Ecology of a vector-borne zoonosis in a complex ecosystem: trypanosomiasis in Serengeti, Tanzania

Unravelling the complexities of a disease with multiple wildlife host and multiple tsetse vector species is no easy task. After over a century of field observations, experimental studies, anecdotal evidence and conjecture, the role of wildlife in the transmission of trypanosomes is still unclear. Recently, however, frameworks used in the studies of other vector-borne diseases with wildlife reservoirs showed that not only is it possible to understand transmission, but that spatio-temporal predictions of human disease risk and targeted control are realistic aims, even in such complex systems. This thesis explores the epidemiology of human African trypanosomiasis (HAT) in the Serengeti-Mara ecosystem in Northern Tanzania, where recent cases in tourists have highlighted the disease as a public health and economic concern. Assessment of the prevalence of trypanosome infections in different wildlife species is the first step in investigating the relative importance of different species in disease transmission. Identification of trypanosomes relies on sensitive and specific diagnostic tests. Polymerase chain reaction (PCR) protocols based on interspecies differences in the length of the ribosomal internal transcribed spacer (ITS) regions have been widely used in livestock to identify multiple trypanosome species in one PCR reaction. This study represents the first assessment of these protocols on blood samples collected from wildlife. Clonal sequence analysis of PCR products revealed a large range of trypanosomes circulating in wildlife, including Trypanosoma congolense, Trypanosoma brucei, Trypanosoma simiae Tsavo, Trypanosoma godfreyi and Trypanosoma vivax. In addition sequences similar to known sequences, termed Trypanosoma simiae-like and T. vivax-like trypanosomes, may reflect further diversity. However, further characterisation is needed before ITS protocols can be used widely for epidemiological studies in wildlife. The prevalence of T. brucei s.l. and T. congolense varied widely between species. This variation was predominantly explained by taxonomic classification, suggesting intrinsic differences in response to trypanosomes. Trypanosoma brucei rhodesiense, the subspecies responsible for HAT, was identified in lion, hyaena and reedbuck. Age significantly affected the prevalence of T. congolense in lion and hyaena, with the highest prevalence in subadults. The lack of statistically significant differences in prevalence between animals sampled live or after death confirmed that post-mortem sampling provides a method for increasing sample sizes in wildlife studies. The complex relationship between tsetse density and prevalence of trypanosome infections illustrated the difficulties of assessing data from diverse ecosystems with many potential confounding factors. A cross-sectional study of Glossina swynnertoni and Glossina pallidipes, the main tsetse species in Serengeti, highlighted the difficulties of integrating the results of microscopy and PCR to generate meaningful measures of the prevalence of transmissible T. brucei infections for epidemiological studies. However, PCR results suggested that G. pallidipes may be more important as a vector of T. brucei s.l. than has been previously recognised. Spatial variation in both tsetse density and the prevalence of trypanosome infections suggests human disease risk is heterogeneous. The results of this study, along with relevant literature, are considered within the context of frameworks used for other vector-borne diseases and the implications for disease management discussed

Cytotoxic Complexes of Sodium Oleate with β-Lactoglobulin

pre-printA complex of α-lactalbumin and oleic acid has previously been shown to induce apoptosis in cancer cells in a number of in vitro and in vivo trials. This complex is called HAMLET or BAMLET, depending on the origin of α-la (human/bovine alpha-lactalbumin made lethal to tumour cells). In the current study, it was shown that bovine β-lactoglobulin (β-lg), upon binding sodium oleate (NaOle), the salt of oleic acid, also acquires cytotoxicity towards tumour cells (human monocytic cells U937), analogously to HAMLET/BAMLET complexes. The properties of the complex were characterized using FIR spectroscopy, HPLC and SDS-PAGE. It was shown that the level of covalent oligomerization (dimers and trimers) of β-lg increased with increasing the molar ratio of sodium oleate NaOle:β-lg in the preparation procedure. At the same time, increasing the molar ratio of NaOle:β-lg increased the cytotoxicity of the complex. The increase in cytotoxicity appeared to be dependent on the amount of bound NaOle in the complex, but not on the content of multimeric forms of β-lg. The NaOle/β-lg complex also showed similarity with BAMLET in penetrating the cell membrane and co-localizing with the cell nucleus. Furthermore, DNA fragmentation studies suggested that tumour cells (U937) treated with the complex died by apoptosis, as in the case of BAMLET, and healthy cells appeared to be less affected by treatment, as shown with model rat adrenal pheochromocytoma cells PC12. In conclusion, β-lg and NaOle can form complexes with apoptosis-inducing qualities comparable to those of BAMLET.The work was funded by the Irish Dairy Research Trust and The Department of Agriculture (Food Institutional Research Measure – FIRM project 08RDTMFRC650) under the National Development Plan 2007-2013. K. Lišková was funded under the TeagascWalsh Fellowship Scheme

What is needed to achieve effective and sustainable control of African Animal Trypanosomosis?

A welcome resurgence in African animal trypanosomosis (AAT) research has resulted in advances in capabilities, foundational datasets, and understanding. Additionally, there is the prospect of the first new trypanocide in &gt;60 years. However, it is vital to ensure that advances translate to improved and sustainable control in the field. A recent meeting, the Symposium on African Livestock Trypanosomes – Tanzania, convened stakeholders from across the spectrum of AAT research and control to ask how this can be achieved. Current constraints on progress were defined, as were critical gaps and opportunities that need addressing. There is a requirement and opportunity for the AAT research community to communicate, collaborate, and coordinate to maintain momentum and achieve the ultimate goal of sustainable AAT control.</p

Compassion, stigma, and professionalism among emergency personnel responding to the opioid crisis: An exploratory study in New Hampshire, USA.

OBJECTIVE: Drug overdoses are the leading cause of death in the United States for those under 50 years of age, and New Hampshire has been disproportionately affected, resulting in increased encounters with the emergency response system. The ensuing impact on emergency personnel has received little attention. The present study aimed to explore the experiences and perspectives of emergency personnel responding to the opioid crisis in NH, with a focus on their views toward people who use opioids. METHODS: Thirty-six emergency personnel (emergency department clinicians, n = 18; emergency medical service providers, n = 6; firefighters, n = 6; and police officers, n = 6) in 6 New Hampshire counties were interviewed about their experiences responding to overdoses and their perspectives on individuals who use opioids. Directed content analysis was used to identify themes in the transcribed, semistructured interviews. The results were reviewed for consensus. RESULTS: Several categories of themes were identified among emergency personnel's accounts of their overdose response experiences and perspectives, including varied degrees of compassion and stigma toward people who use opioids; associations between compassion or stigma and policy- and practice-related themes, such as prehospital emergency care and the role of emergency departments (EDs); and primarily among personnel expressing compassion, a sense of professional responsibility that outweighed personal biases. CONCLUSIONS: Despite the magnitude of the ongoing opioid crisis, some emergency personnel in New Hampshire have sustained or increased their compassion for people who use opioids. Others' perspectives remain or have become increasingly stigmatizing. The associations of compassion and stigma with various policy- and practice-related themes warrant further investigation

Rvb1p and Rvb2p are essential components of a chromatin remodeling complex that regulates transcription of over 5% of yeast genes

Eukaryotic Rvb1p and Rvb2p are two highly conserved proteins related to the helicase subset of the AAA+ family of ATPases. Conditional mutants in both genes show rapid changes in the transcription of over 5% of yeast genes, with a similar number of genes being repressed and activated. Both Rvb1p and Rvb2p are required for maintaining the induced state of many inducible promoters. ATP binding and hydrolysis by Rvb1p and Rvb2p is individually essential in vivo and the two proteins are associated with each other in a high molecular weight complex that shows ATP-dependent chromatin remodeling activity in vitro. Our findings show that Rvb1p and Rvb2p are essential components of a chromatin remodeling complex and determine genes regulated by the complex

Vulnerability of the British swine industry to Classical Swine Fever

Classical swine fever (CSF) is a notifiable, highly contagious viral disease of swine which results in severe welfare and economic consequences (e.g. barrier to trade) in affected countries. In order to improve preparedness for disease incursion, it is critical to have some understanding of how vulnerable a CSF-free swine industry may be and, thus, evaluate how CSF would spread should it be introduced

Vaccination against Foot-and-mouth disease : do initial conditions affect its benefit?

When facing incursion of a major livestock infectious disease, the decision to implement a vaccination programme is made at the national level. To make this decision, governments must consider whether the benefits of vaccination are sufficient to outweigh potential additional costs, including further trade restrictions that may be imposed due to the implementation of vaccination. However, little consensus exists on the factors triggering its implementation on the field. This work explores the effect of several triggers in the implementation of a reactive vaccination-to-live policy when facing epidemics of foot-and-mouth disease. In particular, we tested whether changes in the location of the incursion and the delay of implementation would affect the epidemiological benefit of such a policy in the context of Scotland. To reach this goal, we used a spatial, premises-based model that has been extensively used to investigate the effectiveness of mitigation procedures in Great Britain. The results show that the decision to vaccinate, or not, is not straightforward and strongly depends on the underlying local structure of the population-at-risk. With regards to disease incursion preparedness, simply identifying areas of highest population density may not capture all complexities that may influence the spread of disease as well as the benefit of implementing vaccination. However, if a decision to vaccinate is made, we show that delaying its implementation in the field may markedly reduce its benefit. This work provides guidelines to support policy makers in their decision to implement, or not, a vaccination-to-live policy when facing epidemics of infectious livestock disease

How commercial and non-commercial swine producers move pigs in Scotland:a detailed descriptive analysis

Background The impact of non-commercial producers on disease spread via livestock movement is related to their level of interaction with other commercial actors within the industry. Although understanding these relationships is crucial in order to identify likely routes of disease incursion and transmission prior to disease detection, there has been little research in this area due to the difficulties of capturing movements of small producers with sufficient resolution. Here, we used the Scottish Livestock Electronic Identification and Traceability (ScotEID) database to describe the movement patterns of different pig production systems which may affect the risk of disease spread within the swine industry. In particular, we focused on the role of small pig producers.&lt;p&gt;&lt;/p&gt; Results Between January 2012 and May 2013, 23,169 batches of pigs were recorded moving animals between 2382 known unique premises. Although the majority of movements (61%) were to a slaughterhouse, the non-commercial and the commercial sectors of the Scottish swine industry coexist, with on- and off-movement of animals occurring relatively frequently. For instance, 13% and 4% of non-slaughter movements from professional producers were sent to a non-assured commercial producer or to a small producer, respectively; whereas 43% and 22% of movements from non-assured commercial farms were sent to a professional or a small producer, respectively. We further identified differences between producer types in several animal movement characteristics which are known to increase the risk of disease spread. Particularly, the distance travelled and the use of haulage were found to be significantly different between producers.&lt;p&gt;&lt;/p&gt; Conclusions These results showed that commercial producers are not isolated from the non-commercial sector of the Scottish swine industry and may frequently interact, either directly or indirectly. The observed patterns in the frequency of movements, the type of producers involved, the distance travelled and the use of haulage companies provide insights into the structure of the Scottish swine industry, but also highlight different features that may increase the risk of infectious diseases spread in both Scotland and the UK. Such knowledge is critical for developing more robust biosecurity and surveillance plans and better preparing Scotland against incursions of emerging swine diseases.&lt;p&gt;&lt;/p&gt

Using zebrafish larval models to study brain injury, locomotor and neuroinflammatory outcomes following intracerebral haemorrhage.

Intracerebral haemorrhage (ICH) is a devastating condition with limited treatment options, and current understanding of pathophysiology is incomplete. Spontaneous cerebral bleeding is a characteristic of the human condition that has proven difficult to recapitulate in existing pre-clinical rodent models. Zebrafish larvae are frequently used as vertebrate disease models and are associated with several advantages, including high fecundity, optical translucency and non-protected status prior to 5 days post-fertilisation. Furthermore, other groups have shown that zebrafish larvae can exhibit spontaneous ICH. The aim of this study was to investigate whether such models can be utilised to study the pathological consequences of bleeding in the brain, in the context of pre-clinical ICH research. Here, we compared existing genetic (bubblehead) and chemically inducible (atorvastatin) zebrafish larval models of spontaneous ICH and studied the subsequent disease processes. Through live, non-invasive imaging of transgenic fluorescent reporter lines and behavioural assessment we quantified brain injury, locomotor function and neuroinflammation following ICH. We show that ICH in both zebrafish larval models is comparable in timing, frequency and location. ICH results in increased brain cell death and a persistent locomotor deficit. Additionally, in haemorrhaged larvae we observed a significant increase in macrophage recruitment to the site of injury. Live in vivo imaging allowed us to track active macrophage-based phagocytosis of dying brain cells 24 hours after haemorrhage. Morphological analyses and quantification indicated that an increase in overall macrophage activation occurs in the haemorrhaged brain. Our study shows that in zebrafish larvae, bleeding in the brain induces quantifiable phenotypic outcomes that mimic key features of human ICH. We hope that this methodology will enable the pre-clinical ICH community to adopt the zebrafish larval model as an alternative to rodents, supporting future high throughput drug screening and as a complementary approach to elucidating crucial mechanisms associated with ICH pathophysiology