First Report of Acanthocheilonema spirocauda in the Mediterranean Monk Seal (Monachus monachus)

Papadopoulos, Elias; Loukopoulos, Panayiotis; Komnenou, Anastasia; Androukaki, E.; Karamanlidis, Alexandros A.

doi:10.7589/0090-3558-46.2.570

Cited by 14 publications

(8 citation statements)

References 13 publications

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“…Prevalence of seal heartworm, A. spirocauda , has been reported to be increasing, thus the possible spread of the parasite into grey seals provides justification for increased monitoring of phocid seal populations to track the spread of disease ( Lehnert et al, 2015 ). Furthermore, the parasite has recently been reported in the highly endangered monk seal population, further stressing the need to accurately monitor the range of this parasite ( Papadopoulos et al, 2010 ). The C20 diagnostic test developed here provides an important tool for monitoring the spread of the disease into new hosts and geographical ranges.…”

Section: Discussionmentioning

confidence: 99%

A novel quantitative real-time PCR diagnostic assay for seal heartworm (Acanthocheilonema spirocauda) provides evidence for possible infection in the grey seal (Halichoerus grypus)

Keroack

Williams

Fessler

et al. 2018

International Journal for Parasitology: Parasites and Wildlife

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The distinct evolutionary pressures faced by Pinnipeds have likely resulted in strong coevolutionary ties to their parasites (Leidenberger et al., 2007). This study focuses on the phocid seal filarial heartworm species Acanthocheilonema spirocauda. A. spirocauda is known to infect a variety of phocid seals, but does not appear to be restricted to a single host species (Measures et al., 1997; Leidenberger et al., 2007; Lehnert et al., 2015). However, to date, seal heartworm has never been reported in grey seals (Halichoerus grypus) (Measures et al., 1997; Leidenberger et al., 2007; Lehnert et al., 2015). The proposed vector for seal heartworm is Echinophthirius horridus, the seal louse. Seal lice are known to parasitize a wide array of phocid seal species, including the grey seal. With the advent of climate change, disease burden is expected to increase across terrestrial and marine mammals (Harvell et al., 2002). Accordingly, increased prevalence of seal heartworm has recently been reported in harbor seals (Phoca vitulina) (Lehnert et al., 2015). Thus, the need for improved, rapid, and cost-effective diagnostics is urgent. Here we present the first A. spirocauda-specific rapid diagnostic test (a quantitative real-time PCR assay), based on a highly repetitive genomic DNA repeat identified using whole genome sequencing and subsequent bioinformatic analysis. The presence of an insect vector provides the opportunity to develop a multifunctional diagnostic tool that can be used not only to detect the parasite directly from blood or tissue specimens, but also as a molecular xenomonitoring (XM) tool that can be used to assess the epidemiological profile of the parasite by screening the arthropod vector. Using this assay, we provide evidence for the first reported case of seal heartworm in a grey seal.

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Section: Discussionmentioning

confidence: 99%

A novel quantitative real-time PCR diagnostic assay for seal heartworm (Acanthocheilonema spirocauda) provides evidence for possible infection in the grey seal (Halichoerus grypus)

Keroack

Williams

Fessler

et al. 2018

International Journal for Parasitology: Parasites and Wildlife

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“…In this context, E. horridus has previously been proposed to be the natural obligate intermediate host of A. spirocauda [7][8][9]10], and different stages of A. spirocauda larvae were found in dissected E. horridus seal lice [7,9]. So far, the heartworm A. spirocauda has been reported from different phocid species such as harbour seals, hooded seals (Cystophora cristata), bearded seals, ribbon seals (Phoca fasciata), harp seals (Phoca groenlandica), ringed seals, spotted seals (Phoca largha), monk seals (Monachus monachus), and recently from grey seals [8,10,37]. Furthermore, there is a significant positive correlation between heartworm infection and infestation of harbour seals with seal lice [11].…”

Section: Discussionmentioning

confidence: 99%

The seal louse (Echinophthirius horridus) in the Dutch Wadden Sea: investigation of vector-borne pathogens

et al. 2021

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Background Belonging to the anopluran family Echinophthiriidae, Echinophthirius horridus, the seal louse, has been reported to parasitise a broad range of representatives of phocid seals. So far, only a few studies have focused on the vector function of echinophthiriid lice, and knowledge about their role in pathogen transmission is still scarce. The current study aims to investigate the possible vector role of E. horridus parasitising seals in the Dutch Wadden Sea. Methods E. horridus seal lice were collected from 54 harbour seals (Phoca vitulina) and one grey seal (Halichoerus grypus) during their rehabilitation period at the Sealcentre Pieterburen, The Netherlands. DNA was extracted from pooled seal lice of individual seals for molecular detection of the seal heartworm Acanthocheilonema spirocauda, the rickettsial intracellular bacterium Anaplasma phagocytophilum, and the cell wall-less bacteria Mycoplasma spp. using PCR assays. Results Seal lice from 35% of the harbour seals (19/54) and from the grey seal proved positive for A. spirocauda. The seal heartworm was molecularly characterised and phylogenetically analysed (rDNA, cox1). A nested PCR was developed for the cox1 gene to detect A. spirocauda stages in seal lice. A. phagocytophilum and a Mycoplasma species previously identified from a patient with disseminated ‘seal finger’ mycoplasmosis were detected for the first time, to our knowledge, in seal lice. Conclusions Our findings support the potential vector role of seal lice in the transmission of A. spirocauda and reveal new insights into the spectrum of pathogens occurring in seal lice. Studies on vector competence of E. horridus, especially for bacterial pathogens, are essentially needed in the future as these pathogens might have detrimental effects on the health of seal populations. Furthermore, studies on the vector role of different echinophthiriid species infecting a wide range of pinniped hosts should be conducted to extend the knowledge of vector-borne pathogens.

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“…In this context, E. horridus has previously been proposed to be the natural obligate intermediate host of A. spirocauda [7,8,9], and different stages of A. spirocauda larvae were found in dissected E. horridus seal lice [7,9]. So far, the heartworm A. spirocauda has been reported from different phocid species such as harbour seals, hooded seals (Cystophora cristata), bearded seals, ribbon seals (Phoca fasciata), harp seals (Phoca groenlandica), ringed seals, spotted seals (Phoca largha), monk seals (Monachus monachus), and recently from grey seals [8,33,37]. Furthermore, there is a signi cant positive correlation between heartworm infection and infestation of harbour seals with seal lice [9,10].…”

Section: Discussionmentioning

confidence: 99%

The seal louse (Echinophthirius horridus) in the Dutch Wadden Sea: investigation of vector-borne pathogens

Hirzmann

Ebmer

Contreras³

et al. 2021

Preprint

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Background: Belonging to the anopluran family Echinophthiriidae, Echinophthirius horridus, the seal louse, has been reported to parasitize a broad range of representatives of phocid seals. So far, only few studies focused on vector function of echinophthiriid lice and knowledge on their role in pathogen transmission is still scarce. The current study aims to investigate the possible vector role of E. horridus parasitizing seals in the Dutch Wadden Sea.Methods: E. horridus seal lice were collected from 54 harbour seals (Phoca vitulina) and one grey seal (Halichoerus grypus) during their rehabilitation period at the Sealcentre Pieterburen, the Netherlands. DNA was extracted from pooled seal lice of individual seals for molecular detection of the seal heartworm Acanthocheilonema spirocauda, the rickettsial intracellular bacterium Anaplasma phagocytophilum, and the cell wall-less bacteria Mycoplasma spp. using PCR assays.Results: Seal lice from 35% of the harbour seals (19/54) and from the grey seal proved positive for A. spirocauda. The seal heartworm was molecularly characterised and phylogenetically analysed (rDNA, cox1). A nested PCR was developed for the cox1 gene to detect A. spirocauda stages in seal lice. A. phagocytophilum and a Mycoplasma species previously identified from a patient with disseminated ‘seal finger’ mycoplasmosis were detected the first time in seal lice. Conclusions: Our findings support the potential vector role of seal lice in transmission of A. spirocauda, and reveal new insights into the spectrum of pathogens occurring in seal lice. Studies on vector competence of E. horridus, especially for bacterial pathogens, are essentially needed in the future as these pathogens might have detrimental effects on the health of seal populations. Further, studies on the vector role of different echinophthiriid species infecting a wide range of pinniped hosts should be conducted to extend the knowledge of vector borne pathogens in seal lice.

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First Report of Acanthocheilonema spirocauda in the Mediterranean Monk Seal (Monachus monachus)

Cited by 14 publications

References 13 publications

A novel quantitative real-time PCR diagnostic assay for seal heartworm (Acanthocheilonema spirocauda) provides evidence for possible infection in the grey seal (Halichoerus grypus)

A novel quantitative real-time PCR diagnostic assay for seal heartworm (Acanthocheilonema spirocauda) provides evidence for possible infection in the grey seal (Halichoerus grypus)

The seal louse (Echinophthirius horridus) in the Dutch Wadden Sea: investigation of vector-borne pathogens

The seal louse (Echinophthirius horridus) in the Dutch Wadden Sea: investigation of vector-borne pathogens

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