Drs Pierre Schembri Wismayer and Mark Muscat (The Sunday Times, August 8) point out that cases of malaria are presently very rare in Malta and that these are mostly reported from immigrants and local travellers who have been to regions where malaria is endemic.
They also rightly point out that there is no valid reason to suppose that malaria can be transmitted locally since none of the malaria-carrying mosquito species (called the vectors) are known to exist in Malta. This is correct for the present time but it has not always been the case.
It may interest your readers to know that as part of its participation in a European Union project known as Fauna Europaea, concerned with cataloguing the animal biodiversity of Europe, my research group at the Department of Biology of the University of Malta keeps records on local biodiversity.
According to our information, the most recent authoritative work on the mosquitoes of the Maltese Islands was that published by Dr Paul Gatt in 1996 in the Bollettino della Società Entomologica Italiana (Vol. 128 pp. 77-84). According to this work, nine species of mosquitoes have been recorded to occur in the Maltese Islands, including one species, Anopheles maculipennis, which is a vector of the malaria parasite.
This species was first reported by Dr Themistocles Zammit in 1905 during an investigation he made following an epidemic of malaria that broke out in 1904. However, this species has not been reported from Malta since 1943, was not found in the extensive field and museum studies made by Dr Paul Gatt, and there is evidence that it has been extinct from Malta for at least 48 years.
As stated by Drs Schembri Wismayer and Muscat, there is therefore no cause for concern that malaria can be transmitted even from the few sporadic cases that occur on the islands.
An interesting question is why has Anopheles maculipennis disappeared from the islands. Apparently, the chief breeding areas of this species were the marshlands in the Salina and Qalet Marku areas. These marshes were drained a long time ago so probably this species became extinct because its habitat no longer exists.