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Mark-Release-Recapture of Aedes albopictus in Portugal: the influence of climatic factors

Publication . Soares, Patricia; Carvalho, Danilo O.; Silva, Susana Pereira; Gomez Pacheco, Maylen; Amaro, Fátima; Amaro F.; Osório, Hugo

Aedes albopictus mosquitoes spread diseases like dengue, Zika, yellow fever, and chikungunya. The Sterile Insect Technique (SIT), which is based on production of male sterile mosquitoes through radiation and in the release in target areas, can be used as a prevention and control tool against Ae. albopictus native populations. Mark-Release-Recapture trials (MRR) estimate the number of mosquitoes to release during the SIT, but weather conditions can affect results. Thus, we aimed to understand the influence of climatic factors on mosquito collection. MRRs were conducted in October 2022 in Faro, Southern Portugal. Mosquito sterilisation, marking and transport followed protocols from the International Atomic Energy Agency. Releases occurred weekly for three consecutive weeks at two different sites, and mosquitoes were collected using Human Landing Collections (HLC) one, two, four and six days after release. Climatic data, such as temperature, humidity, wind intensity (moderate 15-35 km/h vs weak <15 km/h) and precipitation, were obtained from the Portuguese Institute of the Sea and the Atmosphere. We used generalised linear models with a negative binomial family and log function to estimate factors associated with the number of captured mosquitoes, estimated prevalence ratios (PRs), and the 95% confidence intervals (CI). We released 84 000 marked sterile male mosquitoes and recaptured 528 marked males (0.7%) by HLC. The prevalence of captured mosquitoes was 23% lower when the wind intensity was moderate compared with a weak wind intensity (PR: 0.77, 95% CI: 0.61−0.98). We did not find a statistically significant association between the number of captured mosquitoes and humidity (PR: 0.98, 95% CI: 0.96−1.00), temperature (PR: 1.03, 95% CI: 0.83−1.28) and precipitation (PR: 1.07, 95% CI: 0.60−2.03). Conclusion: It is crucial to plan MRRs carefully and consider weather conditions during their execution to avoid underestimating the population needed for the SIT and compromising the effectiveness of this control method.

2023-11Conference object

Open access

Mark–Release–Recapture Trial with Aedes albopictus (Diptera, Culicidae) Irradiated Males: Population Parameters and Climatic Factors

Publication . Amaro, Fátima; Amaro F.; Soares, Patricia; Velo, Enkelejda; Oliveira Carvalho, Danilo; Gomez, Maylen; Balestrino, Fabrizio; Puggioli, Arianna; Bellini, Romeo; Osório, Hugo

Aedes albopictus is considered one of the major invasive species in the world and can transmit viruses such as dengue, Zika, or chikungunya. The Sterile Insect Technique (SIT) can be used to suppress the native populations of Ae. albopictus. Mark–release–recapture (MRR) studies are crucial to support the development of the release strategy during the SIT application. Meanwhile, weather conditions can affect the MRR trial’s results and it is critical to understand the influence of climatic factors on the results. In October 2022, 84,000 irradiated sterile males were released for three consecutive weeks in Faro, Southern Portugal. Mosquitoes were recaptured by human landing collection (HLC) one, two, four, and six days after release. Generalized linear models with a negative binomial family and log function were used to estimate the factors associated with the number of recaptured mosquitoes, prevalence ratios, and the 95% confidence intervals (CIs). A total of 84,000 sterile male mosquitoes were released, with 528 recaptured (0.8%) by HLC. The prevalence of recaptured mosquitoes was 23% lower when the wind intensity was moderate. Marked sterile males had an average median distance travelled of 88.7 m. The median probability of daily survival and the average life expectancy were 61.6% and 2.1 days, respectively. The wild male population estimate was 443.33 males/ha. Despite no statistically significant association being found with humidity, temperature, and precipitation, it is important to consider weather conditions during MRR trial analyses to obtain the best determinant estimation and a more efficient application of the SIT in an integrated vector management program.

2024-09-11Journal article

Open access

Toscana Virus in Wild-Caught Sand Flies in Portugal, Findings from the National Vector Surveillance Network, 2023

Publication . Amaro, Fátima; Zé-Zé, Líbia; Osório, Hugo Costa; Soares, Patrícia; Silva, Manuel; Freitas, Inês Campos; Alves, Maria João

Phlebotomine sand flies play a crucial role in both human and veterinary medicine, acting as vectors for Leishmania parasites and most known phleboviruses. In Portugal, the REVIVE program, a comprehensive national surveillance network under the Ministry of Health, has included sand fly surveys since 2016. REVIVE aims to identify existing sand fly species in the country, determine which pathogens are circulating among them, and provide actionable insights for prevention and control measures when necessary. In this way, annually, from May to October, health technicians collect sand flies across mainland Portugal with CDC light traps. The collected sand flies are sent to the Centre for Vectors and Infectious Diseases Research for species identification and molecular screening of pathogens. On 21 September 2023, Toscana virus (TOSV), a well-known phlebovirus in the Mediterranean region due to its capacity to cause neurological disease, was detected in a pool of 30 sand flies collected in Algarve, the southernmost region of Portugal. A 668 bp partial sequence of the nucleoprotein gene shows similarity with TOSV strains from Spain. To our knowledge, this is the first detection of TOSV in its vector in this country, having previously only been reported in vertebrate hosts. These findings highlight the important role of ongoing surveillance efforts in monitoring and understanding the dynamics of sand fly-borne diseases in Portugal.

2024-10-15Journal article

Open access

Effectiveness of XBB.1.5 Monovalent COVID‐19 Vaccines During a Period of XBB.1.5 Dominance in EU/EEA Countries, October to November 2023: A VEBIS‐EHR Network Study

Publication . Monge, Susana; Humphreys, James; Nicolay, Nathalie; Braeye, Toon; Van Evercooren, Izaak; Holm Hansen, Christian; Emborg, Hanne‐Dorthe; Sacco, Chiara; Mateo‐Urdiales, Alberto; Castilla, Jesús; Martínez‐Baz, Iván; de Gier, Brechje; Hahné, Susan; Meijerink, Hinta; Kristoffersen, Anja Bråthen; Machado, Ausenda; Soares, Patricia; Nardone, Anthony; Bacci, Sabrina; Kissling, Esther; Nunes, Baltazar

Using a common protocol across seven countries in the European Union/European Economic Area, we estimated XBB.1.5 monovalent vaccine effectiveness (VE) against COVID-19 hospitalisation and death in booster-eligible ≥ 65-year-olds, during October–November 2023. We linked electronic records to construct retrospective cohorts and used Cox models to estimate adjusted hazard ratios and derive VE. VE for COVID-19 hospitalisation and death was, respectively, 67% (95%CI: 58–74) and 67% (95%CI: 42–81) in 65- to 79-year-olds and 66% (95%CI: 57–73) and 72% (95%CI: 51–85) in ≥ 80-year-olds. Results indicate that periodic vaccination of individuals ≥ 65 years has an ongoing benefit and support current vaccination strategies in the EU/EEA.

2024-04-23Journal article

Open access

COVID-19 vaccine effectiveness in the paediatric population aged 5-17 years: a multicentre cohort study using electronic health registries in six European countries, 2021 to 2022

Publication . Soares, Patricia; Machado, Ausenda; Nicolay, Nathalie; Monge, Susana; Sacco, Chiara; Hansen, Christian Holm; Meijerink, Hinta; Martínez-Baz, Iván; Schmitz, Susanne; Humphreys, James; Fabiani, Massimo; Echeverria, Aitziber; AlKerwi, Ala'a; Nardone, Anthony; Mateo-Urdiales, Alberto; Castilla, Jesús; Kissling, Esther; Nunes, Baltazar; VEBIS-Lot 4 working group

Background: During the first year of the COVID-19 pandemic, vaccination programmes targeted children and adolescents to prevent severe outcomes of SARS-CoV-2 infection. Aim: To estimate COVID-19 vaccine effectiveness (VE) against hospitalisation due to COVID-19 in the paediatric population, among those with and without previously documented SARS-CoV-2 infection. Methods: We established a fixed cohort followed for 12 months in Denmark, Norway, Italy, Luxembourg, Navarre (Spain) and Portugal using routine electronic health registries. The study commenced with paediatric COVID-19 vaccination campaign at each site between June 2021 and January 2022. The outcome was hospitalisation with a laboratory-confirmed SARS-CoV-2 infection or COVID-19 as the main diagnosis. Using Cox proportional hazard models, VE was estimated as 1 minus the confounder-adjusted hazard ratio of COVID-19 hospitalisation between vaccinated and unvaccinated. A random-effects meta-analysis was used to pool VE estimates. Results: We included 4,144,667 5-11-year-olds and 3,861,841 12-17-year-olds. In 12-17-year-olds without previous infection, overall VE was 69% (95% CI: 40 to 84). VE declined with time since vaccination from 77% ≤ 3 months to 48% 180-365 days after immunisation. VE was 94% (95% CI: 90 to 96), 56% (95% CI: 3 to 80) and 41% (95% CI: -14 to 69) in the Delta, Omicron BA.1/BA.2 and BA.4/BA.5 periods, respectively. In 12-17-year-olds with previous infection, one dose VE was 80% (95% CI: 18 to 95). VE estimates were similar for 5-11-year-olds but with lower precision. Conclusion: Vaccines recommended for 5-17-year-olds provided protection against COVID-19 hospitalisation, regardless of a previously documented infection of SARS-CoV-2, with high levels of protection in the first 3 months of the vaccination.

2025-02-27Journal article

Open access