incubation periods
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2022 ◽  
Vol 20 (6) ◽  
pp. 81-87
Author(s):  
N. N. Zvereva ◽  
M. A. Sayfullin ◽  
E. R. Samitova ◽  
L. N. Mazankova ◽  
V. G. Akimkin ◽  
...  

Relevance. The rapid spread of new pathogens inevitably leads to the occurrence of joint circulation with already known infectious agents, leading to the development of mixed infections. The simultaneous circulation of the pandemic coronavirus SARS-CoV-2 with a highly contagious measles virus leads to the development of mixed infections in people who have not been sick or vaccinated against measles. Aims. Review cases of co-infection with measles and COVID-19 in Moscow. Material and methods. A retrospective study of cases of measles and COVID-19 co-infection in three children with a description of the epidemiological and clinical picture of the disease. Results. In all observed children, the manifestation of the disease was typical for measles, the diagnosis of COVID-19 was established based on a laboratory study carried out in a hospital, which gave reason to count. That the infection with SARSCoV-2 occurred after the infection of children with measles. Conclusions. Different incubation periods can lead to several options for the development of co-infection. The similarity of clinical symptoms at the onset of the disease does not allow excluding a certain infection clinically, without laboratory verification.


Author(s):  
Chiwa Musa Dalah ◽  
◽  
Umar Yusuf Madaki ◽  

Malaria was declared an emergency in Nigeria and strategies for the control of Malaria in Nigeria were adopted to reduce its prevalence to a level at which the disease will no longer constitute public health problems. In this work, we presented a deterministic (Ross–Macdonald model susceptible, expose/ infected, infectious and recovered) model incorporating the method of control adopted by national Malaria and leprosy control program. We established the disease free and the endemic equilibrium states and carried out the stability analysis of the disease. Free and the equilibrium state. We also carried out numerical simulation of the model to have an insight into the dynamics of the model. We found out that the disease free equilibrium state is stable. The feedback dynamics from mosquito to human and back to mosquito involve considerable time due to the incubation periods of the parasites. In this paper, taking explicit account of the incubation periods of parasites within the human and the mosquito, we first propose a Ross–Macdonald model. The Jacobiant results showed that it would be very difficult to completely eradicate Malaria from Nigeria using the method adopted by national Malaria and leprosy control program.


Apidologie ◽  
2021 ◽  
Author(s):  
Karol Giejdasz ◽  
Monika Fliszkiewicz ◽  
Oskar Wasielewski

AbstractThe development of methods aimed at activation of imagos at any point of wintering provides a compelling potential avenue to utilize bees for pollination of greenhouse crops during autumn, winter, and early spring. In this study, we tested methoprene, a juvenile hormone (JH) analogue as a chemical stimulant to end a diapause of Osmia rufa L. and enable bee activation and emergence under experimental conditions. The application of methoprene significantly reduced the emergence time of adult bees in winter months as compared to vehicle (acetone) and negative controls. Bees treated with methoprene started to emerge 3–6 days earlier than bees from acetone and control groups and finished emergence 2–6 days earlier too. Statistically significant differences were observed between methoprene and controls groups of male and female in all tested incubation periods. It was also observed that the effects of methoprene were significantly more effective in female specimens during the first 2 months of winter. Moreover, in females, methoprene improved reproductive traits such as an increase in the size of terminal oocytes. Similarly, in males, methoprene treatment resulted in a significant increase in a seminal vesicle size and dynamic elevation of spermatozoa number. Taken together, our results indicate that methoprene may play an important role in the termination of diapause, bee activation, and emergence.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Subhendu Paul ◽  
Emmanuel Lorin

AbstractWe derive a novel model escorted by large scale compartments, based on a set of coupled delay differential equations with extensive delays, in order to estimate the incubation, recovery and decease periods of COVID-19, and more generally any infectious disease. This is possible thanks to some optimization algorithms applied to publicly available database of confirmed corona cases, recovered cases and death toll. In this purpose, we separate (1) the total cases into 14 groups corresponding to 14 incubation periods, (2) the recovered cases into 406 groups corresponding to a combination of incubation and recovery periods, and (3) the death toll into 406 groups corresponding to a combination of incubation and decease periods. In this paper, we focus on recovery and decease periods and their correlation with the incubation period. The estimated mean recovery period we obtain is 22.14 days (95% Confidence Interval (CI) 22.00–22.27), and the 90th percentile is 28.91 days (95% CI 28.71–29.13), which is in agreement with statistical supported studies. The bimodal gamma distribution reveals that there are two groups of recovered individuals with a short recovery period, mean 21.02 days (95% CI 20.92–21.12), and a long recovery period, mean 38.88 days (95% CI 38.61–39.15). Our study shows that the characteristic of the decease period and the recovery period are alike. From the bivariate analysis, we observe a high probability domain for recovered individuals with respect to incubation and recovery periods. A similar domain is obtained for deaths analyzing bivariate distribution of incubation and decease periods.


2021 ◽  
Vol 8 ◽  
Author(s):  
Tongqing Guo ◽  
Tao Guo ◽  
Yurong Cao ◽  
Long Guo ◽  
Fei Li ◽  
...  

The purpose of the study was to assess the artificial saliva (AS) pH on ruminal fermentation and rumen bacteria community in the rumen simulation technique (RUSITEC) system. The experiment was performed in two treatments (low AS pH vs. high AS pH) with four replicates. The low AS pH was sustained by altering the composition of the AS (NaHCO3 from 9.8 to 1.96 g/L, Na2HPO4 from 9.3 to 1.86 g/L) according to McDougall's method. The diets were supplemented with 16 g basic diets with forage to the concentrate ratio of 50:50. The experiments were conducted over 13-day incubation periods, with 9 days adaption and 4 days sample collection. The results showed low AS pH decreased dry matter (DM) degradability (64.37 vs. 58.67%), organic matter (OM) degradability (64.38 vs. 59.32%), neutral detergent fiber (NDF) degradability (46.87 vs. 39.94%), acid detergent fiber (ADF) degradability (38.16 vs. 31.13%), and crude protein (CP) degradability (70.33 vs. 62.99%), respectively. Compared with the high AS pH, the low AS pH increased the proportion of butyrate (P = 0.008) and decreased the proportion of propionate (P < 0.001). At the bacteria community, the low AS pH increased the abundances of Spirochaetes (P = 0.001) and Synergistetes (P = 0.004) and decreased the Verrucomicrobia abundance (P = 0.004) in solid-associated bacteria. At the genus level, the low AS pH increased the abundance of Lactobacillus (P = 0.050) and decreased the abundance of Schwartzia (P = 0.002) in solid-associated bacteria. The abundances of Prevotellaceae_YAB2003_group (P = 0.040), Schwartzia (P = 0.002), and Ruminobacter (P = 0.043) were lower in the low AS pH group compared with the high AS pH group in liquid-associated bacteria. Low AS pH decreased the number of Ruminococcus albus, Ruminococcus flavefaciens, Fibrobacter succinogenes (P < 0.001) both in the solid- and liquid-associated bacteria, respectively. The results of the present study included three groups of bacteria communities according to the different sensitives to rumen pH: the abundances of Lactobacillus, Succinivibrio, and Prevotella_7 are increased with decreasing AS pH; the amounts of R. albus, R. flavefaciens, F. succinogenes as well as the abundances of Schwartzia and Ruminobacter decreased with the reducing AS pH; the abundances of Selenomonas_1, Rikenellaceae_RC9_gut_group, and Succiniclasticum were not affected by the AS pH in RUSTITEC.


Author(s):  
A. Kizilaslan ◽  
U.G. Simsek

Background: This study was conducted to examine the development of the embryo during incubation and the composition, amount and consumption of the egg nutrients among Chukars (Alectoris chukar). Methods: A total of 1210 eggs were carefully separated into their components (albumen, yolk, shell, amniotic-allantoic fluid and embryo) on day 0 (fresh), in the first (day 7), second (day 14) and third (day 21) weeks of incubation and on the hatching date. The moisture, crude protein, crude fat, carbohydrate, crude ash and energy level were determined in egg components. Result: The albumen, yolk, shell, fluid and embryo rates were calculated to be 53.62, 34.84, 11.53, 0.0 and 0.0% in fresh egg, 16.74, 33.49, 16.22, 31.76 and 2.06% in the first week of incubation, 15.65, 28.32, 15.58, 23.35 and 17.10% in the second week of incubation and 0.0, 23.33, 19.38, 0.0 and 57.29% in the third week of incubation, respectively. The hatching weight of the chick was 16.16 g. The nutrients of the yolk, albumen, fluid and shell proportionally varied significantly in different periods of incubation. According to the nutrient changes calculated based on the weight differences of egg components, carbohydrates were mostly used for nutrients during incubation. It was found that even though the nutrients in all the egg components were used in the different periods of incubation, egg yolk was an important source for the embryo throughout the incubation period.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
K. I. Dhanalekshmi ◽  
P. Magesan ◽  
M. J. Umapathy ◽  
Xiang Zhang ◽  
N. Srinivasan ◽  
...  

AbstractHerein, the work addresses the synthesis of biomaterials (chitosan and garlic) loaded CdO–TiO2 hybrid nanocomposites for photocatalytic water treatment and photodynamic cancer therapeutic applications that were reported the first time. CdO–TiO2 (CT) nanocomposites were synthesized and loaded with the biomaterials such as chitosan and garlic by simple sol–gel method. The nanomaterials were characterized and the photodegradation of three model pollutants, Methylene blue (MB), Methyl orange (MO) and Rhodamine B (Rh-B) was opted to investigate the efficiency of the synthesized photocatalyst under the solar light. From the results, the garlic-loaded CdO–TiO2 (AS-CT) hybrid nanocomposites exhibit a superior photocatalytic activity than the chitosan-loaded CdO–TiO2 (CS-CT) and CdO–TiO2 (CT) nanocomposites under the irradiation of solar light. Additionally, the cell viability of the synthesized nanocomposites was carried out in HeLa cell lines under different concentrations, light doses and incubation periods using an LED light source. Compared to the CS-CT and CT nanocomposites, an efficient photodynamic activity was achieved in the case of AS-CT hybrid nanocomposites. Actually, the end-use properties required for both processes in AS-CT nanocomposites appear similar due to the presence of organo sulphurus compounds.


Author(s):  
Abu El-Eyuoon Abu Zied Amin

An incubation experiment was carried out to assess bone char application on the availability and distribution of phosphorus in agricultural alkaline sandy soils. Three alkaline agricultural sandy soils in Upper Egypt have been collected from Arab El-Awamer at Assiut governorate, West El-Minia at El-Minia governorate, and New Valley Governorate. 100 grams were taken from each soil under study and placed in a plastic jar. The bone char is applied at level 0.4 g jar-1 into these soils. This experiment was incubated at 23 ºC in the dark for periods of 7, 16, 35, 65, and 84 days and arranged in a completely randomized design with three replicates. The results revealed that bone char applications to the soils resulted in a significant positive increase in the availability of phosphorus affected by the soil type and incubation periods in Arab El-Awamer soil. The percentage of increase in available phosphorous after adding bone char compared to before incubation was as follows: Arab El-Awamer soil ˃New Valley soil ˃West El-Minia soil. The available phosphorous was negatively correlated with electrical conductivity (r=-0.288*), soluble calcium (r=-0.306*), and soluble sulfate (r=-0.413*). The concentrations of NH4Cl-Pi, NaHCO3-Pi, NaOH-Pi, HCl-Pi, residual-P fractions increased significantly in some soil types with applying bone char. The concentrations of available phosphorous in all soils under study were positively correlated with all phosphorus fractions. We conclude that bone char applications into P-poor soil are important to potentially enhance phosphorus availability. Bone char is considered a promising strategy in sustainable agriculture.


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