

Sincerely,

XYZ

Answer

XYZ, Thank you for asking this question. Yes, lately we have had scores of cases of Dengue at the Coast. It has not always been a very common condition and neither has it always been very easy to detect as it easily mimics Malaria and Typhoid. Both conditions being common at the Coast. We shall, respond hereby.

What is Dengue?

This is an illness caused by a virus which is transmitted by a variety of Mosquito we call Aedes whose principal cause is often Aedes aegypti. This is a slightly smaller Mosquito than the one that transmits Malaria (we call Anopheles). The virus has five different types. Infection with one type usually gives lifelong immunity to that type, but only short-term immunity to the others. Subsequent infection with a different type increases the risk of severe complications. Infection occurs from a single female mosquito bite and can also be transmitted via infected blood products, through organ donation and pregnant mother to her unborn child via the placenta. Infection by one virus grants lifelong immunity from that virus.

An Aedes female mosquito looks like this

Mosq

What are the signs and symptoms of Dengue

The characteristic symptoms of dengue are sudden-onset fever, headache (typically located behind the eyes), muscle and joint pains, and a body rash. The alternative name for Dengue, “Break-bone fever“, comes from the associated muscle and joint pain. They typically bite during the day, particularly in the early morning and in the evening, but they are able to bite and thus spread infection at any time of day all during the year. The Aedes mosquitos love laying eggs near a homestead. They prefer human hosts rather than animals. So they tend to stay close to human habitation preferring to lay its eggs in artificial water containers, to live in close proximity to humans, and to feed on people rather than other vertebrates

Dengue fever begins with a sudden high fever, then a flat rash may appear over most of the body. Infected people may have increased skin sensitivity and are very uncomfortable from this rash

The rash looks like this

rash

symp

Other symptoms include: fatigue, nausea, swollen lymph nodes, vomiting, cough, sore throat and nasal stuffiness. In a small proportion of cases the disease develops into the life-threatening dengue hemorrhagic fever, resulting in bleeding, or into dengue shock syndrome, where dangerously low blood pressure occurs

Dengue progression

There are 3 phases of the disease

  • Febrile phase – here the patient has fever with high temperatures that will not respond to regular medication. The condition can easily mimic malaria or typhoid. Fever is often associated with headaches, generalized body aches and even nausea and vomiting. At this stage a typical rash forms all over the bod
  • Critical phase – At this time the patient is very ill. Typically starts bleeding from the gut (mouth and rectum), becomes very dehydrated and may eventually go into multiple organ complications (such as kidney failure), shock and even death. This is 5% of all case.
  • Resolution phase – In the majority (80%) of patients, the condition resolves well and the person is cured. The rash disappears and may result in itchy skin and peeling off. The fluid overload may cause altered level of consciousness with even convulsions. But the patient improves completely, leaving fatigue and extreme tiredness which may last for weeks. Our worry is those who end up developing complications in the critical phase above.

Treatment of Dengue

There is no specific treatment to eradicate the virus from the body. Most viral conditions don’t have specific medications as you would for Malaria or Typhoid. The treatment usually consists of symptomatic such as bringing down the fever, rehydrate with intravenous fluids, treating the abdominal upsets/pains, transfusions for the anemia and avoiding convulsions.

Does one become get immunity after infection

The virus has five different types; infection with one type usually gives lifelong immunity to that type, but only short-term immunity to the others. Subsequent infection with a different type increases the risk of severe complications. As there is no commercially available vaccine, prevention is sought by reducing the habitat and the number of mosquitoes and limiting exposure to bites

Prevention of Dengue

To prevent Dengue, a few things you can do include the following

Clear all containers with stagnant water close to homestead. This will eradicate the breeding area for the Aedes mosquitos. We don’t why. But the most predisposed to getting mosquito bites that bring Dengue are youth, women, babies and those women who are big bodied. Probably due to the larger surface area for the mosquito to feed on in these women

Mosquito nets. We cannot overemphasize the need to sleep under a mosquito net. Many people complain that it gets too hot in the Coast. Yet, this remains the one single most effective way of avoiding both Dengue and even Malaria: Sleeping under a mosquito net! Whether a treated net or not, the most important thing is to sleep under a net.

Prevention. Ensure safe pregnancies and blood products screening

In this picture, a community is dispersing stagnant water and thus decreasing mosquito breeding grounds

drain

How about Vaccines

There are no approved vaccines for the dengue virus. Prevention thus depends on control of and protection from the bites of the mosquito that transmits it. The World Health Organization recommends an Integrated Vector Control program. As there is no commercially available vaccine, prevention is sought by reducing the habitat and the number of mosquitoes and limiting exposure to bites

The primary method of controlling Aedes is by eliminating its habitats. This is done by getting rid of open sources of water, or if this is not possible, by adding insecticides or biological control agents to these areas.  Reducing open collections of water through environmental modification is the preferred method of control, given the concerns of negative health effects from insecticides and greater logistical difficulties with control agents. People can prevent mosquito bites by wearing clothing that fully covers the skin, using mosquito netting while resting, and/or the application of insect repellent (DEET being the most effective). However, these methods appear not to be sufficiently effective, as the frequency of outbreaks appears to be increasing in some areas, probably due to urbanization increasing the habitat of Aedes. The range of the disease appears to be expanding possibly due to climate change witnessed in 2014

In short, avoid mosquito bites and you need not worry about getting Dengue

Have a cold Dengue free month

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