November 18, 2006

Dengue fever is an acute viral illness of varying severity. It is caused by one of the four closely related, but antigenically distinct, virus serotypes (DEN-1, DEN-2, Den-3 and Den-4), of the genus Flavi-virus. All four of these dengue virus serotypes appear in Asia, Africa and the Americas. But Southeast Asia and the Western Pacific are the most seriously affected regions. Infection with one of the serotypes provides immunity to only that serotype for life, so people living in a dengue-endemic area can have more than one dengue infection during their life. The subsequent reinfection by another strain of the dengue virus increases the risk of acquiring the more serious form of the disease, that is, Dengue Haemorrhagic Fever, which can be fatal. In 20-30 per cent of Dengue Haemorrhagic Fever (DHF) cases, the patient develops shock, known as the dengue shock syndrome (DSS).

It is a mosquito-borne infection found in tropical and sub-tropical regions around the world. In recent years, it has become a major international public health concern. This disease used to be called "break-bone" fever because it sometimes causes severe joint and muscle pain, which makes the one feel like bones are breaking. DHF is often called “Fever of Unknown Origin”, because many ordinary doctors are not acquainted with the symptoms of this deadly disease.

The dengue virus is transmitted to humans through the bite of the infective female Aedes Aegypti mosquito. Mosquitoes generally acquire the virus while feeding on the blood of an infected person. After virus incubation for 8-10 days, an infected mosquito is capable, during probing and blood feeding, of transmitting the virus to susceptible individuals for the rest of its life.

The virus circulates in the blood of infected humans for two to seven days, at approximately the same time as when they have fever; the vector mosquitoes may acquire the virus when they feed on an individual during this period.

The symptoms of dengue fever include a sudden onset of fever with severe headache, muscle and joint pains and rashes (bright red rashes that usually first occur on the lower limbs and the chest and, in some patients, spread to cover most of the body). There may also be gastritis with a combination of associated abdominal pain, nausea, vomiting or diarrhoea. In DHF, the fever is higher; the blood vessels start to leak and cause bleeding from the nose, mouth and gums. Bruising can be a sign of bleeding inside the body. Without prompt treatment, the blood vessels can collapse, causing shock which has a high mortality rate.

The disease is self-limiting for which only supportive care is required. Paracetamol may be used to treat patients with symptomatic fever, while oral intake, especially fluids, is encouraged. If the patient is unable to maintain oral intake, supplementation with intravenous fluids may be necessary to prevent dehydration and significant haemo-concentration. A platelet transfusion is indicated if the platelet level dropped significantly or if there is significant bleeding. Transfusion is recommended if the platelet count drops below 20,000 without haemorrhage/bleeding or 50,000 with haemorrhage/bleeding.

The disease can be controlled if diagnosed early and the patient is given appropriate treatment.

Since the symptoms of dengue fever are generally similar to that of malaria, doctors start treating fever with anti-malarial or antibiotic medicine. Most of the patients admitted to hospitals here had already used antibiotics or anti-malarial drugs, which complicated their case as these medicines served to reduce the platelet count further. The antibiotics and anti-malarial drugs bear a serious toxic effect on the bone marrow. This impairs the production of white blood cells (WBCs) and platelets. Thus, the dengue fever virus also acts in the same manner by killing WBCs and platelets. The combination of the two worsens the condition.

In an epidemic situation, it is advised that all treatment should follow pre-testing to rule out the possibility of the disease that is spreading. But this is usually not done and in some cases this negligence proves fatal.

There is no vaccine that protects against the dengue virus. The vaccine development for dengue and DHF is difficult because any of the four different viruses may cause the disease, and because protection against only one or two dengue viruses could actually increase the risk of a more serious disease. However, progress is being made in the development of vaccines that may protect against all four dengue viruses.

The dengue virus has emerged as a post-monsoon phenomenon in Southeast Asia and countries like Pakistan, Indonesia and India are in its grip this year.

According to a World Health Organisation (WHO) study, in countries where dengue fever has become endemic, the sequence is more or less the same: first there are sporadic cases, followed by dengue epidemics which progressively become more frequent until they are seen virtually every year with major epidemics occurring at three to five year intervals.

The sporadic cases of dengue fever occurring in Karachi over the past few years increased to about 200 to 300 cases last year and to about 800 (to date) this year. It is feared that if appropriate measures are not taken, Karachi, and maybe other parts of the country, will be caught in a severe dengue epidemic, affecting thousands of people.

As there is no vaccine or anti-viral drug for dengue fever, the best strategy in the fight against this disease is prevention and the only way to prevent it is to reduce, if not eliminate, the carrier vector and that is possible only by cleaning places where the mosquitoes breed. The city government is running a fumigation campaign to restrict breeding spots in the city. Only 33 per cent of Karachi is under the city government and it can only extend its services to the entire city with the help of the other agencies. People should also make individual efforts to keep their homes and localities clean; water should not be kept in open vessels at homes as the vector mosquito breeds in clean water.

When the first cases started coming in in June, there were no testing facilities in any of the government hospitals in Karachi and the test was quite expensive at one of the most prestigious private hospitals of the city that had the facility. All samples had to be sent to Islamabad and it often took a week for the results to come. Though arrangements have been made and testing facilities are now available in the city, there is a need to establish and extend these facilities on a permanent basis.

According to Dr Kaleem Butt MS, Civil Hospital, Karachi, around 3,000 cases have so far been registered but only 800 have been proved positive for the dengue fever. He suggested that there is a need to investigate the rest of the cases as well as other viruses may be prevalent that remain are going unrecognised and untreated.

“At present, dengue fever is being reported mostly from major cities, but chances of it being spread to rural areas cannot be ruled out”, says Dr Butt. If this happens, the situation can become serious because if a city like Karachi was lacking in facilities for testing, what may happen in rural areas is anybody’s guess. There is a need to set up detection centres at district hospitals so that in case of an outbreak, their patients can be tested and treated promptly.

It is a sad fact that, in Pakistan, hardly any scientific research and investigation is carried out. The problem is compounded because our approach is more treatment- oriented rather than preventive; that is to say, we emphasise on treatment and do not give much importance to prevention and eradication. The virologist, Dr Ashfaq Ahmed Qureshi cited lack of interest as the chief reason for this, though the reason given by the government is none other than lack of funds. Another plight is the lack of co-ordination among various agencies. So it has been suggested that the government should seek the help of WHO to find out ways and means to control the prevailing disease as well as to conduct research for treatment.

There have been reports that the papaya leaf juice is proving to be of some benefit in severe cases as well. In the absence of a comprehensive treatment regimen, it is important that this should be looked into and research be conducted to prove scientifically the benefits or, otherwise, of the papaya leaf juice. In many cases where modern medicine has not yet come up with a sure-shot solution, Ayurvedic treatment has proved beneficial. If research is carried out, there are chances that a medicine could be developed for dengue fever. At this stage when this treatment has no scientific backing, the patients should not depend on this approach as it can lead to delay in proper treatment and complicate the situation, opined Dr Butt. But he agreed that it should be investigated into as if it really has some benefit, a cheap treatment can be made available.

In Pakistan, the management has become all the more difficult as the disease is surrounded by several myths; this is the result of lack of awareness and ignorance.

In many hospitals patients have been kept in isolation wards with the staff treating them wearing masks, which is quite unnecessary as the disease is not contagious and is not transmitted from person to person. This caused fear and confusion among the people. While maintaining hygienic conditions where the patients are kept, it is very important to ensure that there are no mosquitoes.

There is need for a massive awareness campaign to train health care providers and general physicians about the disease protocol of dengue fever particularly, Viral Haemorrhagic Fever. People should also be made aware of not only the dangers of this disease but also signs to recognise it and take immediate and appropriate action. They should also know that the disease is not airborne nor is it contracted through social contact or by working together. Nor does every patient need blood transfusion or even normal drip administration. In this respect, the media, especially the electronic media, can be utilised to create awareness among the masses about dengue fever and other communicable diseases and preventive measures through clear and precise messages and advertisements.

The responsibility lies not only with the government, but the non-government organisations as well as the media to create awareness among the public.

The writer works for Dawn

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