Since the announcement on 4 December of an outbreak of malaria in Kingston, Jamaica, the Cayman Islands Mosquito Research and Control Unit has been closely monitoring the situation and making preparations to deal with any outbreak of locally transmitted malaria in the Cayman Islands.
‘Over the Christmas period many travellers will be heading for Jamaica and there is the possibility a returning resident or visitor could be infected by malaria. Anopheles albimanus, which is the most important mosquito vector of malaria in the Caribbean, is present in the Cayman Islands and is one of the most common biting mosquitoes here,’ Dr. Alan Wheeler, assistant director for Research and Development at the Mosquito Research and Control Unit, said.
Mr. Wheeler explained that Anopheles albimanus is a particularly difficult mosquito to control because of its broad period of activity, biting at anytime between dusk and dawn.
‘It bites mainly outdoors and prefers to feed on the lower legs, ankles and feet and is able to feed through thin clothing such as socks. It is quite an innocuous feeder and quite often it is not until the next day when a person looks down to see numerous small bite marks on their feet and ankles that they realize they have been bitten,’ he said.
‘Over the last few years MRCU’s control operations have been very effective against this mosquito. Since the introduction of large scale aerial larviciding operations in 2003 there has been a 68 per cent reduction in the number of specimens of this species collected in light traps. However the numbers of this mosquito do remain high enough that if a person arrived on the island with malaria it is possible that local transmission could occur and therefore people should take their own precautions to avoid being bitten.’
MRCU advises that the best way to avoid being bitten by Anopheles albimanus is to stay indoors between the hours of dusk and dawn.
‘This advice is not always practical and especially over the Christmas period people will be spending a lot of evenings outside. If you do go outside be sure to apply a good insect repellent. The most effective repellents contain a chemical known as DEET and this can be applied to both skin and clothing to repel mosquitoes. When applying this repellent be sure to pay attention to the lower legs and feet,’ he said.
Over recent months (since the announcement of malaria in the Bahamas in June 2006) MRCU has been looking at methods to specifically target and optimize control operations against Anopheles albimanus using its aerial and ground fogging equipment. Over the next few weeks MRCU will be carrying out increased surveillance of this mosquito and is also working on developing a technique that will enable the detection of the malaria parasite in the mosquito population.
‘In the event of a malaria infection among returning residents or if the malaria parasite is found in local mosquito population MRCU has the necessary resources to prevent or interrupt the transmission cycle quickly and effectively in the local mosquito population’ said Mr. Wheeler.