Dengue fever is an infectious disease found in the tropics and caused by the dengue virus. It is a febrile illness which is potentially fatal. It is caused by the mosquito transmitted viruses. There are four known serotypes, namely; Dengue virus1 ( DENV-1), Dengue virus 2 (DENV-2), Dengue virus 3( DENV-3) and Dengue virus 4 (DENV-4). It is also known as the break bone disease. Dengue is a major public health problem, the global incidence and severity is on the increase, due to urbanization, overpopulation and global warming. It is now endemic in more than a hundred countries in the world. It was first seen in Asia in the fifties and it is presently a major cause of morbidity and mortality among children. In recent years, Dengue fever and Dengue haemorrhagic fever epidemics have occurred in Asian countries such as Pakistan, Sri- Lanka, Bangladesh, China, India and the Maldives. In 1994, an outbreak of Dengue haemorrhagic fever was reported for the first time in Pakistan, in the region of Karachi, and since then, there has been a steady rise in the number of patients with signs and symptoms consistent with the disease. The disease reached a record high last year, with close to 12,000 people infected and about 130 casualties recorded. More than 85% of the infected were from the Lahore region. Health facilities were stretched to their limits and it took sometime before the outbreak was contained. The city's poor environmental hygiene coupled with the heavy rains which led to the accumulation and stagnation of water in open spaces favoured the breeding of the mosquitoes responsible for the disease. The mosquitoes lay eggs in the stagnated water, water holding cans and containers littering the environment and the homes. The arrival of rains and flooding causes the hatching of the eggs into larvae, pupae and subsequently into adult mosquitoes. The increased rains and flooding led to more eggs being hatched and more mosquitoes.
There are several ways of transmitting the infection, but the major one is when bitten by an infected vector. They are Aedes aegypti, Aedes albopictus and Aedes polynesiensis mosquitoes. The most common vector is the Aedes aegypti mosquito. The female mosquitoes acquire the dengue virus after biting viraemic humans. They become infected after an incubation period of between 8 and 12 days. Afterwards, the infected mosquito then transmits the dengue virus for the rest of its life. Other modes of transmission which are less common include; exposure to dengue infected blood, blood transfusion, organs, bone marrow or solid organ transplant and mucous membrane or needle stick injury that make contact with infected blood. Also, there could be vertical transmission from an infected mother to her baby in pregnancy or during childbirth. The incubation period after a bite by an infected mosquito is typically a 4 to 7 day period. Infection with the dengue virus is characterized by a febrile illness which is acute and any two of the following symptoms; retroorbital pain, headache, muscle aches, joint pain, leukopenia or haemorrhagic manifestations. Usually, the appearance of the rash is after the fever has subsided, and it lasts for about 2-4 days. The rash is either maculopapular or macular and generalized. It could be associated with more severe diseases and nausea/vomiting.
The methods employed for dealing with the epidemic in Pakistan in 2011 were simply methods that eliminated the habitats of Aedes aegypti mosquitoes. There was an aggressive media campaign in both electronic and print media that sensitized the populace about the fever. The causes, vectors, the symptoms and the ways the mosquitoes could be rid off were disseminated among the people. Immediately they were privy to this information, there was an attitudinal change from them. Consequently, open collections of water were dealt with by creating drainage channels which prevented stagnant pools of water in the surroundings, better environmental hygienic practices were observed. The empty containers and cans which held tiny ponds of water and served as breeding sites for the Aedes egypti mosquitoes and littered the surroundings were picked, gathered and discarded properly. The bushy surroundings were cut and made neat. People were encouraged to wear full clothing that covers the skin; the protective clothing reduces the exposure to Aedes aegypti bites. DEET containing repellents were applied to skin and clothing. Also, clothing were impregnated with permethrin, this reduced the incidence of mosquito bites. Pyrethroid and organophosphate insecticides were sprayed in the regions affected first, then afterwards in other parts of the country. The infected were identified and immediately taken to the hospitals for effective management.
In conclusion, Dengue is a highly preventable yet a deadly infection that is ravaging the tropics. Though its incidence is on the increase worldwide due to increasing population density, poor environmental hygiene and global warming which has resulted in flooding. Its prevention, through adequate environmental hygiene is key to its eradication.
Work Cited
(2012)http://tribune.com.pk/story/263068/dengue-fever-infects-over-12000-in-pakistan/
