The Namaqua rock mouse (Micaelamys namaquensis) as a potential reservoir and host of arthropod vectors of diseases of medical and veterinary importance in South Africa

BACKGROUND : The role of endemic murid rodents as hosts of arthropod vectors of diseases of medical and veterinary significance is well established in the northern hemisphere. In contrast, endemic murids are comparatively understudied as vector hosts in Africa, particularly in South Africa. Considering the great rodent diversity in South Africa, many of which may occur as human commensals, this is unwarranted. METHODS : In the current study we assessed the ectoparasite community of a widespread southern African endemic, the Namaqua rock mouse (Micaelamys namaquensis), that is known to carry Bartonella spp. and may attain pest status. We aimed to identify possible vectors of medical and/or veterinary importance which this species may harbour and explore the contributions of habitat type, season, host sex and body size on ectoparasite prevalence and abundance. RESULTS : Small mammal abundance was substantially lower in grasslands compared to rocky outcrops. Although the small mammal community comprised of different species in the two habitats, M. namaquensis was the most abundant species in both habitat types. From these 23 ectoparasite species from four taxa (fleas, ticks, mites and lice) were collected. However, only one flea (Xenopsylla brasiliensis) and one tick species (Haemaphysalis elliptica) have a high zoonotic potential and have been implicated as vectors for Yersinia pestis and Bartonella spp. and Rickettsia conorii, respectively. The disease status of the most commonly collected tick (Rhipicephalus distinctus) is currently unknown. Only flea burdens differed markedly between habitat types and increased with body size. With the exception of lice, all parasite taxa exhibited seasonal peaks in abundance during spring and summer. CONCLUSION : M. namaquensis is the dominant small mammal species irrespective of habitat type. Despite the great ectoparasite diversity harboured by M. namaquensis, only a small number of these are known as vectors of diseases of medical and/or veterinary importance but occur at high prevalence and/or abundance. This raises concern regarding the potential of this host as an endemic reservoir for zoonotic diseases. Consequently, additional sampling throughout its distributional range and research addressing the role of M. namaquensis as a reservoir for zoonotic diseases in southern Africa is urgently needed.University of Pretoria (EC015-10).Third World Organization for Women in Science(TWOWS) and the National Research Foundation (NRF).http://www.parasitesandvectors.comhb201

The Namaqua rock mouse (Micaelamys namaquensis) as a potential reservoir and host of arthropod vectors of diseases of medical and veterinary importance in South Africa

BACKGROUND : The role of endemic murid rodents as hosts of arthropod vectors of diseases of medical and veterinary significance is well established in the northern hemisphere. In contrast, endemic murids are comparatively understudied as vector hosts in Africa, particularly in South Africa. Considering the great rodent diversity in South Africa, many of which may occur as human commensals, this is unwarranted. METHODS : In the current study we assessed the ectoparasite community of a widespread southern African endemic, the Namaqua rock mouse (Micaelamys namaquensis), that is known to carry Bartonella spp. and may attain pest status. We aimed to identify possible vectors of medical and/or veterinary importance which this species may harbour and explore the contributions of habitat type, season, host sex and body size on ectoparasite prevalence and abundance. RESULTS : Small mammal abundance was substantially lower in grasslands compared to rocky outcrops. Although the small mammal community comprised of different species in the two habitats, M. namaquensis was the most abundant species in both habitat types. From these 23 ectoparasite species from four taxa (fleas, ticks, mites and lice) were collected. However, only one flea (Xenopsylla brasiliensis) and one tick species (Haemaphysalis elliptica) have a high zoonotic potential and have been implicated as vectors for Yersinia pestis and Bartonella spp. and Rickettsia conorii, respectively. The disease status of the most commonly collected tick (Rhipicephalus distinctus) is currently unknown. Only flea burdens differed markedly between habitat types and increased with body size. With the exception of lice, all parasite taxa exhibited seasonal peaks in abundance during spring and summer. CONCLUSION : M. namaquensis is the dominant small mammal species irrespective of habitat type. Despite the great ectoparasite diversity harboured by M. namaquensis, only a small number of these are known as vectors of diseases of medical and/or veterinary importance but occur at high prevalence and/or abundance. This raises concern regarding the potential of this host as an endemic reservoir for zoonotic diseases. Consequently, additional sampling throughout its distributional range and research addressing the role of M. namaquensis as a reservoir for zoonotic diseases in southern Africa is urgently needed.University of Pretoria (EC015-10).Third World Organization for Women in Science(TWOWS) and the National Research Foundation (NRF).http://www.parasitesandvectors.comhb201

Ectoparasitic community of the Mahali mole-rat, Cryptomys hottentotus mahali : potential host for vectors of medical importance in South Africa

BACKGROUND: The endemic rodent family of Bathyergidae in Africa, particularly South Africa, are understudied as reservoirs of diseases of signifcant medical importance. Considering the diversity and wide distribution of African mole-rats in South Africa, many of these bathyergids could act as carriers of zoonoses. METHODS: The present study assessed the ectoparasite community of the Mahali mole-rat (Cryptomys hottentotus mahali). We aimed to identify possible parasitic arthropods that may infest this mole-rat species and explore host preference, contributions of seasonality, host sex and body mass as well as social class and colony size on ectoparasite assemblage prevalence and abundance. RESULTS: A limited number of ectoparasite species were found on C. h. mahali belonging to two signifcant taxa: mites (Acari) and feas, with mites being the most prevalent and abundant. We recorded the presence of X. philoxera, a fea well known as the principal reservoir of plague in the southern African region on the Mahali mole-rats. Only three mite species were collected: Androlaelaps scapularis, Androlaelaps capensis and Laelaps liberiensis. Seasonal peaks in prevalence and abundance of X. philoxera and A. scapularis were observed during summer. Xenopsylla philoxera abundance and A. scapularis loads signifcantly increased on reproductive mole-rat individuals in comparison to nonreproductive individuals. CONCLUSION: Despite the wide distribution of the subterranean African mole-rats, studies investigating their parasitic fauna remain limited and scarce. This dearth in knowledge raises the concern regarding their potential role as an endemic reservoir for zoonotic diseases. Consequently, additional sampling of their ectoparasitic community throughout their distributional range and research addressing their role as a reservoir for zoonotic diseases in southern Africa are urgently needed.SARChI chair of Mammalian Behavioural Ecology and Physiology from the DST-NRF South Africa; National Research Foundation and University of Pretoria, South Africa.https://parasitesandvectors.biomedcentral.compm2022Zoology and Entomolog

Ectoparasite diversity in the eastern rock sengis (Elephantulus myurus) : the effect of seasonality and host sex

Globally small mammals are important hosts of ectoparasite vectors of pathogens of medical, veterinary and economic importance. Insectivores are currently understudied as hosts of pathogen vectors. However, data are needed on the diversity of such vectors before we can investigate the underlying factors affecting ectoparasite distribution. Abiotic (e.g. temperature and rainfall) and biotic (e.g. host sex) factors have been identified as the main determinants of host–parasite interactions. The present study describes the ectoparasite community of insectivorous eastern rock sengis (Elephantulus myurus) in a nature reserve in the Gauteng province, South Africa, and how it varies with season and host sex. A total of 81 sengis were examined for the presence of ticks, mites, fleas and lice between April 2010 and April 2011. The ectoparasite assemblage comprised 11 groups of tick species, a single mite family, one louse and two flea species, with ticks and mites being the most numerous ectoparasites recovered. The prevalence and/or abundance of two commonly collected ticks (Ixodes spp. and Rhipicephalus warburtoni/arnoldi) and chigger varied with season. In addition, female-biased tick burdens were apparent for one ectoparasite species possibly due to reproductive investment. The mechanisms causing the observed patterns should be addressed in future studies.Third World Organization for Women in Science, the National Research Foundation (NRF) and the University of Pretoria.http://www.tandfonline.com/loi/tafz202016-04-30hb201

Occurrence and molecular prevalence of Anaplasmataceae , Rickettsiaceae and Coxiellaceae in African wildlife : a systematic review and meta-analysis

SUPPLEMENTARY MATERIAL : TABLE S1: PRISMA statement checklist; TABLE S2: PRISMA checklist for abstracts; TABLE S3: additional checklist for systematic reviews and meta-analyses retrieved from Migliavaca et al., 2020; TABLE S4: critical appraisal of included studies; TABLE S5: detailed summary of Anaplasmataceae, Rickettsiaceae and Coxiellaceae detected in African wildlife stratified by country and detection method; TABLE S6: results of the analysis of publication bias; TABLE S7: List of papers excluded during full-text examination and relevant exclusion criteriaINTRODUCTION : Tick-borne pathogens (TBPs) constitute an emerging threat to public and animal health especially in the African continent, where land-use change, and wildlife loss are creating new opportunities for disease transmission. A review of TBPs with a focus on ticks determined the epidemiology of Rhipicephalus ticks in heartwater and the affinity of each Rickettsia species for different tick genera. We conducted a systematic review and meta-analysis to collect, map and estimate the molecular prevalence of Anaplasmataceae, Rickettsiaceae and Coxiellaceae in African wildlife. MATERIALS AND METHODS : Relevant scientific articles were retrieved from five databases: PubMed, ScienceDirect, Scopus, Ovid and OAIster. Publications were selected according to pre-determined exclusion criteria and evaluated for risk of bias using the appraisal tool for cross-sectional studies (AXIS). We conducted an initial descriptive analysis followed by a meta-analysis to estimate the molecular prevalence of each pathogen. Subgroup analysis and meta-regression models were employed to unravel associations with disease determinants. Finally, the quality of evidence of every estimate was finally assessed. RESULTS : Out of 577 retrieved papers, a total of 41 papers were included in the qualitative analysis and 27 in the meta-analysis. We retrieved 21 Anaplasmataceae species, six Rickettsiaceae species and Coxiella burnetii. Meta-analysis was performed for a total of 11 target pathogens. Anaplasma marginale, Ehrlichia ruminantium and Anaplasma centrale were the most prevalent in African bovids (13.9 %, CI: 0–52.4 %; 20.9 %, CI: 4.1–46.2 %; 13.9 %, CI: 0–68.7 %, respectively). Estimated TBPs prevalences were further stratified per animal order, family, species and sampling country. DISCUSSION : We discussed the presence of a sylvatic cycle for A. marginale and E. ruminantium in wild African bovids, the need to investigate A. phagocytophilum in African rodents and non-human primates as well as E. canis in the tissues of wild carnivores, and a lack of data and characterization of Rickettsia species and C. burnetii. CONCLUSION : Given the lack of epidemiological data on wildlife diseases, the current work can serve as a starting point for future epidemiological and/or experimental studies.http://www.elsevier.com/locate/prevetmedhj2024Centre for Veterinary Wildlife StudiesProduction Animal StudiesVeterinary Tropical DiseasesSDG-03:Good heatlh and well-beingSDG-15:Life on lan

SAR AND OBLIQUE AERIAL OPTICAL IMAGE FUSION FOR URBAN AREA IMAGE SEGMENTATION

The fusion of synthetic aperture radar (SAR) and optical data is a dynamic research area, but image segmentation is rarely treated. While a few studies use low-resolution nadir-view optical images, we approached the segmentation of SAR and optical images acquired from the same airborne platform – leading to an oblique view with high resolution and thus increased complexity. To overcome the geometric differences, we generated a digital surface model (DSM) from adjacent optical images and used it to project both the DSM and SAR data into the optical camera frame, followed by segmentation with each channel. The fused segmentation algorithm was found to out-perform the single-channel version

Complex interactions within the ectoparasite community of the eastern rock sengi (Elephantulus myurus)

AbstractConcomitant infection with more than one parasite species is the rule in nature. Since co-infecting parasites are exploiting the same host, interspecific interactions at the infracommunity level are likely. The nature of such interactions can be expected to affect the distribution of parasites within host populations. Intraspecific interactions within the infracommunity are not easily discernible from cross-sectional studies and the focus of most of these studies lies on relationships between endoparasitic micro- and macroparasites. In the current study of the ectoparasite community of wild eastern rock sengis (Elephantulus myurus) we experimentally reduced tick and flea infestations and monitored ectoparasite burdens over the course of three years. We found a number of within-taxon facilitating interactions between tick species that might be the result of decreasing immune responses with increasing tick burden. In contrast, inter-taxon relationships appeared to be dominated by antagonistic relationships likely to be linked to competition over feeding sites. Only one of the observed interspecific interactions was reciprocal. Our experimental manipulation revealed additional antagonistic relationships that cross-sectional studies would not have captured. In addition, we found substantial long-term changes in the sengi ectoparasite community as a result of our experimental manipulation suggesting carry-over effects of our treatment. This study is the first that evaluates interspecific interactions within the entire ectoparasite community exploiting a mammalian host in Africa and highlights the complexity of interspecific interactions within an ectoparasite community