Occurrence and seasonality of internal parasite infection in elephants, Loxodonta africana, in the Okavango Delta, Botswana

Baines, Lydia; Morgan, Eric R.; Ofthile, Mphoeng; Evans, K E

doi:10.1016/j.ijppaw.2015.01.004

Cited by 14 publications

(21 citation statements)

References 24 publications

(34 reference statements)

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“…However, this prevalence was characterized by a significantly higher proportion of nematodes (96.3%) than of trematodes (39.1%). In our study, we modified the sedimentation method commonly used for examining trematodes (which involves examining all of the sediment in a Petri dish under a dissecting microscope) [3]. However, our results were comparable with infection in elephants elsewhere, which suggests that our modifications did not significantly affect the sensitivity of the methodology.…”

Section: Discussionmentioning

confidence: 80%

“…Most studies on the helminths parasitizing African elephants have in the past focused on helminth taxonomy and more recently on within population infection dynamics [1][2][3][4], but no studies have simultaneously examined inter-population and intra-population infection dynamics and their drivers. The most common helminths infecting African elephants are nematodes and trematodes; two groups of helminths that have environmentally dependent transmission mechanisms.…”

Section: Introductionmentioning

confidence: 99%

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Patterns of helminth infection in Kenyan elephant populations

et al. 2020

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Background: The dynamics of helminth infection in African elephant populations are poorly known. We examined the effects of age, sex, social structure and the normalized difference vegetation index (NDVI) as primary drivers of infection patterns within and between elephant populations. Methods: Coprological methods were used to identify helminths and determine infection patterns in distinct elephant populations in Maasai Mara National Reserve, Tsavo East National Park, Amboseli National Park and Laikipia-Samburu Ecosystem. Gaussian finite mixture cluster analyses of egg dimensions were used to classify helminth eggs according to genera. Generalized linear models (GLM) and Chi-square analyses were used to test for variation in helminth infection patterns and to identify drivers in elephant populations. Results: Helminth prevalence varied significantly between the studied populations. Nematode prevalence (96.3%) was over twice as high as that of trematodes (39.1%) in elephants. Trematode prevalence but not nematode prevalence varied between populations. Although we found no associations between helminth infection and elephant social groups (male vs family groups), the median helminth egg output (eggs per gram, epg) did vary between social groups: family groups had significantly higher median epg than solitary males or males in bachelor groups. Young males in mixed sex family groups had lower epg than females when controlling for population and age; these differences, however, were not statistically significant. The average NDVI over a three-month period varied between study locations. Cluster analyses based on egg measurements revealed the presence of Protofasciola sp., Brumptia sp., Murshidia sp., Quilonia sp. and Mammomonogamus sp. GLM analyses showed that the mean epg was positively influenced by a three-month cumulative mean NDVI and by social group; female social groups had higher epg than male groups. GLM analyses also revealed that epg varied between elephant populations: Samburu-Laikipia elephants had a higher and Tsavo elephants a lower epg than Amboseli elephants. Conclusions: Elephants had infection patterns characterized by within-and between-population variation in prevalence and worm burden. Sociality and NDVI were the major drivers of epg but not of helminth prevalence. Gastrointestinal parasites can have a negative impact on the health of wild elephants, especially during resource scarcity. Thus, our results will be important when deciding intervention strategies.

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Section: Discussionmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Patterns of helminth infection in Kenyan elephant populations

et al. 2020

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“…), a second reported helminth and coccidian parasites from African elephants in Botswana (Baines et al. ), while the other selectively concentrated on nematode eggs in Asian elephants (Hing et al. ).…”

Section: Resultsmentioning

confidence: 99%

“…There have been three parasitological surveys of wild elephants in the past decade. The first documented nematode and ciliate populations in the stool of African forest elephants (Kinsella et al 2004), a second reported helminth and coccidian parasites from African elephants in Botswana (Baines et al 2015), while the other selectively concentrated on nematode eggs in Asian elephants (Hing et al 2013). None of the studies reported finding Entamoeba.…”

Section: Entamoeba From Elephantsmentioning

confidence: 99%

Expanding the Entamoeba Universe: New Hosts Yield Novel Ribosomal Lineages

Jacob

Busby

Levy

et al. 2015

J Eukaryotic Microbiology

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24Removing the requirement for cell culture has led to a substantial increase in the number 25 of lineages of Entamoeba recognized as distinct. Surveying the range of potential host 26 species for this parasite genus has barely been started and it is clear that additional 27 sampling of the same host in different locations often identifies additional diversity. In 28 this study, using small subunit ribosomal RNA gene sequencing, we identify four new 29 lineages of Entamoeba, including the first report of Entamoeba from an elephant, and 30 extend the host range of some previously described lineages. Additionally, examination 31 of microbiome data from a number of host animals suggests that substantial Entamoeba 32 diversity remains to be uncovered. 33 34Keywords: Diversity; next generation sequencing; ribosomal RNA; phylogeny; 35 36 37Over the past 25 years, our understanding of diversity in the genus Entamoeba has 38 increased significantly as a result of complementary developments in DNA amplification, 39 purification and sequencing. Traditionally, naming of species in Entamoeba was based on 40 a mixture of host identity and parasite morphology, the latter being rather limited in these 41 amoeboid organisms and the former being of debatable value due to uncertainty over host 42 ranges of the parasites. DNA sequencing allows quantitative measurement of similarity 43 that is not dependent on such characters and although it is not without its own limitations, 44 it has fundamentally changed our approach to studying diversity in organisms such as 45Entamoeba. 46In this time period, the study of Entamoeba has gone from being dependent on 47 stable laboratory cultures of parasites, preferably in the axenic form, to DNA analysis of 48 organisms directly from stool samples in the absence of even microscopic investigation. 49The latter aspect has been problematic as it is not possible to assign new sequences to 50 previously named species where the original description is dependent on morphology. 51For this reason, many new and distinct Entamoeba sequences have been assigned to 52 'ribosomal lineages' rather than species to reflect the absence of morphological 53 information (Stensvold et al. 2011). 54The new approach is dependent on the reliability of DNA purification from stool 55 samples, which are notorious for the presence of enzyme inhibitors, and the specificity of 56 the primers used for PCR amplification. In addition, investigation of Entamoeba in such 57 samples is largely limited to the ribosomal RNA genes due to the complexity of the 58 DNAs extracted from stool, which often contains DNA from multiple other parasites and 59 may include multiple Entamoeba species. The elimination of culture dependency has led 60 to a dramatic expansion in the number of genetically distinct Entamoeba organisms being 61 recognized but also to a greater understanding of sequence variability within species due 62 to the relative ease with which multiple samples can be studied in parallel.

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“…As previous studies of strongylid infection in elephants have not included individual-based social factors (Vidya and Sukumar, 2002;Thurber et al, 2011;Baines et al, 2015), our study makes a significant contribution to the understanding of how social factors influence strongylid infection in these animals. Overall, elephants that spent less time in locations frequented by family groups, be they males or socially isolated orphans, had lower strongylid loads.…”

Section: Discussionmentioning

confidence: 97%

Strongylid infection varies with age, sex, movement and social factors in wild African elephants

Parker¹,

Goldenberg²,

Letitiya³

et al. 2020

Parasitology

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Comparing parasitic infection among individuals of wildlife populations can provide insight into factors that influence wildlife disease ecology. Strongylids are parasitic worms that infect the intestinal tract of vertebrates, and infection with strongylids can be approximated by counting strongylid eggs in dung samples. Here we tested for correlations between strongylid egg counts and 18 different individual characteristics, environmental and social factors in individually known wild African elephants. We counted more eggs in the dung samples of younger elephants and females relative to mature elephants and males. We also found that elephants spending more time outside reserves shed more strongylid eggs than elephants that were more often within reserves. Elephants that were less socially integrated, as measured by how much aggression they received from other elephants, shed fewer strongylid eggs; relatedly, socially isolated orphan elephants that had left their family shed fewer strongylid eggs than elephants that remained with their family. Our results suggest that landscapes altered by livestock grazing and social disruption caused by humans may impact parasitic infection in wildlife.

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Occurrence and seasonality of internal parasite infection in elephants, Loxodonta africana, in the Okavango Delta, Botswana

Cited by 14 publications

References 24 publications

Patterns of helminth infection in Kenyan elephant populations

Patterns of helminth infection in Kenyan elephant populations

Expanding the Entamoeba Universe: New Hosts Yield Novel Ribosomal Lineages

Strongylid infection varies with age, sex, movement and social factors in wild African elephants

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