ANSWERS TO QUESTIONS ON THE SPREAD AND CONTROL OF DISEASES PART 2

Anopheline mosquito with sporozoites in her salivary glands bites human being it transmits malaria. Transfusion of blood containing malarial parasites and lack of prophylaxis can lead to spread of malaria.

Prevention and Control : Chemoprophylaxis is achieved by chloroquine, malarone, doxycycline or mefloquine. Vector control strategies include indoor and outdoor spraying of insecticides, using insecticides treated nets and treatment of mosquito breeding sites with insecticides to eliminate them. The other measures are proper disposal of waste water and filling of waste water reservoirs (Boon, Nicholas, and Davidson 2006).

Dengue

In 1960 there was no case dengue fever, in 1990, the average number of cases reached above 400,000 and in 2005 the number reached above 900,000.In last twenty years geographical distribution of disease and number of cases have increased dramatically. The disease is endemic in south-east Asia, India, Africa, Caribbean and Americas (Mahr 2007).

Causative Organism and vector: Causative organism is dengue flavi virus with four serotypes and all produce similar clinical syndrome. Principal vector is mosquito Aedes Aegypti but Aedes albopictus is also a vector in south-east Asian countries (Mahr 2007).

Transmission: Reservoir of infection is man and mosquito. Transmission cycle includes man-mosquito-man. All ages and sexes are susceptible.

Factors leading to spread of the disease: Increasing population and urbanization lead to improper management of water supply and water storage in open containers. The mosquito breeds in standing water. Air coolers using water and tyre dumps contain stagnant water and act as breeding sites. Global warming leading increased rains causing stagnant water pool thus cause spread of vector. In south-east Asia additional vector Aedes albopictus may also participate in spread of disease (Mahr