Reproduction of the winter tick, Dermacentor albipictus, under laboratory conditions

1987 ◽  
Vol 65 (11) ◽  
pp. 2583-2588 ◽  
Author(s):  
Mark L. Drew ◽  
W. M. Samuel
Keyword(s):  
Time Series ◽  
Mortality Rate ◽  
Relative Humidity ◽  
Cold Stress ◽  
Reproductive Performance ◽  
Treatment Groups ◽  
Preoviposition Period ◽  
Dermacentor Albipictus ◽  
Winter Tick ◽  
Over Time

Reproductive performance and development of the winter tick, Dermacentor albipictus, were studied under controlled conditions using multiple replicates along a time series. Engorged female ticks cold stressed at various temperatures before incubation at 25 °C laid more eggs, and the number of eggs laid per gram of engorged female was higher, than female ticks held at constant 25 °C. No females survived a pretreatment of −22 °C. Females maintained under fluctuating temperature and relative humidity had a higher mortality rate and lower reproductive performance than those in either constant or cold-stress conditions. The preoviposition period decreased over time in most treatment groups.

scholarly journals Evolution of COVID-19 during the epidemiological week 16 to 53 of 2020 in the state of Acre Western Amazonia, Brazil

2021 ◽  
Vol 31 (3) ◽  
pp. 425-435
Author(s):  
Edimilson Lima de Assis ◽  
Mauro José de Deus Morais ◽  
Jorge De Oliveira Eichemberg ◽  
Valéria Rigamonte Azevedo de Assis ◽  
Hugo Macedo Junior ◽  
...  
Keyword(s):  
Time Series ◽  
Mortality Rate ◽  
Skin Color ◽  
Ecological Study ◽  
Rna Viruses ◽  
The State ◽  
Older Age ◽  
Male Sex ◽  
State Capital ◽  
Over Time

Introduction: coronavirus is part of a group of RNA viruses belonging to the Coronaviridae family, widely distributed in humans and other mammals. Currently, it has been seriously affecting the whole world, without a definitive cure yet. Objective: to analyse the association between the HDI and confirmed cumulative cases of COVID-19 that occurred during epidemiological week 16 to 53 of 2020, in the State of Acre. Methods: this is an ecological study of descriptive time series, evaluating the State of Acre and its 22 municipalities affected by COVID-19, in the period corresponding to the epidemiological weeks 16 to 53 of 2020. The State of Acre and its municipalities are aggregated by five regions with a total of approximately 881 thousand inhabitants, with an HDI of 0.663. Rio Branco is the state capital with 407,000 inhabitants. The 22 municipalities were analyzed, relating the HDI variables, confirmed cases per day and number of inhabitants to each other. Results: it was observed that the population evaluated, affected by COVID-19 during SE 16 to 53 of 2020, in the State of Acre, had as predominant general characteristics brown skin color, male sex, and the evolution to death from the disease was related with older age and comorbidity. Acre had a mortality rate (deaths per 100,000 inhabitants) of 90.9 and a lethality rate of 1.9%, with the highest mortality rate observed in the municipality of Rio Branco (121.3/100,000 inhabitants) and lethality in Rodrigues Alves (2.9%). The incidence of COVID-19 in Acre was 4,759.9 cases per 100,000 inhabitants, the municipalities of Assis Brasil and Xapuri had the highest incidences in the state with 10273.7 and 9330.8 new cases per 100,000 inhabitants, respectively. Conclusion: although the accumulated numbers of cases are different for the same day, the behavior is very similar, that is, the curves vary in the same way over time, regardless of the municipality observed.

scholarly journals Prevalence of Winter Ticks (Dermacentor albipictus) in Hunter-Harvested Wild Elk (Cervus canadensis) from Pennsylvania, USA (2017–2018)

2020 ◽  
Vol 7 (4) ◽  
pp. 177
Author(s):  
Elizabeth Calvente ◽  
Samantha Pelletier ◽  
Jeremiah Banfield ◽  
Justin Brown ◽  
Nicole Chinnici
Keyword(s):  
United States ◽  
Tick Infestation ◽  
Severe Winter ◽  
Dermacentor Albipictus ◽  
Cervus Canadensis ◽  
Negative Impacts ◽  
Winter Tick ◽  
Over Time ◽  
Tick Burden ◽  
Tick Load

Winter ticks (Dermacentor albipictus) are an aggressive one-host tick that infest a wide-diversity of ungulates. Infestations can result in anemia, alopecia, emaciation, and death. Most notably, the winter tick has caused negative impacts to moose (Alces alces) populations in the northeast United States and Canada. Winter ticks have been identified on other cervid species, including deer (Odocoileus virginianus) and elk (Cervus canadensis), which generally results in low tick burdens and mild or no disease. Recently, however, a wild yearling bull elk in Pennsylvania was found dead as a result of severe winter tick infestation. To obtain baseline data on winter ticks in wild elk in Pennsylvania, we collected 1453 ticks from 190 hunter-harvested wild elk between 2017–2018. Of the 204 harvested elk, 94.3% (190/204) had ticks collected for this study and none of the sampled elk had evidence of winter-tick associated disease. The average tick burden was 7.7 ticks/elk and average winter tick load on all elk was 0.5. Results of this study indicate that winter ticks do infest wild elk in Pennsylvania. However, during the fall months, the tick burden is low and rarely associated with lesions. These data herein serve as a baseline to monitor winter tick populations over time.

scholarly journals The Impacts of Waterproof Insulated Jackets on Lamb Performance on a UK Lowland Farm

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 217
Author(s):  
Eleanor Brooke Collins ◽  
Nicola Blackie
Keyword(s):  
Weight Gain ◽  
Cold Stress ◽  
Morbidity And Mortality ◽  
Daily Weight Gain ◽  
Birth Date ◽  
Body Temperatures ◽  
Average Daily Weight Gain ◽  
Treatment Groups ◽  
Surface Temperatures ◽  
Weight Gains

The majority of lamb losses occur within the first two weeks of life, with cold stress being a major cause of lamb morbidity and mortality. This study investigated the effect of insulating lamb jackets on newborn lambs. One hundred and four newborn lambs were randomly allocated by birth date to two treatment groups, (a) non-jacketed (n = 52) or (b) jacketed (n = 52), for fourteen days after birth. The live weights of lambs were recorded regularly up to 21 days, and average daily weight gains were calculated from these data. For the first two days after recruitment to the study, surface and body temperatures of lambs were also recorded. The jackets significantly increased the lambs’ surface temperatures, providing a warmer microclimate and reduced cold stress for jacketed lambs. There was no significant effect of the insulating jackets on estimated body temperatures, live weights or average daily weight gain of the lambs in this study. There were no detrimental effects of the jackets, and no rejection of lambs occurred.

Reproductive performance of group-synchronized Merino d'Arles and Romanov crossbred ewes. 1. A note on the effects of lactation on fecundity

1977 ◽  
Vol 24 (1) ◽  
pp. 113-116 ◽  
Author(s):  
F. J. Galindez ◽  
M. Prud'hon ◽  
G. Reboul
Keyword(s):  
Treatment Group ◽  
Reproductive Performance ◽  
The Other ◽  
Fertility Level ◽  
Homogeneous Groups ◽  
Treatment Groups ◽  
Significant Superiority

SUMMARYFifty-six Merino d'Aries and 56 Romanov × Merino crossbred lactating ewes were divided into two treatment groups, one (T1) with a ewe-to-ram ratio of 48: 1 (24 Merino and 24 crossbred) and the other (T2) of 64: 1 (32 Merino and 32 crossbred).Intravaginal sponges with 40 mg FGA (Searle) were inserted in two subgroups at 8-day intervals and withdrawn after 12 and 16 days in situ, in four equal groups at 4-day intervals. A dose of 400 IU pregnant mare's serum gonadotrophin (PMSG) was applied at sponge withdrawal.Fertility after two oestrous cycles was equally satisfactory in both treatments, though it was lower in treatment group T2. This could be due to the significantly low (P<0·01) number of Merino ewes raddled by the T2 ram (0·33 Merino against 0·92 crossbred) suggesting preferential behaviour by the ram in this treatment.Comparisons between breeds show a slight superiority in the fertility of crossbred ewes and a highly significant superiority in prolificacy These results suggest that using the described method, 2% of rams seems more than adequate to mate with progestagen-synchronized ewes with a satisfactory fertility level. It is, however, recommended to use homogeneous groups of ewes.

scholarly journals Stock assessment and projections incorporating discard estimates in some years: an application to the hake stock in ICES Divisions VIIIc and IXa

2010 ◽  
Vol 67 (6) ◽  
pp. 1185-1197 ◽  
Author(s):  
C. Fernández ◽  
S. Cerviño ◽  
N. Pérez ◽  
E. Jardim
Keyword(s):  
Time Series ◽  
Stock Assessment ◽  
Reference Points ◽  
Assessment Model ◽  
Marine Science ◽  
Fishing Mortality ◽  
Change Over Time ◽  
Age Structured ◽  
Available Information ◽  
Over Time

Abstract Fernández, C., Cerviño, S., Pérez, N., and Jardim, E. 2010. Stock assessment and projections incorporating discard estimates in some years: an application to the hake stock in ICES Divisions VIIIc and IXa. – ICES Journal of Marine Science, 67: 1185–1197. A Bayesian age-structured stock assessment model is developed to take into account available information on discards and to handle gaps in the time-series of discard estimates. The model incorporates mortality attributable to discarding, and appropriate assumptions about how this mortality may change over time are made. The result is a stock assessment that accounts for information on discards while, at the same time, producing a complete time-series of discard estimates. The method is applied to the hake stock in ICES Divisions VIIIc and IXa, for which the available data indicate that some 60% of the individuals caught are discarded. The stock is fished by Spain and Portugal, and for each country, there are discard estimates for recent years only. Moreover, the years for which Portuguese estimates are available are only a subset of those with Spanish estimates. Two runs of the model are performed; one assuming zero discards and another incorporating discards. When discards are incorporated, estimated recruitment and fishing mortality for young (discarded) ages increase, resulting in lower values of the biological reference points Fmax and F0.1 and, generally, more optimistic future stock trajectories under F-reduction scenarios.

Estimating long-term tree mortality rate time series by combining data from periodic inventories and harvest reports in a Bayesian state-space model

2013 ◽  
Vol 292 ◽  
pp. 64-74 ◽  
Author(s):  
Katalin Csilléry ◽  
Maëlle Seignobosc ◽  
Valentine Lafond ◽  
Georges Kunstler ◽  
Benoît Courbaud
Keyword(s):  
Time Series ◽  
Mortality Rate ◽  
State Space ◽  
Tree Mortality ◽  
State Space Model ◽  
Space Model ◽  
Combining Data

Following the infection dynamics of the tropical trematode Oligogonotylus mayae in its intermediate and definitive hosts for 13 years

2020 ◽  
Vol 94 ◽  
Author(s):  
A.L. May-Tec ◽  
N.A. Herrera-Castillo ◽  
V.M. Vidal-Martínez ◽  
M.L. Aguirre-Macedo
Keyword(s):  
Time Series ◽  
Cross Correlation ◽  
Southern Oscillation ◽  
Fish Host ◽  
Snail Host ◽  
Monthly Data ◽  
Infection Dynamics ◽  
Infection Parameters ◽  
Over Time

Abstract We present a time series of 13 years (2003–2016) of continuous monthly data on the prevalence and mean abundance of the trematode Oligogonotylus mayae for all the hosts involved in its life cycle. We aimed to determine whether annual (or longer than annual) environmental fluctuations affect these infection parameters of O. mayae in its intermediate snail host Pyrgophorus coronatus, and its second and definitive fish host Mayaheros urophthalmus from the Celestun tropical coastal lagoon, Yucatan, Mexico. Fourier time series analysis was used to identify infection peaks over time, and cross-correlation among environmental forcings and infection parameters. Our results suggest that the transmission of O. mayae in all its hosts was influenced by the annual patterns of temperature, salinity and rainfall. However, there was a biannual accumulation of metacercarial stages of O. mayae in M. urophthalmus, apparently associated with the temporal range of the El Niño-Southern Oscillation (five years) and the recovery of the trematode population after a devasting hurricane. Taking O. mayae as an example of what could be happening to other trematodes, it is becoming clear that environmental forcings acting at long-term temporal scales affect the population dynamics of these parasites.

Algorithms to predict moisture content of grain using relative humidity time-series

2020 ◽  
Author(s):  
Charles B. Delahunt ◽  
Wenbo Wang ◽  
Simon Ghionea ◽  
Andrew Miller ◽  
Austin Chan ◽  
...  
Keyword(s):  
Time Series ◽  
Relative Humidity ◽  
Moisture Content
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