Jeddah Social Affairs said Monday that there could be a rise in the number of dengue fever cases in the next few weeks as the mosquito incubation period at sites of water comes to an end.
The head of Social Affairs’ Preventive Medicine department Anas Al-Baloushi, said that the number of areas of water lying stagnant had risen across the Jeddah region, and that from next week he expected to see a rise in the number of cases of dengue with the end of the incubation period for mosquitoes.
“Social Affairs has put in place all preparations in terms of medical and staff needs to handle any outbreak,” he said. “There have been 61 cases of dengue confirmed since the beginning of the year.”
Al-Baloushi said that all means were being used to raise public awareness of the issue and that sites of mosquito proliferation had been identified and spraying operations were being carried out at various locations. “There are small lakes of water across the Jeddah region, and they still haven’t been dried up which increases the probability of a presence of mosquitoes and renewed cases of dengue fever once again,” he said. He also warned against leaving water exposed in homes or public places.
Saudi Gazette reported Monday that 26 cases of dengue fever had been recorded since the floods struck in Jeddah 12 days earlier.
Al-Baloushi said that sterilizing at sites of stagnant water remained effective for three months and the ideal solution was to pump away stagnant water.
“The problem is that there are many sites that have their water removed only for it to return. We are concerned over the effectiveness of spraying stagnant water due to water continuing to seep up from the ground, which has actually become saturated,” he said.
Mosquito immunity
Environmental specialists, meanwhile, have said that pesticide sprays used to attack mosquitoes require changing from time to time as the insects can acquire immunity to them with prolonged use.
Muhammad Madras, a Maritime Science professor, said that the polluted sites found in many districts of Jeddah are attractive to cats and are fertile ground for insect and mosquito breeding, and that spraying with pesticides is “not the only solution”, particularly for the type of mosquito that carries the dengue fever virus.
“Those areas of water are exacerbating the poor environmental situation in most districts, and they have formed veritable lakes of stagnant water,” he said. “Mosquitoes do not thrive inside polluted water, but live only on the surface areas of less than one centimeter. Mosquito eggs live and grow there and mosquitoes can develop immunity if the spraying of pesticides is not intensive or frequent enough.”
He said that spraying might kill off most mosquitoes, but that it does not kill the eggs lodged in the upper layer of water or in mud.
Ali Ashaqi, a professor of Environmental Science at King Abdul aziz University, said that in times gone by small birds could be observed in the skies above Jeddah, birds that would feed off insects and particularly mosquitoes.
“When crows arrived in 1979 via trade ships they overtook those smaller birds, and their disappearance is one of the most important factors in the increase of insects and mosquitoes, particularly the ones that cause dengue fever,” he said. He said that work should be done to ensure sufficient numbers of those same small birds return, as well as the elimination of crows.
“Pesticides are also harmful to the health of humans, and can cause chest and respiratory illnesses. We need to have the infrastructure in place to tackle the problems concerning the sewer system in ways followed by the rest of the world,” he said.
Nayef Al-Shalhoub, the head of Media and Environmental Awareness at the Presidency of Meteorology and Environment, said that the way to eradicate mosquitoes is by eradicating the pollution on which they thrive.
“Although pesticides are effective, there are also fears that mosquitoes might acquire immunity after a long period of exposure. That’s why the type of pesticide needs to be changed periodically,” he said. “To prevent people being bitten by mosquitoes, first of all we need greater public awareness so that people avoid sites where mosquitoes proliferate, and precautionary measures need to be taken.
They would include using mosquito nets to prevent them from entering the house, using electronic appliances that kill mosquitoes, and addressing the problem of areas of stagnant water in residential districts.”
SR20 million donations
The Ministry of Social Affairs began Monday, meanwhile, to distribute some SR20 million of additional funds to help flood victims.
Priority has been given in the funds to repair houses damaged in the recent, rains as well as the cleaning of water tanks, securing electricity infrastructure, medical supplies and the provision of school materials.
HUSSEIN HAZAZI
Saudi Gazette