[page 2] [Malaria Reports 2011; 1:e2] Anopheles plumbeus Stephens, 1828: a neglected malaria vector in Europe Rubén Bueno-Marí, Ricardo Jiménez-Peydró Entomology and Pest Control Laboratory, Cavanilles Institute of Biodiversity and Evolutionary Biology (ICBiBE), University of Valencia, Valencia, Spain Abstract Traditionally field and laboratory research about malaria vectors in Europe have been mainly focused on the species of the Anopheles maculipennis complex. However, although malaria is essentially a rural disease, potential urban vectors merit attention. Because only a few European Anopheles species can breed in urban environments, improving knowledge about their bioecology is necessary to imple- ment effective control measures. Among these opportunistic species, Anopheles plumbeus has a distinctive dendrolimnic behavior, being able to complete its larval development in small containers. The aim of this paper is to provide a thorough review of the limited studies on An. plumbeus with the aim of providing useful epi- demiological information. Introduction It is well known that malaria is the most important parasitic disease in the world. According to the World Health Organization (WHO), malaria annually affects 250 million people and threatens directly or indirectly 50% of the world population. 1 The disease is endemic in much of Africa and several countries of Asia, Central America, and South America. In Europe, malaria was also an endemic disease until after the end of World War II and was historically eliminated by a mixture of vector control, dis- ease treatment, habitat modification, and improvements in general living standards. The morbidity and mortality from parasitosis was particularly high in Southern Europe, although seasonal epidemics or outbreaks occurred as far north as Scandinavia, even reaching as far as 68°N latitude during the 19 th century. Flooding practices, mainly rice cultivation, were clearly associated with malaria endemic- ity in Mediterranean countries until the begin- ning of the 20 th century. In this area, different multivoltine species of the Anopheles mac- ulipennis complex were considered the main disease vectors. 2 Due to climatic conditions, these anophelines showed an extended period of activity and consequently malaria episodes were continuous in Southern Europe. However, there are several reasons for which it has not been possible to define for certain which mosquito species was the most impor- tant for malaria transmission in Northern Europe. The major reason is related to the fact that temperature conditions of Scandinavian countries should have meant that malaria transmission has mainly occurred under indoor conditions due to transmission of sporozoites throughout the winter by semiac- tive hibernating mosquitoes, 3 since it is well known that in warm conditions the overwinter- ing females of Anopheles can take several blood meals. 4-5 Therefore, the best malaria vec- tors in Northern Europe were those anthro- pophilic and endophagic anophelines, which present hibernating females with semiactive winter habits but not a complete diapause. In conclusion, northern malaria existed in such a cold climate by means of the summer dorman- cy of Plasmodium vivax (Grassi & Feletti, 1890) hypnozoites, in addition to the indoor feeding activity of overwintering Anopheles females mentioned previously. Currently, malaria provides an excellent example of a disease for which the occurrence of several global changes may influence its re- emergence in Europe. 6 Global change can be defined as the impact of human activity on the fundamental mechanisms of biosphere func- tioning. Therefore, global change includes not only climate change, but also globalization, habitat transformation, water cycle modifica- tion, biodiversity loss, synanthropic incursion of alien species into new territories, or the introduction of new chemicals in nature. Given these complex interacting factors, the cycles of malaria transmission in Europe are nowadays relatively common again in Georgia, Azerbaijan, Kyrgyzstan, Tajikistan, Uzbekistan and Turkey. 7 Moreover the recent autochtho- nous cases diagnosed in Spain, France, Greece or Italy 8-11 have shown the need to better understand the potential influence of this trop- ical disease in Southern Europe, where the warmer climate obviously favors the continued development of the disease. The risk of the re-establishment of malaria in Europe is believed to be low. 12-14 This low risk is attributed, among others, to the temper- ature requirements for completing the Plasmodium cycle, to the efficient health sys- tem in Europe, which allows for the early detection of malaria patients, and to the low density of Anopheles vectors in mainly rural areas limiting the contact between vectors and infected persons. The aim of this paper is to discuss the potential increase of malaria risk in urban settings due to the presence and abundance of suitable disease vectors such as Anopheles plumbeus Stephens, 1828. Malaria vectors in Europe Compiling data on the occurrence and dis- tribution of former and present malaria vectors in southern Europe is a difficult task. Firstly, there are several Anopheles species belonging to species complexes, such as the sibling species of the Anopheles maculipennis and the Anopheles claviger complexes, which are very difficult to distinguish morphologically. Therefore, there is much discussion over existing data as they depend on a correct iden- tification of these anophelines. Correct identi- fication is essential because closely related sister species can vary widely in their ability to transmit malaria. Secondly, most of the infor- mation about Anopheles collections is from periods when malaria was endemic. This is important to note because, in the past, malari- ologists sometimes had limited knowledge of the systematics of the genus. Additionally, malaria eradication programs in southern Europe usually included intense mosquito con- trol not only through the use of insecticides, but also through environmental modifications, resulting in changes in the Anopheles fauna. 15 Malaria Reports 2011; volume 1:e2 Correspondence: R. Bueno-Marí, Entomology and Pest Control Laboratory, Cavanilles Institute of Biodiversity and Evolutionary Biology (ICBiBE), University of Valencia, Post 22085, 46071 Valencia, Spain. E-mail: ruben.bueno@uv.es Key words: malaria vectors, Anopheles plumbeus, mosquito control, malaria receptivity, Europe. Acknowledgments: the current work was partially funded by the Research Project CGL 2009-11364 (BOS), supported by the Ministry of Science and Innovation of Spain (Ministerio de Ciencia e Innovación del Gobierno de España). We are also grateful to anonymous reviewers for their helpful comments. Contributions: RB-M conception and design of article, and analysis and interpretation of data. RB-M and RJ-P drafting the article or revising it critically for important intellectual content. Both authors approved the final version to be pub- lished. Conflict of interest: the authors report no con- flicts of interest. Received for publication: 28 April 2011. Accepted for publication: 7 October 2011. This work is licensed under a Creative Commons Attribution NonCommercial 3.0 License (CC BY- NC 3.0). ©Copyright R. Bueno-Marí and R. Jiménez- Peydró, 2011 Licensee PAGEPress, Italy Malaria Reports 2011; 1:e2 doi:10.4081/malaria.2011.e2 Non-commercial use only