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.

The main public health strategies to control communicable diseases include all measures designed to prevent or reduce the incidence, prevalence and consequences of disease (WHO 1984). These measures are included in primary health care and involve participation of community, support from different government, public and private sectors and coordination between these sectors (WHO 1978). The control measures are directed against reservoir or sounce of infection, the root of transmission and susceptible host ( people at risk).

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