Dengue fever how many types

Depending on the type of serotype, the symptoms and severity of the condition persist. If the diagnosis is made in the early stages, the chances of early recovery are high.

Depending on the severity and the symptoms observed in the host, Dengue is classified into:. These symptoms include muscle aches, joint pains, Vomiting, High fever, intense and prolonged headaches. Dengue in this stage when diagnosed early can be intervened with different options depending on the severity of the condition.

Dengue Haemorrhagic fever DHF is a serious condition or form of Dengue, when left untreated or when improper medication is taken, this form of Dengue can be fatal. DHF often occurs when blood transfusion occurs through a mosquito from a viremic person. The symptoms are internal bleeding, sudden fever, cold chills, cold or clammy skin, bleeding and bruising under the skin, nose bleeds, restlessness, and a significant decrease in blood pressure.

In this, the patient experiences a sudden onset of shock, high fever, and is prone to sudden collapse due to a significant drop in blood pressure. In this type of Dengue, the patient showcases severe headache, sore throat, and respiratory irregularities. DSS is majorly seen in children under 10 years of age. This is a severe form of Dengue where the symptoms include Blood in stool, blood in vomit, weak pulse, and spitting up blood. Viremic transfer of Dengue causing virus from a person infected with Dengue to a healthy host through mosquito bites is a major cause of Dengue.

In this, when a mosquito bites an infected person, the virus enters the mosquito through the bloodstream and is later released into the host when the same mosquito bites another person. While there are preventive vaccines available for Dengue, a person suffering from Dengue generally becomes immune to that strain of serotype. Dengue commonly occurs in human-inhabited areas and these disease-causing vectors rapidly breed in stagnant waters like open drains, water-filled disposed tyres, unattended flower vases, open tanks, and other stagnant water sources.

Sometimes, Dengue is also transmitted intravenously and through sex. However, the reported issues for these forms are minute. The global medical community is actively researching for isolating and coming up with vaccinations that could make a person immune to Dengue. As of now, there are no vaccines available to completely prevent the occurrence of Dengue.

Dengue at its core is a disease that is predominantly caused by the Aedes mosquito and measures to prevent such an occurrence can go a long way in preventing a Dengue attack. The tropical countries are infamous for Dengue and it is often advised to be prepared to protect your body from mosquito bites. You can be successful in Dengue fever prevention by following these steps. Cover your body with long pants and long-sleeved t-shirts when visiting mosquito-infested areas.

Use protective clothing like gloves, socks, and hats to leave no area of your skin exposed. It is also recommended to tuck your t-shirt ending near your sleeve into the gloves and the pants in your socks near the ankle to leave no openings for a mosquito to reach exposed skin. This will keep mosquitos away. This formula is commonly formed in brands like Odomos, Good Knight, and Mamaearth natural. If you are camping or are in a mosquito-infested area, it is advised that you spray permethrin on your clothes, tent, and other accessories.

Permethrin is a substance that kills any mosquito that comes in direct contact with the substance. Sometimes, trekkers are advised to buy gear clothes that are lined with Permethrin to reduce any chance of Dengue. Door or window screens are specially crafted in ways that allow free flow of air and sunlight but prevent other tiny insects from coming into the house.

Installing screens on doors, windows, and other inlets can go a long way in preventing Dengue. The male Aedes mosquito often breeds in still standing stagnant waters. Ensuring that there is no water stagnating in flower pots, tyres, buckets, old utensils, Air-conditioning water exhausts, open buckets, and leaky pipes can prevent this.

While camping, it also advised to stay away from areas like ponds, and lakes as these water bodies can be a breeding ground for disease-causing mosquitoes.

After you've recovered from dengue fever, you have long-term immunity to the type of virus that infected you — but not to the other three dengue fever virus types.

This means you can be infected again in the future by one of the other three virus types. Your risk of developing severe dengue fever increases if you get dengue fever a second, third or fourth time. Severe dengue fever can cause internal bleeding and organ damage. Blood pressure can drop to dangerous levels, causing shock. In some cases, severe dengue fever can lead to death. Women who get dengue fever during pregnancy may be able to spread the virus to the baby during childbirth.

Additionally, babies of women who get dengue fever during pregnancy have a higher risk of pre-term birth, low birth weight or fetal distress. In areas of the world where dengue fever is common, one dengue fever vaccine Dengvaxia is approved for people ages 9 to 45 who have already had dengue fever at least once.

The vaccine is given in three doses over the course of 12 months. The vaccine is approved only for people who have a documented history of dengue fever or who have had a blood test that shows previous infection with one of the dengue viruses — called seropositivity. In people who have not had dengue fever in the past seronegative , receiving the vaccine appears to increase the risk of severe dengue fever and hospitalization due to dengue fever in the future. Dengvaxia is not available for travelers or for people who live in the continental United States.

But in , the U. Food and Drug Administration approved the vaccine for people ages 9 to 16 who have had dengue fever in the past and who live in the U. Virgin Islands — where dengue fever is common. The World Health Organization stresses that the vaccine is not an effective tool on its own to reduce dengue fever in areas where the illness is common.

Fluid from the bloodstream leaks through the wall of small blood vessels into body cavities because of endothelial dysfunction. As a result, less blood circulates, and shock may result. Furthermore, dysfunction of the bone marrow due to infection of the stromal cells leads to thrombocytopenia, which increases the risk of bleeding, the other major complication. Once inside the skin, dengue virus binds to Langerhans cells dendritic cells in the skin that are engaged in surveillance for pathogens.

Meanwhile, the virus genome is translated in membrane-bound vesicles associated with the cell's endoplasmic reticulum, where the cell's protein synthesis apparatus produces new viral proteins that then copy the viral RNA and begin to assemble viral particles. The mature new viruses bud inside the cell and are released by exocytosis. They are then able to enter other white blood cells, such as monocytes and macrophages.

The initial reaction of infected cells is to produce interferon, a cytokine that raises a number of defences against viral infection through the innate immune system by augmenting the production of a large group of proteins interferon-stimulated genes or ISGs , a process mediated by the Janus kinase signal transducer and activator of transcription pathway also known as the JAK-STAT pathway.

Some of these antibodies bind tightly to the viral proteins and target them for phagocytosis ingestion by specialized cells and destruction , but others bind the virus less well and appear instead to deliver the virus into a part of the phagocytes where it is not destroyed but is able to replicate further.

It is not entirely clear why secondary infection with a different strain of dengue virus places people at risk of dengue hemorrhagic fever and dengue shock syndrome. The most widely accepted hypothesis is that of antibody-dependent enhancement. The exact mechanism behind antibody-dependent enhancement is unclear.

It may be caused by poor binding of non-neutralizing antibodies and delivery into the wrong compartment of white blood cells that have ingested the virus for destruction. Severe disease is marked by capillary permeability which allows protein-containing fluid to escape from blood vessels and coagulopathy.

The diagnosis of dengue is typically made clinically, on the basis of reported symptoms and physical examination, especially in endemic areas. A higher number of petechiae makes diagnosis of dengue more likely; the lower limit for diagnosis is variably defined as 10—20 petechiae per 2.

The diagnosis of dengue fever should be considered in anyone who experiences fever within 2 weeks of being in the tropics or subtropics. The classification of the World Health Organization WHO divides dengue fever into 2 groups: uncomplicated and severe. The graph shown in Figure 6 online illustrates the points when various laboratory tests for dengue fever become positive in relation to the course of illness, with day 0 being the first day of symptoms.

The earliest change detectable on laboratory investigations is leukopenia, which may be followed by thrombocytopenia and metabolic acidosis.

The diagnosis of dengue fever can be confirmed by microbiological laboratory testing. Except for serology tests, these laboratory investigations are of diagnostic value only during the acute phase of the illness. Tests for dengue virus—specific antibodies immunoglobulins G and M [IgG and IgM] can be useful in confirming the diagnosis in the later stages of the infection. Both IgG and IgM are produced after 5—7 days. The highest levels titres of IgM are detected following a primary infection, but IgM is also produced during re-infection.

IgM becomes undetectable 30—90 days after a primary infection, but earlier following re-infections. IgG, by contrast, remains detectable for over 60 years and, in the absence of symptoms, is a useful indicator of past infection. After a primary infection, IgG reaches peak levels in the blood after 14—21 days. During subsequent infections, levels peak earlier and titres are usually higher. Both IgG and IgM provide protective immunity to the infecting serotype of the virus.

In a person with symptoms, the detection of IgM is considered diagnostic. There are no approved vaccines for the dengue virus. The primary method of controlling A. If removal of habitat is not possible, another option is adding insecticides or biological control agents to standing water. There are no specific antiviral drugs for dengue; however, maintaining proper fluid balance is important.

Intravenous hydration, if required, is typically needed for only 1 or 2 days. For patients presenting with unstable vital signs in the face of decreasing hematocrit, blood transfusion should be initiated early, rather than waiting for the hemoglobin concentration to decline to some predetermined "transfusion trigger" level. Packed red blood cells or whole blood is recommended; platelets and fresh frozen plasma are usually not recommended.

During the recovery phase, intravenous fluids are discontinued to prevent fluid overload. If the person is outside the critical phase, a loop diuretic such as furosemide may be used to eliminate excess fluid from the circulation.

Most people with dengue recover without any ongoing problems. Current estimates of incidence range from 50 million 2 to million 3 people infected yearly, leading to half a million hospital admissions 2 and about 25 deaths. Global dengue distribution in Infections are most commonly acquired in the urban environment. Dengue fever, which was once confined to South-East Asia, has now spread to southern China, as well as countries in the Pacific Ocean, Africa, and the Americas.

The incidence of dengue increased fold between and Of the 2. Like most arboviruses, dengue virus is maintained in nature in cycles that involve preferred bloodsucking vectors and vertebrate hosts. The viruses are maintained in the forests of South-East Asia and Africa by transmission from female Aedes mosquitoes—of species other than A. In towns and cities, the virus is primarily transmitted by the highly domesticated A. In rural settings, the virus is transmitted to humans by A.

The first record of a case of probable dengue fever is in a Chinese medical encyclopedia from the Jin dynasty AD — , which referred to a "water poison" associated with flying insects. From that time until , epidemics were infrequent. The marked spread of dengue during and after the Second World War has been attributed to ecologic disturbances. The same trends also led to the spread of different serotypes of the disease to new areas and to the emergence of dengue hemorrhagic fever.

This severe form of the disease was first reported in the Philippines in ; by the s, it had become a major cause of child mortality and had emerged in the Pacific and the Americas.

The origins of the word "dengue" are unclear, but one theory is that it is derived from the Swahili phrase "Ka-dinga pepo," which describes the disease as being caused by an evil spirit. In the report's title he also used the term "bilious remitting fever.

Other historical terms include "breakheart fever" and "la dengue. Research efforts to prevent and treat dengue include various means of vector control, 49 vaccine development, and antiviral drugs. With regard to vector control, a number of novel methods have been used to reduce mosquito numbers, with some success, including placement of the guppy Poecilia reticulata or copepods in standing water to eat the mosquito larvae. Attempts are ongoing to infect the mosquito population with bacteria of the Wolbachia genus, which makes the mosquitoes partially resistant to dengue virus.

Programs are underway to develop a dengue vaccine that will cover serotypes 1 through 4, 13 and now that there is a fifth serotype, it will need to be factored in to these efforts.

In addition to attempts to control the spread of Aedes mosquitos and work to develop a vaccine against dengue, efforts are being made to develop antiviral drugs that would be used to treat attacks of dengue fever and prevent severe complications.

One approach uses nucleoside analogues to inhibit the viral RNA—dependent RNA polymerase within the NS5 protein , which copies the viral genetic material. Clothing : Reduce the amount of skin exposed by wearing long pants, long-sleeved shirts, and socks, tucking pant legs into shoes or socks, and wearing a hat. Mosquito repellents : Use a repellent with at least 10 percent concentration of diethyltoluamide DEET , or a higher concentration for longer lengths of exposure.

Avoid using DEET on young children. Mosquito traps and nets : Nets treated with insecticide are more effective, otherwise the mosquito can bite through the net if the person is standing next to it. The insecticide will kill mosquitoes and other insects, and it will repel insects from entering the room. Door and window screens : Structural barriers, such as screens or netting, can keep mosquitos out. Camping gear : Treat clothes, shoes, and camping gear with permethrin, or purchase clothes that have been pretreated.

Stagnant water : The Aedes mosquito breeds in clean, stagnant water. Checking for and removing stagnant water can help reduce the risk. Thermoregulation is how the body maintains a steady internal temperature, which is essential for keeping it healthy. Learn more here. A febrile seizure can occur in a young child when their body temperature suddenly rises, usually as a result of infection or inflammation.

Learn more…. Several conditions, such as the flu, may cause chills with a fever. Learn more about chills with a fever here. Fever in toddlers normally resolves without treatment. However, some situations warrant medical attention.