158 research outputs found
An Emerging Pulmonary Haemorrhagic Syndrome in Dogs: Similar to the Human Leptospiral Pulmonary Haemorrhagic Syndrome?
Severe pulmonary haemorrhage is a rare necropsy finding in dogs but the leptospiral pulmonary haemorrhagic syndrome (LPHS) is a well recognized disease in humans. Here we report a pulmonary haemorrhagic syndrome in dogs that closely resembles the human disease. All 15 dogs had massive, pulmonary haemorrhage affecting all lung lobes while haemorrhage in other organs was minimal. Histologically, pulmonary lesions were characterized by acute, alveolar haemorrhage without identifiable vascular lesions. Seven dogs had mild alveolar wall necrosis with hyaline membranes and minimal intraalveolar fibrin. In addition, eight dogs had acute renal tubular necrosis. Six dogs had a clinical diagnosis of leptospirosis based on renal and hepatic failure, positive microscopic agglutination test (MAT) and/or positive blood/urine Leptospira-specific PCR. Leptospira could not be cultured post mortem from the lungs or kidneys. However, Leptospira-specific PCR was positive in lung, liver or kidneys of three dogs. In summary, a novel pulmonary haemorrhagic syndrome was identified in dogs but the mechanism of the massive pulmonary erythrocyte extravasation remains elusive. The lack of a consistent post mortem identification of Leptospira spp. in dogs with pulmonary haemorrhage raise questions as to whether additional factors besides Leptospira may cause this as yet unrecognized entity in dogs
Reservoirs of pathogenic Leptospira species in Uganda
Introduction
Leptospira are spirochete bacteria, including pathogenic species that cause leptospirosis, a zoonotic disease endemic in the tropics. In Uganda, Leptospira seroprevalence has been reported among outpatients at three hospitals, with human-animal interaction implicated as source of human Leptospira exposures. However, corresponding animal Leptospira infection has only been demonstrated in cattle, leaving the status in several potential reservoirs like other livestock species and environmental sources unknown. The current study aims at determining the occurrence, and risk factors for Leptospira infection among livestock species and environmental sources in Uganda.
Method
From a nationwide cross-sectional survey in major livestock slaughter facilities, we performed a real-time PCR test on 2,063 livestock kidney samples from 844 cattle, 761 pigs, 341 goats,117 sheep; and on 93 small mammals. Small mammals (rodents and shrews) were trapped at slaughter facilities and communities within a 500metre radius from slaughter facilities. Age, sex, breed and origin of each sampled animal were noted. Leptospira prevalence was estimated and risk factors for infection among livestock species determined using univariate logistic regression model.
Results
Leptospira infection was detected in 43 of 2,063 livestock samples tested (2.08%, 95% C.I = 1.52-2.80). Infection was highest in sheep (5.13% C.I = 2.25-10.80), 3.32% (95% C.I = 2.26-4.75) in cattle, 1.76% (95% C. I=0.77-3.70) in goats, and 0.39 (95% C.I = 0.10-1.13) in pigs.
Pigs were significantly less infected compared to all other species (pâvalue= 0.0008). Indigenous livestock breeds were more infected (pâvalue =0.005) compared to their exotic and crossed counterpart. Additionally, older livestock species were significantly infected than the younger ones (pâvalue = 0.052). None of the small mammals tested positive.
Conclusion
Livestock in Uganda reserve pathogenic Leptospira species, with sheep and cattle especially of indigenous breed being more significant reservoirs. Small mammals may play a limited role in Leptospira maintenance and transmission in Uganda
Exposure to Leptospira spp. and associated risk factors in the human, cattle and dog populations in Bhutan
Leptospirosis is a neglected worldwide zoonotic bacterial disease with a high prevalence in subtropical and tropical countries. The prevalence of Leptospira spp. in humans, cattle and dogs is unknown in Bhutan. Therefore, we sought to find out whether humans, cattle or dogs had been infected in the past with leptospires by measuring antibodies in the serum. We therefore collected blood from 864 humans >/=13 years of age, 130 bovines and 84 dogs from different rural and urban areas in Bhutan and tested the serum for antibodies specific for leptospires with a screening of enzyme-linked immunosorbent assays (ELISA) and a confirmatory microscopic agglutination test (MAT). In humans, 17.6% were seropositive by ELISA and 1.6% by MAT. The seropositivity was stronger in bovines (36.9%) and dogs (47.6%). "Having had a fever recently" (OR 5.2, p = 0.004), "working for the military" (OR 26.6, p = 0.028) and "being unemployed" (OR 12.9, p = 0.041) (reference category = housemaker) were statistically significantly associated with seropositivity when controlled for the effects of other risk factors. However, due to the small number of positive test results, the findings on risk factors should be interpreted with caution. Based on the serogroups found in the three species, dogs could be a source of infection for humans, or dogs and humans are exposed to the same environmental risk factors Clinical leptospirosis in humans and domestic animals should be investigated by testing blood and urine for the presence of leptospires by molecular methods (qPCR)
Detection and Characterization of Planets in Binary and Multiple Systems
Moderately close binaries are a special class of targets for planet searches.
From a theoretical standpoint, their hospitality to giant planets is
uncertain and debated. From an observational standpoint, many of these systems
present technical difficulties for precise radial-velocity measurements and
classical Doppler surveys avoid them accordingly. In spite of these adverse
factors, present data support the idea that giant planets residing in binary
and hierarchical systems provide unique observational constraints on the
processes of planet formation and evolution. The interest and the importance of
including various types of binary stars in extrasolar planet studies have thus
grown over time and significant efforts have recently been put into: (i)
searching for stellar companions to the known planet-host stars using direct
imaging, and (ii) extending Doppler planet searches to spectroscopic and
moderately close visual binaries. In this contribution we review the
observational progresses made over the past years to detect and study
extrasolar planets in binary systems, putting special emphasis on the two
developments mentioned above.Comment: 20 pages, 4 figures, review to appear in Extrasolar Planets in
Multi-Body Systems: Theory and Observations, ed. K. Gozdziewski, A.
Niedzielski, and J. Schneider, EAS Publications Serie
Causes of non-malarial fever in Africa: A systematic review and meta-analysis
Objectives
The awareness of non-malarial febrile illnesses (NMFIs) has been on the rise over the last decades.
Therefore, we undertook a systematic literature review and meta-analysis of causative agents of
non-malarial fevers on the African continent.
Materials and methods
We searched for literature in African Journals Online, EMBASE, PubMed, Scopus, and Web of
Science databases to identify aetiologic agents that had been reported and to determine summary
estimates of the proportional morbidity rates (PMr) associated with these pathogens among fever
patients.
Results
A total of 133 studies comprising 391,835 patients from 25 of the 54 African countries were eligible.
A wide array of aetiologic agents were described with considerable regional differences among the
leading agents. Overall, bacterial pathogens tested from blood samples accounted for the largest
proportion. The summary estimates from the meta-analysis were low for most of the agents. This
may have resulted from a true low prevalence of the agents, the failure to test for many agents or
the low sensitivity of the diagnostic methods applied. Our meta-regression analysis of study and
population variables showed that diagnostic methods determined the PMr estimates of typhoidal
Salmonella and Dengue virus. An increase in the PMr of Klebsiella spp. infections was observed
over time. Furthermore, the status of patients as either inpatient or outpatient predicted the PMr of
Klebsiella spp. infections.
Conclusion
The small number of epidemiological studies and the variety of NMFI agents on the African
continent emphasizes the need for harmonized studies with larger sample sizes. In particular,
diagnostic procedures for NMFIs should be standardized to facilitate comparability of study results
and to improve future meta-analyses. Reliable NMFI burden estimates will inform regional public
health strategies
Loss of CD4+ TÂ cell-intrinsic arginase 1 accelerates Th1 response kinetics and reduces lung pathology during influenza infection
Arginase 1 (Arg1), the enzyme catalyzing the conversion of arginine to ornithine, is a hallmark of IL-10-producing immunoregulatory M2 macrophages. However, its expression in T cells is disputed. Here, we demonstrate that induction of Arg1 expression is a key feature of lung CD4+ T cells during mouse in vivo influenza infection. Conditional ablation of Arg1 in CD4+ T cells accelerated both virus-specific T helper 1 (Th1) effector responses and its resolution, resulting in efficient viral clearance and reduced lung pathology. Using unbiased transcriptomics and metabolomics, we found that Arg1-deficiency was distinct from Arg2-deficiency and caused altered glutamine metabolism. Rebalancing this perturbed glutamine flux normalized the cellular Th1 response. CD4+ T cells from rare ARG1-deficient patients or CRISPR-Cas9-mediated ARG1-deletion in healthy donor cells phenocopied the murine cellular phenotype. Collectively, CD4+ T cell-intrinsic Arg1 functions as an unexpected rheostat regulating the kinetics of the mammalian Th1 lifecycle with implications for Th1-associated tissue pathologies
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