scholarly journals Influence of Temperature on the Life-Cycle Dynamics of Aedes albopictus Population Established at Temperate Latitudes: A Laboratory Experiment

Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 808
Author(s):  
Giovanni Marini ◽  
Mattia Manica ◽  
Daniele Arnoldi ◽  
Enrico Inama ◽  
Roberto Rosà ◽  
...  

The mosquito species Aedes albopictus has successfully colonized many areas at temperate latitudes, representing a major public health concern. As mosquito bionomics is critically affected by temperature, we experimentally investigated the influence of different constant rearing temperatures (10, 15, 25, and 30 °C) on the survival rates, fecundity, and developmental times of different life stages of Ae. albopictus using a laboratory colony established from specimens collected in northern Italy. We compared our results with previously published data obtained with subtropical populations. We found that temperate Ae. albopictus immature stages are better adapted to colder temperatures: temperate larvae were able to develop even at 10 °C and at 15 °C, larval survivorship was comparable to the one observed at warmer conditions. Nonetheless, at these lower temperatures, we did not observe any blood-feeding activity. Adult longevity and fecundity were substantially greater at 25 °C with respect to the other tested temperatures. Our findings highlight the ability of Ae. albopictus to quickly adapt to colder environments and provide new important insights on the bionomics of this species at temperate latitudes.

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Giovanni Marini ◽  
Daniele Arnoldi ◽  
Frederic Baldacchino ◽  
Gioia Capelli ◽  
Giorgio Guzzetta ◽  
...  

Abstract Background Aedes koreicus was detected in northern Italy for the first time in 2011, and it is now well established in several areas as a new invasive mosquito species. Data regarding the influence of temperature on mosquito survival and development are not available yet for this species. Methods We experimentally investigated the influence of different constant rearing temperatures (between 4 and 33 °C) on the survival rates and developmental times of different life stages of Ae. koreicus under laboratory conditions. The resulting data were subsequently used to inform a mathematical model reproducing the Ae. koreicus life-cycle calibrated to counts of adult females captured in the field in the autonomous province of Trento (northern Italy) between 2016 and 2018. Results We found that temperatures above 28 °C are not optimal for the survival of pupae and adults, whereas temperate conditions of 23–28 °C seem to be very favorable, explaining the recent success of Ae. koreicus at establishing into new specific areas. Our results indicate that Ae. koreicus is less adapted to local climatic conditions compared to Ae. albopictus, another invasive species which has been invading the area for the last three decades. Warmer seasons, which are more likely to occur in the future because of climate change, might extend the breeding time and therefore increase the abundance of Ae. koreicus in the study region. Conclusions Our findings provide, to our knowledge, the first evidence on how temperature influences the bionomics and dynamics of Ae. koreicus and highlight the need for further studies on the phenology of this species in temperate areas of Europe.


Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 755
Author(s):  
Silvana F. de Mendonça ◽  
Marcele N. Rocha ◽  
Flávia V. Ferreira ◽  
Thiago H. J. F Leite ◽  
Siad C. G. Amadou ◽  
...  

The emergence of new human viral pathogens and re-emergence of several diseases are of particular concern in the last decades. Oropouche orthobunyavirus (OROV) is an arbovirus endemic to South and Central America tropical regions, responsible to several epidemic events in the last decades. There is little information regarding the ability of OROV to be transmitted by urban/peri-urban mosquitoes, which has limited the predictability of the emergence of permanent urban transmission cycles. Here, we evaluated the ability of OROV to infect, replicate, and be transmitted by three anthropophilic and urban species of mosquitoes, Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus. We show that OROV is able to infect and efficiently replicate when systemically injected in all three species tested, but not when orally ingested. Moreover, we find that, once OROV replication has occurred in the mosquito body, all three species were able to transmit the virus to immunocompromised mice during blood feeding. These data provide evidence that OROV is restricted by the midgut barrier of three major urban mosquito species, but, if this restriction is overcome, could be efficiently transmitted to vertebrate hosts. This poses a great risk for the emergence of permanent urban cycles and geographic expansion of OROV to other continents.


Author(s):  
L. Toma ◽  
F. Severini ◽  
R. Romi ◽  
M. Goffredo ◽  
A. Torina ◽  
...  

The present study reports the results of the first survey of mosquito species in four of the minor Sicilian Islands, namely Lampedusa, Linosa, Pantelleria and Ustica. These surveys were carried out during field activities aimed at recording the occurrence of Aedes albopictus, now reported in all these territories. Adult mosquitoes were collected by traps or by handheld electric aspirators. Larval collections were performed using dippers and droppers. Samples were morphologically identified and molecular investigations were carried out when needed. A total of 6 species were found, namely Aedes (Stegomyia) albopictus, Culex (Culex) pipiens, Culex (Culex) laticinctus, Aedes (Ochlerotatus) mariae, Aedes (Ochlerotatus) zammitii, and Culiseta (Allotheobaldia) longiareolata, the first 2 of which are already a known health concern. This checklist of mosquito species shows the widespread occurrence of Culex laticinctus whose distribution in Italy has still not been thoroughly investigated, whose ecology is poorly known and whose competence as a vector of pathogens is unknown. In Pantelleria, we found larvae of an Aedes species worthy of further investigation.


2020 ◽  
Vol 10 (1) ◽  
pp. 67-77
Author(s):  
Amos Watentena ◽  
Ikem Chris Okoye ◽  
Ikechukwu Eugene Onah ◽  
Onwude Cosmas Ogbonnaya ◽  
Emmanuel Ogudu

Mosquitoes of Aedes species are vectors of several arboviral diseases which continue to be a major public health problem in Nigeria. This study among other things, morphologically identified Aedes mosquitoes collected from Nsukka LGA and used an allele specific PCR amplification for discrimination of dengue vectors. Larval sampling, BG-sentinel traps and modified human landing catches were used for mosquito sampling in two selected autonomous communities of Nsukka LGA (Nsukka and Obimo). A total of 124 Aedes mosquitoes consisting of five (5) different species were collected from April to June, 2019 in a cross-sectional study that covered 126 households, under 76 distinct geographical coordinates. Larvae was mainly collected from plastic containers 73% (n=224), metallic containers 14% (n=43), earthen pots 9% (n=29) and used car tyres 3% (n=9), reared to adult stage 69.35% (n=86), and all mosquitoes were identified using standard morphological keys. Five (5) Aedes mosquito species were captured; Aedes aegypti 83(66.94%), Aedes albopictus 33(26.61%), Aedes simpsoni (4.48%), Aedes luteocephalus (≤1%) and Aedes vittatus (≤1%). Nsukka autonomous community had higher species diversity than Obimo. Allele specific amplification confirmed dengue vectors, Aedes aegypti and Aedes albopictus species on a 2% agarose gel. Since the most recent re-emergence of arboviral diseases is closely associated with Aedes species, findings of this study, therefore, give further evidence about the presence of potential arboviral vectors in Nigeria and describe the role of a simple PCR in discriminating some. Further entomological studies should integrate PCR assays in mosquito vector surveillance.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1132.3-1133
Author(s):  
G. Jurado Quijano ◽  
L. Fernández de la Fuente Bursón ◽  
B. Hernández-Cruz ◽  
P. Muñoz Reinoso ◽  
V. Merino Bohóquez ◽  
...  

Background:Rituximab (RTX) is a monoclonal antibody against the CD20 B cell antigen that has been used successfully in recent years for the treatment of rheumatoid arthritis (RA). It is an effective drug that reaches survival rates of 60% at 5 years of treatment as reflected in the British experience. However, survival in Spanish patients is unknown.Objectives:To study the survival of RTX treatment and the characteristics of patients with RA treated with the drug since its commercialization in Spain.Methods:Observational, retrospective and analytical study of a cohort of patients with RA treated with at least one dose of RTX. We reviewed the medical records of all patients with RA from January 2007 to June 2017. A total of 178 previous defined variables were collected, highlighting data about treatment (use of RTX, associated conventional synthetic disease modifying drugs [FAMEsc], doses of corticosteroids [GC] used) and activity indices. Descriptive statistics were performed (median and the 25th and 75th percentiles are shown). The comparative analysis was done with χ2 and U of Mann Whitney for categorical variables and paired sign rank test or Student’s t for continuous. Survival Kaplan Mayer curves were constructed. The study was carried out in accordance with the standards of our Clinical Research Ethics Committee.Results:A total of 54 patients were analyzed. 74% (n = 40) of them were women, the age was 61.2 years (51.0 - 67.4). 74% (n = 40) presented some type of relevant comorbidity. Its RA was FR + in 96% (n = 52) and ACCP + in 78% (n = 42) of the cases, with an evolution time of 9.3 years (3.5-19, 2), and with radiographic erosions in up to 63% (n = 34). At the time of the start of the RTX, 100% of the patients (n = 54) received some FAMEsc, and 33 (61%) were treated with prednisone; the daily dose of prednisone was 9 (6-12) mg. The baseline DAS28-VSG was 5 (4.1 - 6.0). The duration of the follow-up was 56.6 (29.3-92.1) months. Patients received a mean of 5 (1-6) cycles of RTX at a dose of 1000 mg on days 0 and 15 in most cases. The final DAS28-VSG was 2.6 (2.1 - 4.0), p = 0.00001 compared to baseline. The delta between baseline and final DAS was -2.36 (-0.55 - -3.1). At the end of the RTX treatment, the EULAR response rate was good in 64% (n = 25), reaching remission in 17 (31%) of the patients, and moderate response in 21% (n = 8) of them (Figure 1). Only 2 (4%) patients were treated with GCC at the end of the follow-up, p<0,00001 compared to baseline. The daily dose of PDN at the end of follow-up was 6 mg in a case and 12 mg in the other, p=00001 compared to baseline. At the end of the follow-up 24%of the patients (n = 13) changed or discontinued the drug: 9 changed due to secondary failure, 2 suspended due to adverse events, 1 due to death due to prior neoplastic process and 1 due to complete disease remission. Survival at 1, 2, 3, 4, 5, 6 and 7 years was 92%, 92%, 82% 78%, 75%, 75% and 65% respectively; with a mean survival rate of 90 months (Figure 1).Conclusion:The results of our analysis show that patients with RA undergoing RTX treatment have adequate control of disease activity and drug survival rates, like published data. RTX treatment allowed stopped GCC treatment in 31 cases (90%).References:[1]Oldroyd AGS, et al. Rheumatology (Oxford). 2018 Jun 1;57(6):1089-1096.Disclosure of Interests:Gonzalo Jurado Quijano: None declared, Lola Fernández de la Fuente Bursón: None declared, Blanca Hernández-Cruz Speakers bureau: Sociedad Española de Reumatología, Abbvie, Roche, Bristol, MSD, Lilly, Pfizer, Amgen, Sanofi, Consultant of: Abbvie, Lilly, Sanofi, STADA, UCB, Amgen, Grant/research support from: Fundación para la Investigación Sevilla, Junta de Andalucía, Fundación Andaluza de Reumatología, Paloma Muñoz Reinoso: None declared, Vicente Merino Bohóquez: None declared, José Javier Pérez Venegas: None declared


2021 ◽  
Vol 10 (15) ◽  
pp. 3321
Author(s):  
Young-Gun Shin ◽  
Won-Tak Cho ◽  
Ho-Kyung Lim ◽  
Su-Hyun Hwang ◽  
Ji-Hyeon Bae ◽  
...  

This prospective study was undertaken to evaluate the clinical usefulness of a newly developed one-piece, screw-free, and micro-locking implant system, which was designed to overcome the shortcomings of the existing implant systems. Thirty-eight patients were recruited and randomly and equally assigned to an experimental group (micro-locking one-piece fixture, MLF; n = 19) or a control group (micro-locking abutment, MLA). Cumulative implant survival rates, marginal bone resorptions, probing depths, plaque indices, bleeding indices, and complications were obtained by using clinical and radiographic findings at 6 months and 12 months after prosthesis placement. Complications that occurred multiple times for single implants were counted. During the 12 month observation period, survival rates were 100% in both groups. No significant intergroup differences were observed for marginal bone resorption, probe depth, or bleeding index. However, mean plaque index was significantly lower in the MLF group at 12 months (p < 0.05). During the 12-month observation period, food impaction (26.3%) was the maincomplication in the MLF group and screw loosening (5.3%), prosthesis detachment (5.3%), and food impaction (5.3%) were observed in the MLA group. The results of this study suggest that the one-piece micro-locking implant system offers a predictable treatment method.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Emma Stump ◽  
Lauren M. Childs ◽  
Melody Walker

Abstract Background Mosquitoes are vectors for diseases such as dengue, malaria and La Crosse virus that significantly impact the human population. When multiple mosquito species are present, the competition between species may alter population dynamics as well as disease spread. Two mosquito species, Aedes albopictus and Aedes triseriatus, both inhabit areas where La Crosse virus is found. Infection of Aedes albopictus by the parasite Ascogregarina taiwanensis and Aedes triseriatus by the parasite Ascogregarina barretti can decrease a mosquito’s fitness, respectively. In particular, the decrease in fitness of Aedes albopictus occurs through the impact of Ascogregarina taiwanensis on female fecundity, larval development rate, and larval mortality and may impact its initial competitive advantage over Aedes triseriatus during invasion. Methods We examine the effects of parasitism of gregarine parasites on Aedes albopictus and triseriatus population dynamics and competition with a focus on when Aedes albopictus is new to an area. We build a compartmental model including competition between Aedes albopictus and triseriatus while under parasitism of the gregarine parasites. Using parameters based on the literature, we simulate the dynamics and analyze the equilibrium population proportion of the two species. We consider the presence of both parasites and potential dilution effects. Results We show that increased levels of parasitism in Aedes albopictus will decrease the initial competitive advantage of the species over Aedes triseriatus and increase the survivorship of Aedes triseriatus. We find Aedes albopictus is better able to invade when there is more extreme parasitism of Aedes triseriatus. Furthermore, although the transient dynamics differ, dilution of the parasite density through uptake by both species does not alter the equilibrium population sizes of either species. Conclusions Mosquito population dynamics are affected by many factors, such as abiotic factors (e.g. temperature and humidity) and competition between mosquito species. This is especially true when multiple mosquito species are vying to live in the same area. Knowledge of how population dynamics are affected by gregarine parasites among competing species can inform future mosquito control efforts and help prevent the spread of vector-borne disease.


Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3784
Author(s):  
Mark Stasiewicz ◽  
Marek Kwaśniewski ◽  
Tomasz M. Karpiński

Pancreatic cancer (PC) remains a global health concern with high mortality and is expected to increase as a proportion of overall cancer cases in the coming years. Most patients are diagnosed at a late stage of disease progression, which contributes to the extremely low 5-year survival rates. Presently, screening for PC remains costly and time consuming, precluding the use of widespread testing. Biomarkers have been explored as an option by which to ameliorate this situation. The authors conducted a search of available literature on PubMed to present the current state of understanding as it pertains to the use of microbial biomarkers and their associations with PC. Carriage of certain bacteria in the oral cavity (e.g., Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Streptococcus sp.), gut (e.g., Helicobacter pylori, Synergistetes, Proteobacteria), and pancreas (e.g., Fusobacterium sp., Enterobacteriaceae, Pseudomonadaceae) has been associated with an increased risk of developing PC. Additionally, the fungal genus Malassezia has likewise been associated with PC development. This review further outlines potential oncogenic mechanisms involved in the microbial-associated development of PC.


2021 ◽  
Vol 6 (3) ◽  
pp. 115
Author(s):  
Jaruwan Viroj ◽  
Julien Claude ◽  
Claire Lajaunie ◽  
Julien Cappelle ◽  
Anamika Kritiyakan ◽  
...  

Leptospirosis has been recognized as a major public health concern in Thailand following dramatic outbreaks. We analyzed human leptospirosis incidence between 2004 and 2014 in Mahasarakham province, Northeastern Thailand, in order to identify the agronomical and environmental factors likely to explain incidence at the level of 133 sub-districts and 1,982 villages of the province. We performed general additive modeling (GAM) in order to take the spatial-temporal epidemiological dynamics into account. The results of GAM analyses showed that the average slope, population size, pig density, cow density and flood cover were significantly associated with leptospirosis occurrence in a district. Our results stress the importance of livestock favoring leptospirosis transmission to humans and suggest that prevention and control of leptospirosis need strong intersectoral collaboration between the public health, the livestock department and local communities. More specifically, such collaboration should integrate leptospirosis surveillance in both public and animal health for a better control of diseases in livestock while promoting public health prevention as encouraged by the One Health approach.


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