Browsing by Author "Nisa S"

Now showing 1 - 14 of 14
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    A cross-sectional investigation of Leptospira at the wildlife-livestock interface in New Zealand
    (PLOS, 2023-09-06) Moinet M; Oosterhof H; Nisa S; Haack N; Wilkinson DA; Aberdein D; Russell JC; Vallée E; Collins-Emerson J; Heuer C; Benschop J; Stevenson B
    There has been a recent upsurge in human cases of leptospirosis in New Zealand, with wildlife a suspected emerging source, but up-to-date knowledge on this topic is lacking. We conducted a cross-sectional study in two farm environments to estimate Leptospira seroprevalence in wildlife and sympatric livestock, PCR/culture prevalence in wildlife, and compare seroprevalence and prevalence between species, sex, and age groups. Traps targeting house mice (Mus musculus), black rats (Rattus rattus), hedgehogs (Erinaceus europaeus) and brushtail possums (Trichosurus vulpecula) were set for 10 trap-nights in March-April 2017 on a dairy (A) and a beef and sheep (B) farm. Trapped wild animals and an age-stratified random sample of domestic animals, namely cattle, sheep and working dogs were blood sampled. Sera were tested by microagglutination test for five serogroups and titres compared using a Proportional Similarity Index (PSI). Wildlife kidneys were sampled for culture and qPCR targeting the lipL32 gene. True prevalence in mice was assessed using occupancy modelling by collating different laboratory results. Infection profiles varied by species, age group and farm. At the MAT cut-point of ≥ 48, up to 78% of wildlife species, and 16-99% of domestic animals were seropositive. Five of nine hedgehogs, 23/105 mice and 1/14 black rats reacted to L. borgpetersenii sv Ballum. The sera of 4/18 possums and 4/9 hedgehogs reacted to L. borgpetersenii sv Hardjobovis whilst 1/18 possums and 1/9 hedgehogs reacted to Tarassovi. In ruminants, seroprevalence for Hardjobovis and Pomona ranged 0-90% and 0-71% depending on the species and age group. Titres against Ballum, Tarassovi and Copenhageni were also observed in 4-20%, 0-25% and 0-21% of domestic species, respectively. The PSI indicated rodents and livestock had the most dissimilar serological responses. Three of nine hedgehogs, 31/105 mice and 2/14 rats were carrying leptospires (PCR and/or culture positive). True prevalence estimated by occupancy modelling in mice was 38% [95% Credible Interval 26, 51%] on Farm A and 22% [11, 40%] on Farm B. In the same environment, exposure to serovars found in wildlife species was commonly detected in livestock. Transmission pathways between and within species should be assessed to help in the development of efficient mitigation strategies against Leptospira.
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    BfpI, BfpJ, and BfpK Minor Pilins Are Important for the Function and Biogenesis of Bundle-Forming Pili Expressed by Enteropathogenic Escherichia coli
    (American Society for Microbiology, 1/03/2016) Nisa S; Martinez de la Peña CF; De Masi L; Mulvey G; Tong J; Donnenberg MS; Armstrong GD
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    Diarrhea, bacteremia and multiorgan dysfunction due to an extraintestinal pathogenic Escherichia coli strain with enteropathogenic E. coli genes
    (Oxford University Press, 26/09/2015) Nisa S; Kessler R; Hazen TH; Horneman A; Amoroso A; Rasko DA; Donnenberg MS
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    Did exposure to a severe outbreak of pandemic influenza in 1918 impact on long-term survival?
    (Cambridge University Press, 1/08/2016) Nisa S; Wilson N; Boyd M; Baker MG; Clement C
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    Diverse Epidemiology of Leptospira serovars Notified in New Zealand, 1999-2017
    (MDPI (Basel, Switzerland), 14/10/2020) Nisa S; Wilkinson DA; Angelin-Bonnet O; Paine S; Cullen K; Wight J; Baker MG; Benschop J
    Leptospirosis in New Zealand has been strongly associated with animal-contact occupations and with serovars Hardjo and Pomona. However, recent data suggest changes in these patterns, hence, serovar-specific epidemiology of leptospirosis from 1999 to 2017 was investigated. The 19-year average annual incidence is 2.01/100,000. Early (1999-2007) and late (2008-2017) study period comparisons showed a significant increase in notifications with serovar Ballum (IRR: 1.59, 95% CI: 1.22-2.09) in all cases and serovar Tarassovi (IRR: 1.75, 95% CI: 1.13-2.78) in Europeans and a decrease in notifications with serovars Hardjo and Pomona in all cases. Incidences of Ballum peaked in winter, Hardjo peaked in spring and Tarassovi peaked in summer. Incidence was highest in Māori (2.24/100,000) with dominant serovars being Hardjo and Pomona. Stratification by occupation showed meat workers had the highest incidence of Hardjo (57.29/100,000) and Pomona (45.32/100,000), farmers had the highest incidence of Ballum (11.09/100,000) and dairy farmers had the highest incidence of Tarassovi (12.59/100,000). Spatial analysis showed predominance of Hardjo and Pomona in Hawke's Bay, Ballum in West Coast and Northland and Tarassovi in Waikato, Taranaki and Northland. This study highlights the serovar-specific heterogeneity of human leptospirosis in New Zealand that should be considered when developing control and prevention strategies.
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    Identification of pathogenic Leptospira species and serovars in New Zealand using metabarcoding.
    (2021) Wilkinson DA; Edwards M; Benschop J; Nisa S
    Leptospirosis is a zoonotic disease of global importance. The breadth of Leptospira diversity associated with both human and animal disease poses major logistical challenges to the use of classical diagnostic techniques, and increasingly molecular diagnostic tools are used for their detection. In New Zealand, this has resulted in an increase in positive cases reported nationally that have not been attributed to the infecting serovar or genomospecies. In this study, we used data from all pathogenic Leptospira genomes to identify a partial region of the glmU gene as a suitable locus for the discrimination of the infecting species and serovars of New Zealand-endemic Leptospira. This method can be used in culture and culture-independent scenarios making it flexible for diagnostics in humans, animals, and environmental samples. We explored the use of this locus as a molecular barcoding tool via the Oxford Nanopore Technology (ONT) sequencing platform MinION. Sequences obtained by this method allowed specific identification of Leptospira species in mixed and enriched environmental cultures, however read error inherent in the MinION sequencing system reduced the accuracy of strain/variant identification. Using this approach to characterise Leptospira in enriched environmental cultures, we detected the likely presence of Leptospira genomospecies that have not been reported in New Zealand to date. This included a strain of L. borgpetersenii that has recently been identified in dairy cattle and sequences similar to those of L. mayottensis. L. tipperaryensis, L. dzianensis and L. alstonii.
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    Longitudinal Testing of Leptospira Antibodies in Horses Located near a Leptospirosis Outbreak in Alpacas.
    (12/08/2022) Bolwell C; Gee E; Adams B; Collins-Emerson J; Scarfe K; Nisa S; Gordon E; Rogers C; Benschop J
    The objectives of this study were to determine if horses located near an outbreak of leptospirosis in alpacas had Leptospira titres indicative of a previous or current infection and, if so, to determine the magnitude in change of titres over time. Further, the objective was to determine if horses with high titre results were shedding Leptospira in their urine. Blood samples were collected from twelve horses located on or next to the farm with the outbreak in alpacas, on day zero and at four subsequent time points (two, four, six and nine weeks). The microscopic agglutination test was used to test sera for five serovars endemic in New Zealand: Ballum, Copenhageni, Hardjo, Pomona and Tarassovi. A reciprocal MAT titre cut-off of ≥1:100 was used to determine positive horses. Seven out of twelve horses (58%) were positive to at least one serovar during one of the time points. Two horses recorded titres of ≥1600, one for both Pomona and Copenhageni and the other for Hardjo, and these two horses were both PCR positive for Leptospira in their urine samples. For five out of seven horses, the titres either remained the same or changed by one dilution across the sampling time points. The study confirmed endemic exposure to five endemic Leptospira serovars in New Zealand in a group of horses located near a confirmed leptospirosis outbreak in alpacas.
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    Molecular typing of Leptospira spp. in farmed and wild mammals reveals new host-serovar associations in New Zealand.
    (Taylor and Francis Group, 2024-01-01) Wilkinson DA; Edwards M; Shum C; Moinet M; Anderson NE; Benschop J; Nisa S
    AIMS: To apply molecular typing to DNA isolated from historical samples to determine Leptospira spp. infecting farmed and wild mammals in New Zealand. MATERIALS AND METHODS: DNA samples used in this study were extracted from urine, serum or kidney samples (or Leptospira spp. cultures isolated from them) collected between 2007 and 2017 from a range of domestic and wildlife mammalian species as part of different research projects at Massey University. Samples were included in the study if they met one of three criteria: samples that tested positive with a lipL32 PCR for pathogenic Leptospira; samples that tested negative by lipL32 PCR but were recorded as positive to PCR for pathogenic Leptospira in the previous studies; or samples that were PCR-negative in all studies but were from animals with positive agglutination titres against serogroup Tarassovi. DNA samples were typed using PCR that targeted either the glmU or gyrB genetic loci. The resulting amplicons were sequenced and typed relative to reference sequences. RESULTS: We identified several associations between mammalian hosts and Leptospira strains/serovars that had not been previously reported in New Zealand. Leptospira borgpetersenii strain Pacifica was found in farmed red deer (Cervus elaphus) samples, L. borgpetersenii serovars Balcanica and Ballum were found in wild red deer samples, Leptospira interrogans serovar Copenhageni was found in stoats (Mustela erminea) and brushtail possums (Trichosurus vulpecula), and L. borgpetersenii was found in a ferret (Mustela putorius furo). Furthermore, we reconfirmed previously described associations including dairy cattle with L. interrogans serovars Copenhageni and Pomona and L. borgpetersenii serovars Ballum, Hardjo type bovis and strain Pacifica, sheep with L. interrogans serovar Pomona and L. borgpetersenii serovar Hardjo type bovis, brushtail possum with L. borgpetersenii serovar Balcanica, farmed deer with L. borgpetersenii serovar Hardjo type bovis and hedgehogs (Erinaceus europaeus) with L. borgpetersenii serovar Ballum. CONCLUSIONS: This study provides an updated summary of host-Leptospira associations in New Zealand and highlights the importance of molecular typing. Furthermore, strain Pacifica, which was first identified as Tarassovi using serological methods in dairy cattle in 2016, has circulated in animal communities since at least 2007 but remained undetected as serology is unable to distinguish the different genotypes. CLINICAL RELEVANCE: To date, leptospirosis in New Zealand has been diagnosed with serological typing, which is deficient in typing all strains in circulation. Molecular methods are necessary to accurately type strains of Leptospira spp. infecting mammals in New Zealand.
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    Still 'dairy farm fever'? A Bayesian model for leptospirosis notification data in New Zealand.
    (2021-02) Benschop J; Nisa S; Spencer SEF
    Routinely collected public health surveillance data are often partially complete, yet remain a useful source by which to monitor incidence and track progress during disease intervention. In the 1970s, leptospirosis in New Zealand (NZ) was known as 'dairy farm fever' and the disease was frequently associated with serovars Hardjo and Pomona. To reduce infection, interventions such as vaccination of dairy cattle with these two serovars was implemented. These interventions have been associated with significant reduction in leptospirosis incidence, however, livestock-based occupations continue to predominate notifications. In recent years, diagnosis is increasingly made by nucleic acid detection which currently does not provide serovar information. Serovar information can assist in linking the recognized maintenance host, such as livestock and wildlife, to infecting serovars in human cases which can feed back into the design of intervention strategies. In this study, confirmed and probable leptospirosis notification data from 1 January 1999 to 31 December 2016 were used to build a model to impute the number of cases from different occupational groups based on serovar and month of occurrence. We imputed missing occupation and serovar data within a Bayesian framework assuming a Poisson process for the occurrence of notified cases. The dataset contained 1430 notified cases, of which 927 had a specific occupation (181 dairy farmers, 45 dry stock farmers, 454 meatworkers, 247 other) while the remaining 503 had non-specified occupations. Of the 1430 cases, 1036 had specified serovars (231 Ballum, 460 Hardjo, 249 Pomona, 96 Tarassovi) while the remaining 394 had an unknown serovar. Thus, 47% (674/1430) of observations had both a serovar and a specific occupation. The results show that although all occupations have some degree of under-reporting, dry stock farmers were most strongly affected and were inferred to contribute as many cases as dairy farmers to the burden of disease, despite dairy farmer being recorded much more frequently. Rather than discard records with some missingness, we have illustrated how mathematical modelling can be used to leverage information from these partially complete cases. Our finding provides important evidence for reassessing the current minimal use of animal vaccinations in dry stock. Improving the capture of specific farming type in case report forms is an important next step.
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    Targeting the chromosome partitioning protein ParA in tuberculosis drug discovery.
    (2010-11) Nisa S; Blokpoel MCJ; Robertson BD; Tyndall JDA; Lun S; Bishai WR; O'Toole R
    OBJECTIVE: To identify inhibitors of the essential chromosome partitioning protein ParA that are active against Mycobacterium tuberculosis. METHODS: Antisense expression of the parA orthologue MSMEG_6939 was induced on the Mycobacterium smegmatis background. Screening of synthetic chemical libraries was performed to identify compounds with higher anti-mycobacterial activity in the presence of parA antisense. Differentially active compounds were validated for specific inhibition of purified ParA protein from M. tuberculosis (Rv3918c). ParA inhibitors were then characterized for their activity towards M. tuberculosis in vitro. RESULTS: Under a number of culture conditions, parA antisense expression in M. smegmatis resulted in reduced growth. This effect on growth provided a basis for the detection of compounds that increased susceptibility to expression of parA antisense. Two compounds identified from library screening, phenoxybenzamine and octoclothepin, also inhibited the in vitro ATPase activity of ParA from M. tuberculosis. Structural in silico analyses predict that phenoxybenzamine and octoclothepin undergo interactions compatible with the active site of ParA. Octoclothepin exhibited significant bacteriostatic activity towards M. tuberculosis. CONCLUSIONS: Our data support the use of whole-cell differential antisense screens for the discovery of inhibitors of specific anti-tubercular drug targets. Using this approach, we have identified an inhibitor of purified ParA and whole cells of M. tuberculosis.
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    The E. coli effector protein NleF is a caspase inhibitor
    (Public Library of Science (PLoS), 14/03/2013) Nisa S; Blasche S; Mörtl M; Steuber H; Siszler G; Schwarz F; Lavrik I; Gronewold TMA; Maskos K; Donnenberg MS; Ullmann D; Uetz P; Kögl M
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    ‘The reason why I got it … ’ – messages from people diagnosed with leptospirosis about infection in the workplace and its impact on livelihoods
    (Taylor and Francis Group on behalf of the Royal Society of New Zealand, 2024-01-24) Prinsen G; Benschop J; Collins-Emerson J; Nisa S; Yeung P
    In Aotearoa New Zealand, leptospirosis is a disease that mostly affects people working with livestock on farms and in abattoirs, with Māori and Pasifika workers more likely to be hospitalised than others. This article shares an analysis of thirteen interviews with people diagnosed with leptospirosis. They were asked to advise colleagues and employers, as well as share how their illness had affected their income – informing health officials and workplace insurers. Their comments suggest that most workers are aware of the importance of Personal Protective Equipment (PPE) and safe operating environments, and they know how they contracted the disease. However, they remove PPE or take shortcuts knowingly, often under time pressure. Comments on the financial impact of their illness suggest most farmers received support from family and community, but most meat-processing workers did not. Worse, while most farmers said their financial losses were limited, many meat-processing workers felt forced to return to work too soon because they needed the income. Farmers were almost exclusively farm owners. Financial assistance (ACC) is more needed for some than for others. However, while such assistance is welcomed when it arrives, all interviewees described personal interactions with the administration of financial assistance as disrespectful or dispiriting.
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    Transmission Dynamics of Shiga Toxin-Producing Escherichia coli in New Zealand Cattle from Farm to Slaughter.
    (American Society for Microbiology, 2021-05-11) Browne AS; Midwinter AC; Withers H; Cookson AL; Biggs PJ; Marshall JC; Benschop J; Hathaway S; Rogers L; Nisa S; Hranac CR; Winkleman T; French NP
    Cattle are asymptomatic carriers of Shiga toxin-producing Escherichiacoli (STEC) strains that can cause serious illness or death in humans. In New Zealand, contact with cattle feces and living near cattle populations are known risk factors for human STEC infection. Contamination of fresh meat with STEC strains also leads to the potential for rejection of consignments by importing countries. We used a combination of PCR/matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) and whole-genome sequencing (WGS) to evaluate the presence and transmission of STEC on farms and in processing plants to better understand the potential pathways for human exposure and thus mitigate risk. Animal and environmental samples (n = 2,580) were collected from six farms and three meat processing plants in New Zealand during multiple sampling sessions in spring of 2015 and 2016. PCR/MALDI-TOF analysis revealed that 6.2% were positive for "Top 7" STEC. Top 7 STEC strains were identified in all sample sources (n = 17) tested. A marked increase in Top 7 STEC prevalence was observed between calf hides on farm (6.3% prevalence) and calf hides at processing plants (25.1% prevalence). Whole-genome sequencing was performed on Top 7 STEC bacterial isolates (n = 40). Analysis of STEC O26 (n = 25 isolates) revealed relatively low genetic diversity on individual farms, consistent with the presence of a resident strain disseminated within the farm environment. Public health efforts should focus on minimizing human contact with fecal material on farms and during handling, transport, and slaughter of calves. Meat processing plants should focus on minimizing cross-contamination between the hides of calves in a cohort during transport, lairage, and slaughter. IMPORTANCE Cattle are asymptomatic carriers of Shiga toxin-producing E. coli (STEC) strains, which can cause serious illness or death in humans. Contact with cattle feces and living near cattle are known risk factors for human STEC infection. This study evaluated STEC carriage in young calves and the farm environment with an in-depth evaluation of six farms and three meat processing plants over 2 years. An advanced molecular detection method and whole-genome sequencing were used to provide a detailed evaluation of the transmission of STEC both within and between farms. The study revealed widespread STEC contamination within the farm environment, but no evidence of recent spread between farms. Contamination of young dairy calf hides increased following transport and holding at meat processing plants. The elimination of STEC in farm environments may be very difficult given the multiple transmission routes; interventions should be targeted at decreasing fecal contamination of calf hides during transport, lairage, and processing.
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    "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.