Impact of climate, human behaviour should be studied for dengue fever control during off-season

Islamabad
With 526 confirmed cases and one death so far in the federal capital, the dengue fever outbreak appeared as a greater health threat after major outbreak of the infection in 2011 compelling planners and authorities to plan for developing a foolproof mechanism and achieve a better level of preparedness to deal with the infection’s expected outbreak in the coming year that might be far more aggressive.
In the face of existing threat of the disease as epidemiologically if there are more cases in the current year more would be the chances of hemorrhagic manifestations in 2016 as the disease is expected to re-appear in the months from August to November.
In Islamabad rural, technically qualified and trained staff successfully monitored the trend of the disease and analyzed data for taking prompt and timely interventions. It is obvious that the experience of dealing with the outbreak demands exercising a high level of preparedness in the dengue high transmission season next year.
District Health Officer Islamabad Dr. Muhammad Najeeb Durrani, who is an epidemiologist, expressed this while talking to ‘The News’ on Thursday in connection with preparatory actions required during the off season for prevention and control of dengue fever in the year 2016.
Gradual distribution and expansion of dengue fever was seen from lower areas to upper areas of the country in the decade, from 2003-2013, till it became endemic in Pakistan with periodic outbreaks and has spread to affect both urban and rural areas and is present in most parts of the country. It has special relation to temperature, rains, congested population, infected population and human behavior, said Dr. Durrani.
He believes that the measures taken by the Health Department ICT for prevention and control of dengue fever from August to November this year need to be complemented by the well-thought off actions on the basis of scientific evidences generated through previous five years data and experiences for the next appearance of disease in 2016 to sustain efforts and to further improve disease surveillance, case response through specifically targeting areas where the disease had struck last year, thereby strengthening early warning and timely epidemiological response and capacity building.
Dengue, which is the fastest re-emerging arboviral disease in the world, imposes a heavy economic and health burden on countries, families and individual patients. In the absence of an effective drug or vaccine, the only strategic options presently available are effective case management to prevent death and vector control to reduce viral transmission.
Like other health experts, Dr. Durrani said the best method to reduce transmission of dengue virus is to control vector mosquitoes and protection against mosquitoes bites.
He added that Pakistan is currently facing a burden of diseases on several fronts, related to the rapid epidemiological transition, demographic transition, economic and socio-cultural transitions. Country faces a substantial morbidity burden from communicable diseases mainly from dengue fever, diarrheal diseases and tuberculosis. Most of the risk factors of these diseases are known although the role of climate change in relation to the increase in trends, occurrence of outbreaks and increase in incidence in some areas, and not in others, has not been studied so far. In general, high humidity and temperature are conditions that favor dengue vector’s survival, increasing the likelihood of transmission that requires an infected traveler in the season. Human behavior plays an important role in spread and control of dengue. Congested living, presence of solid waste, trash, and poor water storage practices are the main reasons for poor control, he said.
Dengue fever was reported in this region of the country in September 2003 from Mangla near Jehlum and in Haripur and in October same year in Soon Valley Khoshab, although it was discovered first in Hub District Lasbella in Balochistan among factory workers in 1992.
Later, two years after its appearance in 2003 it was reported from Kotli, AJK, and after four years in 2007, the dengue fever was reported from Islamabad and was confirmed. Mass transit or human travel is an important factor in spread and propagation of the disease to new areas, said Dr. Durrani adding fortunately he investigated all these outbreaks from the platform of National Institute of Health and WHO by visiting all these areas.
Talking of preventive measures at the moment, he said during the off season in the beginning of winter, the main action against dengue vectors should be spraying with insecticides, as dengue vector tries to fly from outside environment to inside rooms in search of relatively warmer places.
It is time for water treatment of stagnant water ponds and over flowing water in buildings by temephos granules, container checking and health education to community. In cold weather, the biting and flying ability of the mosquitoes is diminished to a minimal level, he added.
He said during off season, inspectors from the vector control section of the health departments should work hard for outdoor surveillance particularly at sites regarded as hot spots like solid waste dumps, junkyards, grave yards, tire shops, under construction and abandoned buildings, nurseries etc. on regular basis.
He added the field teams must give attention to scrubbing means destroying laid down eggs that look like as thick black line on the border where water film touches the cistern, water tank or the water container. This action which is often a neglected is very important measure to prevent mosquitoes to hatch from the eggs that have been laid in the start of winter season and these would be ready for the next summer to sprout and become adult mosquitoes to acquire infection by biting infected people and cause transmission of disease, said Dr. Durrani while responding to a query.
He added solid waste remains a major risk factor and its swift disposal is the main challenging job for the municipal authorities and the local government departments. Social mobilization and continued indoor surveillance by Lady Health Workers during off season is a must if we want to avoid dengue fever outbreak in future, said Dr. Durrani.
He said LHWs should visit each and every house in their catchment areas on regular basis to check for any breeding site and should mechanically destroy those besides educating women and children in the community about safe water storage practices and keeping vigilance in their homes and around where rain water could be collected leading to mosquitoes breeding.
Off season is a good period for capacity building of health care workers on vector control activities for outreach teams and clinical case management for the hospital staff. School children are to be educated on regular basis through small and simple topics in the school about preventive measures against dengue fever, said Dr Durrani.
He said it is convenient for the health departments to initiate procurement process for acquiring WHO prequalified insecticides that are effective and not toxic to humans. Similarly quality fogging machines and spray pumps are to be acquired and should be kept in a ready position. Also during the off season, health departments should arrange for Insecticide Treated Bed Nets (ITNs) for the next season, said Dr. Durrani.