CLEANLINESS DRIVE TO COUNTER DENGUE EPIDEMIC IN PAKISTAN

Dengue is a mosquito-borne infection found in tropical and sub-tropical regions around the world. In recent years, transmission has increased predominantly in urban and semi-urban areas and has become a major international public health concern. Severe dengue was first recognized in the 1950s during dengue epidemics in the Philippines and Thailand. Each year dengue affects approximately 100 millions people in the tropics and subtropics, resulting in fever, muscle and joint ache. There are four distinct, but closely related, serotypes of the virus that cause dengue (DEN-1, DEN-2, DEN-3 and DEN-4). Recovery from infection by one provides lifelong immunity against that particular serotype. However, cross-immunity to the other serotypes after recovery is only partial and temporary. Subsequent infections by other serotypes increase the risk of developing severe dengue.

In Pakistan, an outbreak of dengue was first reported in Karachi in 1994. Today the Epidemic of Dengue Viral Infections has spread severely through out the country.
This recent outbreak of dengue fever in Pakistan confirmed the presence of all four types of dengue viral infections. Two of these were reported in previous outbreaks in Karachi city, while a third has been reported in the Lahore outbreak of 2008. Now all four types of dengue serotypes have been confirmed in Punjab. In November 2010, more than 21,204 people were infected with dengue. Since 2011 it is increasingly becoming an epidemic in Pakistan. The disease is spreading more rapidly than the previous years. It has attracted the attention of the Government of Pakistan, especially the Punjab Government since it is widespread in that particular province of the country. As of November 2011, it has killed over 300 people in the last several months. Majority of the people died and infected are from the Lahore area in Punjab, Pakistan.

Transmission

The Aedes aegypti mosquito is the primary vector of dengue. The virus is transmitted to humans through the bites of infected female mosquitoes. After virus incubation for 4–10 days, an infected mosquito is capable of transmitting the virus for the rest of its life.

Infected humans are the main carriers and multipliers of the virus, serving as a source of the virus for uninfected mosquitoes. Patients who are already infected with the dengue virus can transmit the infection (for 4–5 days; maximum 12) via Aedes mosquitoes after their first symptoms appear.

The Aedes aegypti mosquito lives in urban habitats and breeds mostly in man-made containers. Unlike other mosquitoes Ae. aegypti is a daytime feeder; its peak biting periods are early in the morning and in the evening before dusk. Female Ae. aegypti bites multiple people during each feeding period.

Aedes albopictus, a secondary dengue vector in Asia, has spreaded from North America and Europe largely due to the international trade in used tyres and other goods. Ae. albopictus is highly adaptive and therefore can survive in cooler temperate regions of Europe. Its spread is due to its tolerance to temperatures below freezing, hibernation, and ability to shelter in microhabitats.

Characteristics

After being bitten by a mosquito carrying the virus, the incubation period ranges from three to fifteen (usually five to eight) days before the signs and symptoms of dengue appear in stages. Dengue Fever starts with:

• Chills, Headache, Pain upon moving the eyes, and low backache.
• Painful aching in the legs and joints occurs during the first hours of illness.
• The temperature rises quickly as high as 104 F (40 °C), with relatively low heart rate (bradycardia) and low blood pressure (hypotension).
• The eyes become reddened.
• A flushing or pale pink rash comes over the face and then disappears.
• The glands (lymph nodes) in the neck and groin are often swollen.
• A characteristic rash appears along with the fever and spreads from the extremities to cover the entire body except the face.
• The palms and soles may be bright red and swollen.
• Fever and other signs of dengue last for two to four days, followed by a rapid drop in body temperature with profuse sweating. A second rapid rise in temperature follows.

Severe dengue is a potentially deadly complication due to plasma leaking, fluid accumulation, respiratory distress, severe bleeding, or organ impairment. Warning signs occur 3–7 days after the first symptoms in conjunction with a decrease in temperature (below 38°C/ 100°F) and include: severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums, fatigue, restlessness, blood in vomit. The next 24–48 hours of the critical stage can be lethal; proper medical care is needed to avoid complications and risk of death.

Treatment

There is no specific treatment for dengue fever. Government of Pakistan and is working hard on the preventive measures to reduce the spread of the epidemic. The Government of Punjab has opened a hotline called Punjab Health Line Project for Dengue which can be reached at 0800-99000. This is to facilitate the circulation on the signs and symptoms of dengue, reach for help for suspected cases and ultimately help identify areas where the epidemic may have reached. Spraying teams have been organized for the purpose of fumigating, spraying and fogging areas where the mosquitoes have known to infect people with the virus. Supportive care with analgesics like paracetamol,  fluid replacement, and bed rest is usually sufficient. Aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and corticosteroids should be avoided. Management of severe dengue requires careful attention to fluid management and proactive treatment of hemorrhage. There is no vaccine to protect against dengue. Developing a vaccine against dengue/ severe dengue has been challenging although there has been recent progress in vaccine development. WHO provides technical advice and guidance to countries and private partners to support vaccine research and evaluation. Several candidate vaccines are in various phases of trials.

Prevention and control

At present, the only method to control or prevent the transmission of dengue virus is to combat vector mosquitoes through:

• Preventing mosquitoes from accessing egg-laying habitats by environmental management and modification;
• Disposing of solid waste properly and removing artificial man-made habitats;
• Heavy monsoon rains in Punjab provide ideal conditions for dengue-carrying mosquitoes to thrive in stagnant waters. This mosquito breeds in fresh water (rainy water in air cooler, at roofs, flower pots etc). So covering, emptying and cleaning of water storage containers must be done on a weekly basis;
• Applying appropriate insecticides to water storage outdoor containers;
• Using of personal household protection such as window screens, long-sleeved clothes, insecticide treated materials, coils and vaporizers;
• Improving community participation and mobilsation for sustained vector control;
• applying insecticides as space spraying during outbreaks as one of the emergency vector control measures;
• Active monitoring and surveillance of vectors should be carried out to determine effectiveness of control interventions.