Browsing by Author "Littlejohn S"

Now showing 1 - 5 of 5

Case-control study of leptospirosis in Aotearoa New Zealand reveals behavioural, occupational, and environmental risk factors
(Cambridge University Press, 2025-06-02) Nisa S; Ortolani E; Vallée E; Marshall J; Collins-Emerson J; Yeung P; Prinsen G; Wright J; Quin T; Fayaz A; Littlejohn S; Baker MG; Douwes J; Benschop J; Hahné S
Leptospirosis in NZ has historically been associated with male workers in livestock industries; however, the disease epidemiology is changing. This study identified risk factors amid these shifts. Participants (95 cases:300 controls) were recruited nationwide between 22 July 2019 and 31 January 2022, and controls were frequency-matched by sex (90% male) and rurality (65% rural). Multivariable logistic regression models, adjusted for sex, rurality, age, and season - with one model additionally including occupational sector - identified risk factors including contact with dairy cattle (aOR 2.5; CI: 1.0-6.0), activities with beef cattle (aOR 3.0; 95% CI: 1.1-8.2), cleaning urine/faeces from yard surfaces (aOR 3.9; 95% CI: 1.5-10.3), uncovered cuts/scratches (aOR 4.6; 95% CI: 1.9-11.7), evidence of rodents (aOR 2.2; 95% CI: 1.0-5.0), and work water supply from multiple sources - especially creeks/streams (aOR 7.8; 95% CI: 1.5-45.1) or roof-collected rainwater (aOR 6.6; 95% CI: 1.4-33.7). When adjusted for occupational sector, risk factors remained significant except for contact with dairy cattle, and slaughter without gloves emerged as a risk (aOR 3.3; 95% CI: 0.9-12.9). This study highlights novel behavioural factors, such as uncovered cuts and inconsistent glove use, alongside environmental risks from rodents and natural water sources.
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.
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
Leptospirosis in Campinas, Brazil: The interplay between drainage, impermeable areas, and social vulnerability
(PLOS (Public Library of Science), California, United States of America, 2025-09) de Azevedo TSDD; Nisa S; Littlejohn S; Muylaert RL; Gomes-Solecki M
Leptospirosis is an epidemic disease caused by bacteria of the Leptospira genus. Its risk is closely associated with inadequate sanitation and flooding, a common public health challenge in large urban centers together with urban environmental modifications, and socio-economic factors. This retrospective observational research investigated the association between the distribution of leptospirosis cases and three contextual factors, drainage, soil impermeability and social vulnerability in Campinas city, São Paulo, Brazil. We hypothesized that the number of cases will increase in areas that are impermeable and in proximity to drainage systems as well as where social vulnerability is high. We investigated the associations based on 86 autochthonous cases, comparing cases where infection risk was linked to contact with floodwater or mud (n = 54) to cases associated with other exposures (n = 32). Spatial statistics were used to map disease distribution and investigate the relationship between leptospirosis cases and contextual factors. Our results indicate that leptospirosis cases density rises near drainage systems, peaking at 200 m. Risk is elevated in socially vulnerable areas, particularly where floodwater or mud exposure is high, and in highly impermeable areas. This study demonstrated that leptospirosis risk remains highly determined by living and working conditions. These findings support targeted strategies to deliver effective prevention, treatment and control interventions in highly populated urban areas of the Global South and similar contexts. Furthermore, combining local contextual environmental information with spatial analysis produces relevant evidence for guiding health public policy and spatial planning and provides precise parameters for future epidemiological models and prevention actions.
"We don't really do doctors." messages from people diagnosed with occupational leptospirosis for medical professionals on infection, hospitalisation, and long-term effects.
(Elsevier B.V., 2023-09) Prinsen G; Baker M; Benschop J; Collins-Emerson J; Douwes J; Fayaz A; Littlejohn S; Nisa S; Quin T; Yeung P
Leptospirosis is largely an occupational disease for people working with livestock in Aotearoa New Zealand. Introduction of livestock vaccination and use of personal protective equipment has been associated with a reduction in the incidence. However, the incidence of occupational leptospirosis remains high, with significant burdens for affected families and healthcare system. For this article, a subset of thirteen participants from a nationwide leptospirosis case-control study (2019-2021) who were diagnosed with leptospirosis and worked with livestock at the time of illness were invited and agreed to a semi-structured interview. Interviewees reflected on their experiences as messages for medical professionals. The analysis of transcripts reveals widely shared experiences with infection, hospitalisation, and treatment, as well as long-term effects and recovery. Conclusions for medical professionals include that ill workers continue to have their diagnosis of leptospirosis delayed. This delay may contribute to more than half the people ill with leptospirosis hospitalised. Further, medical professionals' communication and relationship with ill people strongly colours the latter's experience, for good or for bad. Moreover, most interviewees experienced a recovery process that took several months of feeling tired, which undermined professional performance and emotional wellbeing.