By Fauzia Saeed, Psychologist/Counselor, VCCTC PRCS Punjab Branch, Lahore
Dengue and dengue hemorrhagic fever (DHF) are acute febrile diseases, found in the tropics, with a geographical spread similar to malaria. Caused by one of four closely related virus serotypes of the genus Flavivirus, family Flaviviridae, each serotype is sufficiently different that there is no cross-protection and epidemics caused by multiple serotypes (hyperendemicity) can occur. Dengue is transmitted to humans by the mosquito Aedes aegypti (rarely Aedes albopictus).
TRANSMISSION
Dengue viruses are transmitted to humans through the bites of infective female Aedes mosquitoes. Mosquitoes generally acquire the virus while feeding on the blood of an infected person. Once infective a mosquito is capable of transmitting the virus to susceptible individuals for the rest of its life, during probing and blood feeding. Infected femalemosquitoes may also transmit the virus to the next generation of mosquitoes by transovarial transmission i.e. via its eggs, but the role of this in sustaining transmission of virus to humans has not yet been delineated. Humans are the main amplifying host of the virus, although studies have shown that in some parts of the world monkeys may become infected and perhaps serve as a source of virus for uninfected mosquitoes. The virus circulates in the blood of infected humans for 2-7 days, at approximately the same time as they have fever; Aedes mosquitoes may acquire the virus when they feed on an individual at this time.
TYPES OF DENGUE FEVER
- DF Dengue Fever
- DHF Dengue Hemorrhagic Fever
- DSF Dengue Shock Fever
CHARACTERISTICS
Dengue fever is a severe, flu-like illness that affects infants, young children and adults but rarely causes death. The clinical features of dengue fever vary according to the age of the patient. Infants and young children may have a non-specific febrile illness with rash. Older children and adults may have either a mild febrile syndrome or the classical incapacitating disease with abrupt onset and high fever, severe headache, pain behind the eyes, muscle and joint pains, and rash. Dengue haemorrhagic fever is a potentially deadly complication that is characterized by high fever, haemorrhagic phenomena—often with enlargement of the liver—and in severe cases, circulatory failure. The illness commonly begins with a sudden rise in temperature accompanied by facial flush and other non-specific constitutional symptoms of dengue fever. The fever usually continues for 2-7 days and can be as high as 40-41° C, possibly with febrile convulsions and haemorrhagic phenomena. In moderate DHF cases, all signs and symptoms abate after the fever subsides. In severe cases, the patient’s condition may suddenly deteriorate after a few days of fever; the temperature drops, followed by signs of circulatory failure, and the patient may rapidly go into a critical state of shock and die within 12-24 hours, or quickly recover following appropriate volume replacement therapy.
SIGNS & SYMPTOMS OF DENGUE FEVER
Dengue fever is manifested by a sudden onset of fever, with severe headache, joint and muscular pains (myalgias and arthralgias, severe pain gives it the name break-bone fever) and rashes; the dengue rash is characteristically bright red, petechia and usually appears first on the lower limbs and the chest – in some patients, it spreads to cover most of the body. There may also be gastritis with some combination of associated abdominal pain, nausea, vomiting or diarrhea.
Some cases of dengue fever develop much milder symptoms, than can, when no rash is present, be missdiagnosed as a flu or other viriasis. This is the cause of some travelers from tropical areas passing through denge in their home countries without being properly diagnosed.
The classical dengue fever lasts about six to seven days with a smaller peak of fever at the trailing end of the fever (the so-called “biphasic pattern”). Clinically, the platelet count will drop until the patient is afebrile.
HAEMORRHAGIC SYMPTOMS
Bleeding, particularly in skin (petichiae), occaisionally in gunms and nose increased vascular permeability, resulting in leakage of plasma into extravascular spaces and which leads to hypovolaemia haemorrhagic symptoms reduced blood pressure vascular changes and coagulopathy circulatory shock vomiting and abdominal pain lymphadenopathy and hepatomegaly may occur presence of blood in stools, vomitus, urine
Cases of DHF also shows higher fever, haemorrhagic phenomena, thrombocytopenia and haemoconcentration. A small proportion of cases leads to dengue shock syndrome (DDS) which has a high mortality rate.
MORPHOLOGY
RNA viruses belong to family Flaviviridae four serotypes (1, 2, 3 and 4) different strains within each serotype
PATHOGENESIS
Transmitted by mosquito, principally Aedes aegypti incubation time ranges from 3 to 10 days
CLINICAL ASPECTS
Primary Infection acute febrile illness of sudden onset fever lasting 3 to 5 days headache, myalgia, arthralgia or muscular pain, retro-orbital pain, anorexia fine mculopapular rash on extremities recovery may be associated with fatigue and depression chidren usually have milder disease than adults
ANTIBODY RESPONSE
Infection will result in lifelong immunity to that serotype, but only temporary immunity to other serotypes
PRIMARY INFECTION
- IgM antibodies appear approximately 5 days after onset of symptoms and rise for the next 1-3 weeks
- IgM antibodies detectable for up to 6 months
- IgG are detectable at approximately 14 days after onset of symptoms and are maintained for life
SECONDARY INFECTION
Approximately 5% patients do not produce detectable levels of specific IgM
- IgM titre can be slower to rise in secondary infection
- IgG appears approximately 2 days after symptoms appear
- IgG titre significantly higher in secondary infection
DIAGNOSIS OF DENGUE FEVER
The diagnosis of dengue is usually made clinically. The classical picture is of high fever with no localising source of infection, a petechial rash with thrombocytopenia and relative leukopenia.
ELISA
Pre-treatment of sera is not required serial dilution not required – diagnosis can be made from a single serum specimen diagnosis can be from a single serum sample
Serology and PCR (polymerase chain reaction) studies are available to confirm the diagnosis of dengue if clinically indicated.
DENGUE FEVER TREATMENT
The mainstay of treatment is supportive therapy. The patient is encouraged to keep up oral intake, especially of oral fluids. If the patient is unable to maintain oral intake, supplementation with intravenous fluids may be necessary to prevent dehydration and significant hemoconcentration. A platelet transfusion is indicated if the platelet level drops significantly.
EPIDEMIOLOGY
The first epidemics occurred almost simultaneously, in Asia, Africa, and North America in the 1780s. The disease was identified and named in 1779. A global pandemic began in Southeast Asia in the 1950s and by 1975 DHF had become a leading cause of death among children in many countries in that region. Epidemic dengue has become more common since the 1980s – by the late 1990s, dengue was the most important mosquito-borne viral disease affecting humans after malaria, there being around 40 million cases of dengue fever and several hundred thousand cases of dengue hemorrhagic fever each year. In February 2002 there was a serious outbreak in Rio De Janeiro, affecting around one million people but only killing sixteen.
Significant outbreaks of dengue fever tend to occur every five or six years. There tend to remain large numbers of susceptible people in the population despite previous outbreaks because there are four different strains of the dengue virus and because of new susceptible individuals entering the target population, either through childbirth or immigration.
There is significant evidence, as suggested bu S.B. Halstead in the 1970s, of enhancement of DHF incidence in secondary infections by serotypes different from the one that caused the primary infection in a process known as antibody-dependent enhancment (ADE). Therefore, people that have passed a primary infection are usually advised to avoid the risk of a second one.
In Singapore, there are about 4-5000 reported cases of dengue fever or dengue hemorrhagic fever every year. In the year 2003, there were 6 deaths from dengue shock syndrome. It is believed that the reported cases of dengue are an underrepresentation of all the cases of dengue as it would ignore subclinical cases and cases where the patient did not present for medical treatment. The mortality rate for dengue is therefore probably less than 1 in 1000.
Current Situation of Dengue Fever in Pakistan
LAHORE:
Treating the dengue virus is a serious issue of every citizen Lahore. Section-144 has been enforced in Lahore to control the dengue outbreak which killed over 30 in the city. At least 11 more dengue fever patients died in Punjab and Khyber Pakhtunkhwa, as the number of people infected with the virus reached 6,000 in Punjab according to an official count.
Dengue also infected prisoners in two jails of Lahore, including Kot Lakhpat Jail and Camp Jail. According to reports, six people died in Punjab in the last 24 hours because of the dengue virus.
It was confirmed from the analysis of the samples from hospitals that despite sprays and fumigation, dengue carrier mosquitoes were breeding there and had also affected people coming to these hospitals.
Separately, the Khyber Pakhtunkhwa Health Department said 125 suspected cases were reported in the province of which 48 were confirmed. According to details, 14 were confirmed in Abbottabad, 11 in Haripur, 10 in Mansehra, 4 in Peshawar, 2 each in Bannu and Mardan and one each in Batagram, Lakki Marwat, Nowshera and Khyber Agency. Five people have so far died from dengue, including 3 in Haripur and one each in Mansehra and Nowshera, respectively.
Despite all government efforts hundreds of suspects are coming to different blood testing facilities in both public and private sectors with an increasing number of positive cases everyday, further underlining the gravity of the situation. However, free-of-cost blood testing facility is not available at any of the 12 collection centres of Shaukat Khanum Hospital, which has “disappointed” many dengue suspects coming for a blood test.
KARACHI
Dengue fever is now rapidly spreading in all corner of Pakistan (Dengue Fever information in Pakistan). Earlier this disease was spread in Lahore and Karachi but now cases of Dengue fever are coming from all major cities and towns. The first case of Dengue fever in Pakistan reported in year 1994 in Karachi. After that this disease spread slowly and in 2006 there were large number of patients affected with Dengue fever. In 2006 World Health Organization for the first time recognized the disease in Pakistan and according to their official statistics more then 4800 persons were affected by disease and almost 50 died till 2006. First case of Dengue fever in Lahore was reported in 2007 and since then the cases and causalities are increasing with rapid pace.
Dengue fever is tropical disease and the mosquito responsible for that disease can not fly long distance. Some years before when there was attack of Dengue Disease in USA they investigated the matter and found that the disease was caused by some recycled imported tyres hence it is evident that this disease was also came in Pakistan through that way and
Karachi is the main Sea Port city and worst affected by this disease. All imported material is delivered from Karachi to the all parts of Pakistan and this way the disease is now reached in all corners of Pakistan. According to the statistics provided by local authorities, 689 people are suffering from dengue fever in the city while the total number of cases across the province is 807. According to sources, there are forty-one dengue patients in Ganga Ram Hospital, 5 in Mayo Hospital, 9 in Jinnah Hospital, 3 in Children’s Hospital, 36 in City District Government dispensaries, 2 in Services Hospital and 1 in Punjab Institute of Cardiology. Thirty-two cases were also reported in different private hospitals and clinics in the city.
Health experts are more worried about children catching this infection because extremely high fever is one of the key symptoms of this disease, which can prove to be devastating for kids due to relatively low level of immunity against extreme ailments in their bodies.
In order to prevent and control this menace, the pre-emptive steps and proactive strategy need to be adapted effectively combat any future out break of Dengue Fever (DF) in the province. In this regard, following guideline is being circulated for strict compliance:
- Take effective measures for removal of mosquito breading sites.
- Start Insecticidal Residual spray campaigns in the respective areas of jurisdiction.
- Take integrated mosquito control measures with limited reliance on peak season insecticidal usage.
- Ensure availability of essential medical supplies for emergency use.
- Develop a uniform Data-Base at the Directorate and District Level and establish a disease surveillance system and report Dengue Fever cases on daily basis.
- Laboratory facilities be enhanced and made freely available at Tertiary level Hospitals on round the clock, free of cost basis to all the patients admitted or reported and for back-up support to the DHQ/ THQ Hospitals of respective region.
- Follow and investigate every suspected Dengue Fever Case.
- Institute awareness campaign, orientation seminars and talks on media for raising community awareness.
- Sensities medical community on the disease and encourage factual reporting of dengue fever.
- Coordinate, fore-warm and provide technical advice to other agencies like Military Hospitals, Pakistan Railways, WAPDA, Civil Aviation Authority (CAA) etc. through sharing Dengue Fever prevention guidelines.
SOME OTHER STATISTICS:
- During epidemics of dengue, attack rates among susceptibles are often 40 – 50%, but may reach 80 – 90%.
- An estimated 500 000 cases of DHF require hospitalisation each year, of whom a very large proportion are children and roughly 5% die.
- Without proper treatment, DHF case fatality rates can exceed 20%. With modern intensive supportive therapy, the rate can be reduced to less than 1%.
- The spread of dengue is attributed to expanding geographic distribution of the four dengue viruses and of their mosquito vectors, the most important of which is the predominantly urban species Aedes aegypti. A rapid rise in urban population is bringing ever greater numbers of people into contact with this vector, especially in areas which are favourable for mosquito breeding e.g., where household water storage is common and where solid waste disposal services are inadequate.
IMMUNIZATION
Vaccine development for dengue and DHF is difficult because any of four different viruses may cause disease, and because protection against only one or two dengue viruses could actually increase the risk of more serious disease. Nonetheless, progress is gradually being made in the development of vaccines that may protect against all four dengue viruses. Such products could be commercially available within several years.
DENGUE FEVER PREVENTION
There is no commercially ready vaccine for the dengue flavivirus.
Primary prevention of dengue mainly resides in eliminating or reducing the mosquito vector for dengue. Initiatives to eradicate pools of standing water (such as in flowerpots) have proven useful in controlling mosquito borne diseases.
Methods of prevention of Dengue fever mentioned in various sources include those listed below. This prevention information is gathered from various sources, and may be inaccurate or incomplete. None of these methods guarantee prevention of Dengue fever.
- Avoid mosquito bites
- Mosquito repellant
- Protective clothing
- Window screens
- Remove water-filled mosquito breeding areas
The best way to prevent dengue fever is to take special precautions to avoid contact with mosquitoes. Several dengue vaccines are being developed, but none is likely to be licensed by the U.S. Food and Drug Administration in the next few years.
When outdoors in an area where dengue fever has been found,
- Use a mosquito repellant containing DEET.
- Dress in protective clothing—long-sleeved shirts, long pants, socks, and shoes.
Because Aedes mosquitoes usually bite during the day, be sure to use precautions especially during early morning hours before daybreak and in the late afternoon before dark.
OTHER PRECAUTIONS INCLUDE
- Keep unscreened windows and doors closed.
- Keep window and door screens repaired.
- Get rid of areas where mosquitoes breed, such as standing water in flower pots or discarded tires.
LATEST TREATMENTS FOR DENGUE FEVER
Some of the more recent treatments for Dengue fever include:
- IV fluids
- Acetaminophen
- Analgesics
- Platelet transfusion
TREATMENTS FOR DENGUE FEVER
Treatments to consider for Dengue fever may include:
- Symptomatic and supportive
- Bed rest
- Fluids
- Pain relief medications
CAN DENGUE FEVER LEAD TO OTHER HEALTH PROBLEMS?
Most people who develop dengue fever recover completely within two weeks. Some, however, may go through several weeks of feeling tired and/or depressed. Others develop severe bleeding problems. This complication, dengue hemorrhagic fever, is a very serious illness which can lead to shock (very low blood pressure) and is sometimes fatal, especially in children and young adults.
What You Can Do to Help Fight Mosquitoes
- Empty standing water in old tires, cemetery urns, buckets, plastic covers, toys, or any other container where “wrigglers” and “tumblers” live.
- Empty and change the water in bird baths, fountains, wading pools, rain barrels, and potted plant trays at least once a week if not more often.
- Drain or fill temporary pools with dirt.
- Keep swimming pools treated and circulating and rain gutters unclogged.
- Use mosquito repellents when necessary and follow label directions and precautions closely.
- Use head nets, long sleeves and long pants if you venture into areas with high mosquito populations, such as salt marshes.
- If there is a mosquito-borne disease warning in effect, stay inside during the evening when mosquitoes are most active.
- Make sure window and door screens are “bug tight.”
- Replace your outdoor lights with yellow “bug” lights.
- Contact your local mosquito control district or health department.
NIAID RESEARCH
Scientists supported by the National Institute of Allergy and Infectious Diseases (NIAID) are trying to develop a vaccine against dengue by modifying an existing vaccine for yellow fever. Researchers in NIAID laboratories in Bethesda, Maryland, are using weakened and harmless versions of dengue viruses as potential vaccine candidates against dengue and related viruses.
Other researchers supported by NIAID are investigating ways to prevent dengue viruses from reproducing inside mosquitoes.
Because dengue virus has only recently emerged as a growing global threat, scientists know little about how the virus infects cells and causes disease. New research is beginning to shed light on how the virus interacts with humans — how it damages cells and how the human immune system responds to dengue virus invasion.