Publications by authors named "Conlan A"
Article Synopsis
- Bovine tuberculosis (bTB) is a disease affecting cattle, especially common in crossbred cows in Ethiopia, but there aren't enough checks to find it.
- In a study, scientists checked over 7,640 cattle at slaughterhouses and found that only 2.3% had signs of bTB, with crossbred cows being at higher risk.
- Most of the sick cattle had problems in their lungs or lymph nodes, and tests confirmed that M. bovis, a type of bacteria, was responsible for the infections.
Despite intensive study, much remains unknown about the dynamics of seasonal influenza virus epidemic establishment and spread in the United States (US) each season. By reconstructing transmission lineages from seasonal influenza virus genomes collected in the US from 2014 to 2023, we show that most epidemics consisted of multiple distinct transmission lineages. Spread of these lineages exhibited strong spatiotemporal hierarchies and lineage size was correlated with timing of lineage establishment in the US.
View Article and Find Full Text PDFBacillus Calmette-Guérin (BCG) is a routinely used vaccine for protecting children against that comprises attenuated . BCG can also be used to protect livestock against ; however, its effectiveness has not been quantified for this use. We performed a natural transmission experiment to directly estimate the rate of transmission to and from vaccinated and unvaccinated calves over a 1-year exposure period.
View Article and Find Full Text PDFBackground: Bovine tuberculosis (bTB) is a chronic disease that results from infection with any member of the Mycobacterium tuberculosis complex. Infected animals are typically diagnosed with tuberculin-based intradermal skin tests according to World Organization of Animal Health which are presently in use. However, tuberculin is not suitable for use in BCG-vaccinated animals due to a high rate of false-positive reactions.
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- Bovine tuberculosis, caused by Mycobacterium bovis, is a significant infectious disease affecting cattle globally, with varying responses to infection that are not fully understood.
- A study using advanced assays revealed that cell-mediated immune responses (CMI) appeared as early as two weeks after infection, while antibody responses were also detectable in some cattle within four weeks.
- The findings suggest a need for better biomarkers to predict infection outcomes, especially in low-and-middle income countries where traditional control methods, like test-and-slaughter, are impractical.
Bovine tuberculosis (bTB) is a disease with impact on dairy productivity, as well as having the potential for zoonotic transmission. Understanding the genetic diversity of the disease agent is important for identifying its routes of transmission. Here we investigated the level of genetic diversity of isolates and assessed the zoonotic potential in risk groups of people working in bTB-infected dairy farms in central Ethiopia.
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- Aggregation of children in schools significantly contributes to the spread of infectious diseases, but self-reported contact data lacks a strong link to pathogen transmission.
- Researchers conducted a study in two secondary schools in England, using students' social contact surveys and genetic analysis of bacteria to explore this relationship.
- The study found that while direct transmission within schools is infrequent, higher colonization rates suggest school-age children could be key contributors to community transmission.
Article Synopsis
- - Zoonotic tuberculosis in humans is primarily caused by bacteria from cattle, and with India holding the highest rate of human tuberculosis globally, managing this risk at its source is crucial for tackling the epidemic.
- - The study found a significant association between human tuberculosis cases and factors like bovine density and ownership; specifically, higher buffalo density correlated with an increased risk of tuberculosis while cattle density offered some protective benefits.
- - The findings suggest a need for better surveillance of tuberculosis in livestock and further research into how bovine interactions might influence human tuberculosis reporting and variability in transmission dynamics.
Anthrax is caused by, Bacillus anthracis, a soil-borne bacterium that infects grazing animals. Kenya reported a sharp increase in livestock anthrax cases from 2005, with only 12% of the sub-counties (decentralised administrative units used by Kenyan county governments to facilitate service provision) accounting for almost a third of the livestock cases. Recent studies of the spatial extent of B.
View Article and Find Full Text PDFTo reduce the veterinary, public health, environmental, and economic burden associated with anthrax outbreaks, it is vital to identify the spatial distribution of areas suitable for Bacillus anthracis, the causative agent of the disease. Bayesian approaches have previously been applied to estimate uncertainty around detected areas of B. anthracis suitability.
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- * Genomic data was used to trace the transmission history of SARS-CoV-2 between humans and deer, revealing no direct evidence of deer transmitting the virus back to humans, but indicating a low detection rate of cases at only 4.2%.
- * The significant spread of the virus within deer populations and unsampled cases suggests a need for ongoing monitoring and surveillance where humans and animals interact to prevent potential spillback to humans.
Bovine tuberculosis (BTB) is endemic in Ethiopia. Although upgraded dairy cattle account for only 1% of the total cattle population, they are the backbone of the marketed milk production in the country. Supported by research data outputs from three years, we report in this paper an estimate of the productivity loss and cost of BTB to the Ethiopian dairy sector in two dairy settings, the urban production system in Central Ethiopia (model 1) and the national upgraded dairy production (model 2).
View Article and Find Full Text PDFMultiple spillovers from humans and onward transmission of SARS-CoV-2 in white-tailed deer.
Proc Natl Acad Sci U S A
February 2022
Article Synopsis
- Many animal species, including white-tailed deer, can contract SARS-CoV-2, and there’s evidence that deer can transmit the virus to one another.
- A study conducted in Iowa from April 2020 to January 2021 found that 33.2% of sampled deer tested positive for SARS-CoV-2 RNA, with a significant spike during the peak of human cases and the deer hunting season.
- The research identified 12 lineages of the virus in deer, suggesting multiple instances of human-to-deer transmission, indicating a need for a comprehensive "One Health" approach to better understand how SARS-CoV-2 spreads among animals and humans.
Article Synopsis
- Mycobacterium bovis (M. bovis) causes bovine tuberculosis, leading to significant health issues in cattle worldwide, and a trial in England investigated its transmission between badgers and cattle.
- The study used whole genome sequencing of 1,442 isolates and tracked cattle movements to understand transmission patterns, finding that badgers transmit M. bovis to cattle at a higher rate than vice versa.
- The results indicated that ongoing transmission clusters resulted mainly from cattle movement rather than from wildlife reservoirs, with cattle being the primary contributors to new outbreaks.
Article Synopsis
- The study utilizes electron beam induced current (EBIC) to examine Al/SiGe and Al/Si-rich/SiGe nanowire heterostructures, focusing on their structural and electronic characteristics.
- The research reveals that these heterostructures function as Schottky contacts with varying barrier heights, and identifies the intrinsic doping of the semiconductors as n-type based on the induced current.
- Findings indicate that the silicon-rich interface has a lower barrier height and impacts the depletion region and carrier diffusion length, suggesting greater residual doping in that area; highlighting EBIC as an effective tool for analyzing electric fields in tiny devices.
Bovine tuberculosis (bTB) is prevalent in intensive dairy farms in Ethiopia. Vaccination could be an alternative control approach given the socio-economic challenges of a test-and-slaughter control strategy. The efficacy of the BCG was evaluated on 40 Holstein-Friesian (HF) and zebu crossbred calves recruited from single intradermal cervical comparative tuberculin (SICCT) test negative herds and randomly allocated into two groups.
View Article and Find Full Text PDFBovine tuberculosis (BTB) has substantial impact on fertility, milk, and meat productivity in cattle. However, these assumptions are based on outdated data. Recent global studies on the impact of BTB on cattle productivity are scarce and show sometimes inconclusive and/or contradicting results.
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- *The study, conducted from March 2016 to May 2017, involved testing 5,675 cattle across 299 dairy herds, resulting in an estimated herd-level prevalence of 54.4% and an individual animal prevalence of 24.5%.
- *Risk factors identified for bTB positivity included herd size, age, previous bTB history, and breed, with larger herds facing significantly increased odds of infection, particularly in older animals.
Bovine tuberculosis (bTB) is endemic in cattle in Ethiopia, a country that hosts the largest national cattle herd in Africa. The intensive dairy sector, most of which is peri-urban, has the highest prevalence of disease. Previous studies in Ethiopia have demonstrated that the main cause is , which has been investigated using conventional molecular tools including deletion typing, spoligotyping and Mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR).
View Article and Find Full Text PDFMore than 50 million cattle are likely exposed to bovine tuberculosis (bTB) worldwide, highlighting an urgent need for bTB control strategies in low- and middle-income countries (LMICs) and other regions where the disease remains endemic and test-and-slaughter approaches are unfeasible. While Bacillus Calmette-Guérin (BCG) was first developed as a vaccine for use in cattle even before its widespread use in humans, its efficacy against bTB remains poorly understood. To address this important knowledge gap, we conducted a systematic review and meta-analysis to determine the direct efficacy of BCG against bTB challenge in cattle, and performed scenario analyses with transmission dynamic models incorporating direct and indirect vaccinal effects ("herd-immunity") to assess potential impact on herd level disease control.
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- Researchers developed a transmission dynamic model for serogroup A meningitis (NmA) to evaluate the effectiveness of different immunization strategies using the MenAfriVac vaccine.
- The study found that incorporating MenAfriVac into the Expanded Programme on Immunisation (EPI) is the most effective strategy for maintaining disease control against NmA in the meningitis belt.
- New data indicates that the timing of vaccination affects immune responses, prompting an investigation into how the duration and age of vaccine-induced protection could influence long-term vaccination strategies, suggesting that routine immunization of older children may be more effective if protection lasts longer for those vaccinated after age 5.
The Ethiopian government has several initiatives to expand and intensify the dairy industry; however, the risk of bovine tuberculosis (bTB) spread is a challenge. To assess the rate of expansion and risk factors for transmission of bTB within-herds, we carried out a repeated cross-sectional survey at two time points, 2016/17 and 2018, in three regional cities, namely, Gondar, Hawassa and Mekelle, representing the emerging dairy belts of Ethiopia. The total number of herds involved was 128, comprising an average of 2303 cattle in each round.
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- Calves can get infected with bovine tuberculosis at a young age, especially in natural settings.
- The disease can progress quickly in these animals.
- It's important to test calves as part of any control strategy to help minimize the spread of infection.
In most low- and middle-income countries (LMICs), bovine tuberculosis (bTB) remains endemic due to the absence of control programs. This is because successful bTB control and eradication programs have relied on test-and-slaughter strategies that are socioeconomically unfeasible in LMICs. While Bacillus Calmette-Guérin (BCG) vaccine-induced protection for cattle has long been documented in experimental and field trials, its use in control programs has been precluded by the inability to differentiate BCG-vaccinated from naturally infected animals using the OIE-prescribed purified protein derivative (PPD)-based tuberculin skin tests.
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