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Epidemiological traits of the malaria-like parasite Polychromophilus murinus in the Daubenton's bat Myotis daubentonii.

Witsenburg F, Schneider F, Christe P - Parasit Vectors (2014)

Bottom Line: Yet most of these studies provide only snapshots in time of the parasites discovered.During one year, we additionally measured body temperature and haematocrit values.Confusion over the identities and nomenclature of malarial-like parasites requires that molecular barcodes are coupled to accurate morphological descriptions.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolution, University of Lausanne, Biophore, CH-1015, Lausanne, Switzerland. fardo.witsenburg@unil.ch.

ABSTRACT

Background: The great diversity of bat haemosporidians is being uncovered with the help of molecular tools. Yet most of these studies provide only snapshots in time of the parasites discovered. Polychromophilus murinus, a malaria-like blood parasite, specialised on temperate-zone bats is a species that is being 'rediscovered'. This study describes the infection dynamics over time and between host sex and age classes.

Methods: For three years we followed the members of three breeding colonies of Myotis daubentonii in Western Switzerland and screened them for the prevalence and parasitemia of P. murinus using both molecular tools and traditional microscopy. In order to identify more susceptible classes of hosts, we measured, sexed and aged all individuals. During one year, we additionally measured body temperature and haematocrit values.

Results: Juvenile bats demonstrated much higher parasitemia than any other age class sampled, suggesting that first exposure to the parasite is very early in life during which infections are also at their most intense. Moreover, in subadults there was a clear negative correlation between body condition and intensity of infection, whereas a weak positive correlation was observed in adults. Neither body temperature, nor haematocrit, two proxies used for pathology, could be linked to intensities of infection.

Conclusion: If both weaker condition and younger age are associated with higher infection intensity, then the highest selection pressure exerted by P. murinus should be at the juvenile stage. Confusion over the identities and nomenclature of malarial-like parasites requires that molecular barcodes are coupled to accurate morphological descriptions.

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Related in: MedlinePlus

The abundance ofP. murinusgametocytes in the blood of different bat age classes. Parasitemia of M. daubentonii caught in September and October 2012. Young of the year (juveniles) have significantly higher parasitemia than older age classes. The y-axis, the number of blood parasites observed, is on a log scale. For visualisation purposes, 0.5 is added to parasitemia.
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Fig4: The abundance ofP. murinusgametocytes in the blood of different bat age classes. Parasitemia of M. daubentonii caught in September and October 2012. Young of the year (juveniles) have significantly higher parasitemia than older age classes. The y-axis, the number of blood parasites observed, is on a log scale. For visualisation purposes, 0.5 is added to parasitemia.

Mentions: Parasitemia data were collected from a total of 186 M. daubentonii for the analysis of blood parasite abundances. The minimal adequate ZINB model retained multiple terms in the count model, but none in the false-zero portion (Table 3, Table S2 in Additional file 1), though the difference between the last two models (with or without age in the false-zero part of the model) was only marginal (ΔAICc = 0.58; Table S2 in Additional file 1). The count portion of the ZINB model retained several variables. Condition and age had a significant interaction. In adults, parasitemia increased slightly with increasing body condition, whereas in subadults a strong negative relationship existed between parasitemia and body condition (Table 3, Figure 3A). In general, individuals in higher body condition had lower parasitemia, and the interaction with date indicated that peak parasitemia was reached sooner in bats in high body condition (Figure 3B). Though ranges overlapped, juveniles had higher median and maximum parasitemia by one and two orders of magnitude respectively (Figure 4, randomized F-test: n = 23, randomizations = 999, p = 0.014).Table 3


Epidemiological traits of the malaria-like parasite Polychromophilus murinus in the Daubenton's bat Myotis daubentonii.

Witsenburg F, Schneider F, Christe P - Parasit Vectors (2014)

The abundance ofP. murinusgametocytes in the blood of different bat age classes. Parasitemia of M. daubentonii caught in September and October 2012. Young of the year (juveniles) have significantly higher parasitemia than older age classes. The y-axis, the number of blood parasites observed, is on a log scale. For visualisation purposes, 0.5 is added to parasitemia.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4269171&req=5

Fig4: The abundance ofP. murinusgametocytes in the blood of different bat age classes. Parasitemia of M. daubentonii caught in September and October 2012. Young of the year (juveniles) have significantly higher parasitemia than older age classes. The y-axis, the number of blood parasites observed, is on a log scale. For visualisation purposes, 0.5 is added to parasitemia.
Mentions: Parasitemia data were collected from a total of 186 M. daubentonii for the analysis of blood parasite abundances. The minimal adequate ZINB model retained multiple terms in the count model, but none in the false-zero portion (Table 3, Table S2 in Additional file 1), though the difference between the last two models (with or without age in the false-zero part of the model) was only marginal (ΔAICc = 0.58; Table S2 in Additional file 1). The count portion of the ZINB model retained several variables. Condition and age had a significant interaction. In adults, parasitemia increased slightly with increasing body condition, whereas in subadults a strong negative relationship existed between parasitemia and body condition (Table 3, Figure 3A). In general, individuals in higher body condition had lower parasitemia, and the interaction with date indicated that peak parasitemia was reached sooner in bats in high body condition (Figure 3B). Though ranges overlapped, juveniles had higher median and maximum parasitemia by one and two orders of magnitude respectively (Figure 4, randomized F-test: n = 23, randomizations = 999, p = 0.014).Table 3

Bottom Line: Yet most of these studies provide only snapshots in time of the parasites discovered.During one year, we additionally measured body temperature and haematocrit values.Confusion over the identities and nomenclature of malarial-like parasites requires that molecular barcodes are coupled to accurate morphological descriptions.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolution, University of Lausanne, Biophore, CH-1015, Lausanne, Switzerland. fardo.witsenburg@unil.ch.

ABSTRACT

Background: The great diversity of bat haemosporidians is being uncovered with the help of molecular tools. Yet most of these studies provide only snapshots in time of the parasites discovered. Polychromophilus murinus, a malaria-like blood parasite, specialised on temperate-zone bats is a species that is being 'rediscovered'. This study describes the infection dynamics over time and between host sex and age classes.

Methods: For three years we followed the members of three breeding colonies of Myotis daubentonii in Western Switzerland and screened them for the prevalence and parasitemia of P. murinus using both molecular tools and traditional microscopy. In order to identify more susceptible classes of hosts, we measured, sexed and aged all individuals. During one year, we additionally measured body temperature and haematocrit values.

Results: Juvenile bats demonstrated much higher parasitemia than any other age class sampled, suggesting that first exposure to the parasite is very early in life during which infections are also at their most intense. Moreover, in subadults there was a clear negative correlation between body condition and intensity of infection, whereas a weak positive correlation was observed in adults. Neither body temperature, nor haematocrit, two proxies used for pathology, could be linked to intensities of infection.

Conclusion: If both weaker condition and younger age are associated with higher infection intensity, then the highest selection pressure exerted by P. murinus should be at the juvenile stage. Confusion over the identities and nomenclature of malarial-like parasites requires that molecular barcodes are coupled to accurate morphological descriptions.

Show MeSH
Related in: MedlinePlus