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- The first detection of Leishmania major in naturally infected Sergentomyia minuta in PortugalPublication . Campino, Lenea; Cortes, Sofia; Dionisio, Lidia; Neto, Luis; Afonso, Maria Odete; Maia, CarlaPhlebotomine sandflies of the genus Sergentomyia are widely distributed throughout the Old World. It has been suggested that Sergentomyia spp are involved in the transmission of Leishmania in India and Africa, whereas Phlebotomus spp are thought to be the sole vectors of Leishmania in the Old World. In this study, Leishmania major DNA was detected in one Sergentomyia minuta specimen that was collected in the southern region of Portugal. This study challenges the dogma that Leishmania is exclusively transmitted by species of the genus Phlebotomus in the Old World.
- Áreas de gestão fitossanitária para Ceratitis capitata e Trioza erytreae: nova abordagem para a citricultura portuguesaPublication . Paiva, Paulo; Neto, Luis; Duarte, AmilcarO controlo de pragas em áreas de gestão fitossanitária - AGF - (area wide pest management) é uma extensão da proteção integrada aplicada a uma praga alvo numa dada área geográfica, geralmente envolvendo várias explorações agrícolas e áreas vizinhas com plantas hospedeiras ou de refúgio do organismo alvo. Estas áreas incluem, para além das explorações comerciais, culturas abandonadas, hospedeiros alternativos e quintais que, sendo hospedeiros da praga, são fontes de novas infestações e justificam a sua incorporação nas áreas de gestão fitossanitária. A supressão da praga numa área de gestão fitossanitária reduz a reinfestação vinda de áreas não controladas, aumentando a eficácia das táticas de proteção integrada.
- No induction of antimicrobial resistance in Staphylococcus aureus and Listeria monocytogenes during continuous exposure to eugenol and citralPublication . Apolonio, Joana; Faleiro, Maria L.; Miguel, Maria Graca; Neto, LuisThe aim of this study was to evaluate the adaptation response of Staphylococcus aureus, methicillin-resistant S.aureus (MRSA), and Listeria monocytogenes to the essential oil (EO), eugenol, and citral. The minimum inhibitory concentration of eugenol and citral was determined by agar dilution and microdilution. Adaptation to eugenol and citral was done by sequential exposure of the pathogens to increasing concentrations of the essential oils. The M2-A9 standard was used to determine the antibiotic susceptibility. The effect of eugenol and citral on the adherence ability was evaluated by the crystal violet assay. The impact of adaptation to eugenol on virulence was estimated using the Galleria mellonella model. No development of resistance to the components and antibiotics was observed in the adapted cells of S.aureus, MRSA, and L.monocytogenes. Eugenol and citral at subinhibitory concentration reduced the bacterial adherence. Adaptation to subinhibitory concentration of eugenol affected the virulence potential of S.aureus, MRSA, and L.monocytogenes. Eugenol and citral do not pose a risk of resistance development in a continuous mode of use. These EO components showed a high efficacy as antistaphylococcal and antilisterial biofilm agents. Adaptation at subinhibitory concentration of eugenol protected the larvae against listerial and staphylococcal infection.
- Citrus aphids in Algarve Region (Portugal): Species, hosts, and biological controlPublication . Paiva, Paulo Eduardo Branco; Neto, Luis; Marques, Natália; Duarte, Beatriz; Duarte, AmilcarAphids affect citrus by causing leaf deformations and reducing fruit production. Additionally, aphids are a great concern due to their ability to transmit Citrus tristeza virus (CTV), the cause of tristeza, one of the main citrus diseases. In the last four years, citrus orchards in the south of Portugal (Algarve region) were sampled for aphid species identification and counting. Aphis spiraecola was the most abundant species, representing more than 80% of all identified aphids, and the damage (leaf deformation) it causes was directly proportional to its density. A. gossypii was the second most common species, followed by A. aurantii and Macrosiphum euphorbiae. The number of aphids in nymph stages was predominant over the adult stages (both wingless and winged) in all species. A. citricidus, the most efficient CTV vector, was not detected. The largest populations of A. spiraecola were observed in lemon and orange trees during spring (>100 individuals per shoot), with great damage observed in orange, lemon, and mandarin trees. A. gossypii was observed mainly in mandarin and tangor trees. There was a low activity of natural biological control agents, with the parasitism of A. spiraecola by Lysiphlebus spp. and Binodoxys spp. ranging from 0.3 to 1.5%. The numerical ratio ranged from 150 to 440 aphids per predator, and among these, syrphids were the most abundant, followed by lacewings and coccinellids (Scymnus).
- Report of in vitro antileishmanial properties of Iberian macroalgaePublication . Bruno De Sousa, Carolina; Lago, Joao Henrique G.; Macridachis, Jorge; Oliveira, Marta; Fonseca Brito, Luis; Vizetto-Duarte, Catarina; Florindo, Claudia; Hendrickx, Sarah; Maes, Louis; Morais, Thiago; Uemi, Miriam; Neto, Luis; Dionísio, Lídia; Cortes, Sofia; Barreira, Luísa; Custódio, Luísa; Albericio, Fernando; Campino, Lenea; Varela, J.Here is reported the anti Leishmania infantum activity of 48 hexane, CH2Cl2 and MeOH extracts from 16 macroalgae collected on the Iberian Coast. Seven hexane and CH2Cl2 Cystoseira baccata, Cystoseira barbata, Cystoseira tamariscifolia, Cystoseira usneoides, Dictyota spiralis and Plocamium cartilagineum extracts were active towards promastigotes (IC50 29.8-101.8 mu g/mL) inducing strong morphological alterations in the parasites. Hexane extracts of C. baccata and C. barbata were also active against intracellular amastigotes (IC50 5.1 and 6.8 mu g/mL, respectively). Fatty acids, triacylglycerols, carotenoids, steroids and meroterpenoids were detected by nuclear magnetic resonance (NMR), and gas chromatography in the Cystoseira extracts. These results suggest that Cystoseira macroalgae contain compounds with antileishmanial activity, which could be explored as scaffolds to the development of novel sources of antiparasitic derivatives. [GRAPHICS] .
- Water vapor pressure deficit in Portugal and implications for the development of the invasive African citrus psyllid trioza erytreaePublication . Paiva, Paulo Eduardo Branco; Cota, Tânia; Neto, Luis; Soares, Celestino; Tomás, José Carlos; Duarte, AmilcarAfrican citrus psyllid (Trioza erytreae (Del Guercio)) is a vector insect of the bacterium Candidatus Liberibacter africanus, the putative causal agent of Huanglongbing, the most devastating citrus disease in the world. The insect was found on the island of Madeira in 1994 and in mainland Portugal in 2015. Present in the north and center of the country, it is a threat to Algarve, the main citrus-producing region. Trioza erytreae eggs and first instar nymphs are sensitive to the combination of high temperatures and low relative humidity. Daily maximum air temperature and minimum relative humidity data from 18 weather stations were used to calculate the water vapor pressure deficit (vpd) from 2004 to 2018 at various locations. Based on the mean vpd and the number of unfavorable days (vpd < 34.5 and vpd < 56 mbar) of two time periods (February to May and June to September), less favorable zones for T. erytreae were identified. The zones with thermal and water conditions like those observed in the Castelo Branco and Portalegre (Center), Beja (Alentejo), Alte, and Norinha (Algarve) stations showed climatic restrictions to the development of eggs and first instar nymphs of African citrus psyllid. Effective control measures, such as the introduction and mass release of Tamarixia dryi (Waterson), a specific parasitoid, and chemical control are necessary in favorable periods for T. erytreae development, such as in spring and in areas with limited or no climate restrictions.
- Leishmania infection and host-blood feeding preferences of phlebotomine sandflies and canine leishmaniasis in an endemic European area, the Algarve Region in PortugalPublication . Maia, Carla; Dionisio, Lidia; Afonso, Maria Odete; Neto, Luis; Cristovao, Jose Manuel; Campino, LeneaThe Algarve Region (AR) in southern Portugal, which is an international tourist destination, has been considered an endemic region of zoonotic leishmaniasis caused by Leishmania infantum since the 1980s. In the present study, phlebotomine and canine surveys were conducted to identify sandfly blood meal sources and to update the occurrence of Leishmania infection in vectors and dogs. Four sandfly species were captured: Phlebotomus perniciosus, Phlebotomus ariasi, Phlebotomus sergenti and Sergentomyia minuta. In one P. perniciosus female, L. infantum DNA was detected. Blood meal tests showed that this species had no host preferences and was an opportunistic feeder. An overall canine leishmaniasis (CanL) seroprevalence of 16.06% was found; the seroprevalence was 3.88% in dogs housed in kennels and 40.63% in dogs that attended veterinary clinics. The simultaneous occurrence of dogs and P. perniciosus infected with L. infantum in the AR indicates that the region continues to be an endemic area for CanL. Our results reinforce the need for the systematic spatial distribution of phlebotomine populations and their Leishmania infection rates and the need to simultaneously perform pathogen monitoring in both invertebrate and vertebrate hosts to investigate the transmission, distribution and spreading of Leishmania infection.