Comparative Study of the Effect of Solvents on the Efficacy of Neonicotinoid Insecticides Against Malaria Vector Populations Across Africa

Background New insecticides with a novel mode of action such as neonicotinoids have recently been recommended for public health by WHO. Resistance monitoring of such novel insecticides requires a robust protocol to monitor the development of resistance in natural populations. In this study, we comparatively used three different solvents to assess the susceptibility of malaria vectors to neonicotinoids across Africa.MethodsMosquitoes were collected from May to July 2021 from three agricultural settings in Cameroon (Njombe-Penja, Nkolondom, and Mangoum), the Democratic Republic of Congo (Ndjili-Brasserie), Ghana (Obuasi), and Uganda (Mayuge). Using the CDC bottle test, we compared the effect of three different solvents (ethanol, acetone, MERO) on the efficacy of neonicotinoids against Anopheles gambiae s.l. In addition, TaqMan assays were used to genotype key pyrethroid-resistant markers in An. gambiae and to evaluate potential cross-resistance between pyrethroids and clothianidin.ResultsLower mortality were observed when using absolute ethanol or acetone alone as solvent (11.4- 51.9% mortality in Nkolondom, 31.7- 48.2% in Mangoum, 34.6- 56.1% in Mayµge, 39.4- 45.6% in Obuasi, 83.7- 89.3% in Congo and 71.05- 95.9% in Njombe pendja) compared to acetone + MERO for which 100% mortality were observed for all the populations. Synergist assays (PBO, DEM and DEF) revealed a significant increase of mortality suggesting that metabolic resistance mechanisms are contributing to the reduced susceptibility. A negative association was observed between the L1014F-kdr mutation and clothianidin resistance with a greater frequency of homozygote resistant mosquitoes among the dead than among survivors (OR=0.5; P=0.02). However, the I114T-GSTe2 was in contrast significantly associated with a greater ability to survive clothianidin with a higher frequency of homozygote resistant among survivors than other genotypes (OR=2.10; P=0.013). ConclusionsThis study revealed a contrasted susceptibility pattern depending on the solvents with ethanol/acetone resulting to lower mortality, thus possibly overestimating resistance, whereas the MERO consistently showed a greater efficacy of neonicotinoids but it could prevent to detect early resistance development. Therefore, we recommend monitoring the susceptibility using both acetone alone and acetone+MERO (8-10µg/ml for clothianidin) to capture the accurate resistance profile of the mosquito populations.

Hatching, embryo death and chicks growth in dual purpose and brawl hens under natural hypobaric conditions

The present study aimed to compare results for hatchability and growing performance of chicks from 2 biotypes, dual purpose (DP) and brawl (BR), in hipobaric conditions (2718 m above sea level). In experiment 1, a total of 352 hatching eggs were randomly arranged, 176 egg of DP y 176 BR. In experiment 2, a total of 114 one-day-old unsexed chickens were reared for 28 d. The experimental design for hatchability and chick performance variables was completely randomized with 2 treatments (DP and BR). There were no differences between the studied treatments for hatchability results (p>0.05). Hens’ biotype affected chicken performance in the rearing phase (p<0.01), where the DP chickens had better body weight and feed conversion than BR, but BR chickens had lower mortality than DP chickens.

Protective Effects of Familial Longevity Decrease with Age and Become Negligible for Centenarians

It is known that biological relatives of long-lived individuals demonstrate lower mortality and longer lifespan compared to relatives of shorter-lived individuals, and at least part of this advantage is likely to be genetic. Less information, however, is available about effects of familial longevity on age-specific mortality trajectories. We compared mortality patterns after age 50 years for 10,045 siblings of U.S. centenarians and 12,308 siblings of shorter-lived individuals (died at age 65 years). Similar comparisons were made for sons and daughters of longer-lived parents (both parents lived 80 years and more) and shorter-lived parents (both parents lived less than 80 years) within each group of siblings. Although relatives of longer-lived individuals have lower mortality at younger ages compared to relatives of shorter lived individuals, this mortality advantage practically disappears by age 100 years. To validate this observation further, we analyzed survival of 3,408 U.S. centenarians born in 1890-97 with known information on maternal and paternal lifespan. We found using the Cox proportional hazards model that both maternal and paternal longevity (lifespan 80+ years) is not significantly associated with survival after age 100 years. The results are compatible with the predictions of reliability theory of aging suggesting higher initial levels of system redundancy (reserves) in individuals with protective familial/genetic background and hence lower initial mortality. Heterogeneity hypothesis is another possible explanation for the observed phenomena.

Recruitment of Ostrea chilensis (Philippi, 1844) in Foveaux Strait, Southern New Zealand

<p>This research evaluates fundamental ecological processes to facilitate an understanding of recruitment in Ostrea chilensis from Foveaux Strait, southern New Zealand. Foveaux Strait represents an extreme habitat for oysters that differs to the sheltered nearshore, muddy habitats of most other oyster populations. O. chilensis exhibits the extreme end of brooding strategies in Ostreinae, does not form extensive reefs, and comprises putative self-recruiting populations. The Foveaux Strait oyster fishery is nationally important. Recurrent disease mortality in these populations has put greater onus on understanding recruitment. To evaluate the strength of a recruit-per-spawner relationship in oysters, seasonality in the settlement of larvae was determined. Most recruitment in any given year, over a 6-year period, occurred in the austral spring and summer (November to February). Fishery-wide, recruitment varied significantly between years, with most variation (50.8%) explained by a year effect that represents the combined influences of climatic and biological conditions. Spawner densities and fishery areas explain further variation (13.8% and 11.6%, respectively), with further 2-way interactions between these factors. Recruits-per-spawner declined serially over time, despite similar or increasing densities of spawning-sized oysters. Average recruitment was lowest when spawner densities were highest; this suggests a more complex relationship between recruitment and density that has implications for management of this oyster fishery. Recruitment to the O. chilensis fishery declined abruptly to low levels in 2010 and remained low until 2017. Relatively high spawning-stock sizes over this period had previously supported high recruitment. Density and oyster mortality from Bonamia exitiosa (a proxy for one or more infections) and their two-way interaction were the main determinants of recruitment. The highest recruitment occurred at times of low mortality and low density, suggesting reduced effects of disease on gametogenesis and reduced disease transmission. The contributions of climate factors were minor; however, a 3-way interaction between oyster density, mortality, and climate is likely to drive variation in recruitment. Pathobiomes (multiple infections in populations) may be important determinants of shellfish recruitment and population dynamics. This research evaluates the hypothesis of self-recruitment from distributions of recruit densities around an isolated natal population, and from the relationship between recruitment and brooding-sized oyster densities. Distance from the natal population, direction along or across the tidal current, or brooders did not predict recruit densities. Recruit distributions imply greater dispersal and larval mixing than previously reported. The swift tidal currents and possibility of more variable pelagic larval durations may enhance mixing and connectivity between populations in Foveaux Strait. Post-settlement mortality is the primary determinant of spatial structure in Foveaux Strait oysters. Productive fishery areas comprise mostly stable substrates of shells, sand, and gravel, with no or little other epifauna. Most (66.8%) post-settlement survivors were on the heavy shells of both live and dead O. chilensis, which suggests an unusual recruit-adult relationship based on survival rather than settlement. Recruits and 1+ year spat grew larger and had lower mortality at eastern sites with the lowest exposure to oceanic swells and putative lowest sediment movement. Moreover, recruits on spat collectors also grew larger and had lower mortality at heights ≥ 12 cm than those 2 cm off the seabed. This research suggests the effects of disease on brooding percentages and thereby larval supply may be the main determinant of the variation in recruitment in O. chilenesis, and the spatial structure of oyster populations in Foveaux Strait shaped by abiotic as well as biotic post-settlement mortality.</p>

Recruitment of Ostrea chilensis (Philippi, 1844) in Foveaux Strait, Southern New Zealand

<p>This research evaluates fundamental ecological processes to facilitate an understanding of recruitment in Ostrea chilensis from Foveaux Strait, southern New Zealand. Foveaux Strait represents an extreme habitat for oysters that differs to the sheltered nearshore, muddy habitats of most other oyster populations. O. chilensis exhibits the extreme end of brooding strategies in Ostreinae, does not form extensive reefs, and comprises putative self-recruiting populations. The Foveaux Strait oyster fishery is nationally important. Recurrent disease mortality in these populations has put greater onus on understanding recruitment. To evaluate the strength of a recruit-per-spawner relationship in oysters, seasonality in the settlement of larvae was determined. Most recruitment in any given year, over a 6-year period, occurred in the austral spring and summer (November to February). Fishery-wide, recruitment varied significantly between years, with most variation (50.8%) explained by a year effect that represents the combined influences of climatic and biological conditions. Spawner densities and fishery areas explain further variation (13.8% and 11.6%, respectively), with further 2-way interactions between these factors. Recruits-per-spawner declined serially over time, despite similar or increasing densities of spawning-sized oysters. Average recruitment was lowest when spawner densities were highest; this suggests a more complex relationship between recruitment and density that has implications for management of this oyster fishery. Recruitment to the O. chilensis fishery declined abruptly to low levels in 2010 and remained low until 2017. Relatively high spawning-stock sizes over this period had previously supported high recruitment. Density and oyster mortality from Bonamia exitiosa (a proxy for one or more infections) and their two-way interaction were the main determinants of recruitment. The highest recruitment occurred at times of low mortality and low density, suggesting reduced effects of disease on gametogenesis and reduced disease transmission. The contributions of climate factors were minor; however, a 3-way interaction between oyster density, mortality, and climate is likely to drive variation in recruitment. Pathobiomes (multiple infections in populations) may be important determinants of shellfish recruitment and population dynamics. This research evaluates the hypothesis of self-recruitment from distributions of recruit densities around an isolated natal population, and from the relationship between recruitment and brooding-sized oyster densities. Distance from the natal population, direction along or across the tidal current, or brooders did not predict recruit densities. Recruit distributions imply greater dispersal and larval mixing than previously reported. The swift tidal currents and possibility of more variable pelagic larval durations may enhance mixing and connectivity between populations in Foveaux Strait. Post-settlement mortality is the primary determinant of spatial structure in Foveaux Strait oysters. Productive fishery areas comprise mostly stable substrates of shells, sand, and gravel, with no or little other epifauna. Most (66.8%) post-settlement survivors were on the heavy shells of both live and dead O. chilensis, which suggests an unusual recruit-adult relationship based on survival rather than settlement. Recruits and 1+ year spat grew larger and had lower mortality at eastern sites with the lowest exposure to oceanic swells and putative lowest sediment movement. Moreover, recruits on spat collectors also grew larger and had lower mortality at heights ≥ 12 cm than those 2 cm off the seabed. This research suggests the effects of disease on brooding percentages and thereby larval supply may be the main determinant of the variation in recruitment in O. chilenesis, and the spatial structure of oyster populations in Foveaux Strait shaped by abiotic as well as biotic post-settlement mortality.</p>

Association of Sedentary and Active Bout Frequency With Mortality in Older Men Using Accelerometry

Background Time spent sedentary increases with age and has several negative health consequences. We sought to examine associations between daily sedentary and active bout frequency with all-cause mortality. Methods Data are from 2,918 men in the Osteoporotic Fractures in Men (MrOS) study (mean age at Visit 3±SD: 79.0±5.1 years) with valid activity monitor data (5.1±0.3 days worn&gt;90%) at Year 7 visit (Visit 3, 2007-2009). Sedentary and active bout frequencies are defined as the daily transition frequency from a sedentary bout lasting 5+ minutes to activity of any intensity, and the transition frequency from an active bout lasting 5+ minutes to sedentary. Deaths were centrally adjudicated using death certificates. Cox proportional hazard models were used to examine associations between quartiles of sedentary (Q1 referent, &lt;13.6 bouts/day) or active (Q1 referent, &lt;5 bouts/day) bout frequency and mortality. Models were repeated, stratifying by median daily total time spent sedentary and active. Results After 9.4±3.7 years of follow-up, 1,487 (51.0%) men died. Men averaged 16.9±5.1 and 8.2±4.2 sedentary and active bouts/day, respectively. After full covariate adjustment, each quartile reflecting a higher sedentary (Q4 vs Q1 HR: 0.68, 95%CI: 0.58-0.81, p-trend&lt;0.001) and active bout (Q4 vs Q1 HR: 0.57, 95%CI: 0.48-0.68, p-trend&lt;0.001) frequency was associated with lower mortality risk. There was no evidence that effects differed by total sedentary time (p-interaction for sedentary bout frequency and total sedentary time&gt;0.05). Conclusions More frequent, prolonged sedentary and active bouts are associated with a lower mortality risk in older men and is not moderated by total sedentary time.

Canadian Multicenter Chronic Total Occlusion Registry: Ten-Year Follow-Up Results of Chronic Total Occlusion Revascularization

Background: Chronic total occlusions (CTO) occur in nearly 20% of coronary angiograms. CTO revascularization, either by percutaneous coronary intervention (PCI) or coronary artery bypass grafting surgery (CABG), is infrequently performed, approximately one-third of cases. Long-term outcomes are unknown. The objective of the study was to determine whether early CTO revascularization of patients, either by CABG or PCI, was associated with improved clinical outcomes. Methods: One thousand six hundred twenty-four patients from the Canadian CTO registry were followed for at least 9.75 years. Revascularization was performed according to routine clinical practice. Patients were grouped according to CTO revascularization status (PCI or CABG of CTO vessel, CTO revasc) or no CTO revasc (medical therapy only, or PCI/CABG of non-CTO vessels only), within 3 months of initial angiogram. Patients were followed for mortality, revascularization procedures (PCI and CABG), and hospitalizations for acute coronary syndromes and heart failure. Results: Early CTO revasc was performed in 28.2% of patients (17.5% CABG, 10.7% PCI). The CTO revasc group was younger, with more males and generally fewer comorbidities. There was a significantly lower mortality probability at 10 years in the CTO revascularization group (22.7% [95% CI, 19.0%–26.9%]) compared with the no CTO revasc group (36.6% [95% CI, 33.8%–39.5%]). At 10 years, revascularization rates (14.0% versus 22.8%) and acute coronary syndrome hospitalization rates (10.0% versus 16.6%) were significantly lower in the CTO revasc group. Baseline-adjusted analysis showed CTO revasc was associated with significantly lower all-cause mortality (hazard ratio, 0.67 [95% CI, 0.54–0.84]). In both landmark and time varying analyses, association with lower mortality was particularly robust for CTO revascularization by CABG (hazard ratio 0.56 and 0.60, respectively), with a marginally significant result for PCI in the time varying analysis (hazard ratio 0.711 [95% CI, 0.51–0.998]). Conclusions: Early CTO revascularization was associated with significantly lower all-cause mortality, revascularization rates, and hospitalization for acute coronary syndrome at 10 years, and mainly driven by outcomes in patients with CABG.