Emerging Leptospira strain poses public health risk for dairy farmers in New Zealand

Yupiana, Yuni; Vallée, Emilie; Wilson, Peter R.; Collins-Emerson, Julie; Weston, J F; Benschop, Jackie; Heuer, C

doi:10.1016/j.prevetmed.2019.104727

Cited by 28 publications

(40 citation statements)

References 18 publications

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“…The production loss due to leptospirosis could not be estimated for dairy cattle since most herds (99.5%) are vaccinated against this disease (Yupiana et al, ), and no investigations were carried out in the past 20 years.…”

Section: Methodsmentioning

confidence: 99%

“…Vaccination coverage was simulated using beta distributions of mode 0.181 (95% UL: 0.25), 0.006 (95% UL: 0.018) and 0.051 (95% UL: 0.094) for beef cattle, sheep and deer, respectively (Dreyfus et al, ). A beta distribution of mode 0.995 (95% lower limit 0.985) was used to simulate vaccination coverage in dairy cattle (Yupiana et al, ). The cost of a vaccine dose used was a fixed value of USD 0.525/ml, which resulted in a cost of USD 1.05 for beef cattle and deer, and USD 0.79 for sheep.…”

Section: Methodsmentioning

confidence: 99%

“…Although production loss associated with leptospirosis was reported in dairy cattle in other countries, in New Zealand most farms vaccinate routinely against leptospirosis. A recent survey estimated that 99.5% of randomly selected dairy farms had a current Leptospira vaccination programme (Yupiana et al, ). Additionally, the efficacy of Leptospira vaccines to reduce urinary shedding of Hardjo in cattle was estimated at 89.9% in a meta‐analysis of field trials (Sanhueza, Wilson, Benschop, Collins‐Emerson & Heuer, ).…”

Section: Introductionmentioning

confidence: 99%

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Estimation of the burden of leptospirosis in New Zealand

Sanhueza

Baker

Benschop

et al. 2019

Zoonoses and Public Health

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Background Human leptospirosis mainly affects people in close occupational contact with domestic livestock and their products in New Zealand. The disease has an unquantified impact on both human health and animal production in the country. This study aimed to estimate the burden of leptospirosis in terms of disability‐adjusted life years (DALYs) and cost associated with loss due to absence from work, treatment of disease, animal production loss and cost of vaccination. Methods Previously published studies of abattoir workers farmers, and veterinarians, reporting annual risks of influenza‐like illness attributable to Leptospira infection, were used to estimate the expected number of cases in a year. The cost of lost animal production was based on results of observational studies in beef cattle, sheep and deer conducted in New Zealand. Results Expected median annual number of severe and mild cases of human leptospirosis was 2,025 (95% probability interval [95% PI] 1,138–3,422). Median annual DALYs were 0.42 (95% PI: 0.06–2.40) per 100,000 people for the entire population, and 15.82 (95% PI: 2.09–90.80) per 100,000 people working in at‐risk occupations (i.e. abattoir workers, farmers and veterinarians). Human infection resulted in a median cost of 4.42 (95% PI: 2.04–8.62) million US dollars (USD) due to absence from work and disease treatment. Median production loss cost in beef cattle, sheep and deer was USD 7.92 (95% PI: 3.75–15.48) million, while median vaccination cost in cattle, (including dairy), sheep and deer was USD 6.15 (95% PI: 5.30–7.03) million. Total annual cost of leptospirosis plus vaccination was USD 18.80 (95% PI: 13.47–27.15) million, equivalent to USD 440,000 (95% PI: 320,000–640,000) per 100,000 people. Conclusion This study provides an estimate of the disease burden and cost of leptospirosis in New Zealand that could support occupational health authorities and livestock industries in assessing interventions for this disease.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Estimation of the burden of leptospirosis in New Zealand

Sanhueza

Baker

Benschop

et al. 2019

Zoonoses and Public Health

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“…More recent research has been reported from New Zealand, where the pathogen is a serious zoonotic risk to people working in the livestock industry 15 . In New Zealand another strain, sv Tarassovi, has emerged, 16 which is not covered by vaccines on the market.…”

mentioning

confidence: 99%

“…Studies indicate that livestock workers in New Zealand are at risk of leptospirosis, suggesting that the pathogen is still present, despite widespread vaccination programs in dairy cattle against leptospirosis 15,16 …”

mentioning

confidence: 99%

A cross‐sectional pilot study to estimate the prevalence of and risk factors for leptospirosis in South‐Western Victorian dairy herds, 2017

et al. 2020

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Leptospirosis is a zoonosis, found worldwide, affecting many species of animals. We conducted a cross‐sectional study to estimate the prevalence of Leptospira borgpetersenii sv Hardjo and Leptospira interrogans sv Pomona in cattle in dairy herds in South‐Western Victoria, Australia. Fifty‐three herds were enrolled in the study. Urine samples were collected from 15 late‐lactation cows in each herd. A questionnaire was provided to herd managers at the time of each herd visit, asking them to describe the methods they used for controlling leptospirosis, including vaccination. Urine samples were pooled at the herd level and tested for leptospira spp. using real time PCR. Urine samples from individual cows within the positive pooled samples were then tested for Leptospira Hardjo and Leptospira Pomona using qPCR. Four of the 53 herds showed positive leptospirosis results giving an apparent prevalence of 8 (95% CI 2–18) leptospira‐positive herds per 100 herds at risk. Based on the 53 completed questionnaires, leptospirosis vaccination programs were not compliant with label directions in 36 of the 52 vaccinated herds: 69 (95% CI 55–81) of 100 herd managers that routinely vaccinated for leptospirosis did not comply with label directions. One herd was completely unvaccinated. Based on our findings, we estimate that approximately 10% of dairy farms in South‐Western Victoria are likely to be infected with leptospirosis. While most herds are vaccinating for leptospirosis, most are not doing so according to label directions. We conclude that herd managers need to be better educated regarding leptospirosis vaccination programs.

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Presence of Leptospira spp. in Caiman latirostris (Crocodylia, Alligatoridae) populations in Santa Fe, Argentina

Bauso

Simoncini

Chiani

et al. 2020

Heliyon

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Leptospirosis is a disease caused by pathogenic spirochetes of the genus Leptospira, transmitted by wild and domestic animals. Rodents play a fundamental role in the transmission cycle of this zoonosis but the function of reptiles is unknown. For example, crocodilians could play an important role in the transmission of this disease by living in ideal environments (bodies of shallow water and high temperatures) for the colonization of this bacterium. However, few studies have documented the presence of zoonotic diseases in caiman populations. Our objective was to assess the prevalence of antibodies to leptospira and the presence of Leptospira spp. in wild and captive Caiman latirostris. Blood samples were taken from 45 individuals (20 wild and 25 captive). Before extraction, we cleaned each caiman's neck in order to prevent contamination of samples. We determined the presence of antibodies in serum by microscopic agglutination test (MAT) and polymerase chain reaction (PCR) to detect DNA of the bacteria. We excluded 9 of the 45 samples analyzed by MAT because 5 had lipemic serum and 4 were contaminated (colonized by other organisms). Of the 36 caimans studied by microscopic agglutination test (MAT), 56% (20/36) were considered reactive (titers 50). In 74% (14/19) of captive samples and 35% (6/17) of wild samples, antibodies to leptospira were detected by MAT. The serogroup with highest occurrence was Pyrogenes (85%, n ¼ 17/20), presenting coagglutinations with Icterohaemorrhagiae (25%, n ¼ 5/20). One sample from a captive animal was positive for PCR, and we could not isolate leptospires because of agar contamination. Of the 45 blood agar media, 17.8% were contaminated and the rest were negative. This work determined the presence of Leptospira spp. in one caiman and a high prevalence of antibodies in captive caiman relative to wild individuals.

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Emerging Leptospira strain poses public health risk for dairy farmers in New Zealand

Cited by 28 publications

References 18 publications

Estimation of the burden of leptospirosis in New Zealand

Estimation of the burden of leptospirosis in New Zealand

A cross‐sectional pilot study to estimate the prevalence of and risk factors for leptospirosis in South‐Western Victorian dairy herds, 2017

Presence of Leptospira spp. in Caiman latirostris (Crocodylia, Alligatoridae) populations in Santa Fe, Argentina

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