The Within-Host Population Dynamics of Antibacterial Chemotherapy: Conditions for the Evolution of Resistance

2007 ◽  
pp. 112-130
Author(s):  
Marc Lipsitch ◽  
Bruce R. Levin
Keyword(s):  
Population Dynamics ◽  
Host Population ◽  
Evolution Of Resistance ◽  
Antibacterial Chemotherapy

scholarly journals Microfilarial distribution of Loa loa in the human host: population dynamics and epidemiological implications

Parasitology ◽  
2006 ◽  
Vol 133 (01) ◽  
pp. 101 ◽  
Author(s):  
S. D. S. PION ◽  
J. A. N. FILIPE ◽  
J. KAMGNO ◽  
J. GARDON ◽  
M.-G. BASÁÑEZ ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Host Population ◽  
Loa Loa ◽  
Human Host

An Experimental Field Study to Examine Whether Capillaria Hepatica (Nematoda) Can Limit House Mouse Populations in Eastern Australia.

1995 ◽  
Vol 22 (1) ◽  
pp. 31 ◽  
Author(s):  
GR Singleton ◽  
GR Singleton ◽  
LK Chambers ◽  
LK Chambers ◽  
DM Spratt ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Host Population ◽  
Rapid Decline ◽  
Low Density ◽  
Noticeable Effect ◽  
Mouse Population ◽  
Apparent Lack ◽  
Capillaria Hepatica ◽  
Experimental Field ◽  
Eastern Australia

A replicated experimental field investigation to examine the effect of the nematode parasite Capillaria hepatica on populations of Mus domesticus is described. A 2-year study was conducted at 7 sites with matching farming practices, soil types, topography and habitat heterogeneity on the Darling Downs in south-eastern Queensland, Australia, where mice cause substantial economic, social and environmental problems. A 4 km2 sampling zone was designated on each site and sites were assigned randomly to one of 3 untreated and 4 treated groups. The parasite was released successfully on 3 occasions at 3 markedly different stages of mouse population dynamics. The first release was in winter 1992 into a low-density, non-breeding population. Mice on treated sites had significantly lower survival for 6 months after the release than mice on untreated sites. The parasite had a relatively high impact on survival of young mice (<72 mm long) 2 months after its release. The greatest impact on old mice (>76 mm) occurred a month later. The most pronounced effects of C. hepatica on mouse abundance occurred during the 4 months after its release (June-September). Mice on the untreated sites, however, had poor survival in September, so by October their population abundance was at a level similar to that of the treated populations. Once breeding began in mid-October C. hepatica had no noticeable effect on mouse population dynamics. This was because the parasite (i) had no effect on breeding of mice, (ii) had minimal transmission and (iii) had a diminishing effect on survival after October. The apparent lack of transmission of C. hepatica was probably due to a combination of low population density, the transient nature of the mouse population and predominantly dry weather for 6 months after the release. A second release was made in February 1993 into a breeding, medium-density host population that was rapidly increasing in abundance. Less than 2% of the population was affected during the release so interest focused on transmission rather than the effect of the parasite on the host's demographic machinery. Transmission did occur at a low rate and the parasite persisted for 4.5 months (to June) when it was decided to boost the proportion of mice infected in order to follow its effect on the overwintering population and the demographic effects during the next breeding season. This late release was compromised by synchronous, widespread and rapid decline in mouse densities. Densities fell from greater than 500 ha to less than 1 ha in less than 6 weeks. Two messages emerge from these studies. First, C. hepatica will not limit mouse populations if it is released into a low-density population during a long dry period on the Darling Downs. Second, more information is needed about the factors that influence the survival and transmission of the parasite under field conditions.

scholarly journals Space and time predictions of schistosomiasis snail host population dynamics across hydrologic regimes in Burkina Faso

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Javier Perez-Saez ◽  
Theophile Mande ◽  
Andrea Rinaldo
Keyword(s):  
Population Dynamics ◽  
Burkina Faso ◽  
Spatial Patterns ◽  
Large Scale ◽  
Remotely Sensed ◽  
Host Population ◽  
Snail Host ◽  
Intermediate Hosts ◽  
National Scale ◽  
Temperature And Precipitation

The ecology of the aquatic snails that serve as obligatory intermediate hosts of human schistosomiasis is driven by climatic and hydrological factors which result in specific spatial patterns of occurrence and abundance. These patterns in turn affect, jointly with other determinants, the geography of the disease and the timing of transmission windows, with direct implications for the success of control and elimination programmes in the endemic countries. We address the spatial distribution of the intermediate hosts and their seasonal population dynamics within a predictive ecohydrological framework developed at the national scale for Burkina Faso, West Africa. The approach blends river network-wide information on hydrological ephemerality which conditions snail habitat suitability together with ensembles of discrete time ecological models forced by remotely sensed estimates of temperature and precipitation. The models were validated against up to four years of monthly snail abundance data. Simulations of model ensembles accounting for the uncertainty in remotely sensed products adequately reproduce observed snail demographic fluctuations observed in the field across habitat types, and produce national scale predictions by accounting for spatial patterns of hydrological conditions in the country. Geospatial estimates of seasonal snail abundance underpin large-scale, spatially explicit predictions of schistosomiasis incidence. This work can therefore contribute to the development of disease control and elimination programmes.

Monogenean parasites from fishes of the Vaal Dam, Gauteng Province, South Africa. I. Winter survey versus summer survey comparison from Labeo capensis (Smith, 1841) and Labeo umbratus (Smith, 1841) hosts

2014 ◽  
Vol 59 (1) ◽  
Author(s):  
Dionne Crafford ◽  
Wilmien Luus-Powell ◽  
Annemariè Avenant-Oldewage
Keyword(s):  
Population Dynamics ◽  
Large Scale ◽  
Experimental Studies ◽  
Attachment Site ◽  
Host Population ◽  
Site Preference ◽  
Gauteng Province ◽  
Active Choice ◽  
Vaal Dam ◽  
Intensive Aquaculture

AbstractIndigenous South African Labeo spp. show promise with regard to development of semi-intensive aquaculture, yet little research on their monogenean fauna has been conducted. Ecological aspects of monogenean fauna of the moggel Labeo umbratus (Smith 1841) and the Orange River mudfish Labeo capensis (Smith 1841), as recorded during both winter and summer sampling surveys, are reported here. Fish were collected using gill nets, euthanized and gills removed and examined to both quantify parasite numbers and distribution on the gills. Results obtained support the hypothesis that gill site preference is not due to active choice for a particular attachment site, but rather a result of water flow over gills during respiration in conjunction with fish behaviour and habitat use. Interaction between individual elements investigated (temperature effects, parasite population dynamics and host population dynamics) may be largely responsible for seasonal differences in infection statistics of monogenean parasites. Such interactions should be investigated in future large scale ecological studies, in combination with experimental studies, to further elucidate these effects.

Testing local-scale panmixia provides insights into the cryptic ecology, evolution, and epidemiology of metazoan animal parasites

Parasitology ◽  
2012 ◽  
Vol 139 (8) ◽  
pp. 981-997 ◽  
Author(s):  
MARY J. GORTON ◽  
EMILY L. KASL ◽  
JILLIAN T. DETWILER ◽  
CHARLES D. CRISCIONE
Keyword(s):  
Population Dynamics ◽  
Random Mating ◽  
Local Scale ◽  
Host Population ◽  
Parasite Population ◽  
Evolutionary Significance ◽  
Metazoan Parasites ◽  
Equal Chance ◽  
Single Host ◽  
Species Population

SUMMARYWhen every individual has an equal chance of mating with other individuals, the population is classified as panmictic. Amongst metazoan parasites of animals, local-scale panmixia can be disrupted due to not only non-random mating, but also non-random transmission among individual hosts of a single host population or non-random transmission among sympatric host species. Population genetics theory and analyses can be used to test the null hypothesis of panmixia and thus, allow one to draw inferences about parasite population dynamics that are difficult to observe directly. We provide an outline that addresses 3 tiered questions when testing parasite panmixia on local scales: is there greater than 1 parasite population/species, is there genetic subdivision amongst infrapopulations within a host population, and is there asexual reproduction or a non-random mating system? In this review, we highlight the evolutionary significance of non-panmixia on local scales and the genetic patterns that have been used to identify the different factors that may cause or explain deviations from panmixia on a local scale. We also discuss how tests of local-scale panmixia can provide a means to infer parasite population dynamics and epidemiology of medically relevant parasites.

Persistence of plague outbreaks among great gerbils in Kazakhstan: effects of host population dynamics

2015 ◽  
Vol 57 (3) ◽  
pp. 473-484 ◽  
Author(s):  
Lise Heier ◽  
Hildegunn Viljugrein ◽  
Geir O. Storvik
Keyword(s):  
Population Dynamics ◽  
Host Population
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