Journal Articles

Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915

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Author: search.filters.author.Fayaz ASubject: search.filters.subject.Leptospira

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    Genotyping Reveals Potential Sources of Human Leptospirosis Outbreaks in Aotearoa New Zealand
    (Wiley-VCH GmbH, 2026-02-01) Nisa S; Littlejohn S; Fayaz A; Deen S; Sokolova M; Ogbuigwe P; Moinet M; Cookson AL; Collins-Emerson J; Niebuhr CN; Vallee EM; Marshall J; Benschop J
    Introduction: The introduction of PCR testing for leptospirosis in Aotearoa New Zealand has reduced the availability of serotyping data, and current diagnostic PCRs do not routinely genotype Leptospira. This study genotyped Leptospira from PCR-confirmed human cases between 2016 and 2023 and compared them with genotypes found in animals to identify potential sources of infection in a 2023 human leptospirosis outbreak. Methods: Human samples were genotyped using glmU amplicon sequencing and compared to animal genotypes from previous studies. In addition, human national surveillance data were analysed to provide broader epidemiological context including regional distribution to reveal outbreak areas; diagnostic test usage to assess trends; serotyping results to evaluate consistency across methods; and demographic information to evaluate the representativeness of the genotyped dataset. Chi-squared and Poisson regression were used to assess host-genotype associations, and phylogenetics evaluated genetic relatedness. Results: Surveillance data showed flood-associated outbreaks in several regions and a significant shift in diagnostic practice (p ≤ 0.001), with increased use of PCR. Genotyping of PCR-confirmed cases revealed a rise in Pomona infections in 2023 across rural flood-associated regions (Gisborne, Hawke's Bay, Manawatū-Whanganui, Waikato and Wairarapa). In contrast, the Auckland region—including Aotearoa's largest city which also experienced flooding—had infections linked to Ballum, Copenhageni and Balcanica NZ. In animals, Pomona was primarily detected in sheep (Ovis aries), followed by cattle, while Ballum, Copenhageni and Balcanica NZ were primarily detected in mice (Mus musculus), Norway rats (Rattus norvegicus) and brushtail possums (Trichosurus vulpecula), respectively. Conclusions: Flooding-driven outbreaks in rural areas with pastoral livestock were predominantly linked to livestock-associated strains, while urban cases were associated with rodents and small wildlife. These findings highlight the need for tailored mitigation strategies addressing distinct epidemiological risks in rural and urban settings. Surveillance strategies should be adapted to preserve typing capabilities to better inform public health responses in future outbreaks.
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    Investigating animals and environments in contact with leptospirosis patients in Aotearoa New Zealand reveals complex exposure pathways.
    (Taylor and Francis Group, 2025-02-12) Benschop J; Collins-Emerson JM; Vallee E; Prinsen G; Yeung P; Wright J; Littlejohn S; Douwes J; Fayaz A; Marshall JC; Baker MG; Quin T; Nisa S
    CASE HISTORY: Three human leptospirosis cases from a case-control study were recruited for in-contact animal and environment sampling and Leptospira testing between October 2020 and December 2021. These cases were selected because of regular exposure to livestock, pets, and/or wildlife, and sampling was carried out on their farms or lifestyle blocks (sites A-C), with veterinarians overseeing the process for livestock, and cases collecting environmental and wildlife samples. LABORATORY FINDINGS: Across the three sites, a total of 137 cattle, > 40 sheep, 28 possums, six dogs, six rats, three pigs and three rabbits were tested. Herd serology results on Site A, a dairy farm, showed infection with Tarassovi and Pomona; urinary shedding showed Leptospira borgpetersenii str. Pacifica. Animals were vaccinated against Hardjo, Pomona and Copenhageni. The farmer was diagnosed with Ballum. On Site B, a beef and sheep farm, serology showed infection with Pomona; animals were not vaccinated, and the farmer was diagnosed with Hardjo. On Site C, cattle were shedding L. borgpetersenii; animals were not vaccinated, and the case's serovar was indeterminate. Six wild animals associated with Sites A and C and one environmental sample from Site A were positive for pathogenic Leptospira by PCR. CONCLUSION: These findings highlight the complexity of potential exposures and the difficulty in identifying infection sources for human cases. This reinforces the need for multiple preventive measures such as animal vaccination, the use of personal protective equipment, pest control, and general awareness of leptospirosis to reduce infection risk in agricultural settings. CLINICAL RELEVANCE: Farms with unvaccinated livestock had Leptospira infections, highlighting the importance of animal vaccination. Infections amongst stock that were vaccinated emphasise the importance of best practice vaccination recommendations and pest control. Abbreviations: MAT: Microscopic agglutination test; PIC: Person in charge; PPE: Personalprotective equipment