Leptospirosis is a zoonotic bacterial disease that affects more than one million people worldwide each year. Human infection is acquired through direct or indirect contact with the urine of an ...infected animal. A wide range of animals including rodents and livestock may shed Leptospira bacteria and act as a source of infection for people. In the Kilimanjaro Region of northern Tanzania, leptospirosis is an important cause of acute febrile illness, yet relatively little is known about animal hosts of Leptospira infection in this area. The roles of rodents and ruminant livestock in the epidemiology of leptospirosis were evaluated through two linked studies. A cross-sectional study of peri-domestic rodents performed in two districts with a high reported incidence of human leptospirosis found no evidence of Leptospira infection among rodent species trapped in and around randomly selected households. In contrast, pathogenic Leptospira infection was detected in 7.08% cattle (n = 452 5.1-9.8%), 1.20% goats (n = 167 0.3-4.3%) and 1.12% sheep (n = 89 0.1-60.0%) sampled in local slaughterhouses. Four Leptospira genotypes were detected in livestock. Two distinct clades of L. borgpetersenii were identified in cattle as well as a clade of novel secY sequences that showed only 95% identity to known Leptospira sequences. Identical L. kirschneri sequences were obtained from qPCR-positive kidney samples from cattle, sheep and goats. These results indicate that ruminant livestock are important hosts of Leptospira in northern Tanzania. Infected livestock may act as a source of Leptospira infection for people. Additional work is needed to understand the role of livestock in the maintenance and transmission of Leptospira infection in this region and to examine linkages between human and livestock infections.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Legionella longbeachae is the most common cause of Legionnaires' disease in Australasia. Legionella species are considered a rare cause of pleural infection, and empyema and lung abscess due to L. ...longbeachae has not previously been reported. Our patient presented with a 2–3 week history of breathlessness, lethargy, dry cough and headaches. Initial chest radiograph showed extensive left sided consolidation with an associated pleural effusion. An area of necrotising pneumonia evident on computed tomography scan evolved into a multiloculated intrapulmonary abscess. Sputum culture isolated L. longbeachae, which prompted culture of pleural fluid on buffered charcoal yeast extract agar and isolation of the organism. This case provides evidence that L. longbeachae can cause both empyema and lung abscess, and in areas where it is prevalent, increased use of Legionella specific agar for pleural fluid culture should be considered.
Legionella longbeachae is a common cause of pneumonia in Australasia but rarely identified as the cause of empyema. We report a case of L. longbeachae empyema and lung abscess and highlight the need for specific culture media or molecular testing to identify this organism in pleural fluid.
Leptospirosis is a major cause of febrile illness in Africa but little is known about risk factors for human infection. We conducted a cross-sectional study to investigate risk factors for acute ...leptospirosis and Leptospira seropositivity among patients with fever attending referral hospitals in northern Tanzania.
We enrolled patients with fever from two referral hospitals in Moshi, Tanzania, 2012-2014, and performed Leptospira microscopic agglutination testing on acute and convalescent serum. Cases of acute leptospirosis were participants with a four-fold rise in antibody titers, or a single reciprocal titer ≥800. Seropositive participants required a single titer ≥100, and controls had titers <100 in both acute and convalescent samples. We administered a questionnaire to assess risk behaviors over the preceding 30 days. We created cumulative scales of exposure to livestock urine, rodents, and surface water, and calculated odds ratios (OR) for individual behaviors and for cumulative exposure variables.
We identified 24 acute cases, 252 seropositive participants, and 592 controls. Rice farming (OR 14.6), cleaning cattle waste (OR 4.3), feeding cattle (OR 3.9), farm work (OR 3.3), and an increasing cattle urine exposure score (OR 1.2 per point) were associated with acute leptospirosis.
In our population, exposure to cattle and rice farming were risk factors for acute leptospirosis. Although further data is needed, these results suggest that cattle may be an important source of human leptospirosis. Further investigation is needed to explore the potential for control of livestock Leptospira infection to reduce human disease.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Reflects on the implications of two recent articles on aspects of the impact of the 1918-1919 epidemic in NZ not necessarily captured in traditional burden of disease estimates, and steps that need ...to be considered when preparing for future influenza pandemics. Focuses on identifying vulnerable populations, availability of influenza vaccination, vaccination failure and strategies for improving vaccination effectiveness, priorities for infection control, and health system response to future pandemics. Source: National Library of New Zealand Te Puna Matauranga o Aotearoa, licensed by the Department of Internal Affairs for re-use under the Creative Commons Attribution 3.0 New Zealand Licence.
It is difficult to estimate sensitivity and specificity of diagnostic tests when there is no gold standard. Latent class models have been proposed as a potential solution as they provide estimates ...without the need for a gold standard. Using a motivating example of the evaluation of point of care tests for leptospirosis in Tanzania, we show how a realistic violation of assumptions underpinning the latent class model can lead directly to substantial bias in the estimates of the parameters of interest. In particular, we consider the robustness of estimates of sensitivity, specificity, and prevalence, to the presence of additional latent states when fitting a two‐state latent class model. The violation is minor in the sense that it cannot be routinely detected with goodness‐of‐fit procedures, but is major with regard to the resulting bias.
Looks back at the work of three NZ scientists during the 1940s and 1950s towards confirming the presence of leptospirosis in New Zealand, identifying the initial human and livestock infections, ...collating epidemiologic data to reveal the scale of occupational disease, and performing fundamental work on environmental persistence of the organism. Source: National Library of New Zealand Te Puna Matauranga o Aotearoa, licensed by the Department of Internal Affairs for re-use under the Creative Commons Attribution 3.0 New Zealand Licence.
Background. Legionnaires' disease cannot be clinically or radiographically distinguished from other causes of pneumonia, and specific tests are required to make the diagnosis. Currently, testing ...occurs erratically and, instead, clinicians rely on empiric treatment strategies and ignore public health implications of the diagnosis. We aimed to measure the increase in case detection of Legionnaires' disease following the introduction of routine polymerase chain reaction (PCR) testing of respiratory specimens. PCR is the most sensitive diagnostic tool for Legionnaires' disease. Methods. In a quasi-experimental study in Christchurch, New Zealand, we compared the number of cases of Legionnaires' disease requiring hospitalization diagnosed during a 2-year period before the introduction of a routine PCR testing strategy (November 2008–October 2010) with a similar period after the introduction (November 2010–October 2012). With this testing strategy, all respiratory specimens from hospitalized patients with pneumonia sent to the region's sole tertiary-level laboratory were tested for Legionella by PCR, whether requested or not. Results. During November 2008 to October 2010, there were 22 cases of Legionnaires' disease compared with 92 during November 2010 to October 2012. Of 1834 samples tested since November 2010, 1 in 20 was positive, increasing to 1 in 9 during peak Legionella season (November to January). Increasing bacterial load was associated with increasing disease severity. Conclusions. In our region, the burden of Legionnaires' disease is much greater than was previously recognized. Routine PCR testing provides results within a clinically relevant time frame and enables improved characterization of the regional epidemiology of Legionnaires' disease.
Background
Cytological examination of pleural fluid has good specificity, but imperfect sensitivity for the diagnosis of malignant pleural effusion (MPE). Published estimates of sensitivity vary and ...predictors of false negative cytology are not well established.
Aims
To estimate pleural fluid cytology sensitivity and identify risk factors for false negative cytology.
Methods
We conducted a retrospective cohort study of patients who had cytology testing of pleural fluid at Christchurch Hospital, New Zealand, from July 2017 to October 2019. Data on clinical and pleural fluid characteristics were collected. MPE was defined by positive pleural fluid cytology, tissue histology or multidisciplinary meeting consensus. We estimated sensitivity of the first pleural cytology assessment. We performed multivariate logistic regression to ascertain patient groups at greatest risk of false negative results.
Results
Initial pleural fluid cytology was diagnostic in 117 of 156 patients, providing a sensitivity (95% confidence interval (CI)) of 75.0% (67.4–81.6%). The sensitivity was 79.0% (66.8–88.3%) for lung cancer, 91.3% (72.0–98.9%) for breast cancer and 33.3% (95% CI 11.8–61.6%) for mesothelioma. Cloudy appearance of pleural fluid (odds ratio (OR) 0.12; 95% CI 0.03–0.54) and yellow/gold pleural fluid (OR 0.24; 95% CI 0.06–0.96) reduced the odds of false negative pleural cytology. Pleural thickening on computed tomography scan (OR 3.3; 95% CI 1.2–9.4) was a risk factor for false negative cytology.
Conclusion
Sensitivity of pleural fluid cytology was greatest in primary lung and breast cancer, and lowest in mesothelioma. Clinicians should be alert to false negative results when suspecting mesothelioma or if pleural thickening is present.
Patients hospitalised with community acquired pneumonia (CAP) have low peripheral blood vitamin C concentrations and limited antioxidant capacity. The feasibility of a trial of vitamin C ...supplementation to improve patient outcomes was assessed. Participants with moderate and severe CAP (CURB-65 ≥ 2) on intravenous antimicrobial treatment were randomised to either intravenous vitamin C (2.5 g 8 hourly) or placebo before switching to oral intervention (1 g tds) for 7 days when they were prescribed oral antimicrobial therapy. Of 344 patients screened 75 (22%) were randomised and analysed. The median age was 76 years, and 43 (57%) were male. In each group, one serious adverse event that was potentially intervention related occurred, and one subject discontinued treatment. Vitamin C concentrations were 226 µmol/L in the vitamin C group and 19 µmol/L in the placebo group (p < 0.001) after 3 intravneous doses. There were no signficant differences between the vitamin C and placebo groups for death within 28 days (0 vs. 2; p = 0.49), median length of stay (69 vs. 121 h; p = 0.07), time to clinical stability (22 vs. 49 h; p = 0.08), or readmission within 30 days (1 vs. 4; p = 0.22). The vitamin C doses given were safe, well tolerated and saturating. A randomised controlled trial to assess the efficacy of vitamin C in patients with CAP would require 932 participants (CURB-65 ≥ 2) to observe a difference in mortality and 200 participants to observe a difference with a composite endpoint such as mortality plus discharge after 7 days in hospital. These studies are feasible in a multicentre setting.
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