Ecological Analysis of the Helminth Community of the Wood Mouse, Apodemus sylvaticus, along an 18-Year Post-Fire Regeneration Period in a Mediterranean Ecosystem.

The role of helminths of the wood mouse, Apodemus sylvaticus, as biological indicators of the post-fire regeneration process in Serra Calderona Natural Park, a Mediterranean forest ecosystem located between the provinces of València and Castelló (Valencian Country, Spain), has been analysed for almost twenty years. The helminth ecological analysis of 917 A. sylvaticus (675 originating from the burned area and 242 originating from the control area) has been carried out between the 2nd and 18th post-fire years. The influence of intrinsic (host population density, sex and age) and extrinsic (site, period and year of capture, climate variables) factors on the post-fire evolution of the helminth community of the wood mouse, and the biodiversity, species richness and life cycle of the helminth species was studied. Taking into account the most important results obtained, various aspects of the helminth community dynamics of the wood mouse are confirmed as biological indicators of the post-fire regeneration process in Mediterranean ecosystems. The still existing differences between the two areas are mainly related to the influence of climate variables on the post-fire regeneration process. Moreover, the important role that helminth parasites of the wood mouse play as biological indicators of this process in Mediterranean ecosystems is demonstrated.

The helminth community component species of the wood mouse as biological tags of a ten post-fire-year regeneration process in a Mediterranean ecosystem.

Serra Calderona Natural Park, a Mediterranean ecosystem, has been in post-fire regeneration for 10 years. To elucidate which helminth community component species of the wood mouse, Apodemus sylvaticus, can be considered biological tags of this process, the influence of intrinsic (host density; host sex and age) and extrinsic factors (site, year, and period of capture; vegetation recovery) on their prevalence and abundance has been analysed, comparing a burned and an unburned area. A total of 564 wood mice (408 from the burned and 156 from the unburned area), from the 2nd to the10th post-fire year, was included in this helminthoecological study. The results suggest that the area in post-fire regeneration is still more vulnerable to periodic environmental changes than the unburned area as deduced from the analysis of the helminth populations of Pseudocatenotaenia matovi, Skrjabinotaenia lobata, Trichuris muris, Eucoleus bacillatus and Aonchotheca annulosa. The intermediate and definitive host populations presented a greater variability to these environmental changes in the burned area (Taenia parva, P. matovi, S. lobata, A. annulosa, Syphacia stroma and S. frederici). In the regenerating area, some behavioural changes in certain populations determined by the host sex are taking place (T. parva, Helgimosomoides polygyrus and S. frederici). During the last years studied, a greater similarity in the populational development of some component species between both areas can be appreciated (H. polygyrus and S. stroma). The role of the wood mouse and its helminth parasites as biological tags of the post-fire regeneration process in Mediterranean ecosystems has been confirmed.

Hepatic parasitosis in two wood mice, Apodemus sylvaticus (Rodentia: Muridae), due to Aonchotheca annulosa (Nematoda: Trichuridae), and Eucoleus bacillatus (Nematoda: Trichuridae). Erratic parasitism or post mortem migration?

Aonchotheca annulosa and Eucoleus bacillatus are two capillariin nematodes parasitizing the intestinal and stomach mucosa, respectively, of various rodent species, and two, among others, component species of the helminth fauna of the wood mouse, Apodemus sylvaticus. A capillariin each was found in the liver parenchyma of two wood mice in a post-fire regeneration enclave in Serra Calderona Natural Park (Valencian Community, Spain). Due to their location, the preliminary identification of the helminths corresponded to Calodium hepaticum, a hepatic capillariin with rodents as its main host. So far, this species had never been found in Serra Calderona. To verify the preliminary identification, a comparative morphometric study between the specimens from Serra Calderona and a preserved individual of C. hepaticum from another enclave was carried out. Morphometric analysis revealed that the adult helminth as well as the eggs found in the liver of the first mouse belonged to A. annulosa, whereas the second one was identified as a male E. bacillatus. Moreover, the liver from both hosts showed a visible pathology, being the consequence of aberrant migration of the parasites. This is the first evidence that A. annulosa and E. bacillatus may migrate erratically and thus produce ectopic foci in other organs.

Malaria resurgence risk in southern Europe: climate assessment in an historically endemic area of rice fields at the Mediterranean shore of Spain.

BACKGROUND: International travel and immigration have been related with an increase of imported malaria cases. This fact and climate change, prolonging the period favouring vector development, require an analysis of the malaria transmission resurgence risk in areas of southern Europe. Such a study is made for the first time in Spain. The Ebro Delta historically endemic area was selected due to its rice field landscape, the presence of only one vector, Anopheles atroparvus, with densities similar to those it presented when malaria was present, in a situation which pronouncedly differs from already assessed potential resurgence areas in other Mediterranean countries, such as France and Italy, where many different Anopheles species coexist and a different vector species dominates. METHODS: The transmission risk was assessed analysing: 1) climate diagrams including the minimum temperature for Plasmodium falciparum and Plasmodium vivax development; 2) monthly evolution of the Gradient Model Risk (GMR) index, specifying transmission risk period and number of potential Plasmodium generations; 3) ecological characteristics using remote sensing images with the Eurasia Land Cover characteristics database and the monthly evolution of the Normalized Difference Vegetation Index (NDVI); 4) evaluation of A. atroparvus population dynamics. RESULTS: Climatological analyses and GMR index show that a transmission risk presently exists, lasting from May until September for P. falciparum, and from May until October for P. vivax. The GMR index shows that the temperature increase does not actually mean a transmission risk increase if accompanied by a precipitation decrease reducing the number of parasite generations and transmission period. Nevertheless, this limitation is offset by the artificial flooding of the rice fields. Maximum NDVI values and A. atroparvus maximum abundance correspond to months with maximum growth of the rice fields. CONCLUSIONS: The Ebro Delta presents the ecological characteristics that favour transmission. The temperature increase has favoured a widening of the monthly potential transmission window with respect to when malaria was endemic. The combined application of modified climate diagrams and GMR index, together with spatial characterization conforms a useful tool for assessing potential areas at risk of malaria resurgence. NDVI is a good marker when dealing with a rice field area.

La chinche de cama, ¿un ectoparásito emergente? / No disponible

Fundamentos: La chinche de cama, Cimex lectularius, ectoparásito temporal humano, ha pasado desapercibido a lo largo de las últimas décadas. Sin embargo, su reciente hallazgo en viviendas urbanas hace preverla emergencia de este insecto hematófago, potencial vector de patógenos microbiológicos y parasitarios. Material y métodos: Se reporta un caso de presencia, durante el verano de 2004, de chinches de cama en cuatro dependencias de una vivienda del casco antiguo de la ciudad de Valencia. Cinco de los 8 inquilinosse vieron afectados por picaduras que respondieron a las producidas por chinches de cama. Resultados: Los insectos fueron identificados como pertenecientes a la especie C. lectularius. El tratamiento continuado con insecticidas durante 2 meses y la aplicación de otras medidas profilácticas individuales en la vivienda conllevó la desaparición de los ectoparásitos. Conclusiones: El origen de las chinches pudo ser probablemente la introducción de dos camastros de madera y espuma, por tratarse de la forma más habitual de traslado de estos insectos y por su coincidencia temporal con su detección y la aparición de las picaduras. La inspección minuciosa de enseres de dudosa procedencia antes de su introducción en una vivienda, así como la concienciación de la existencia y el diagnóstico de las picaduras de las chinches, se muestran como las principales medidas profilácticas a seguir, sobre todo en aquellos casos en que la posibilidad de pulgas y/o mosquitos haya quedado descartada como causa aparente (AU)

Purpose: The bed bug, Cimex lectularius, a non permanent human parasite seemed to have disappeared over the last decades. However, recent findings in urban dwellings make it possible to foresee the emergence of this hematofagous insect, a potential vector of microbiological and parasitological pathogens. Material and methods: A case of bed bug presence was reported in the summer of 2004 in four rooms of a flat in the old town in the city of Valencia. Five of the eight tenants were affected by bed bug bites. Results: The insects belong to the species of C. lectularius. The insecticide treatment lasted for two months and the employment of further precautious measures in the flat led to the disappearance of this ectoparasite. Conclusions: The introduction of two wooden structures and foam mattresses of dubious origin might have been the way in which the bed bugs entered the flat - the most probable manner of moving these particular insects, which is reinforced by the temporal coincidence of their appearance and the detection of their bites. The thorough inspection of such “dodgy” belongings before moving them into a house or flat together with the awareness of the bugs’ existence and the diagnosis of their bites, ought to be the main preventive measures to be followed especially in cases which the existence of flees and/or mosquitoes can be discarded as the possible cause (AU)