ORCID Profile
0000-0001-7133-4575
Current Organisation
University of Queensland
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Publisher: MDPI
Date: 20-02-2020
Publisher: American Society for Microbiology
Date: 31-08-2022
DOI: 10.1128/SPECTRUM.00873-22
Abstract: Skin lesions in cattle associated with feeding by Haematobia fly species are a significant welfare issue in Australia, North and South America, and Europe. The development of these lesions has been attributed to a number of causal factors, but the exact etiology and pathogenesis were unclear.
Publisher: CRC Press
Date: 03-05-2023
Publisher: Informa UK Limited
Date: 04-12-2019
Publisher: University of Queensland Library
Date: 2022
DOI: 10.14264/77AA687
Publisher: Cold Spring Harbor Laboratory
Date: 12-03-2022
DOI: 10.1101/2022.03.11.483979
Abstract: Buffalo flies ( Haematobia irritans exigua ) are hematophagous ectoparasites of cattle causing production and welfare impacts in northern Australian herds. Skin lesions associated with buffalo fly infestation and Stephanofilaria nematode infection are manifested as focal dermatitis or ulcerated areas most commonly on the medial canthus of the eye, along the lateral and ventral neck and on the abdomen of cattle. For closely related horn flies ( Haematobia irritans irritans ), Staphylococcus aureus have been suggested as a contributing factor in the development of lesions. To investigate the potential role of bacterial infection in the pathogenesis of buffalo fly lesions, swabs were taken from lesions and normal skin, and bacteria were also isolated from surface washings of buffalo flies and surface-sterilised homogenized flies. Bacterial identification was conducted by MALDI-TOF, strain typing by rep-PCR and DNA sequencing to determine species similarity and virulence factors. Of 49 bacterial isolates collected from lesions, 37 were identified as Staphylococcus agnetis and 12 as Staphylococcus hyicus , whereas from normal skin four isolates were S. hyicus and one was Staphylococcus sciuri . Of the Staphylococcus isolates isolated from buffalo flies, five were identified as S. agnetis and three as S. hyicus . Fifty percent of the buffalo fly isolates had rep-PCR genotypic patterns identical to the lesion isolates. Genome sequencing of 16 S. agnetis and four S. hyicus isolates revealed closely similar virulence factor profiles, with all isolates possessing exfoliative toxin A and C genes. The findings from this study suggest the involvement of S. agnetis and S. hyicus in buffalo fly lesion pathogenesis. This should be taken into account in the development of effective treatment and control strategies for lesions.
Publisher: MDPI AG
Date: 17-09-2021
DOI: 10.3390/PATHOGENS10091211
Abstract: Background: Stephanofilaria spp. nematodes are associated with cutaneous lesions in cattle and other livestock and mammalian wildlife species. In Australia, Haematobia irritans exigua, commonly known as buffalo fly (BF) transmits a well-described but presently unnamed species of Stephanofilaria, which has been speculatively implicated in the aetiology of BF lesions. The sensitivity of current techniques for detecting Stephanofilaria spp. in skin lesions and vector species is low, and there is no genomic sequence for any member of the genus Stephanofilaria currently available in sequence databases. Methods: To develop molecular assays for the detection of the Australian Stephanofilaria sp., skin biopsies were collected from freshly slaughtered cattle with typical lesions near the medial canthus. Adult nematodes and microfilariae were isolated from the biopsies using a saline recovery technique. The nematodes were morphologically identified as Stephanofilaria sp. by scanning electron microscopy. DNA was extracted and the internal transcribed spacer 2 (ITS2) region of rDNA, and the cytochrome c oxidase subunit 1 (cox1) region of mtDNA was lified and sequenced. Stephanofilaria sp. specific polymerase chain reaction (PCR) and qPCR assays (SYBR Green® and TaqMan™) were developed and optimised from the novel ITS2 sequence obtained. The specificity of each assay was confirmed by testing against nematode species Onchocerca gibsoni and Dirofilaria immitis, as well as host (bovine) and BF DNA. Results: Scanning electron microscopy of the anterior and posterior ends of isolated nematodes confirmed Stephanofilaria sp. A phylogenetic analysis of the cox1 sequence demonstrated that this species is most closely related to Thelazia callipaeda, a parasitic nematode that is a common cause of thelaziasis (or eyeworm infestation) in humans, dogs, and cats. Both conventional and qPCR assays specifically lified DNA from Stephanofilaria sp. Conventional PCR, TaqMan™, and SYBR Green® assays were shown to detect 1 ng, 1 pg, and 100 fg of Stephanofilaria DNA, respectively. Both qPCR assays detected DNA from single Stephanofilaria microfilaria. Conclusion: Molecular diagnostic assays developed in this study showed high specificity and sensitivity for Stephanofilaria sp. DNA. The availability of an accurate and sensitive PCR assay for Stephanofilaria will assist in determining its role in the pathogenesis of cattle skin lesions, as well as in understanding its epidemiological dynamics. This assay may also have application for use in epidemiological studies with other species of Stephanofilaria, most particularly closely related S. stilesi, but this will require confirmation.
No related grants have been discovered for Muhammad Noman Naseem.