The genera Anaplasma, Ehrlichia, Cowdria, Neorickettsia and Wolbachia encompass a group of obligate intracellular bacteria that reside in vacuoles of eukaryotic cells and were previously placed in taxa based upon morphological, ecological, epidemiological and clinical characteristics. Recent genetic analyses of 16S rRNA genes, groESL and surface protein genes have indicated that the existing taxa designations are flawed. All 16S rRNA gene and groESL sequences deposited in GenBank prior to 2000 and selected sequences deposited thereafter were aligned and phylogenetic trees and bootstrap values were calculated using the neighbour-joining method and compared with trees generated with maximum-probability, maximum-likelihood, majority-rule consensus and parsimony methods. Supported by bootstrap probabilities of at least 54%, 16S rRNA gene comparisons consistently clustered to yield four distinct clades characterized roughly as Anaplasma (including the Ehrlichia phagocytophila group, Ehrlichia platys and Ehrlichia bovis) with a minimum of 96.1% similarity, Ehrlichia (including Cowdria ruminantium) with a minimum of 97.7% similarity, Wolbachia with a minimum of 95.6% similarity and Neorickettsia (including Ehrlichia sennetsu and Ehrlichia risticii) with a minimum of 94.9% similarity. Maximum similarity between clades ranged from 87.1 to 94.9%. Insufficient differences existed among E. phagocytophila, Ehrlichia equi and the human granulocytic ehrlichiosis (HGE) agent to support separate species designations, and this group was at least 98.2% similar to any Anaplasma species. These 16S rRNA gene analyses are strongly supported by similar groESL clades, as well as biological and antigenic characteristics. It is proposed that all members of the tribes Ehrlichieae and Wolbachieae be transferred to the family Anaplasmataceae and that the tribe structure of the family Rickettsiaceae be eliminated. The genus Anaplasma should be emended to include Anaplasma (Ehrlichia) phagocytophila comb. nov. (which also encompasses the former E. equi and the HGE agent), Anaplasma (Ehrlichia) bovis comb. nov. and Anaplasma (Ehrlichia) platys comb. nov., the genus Ehrlichia should be emended to include Ehrlichia (Cowdria) ruminantium comb. nov. and the genus Neorickettsia should be emended to include Neorickettsia (Ehrlichia) risticii comb. nov. and Neorickettsia (Ehrlichia) sennetsu comb. nov.

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Reorganization of genera in the families Rickettsiaceae and Anaplasmataceae in the order Rickettsiales: unification of some species of Ehrlichia with Anaplasma, Cowdria with Ehrlichia and Ehrlichia with Neorickettsia, descriptions of six new species combinations and designation of Ehrlichia equi and 'HGE agent' as subjective synonyms of Ehrlichia phagocytophila.

Ticks and tick-borne diseases affect animal and human health worldwide and are the cause of significant economic losses. Approximately 10% of the currently known 867 tick species act as vectors of a broad range of pathogens of domestic animals and humans and are also responsible for damage directly due to their feeding behaviour. The most important tick species and the effects they cause are listed. The impact on the global economy is considered to be high and although some estimates are given, there is a lack of reliable data. The impact of ticks and tick-borne diseases on animal production and public health and their control are discussed.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/2CCD9EAD34FA5E2FB3CD37DAAFFF7F56/S0031182004005967a.pdf/div-class-title-the-global-importance-of-ticks-div.pdf

The global importance of ticks.

After many years of intense negotiations, the 195 parties to the United Nations Framework Convention on Climate Change (UNFCCC) adopted on 12 December 2015 in Paris a new global agreement on how all countries collectively will tackle climate change. The Paris Agreement is widely recognized as the most significant environmental treaty ever adopted, with strong positive implications on development, international cooperation and, of course, for the climate. The ambition is to hold the increase in the global average temperature to well below 2oC above pre-industrial levels and pursue efforts to limit the temperature increase to 1.5oC.

United nations framework convention on climate change (unfccc)

Farmers in mixed crop-livestock systems produce about half of the world’s food. In small holdings around the world, livestock are reared mostly on grass, browse, and nonfood biomass from maize, millet, rice, and sorghum crops and in their turn supply manure and traction for future crops. Animals act as insurance against hard times and supply farmers with a source of regular income from sales of milk, eggs, and other products. Thus, faced with population growth and climate change, small-holder farmers should be the first target for policies to intensify production by carefully managed inputs of fertilizer, water, and feed to minimize waste and environmental impact, supported by improved access to markets, new varieties, and technologies.

/pdf/smart-investments-in-sustainable-food-production-revisiting-3fs9k59bs2.pdf

Smart investments in sustainable food production: revisiting mixed crop-livestock systems.

Leptospirosis is a widespread and potentially fatal zoonosis that is endemic in many tropical regions and causes large epidemics after heavy rainfall and flooding. Infection results from direct or indirect exposure to infected reservoir host animals that carry the pathogen in their renal tubules and shed pathogenic leptospires in their urine. Although many wild and domestic animals can serve as reservoir hosts , the brown rat (Rattus norvegicus) is the most important source of human infections. Individuals living in urban slum environments characterized by inadequate sanitation and poor housing are at high risk of rat exposure and leptospirosis. The global burden of leptospirosis is expected to rise with demographic shifts that favor increases in the number of urban poor in tropical regions subject to worsening storms and urban flooding due to climate change. Data emerging from prospective surveillance studies suggest that most human leptospiral infections in endemic areas are mild or asymptomatic. Development of more severe outcomes likely depends on three factors: epidemiological conditions, host susceptibility, and pathogen virulence (Fig. 1). Mortality increases with age, particularly in patients older than 60 years of age. High levels of bacteremia are associated with poor clinical outcomes and, based on animal model and in vitro studies, are related in part to poor recognition of leptospiral LPS by human TLR4. Patients with severe leptospirosis experience a cytokine storm characterized by high levels of IL-6, TNF-alpha, and IL-10. Patients with the HLA DQ6 allele are at higher risk of disease, suggesting a role for lymphocyte stimulation by a leptospiral superantigen. Leptospirosis typically presents as a nonspecific, acute febrile illness characterized by fever, myalgia, and headache and may be confused with other entities such as influenza and dengue fever. Newer diagnostic methods facilitate early diagnosis and antibiotic treatment. Patients progressing to multisystem organ failure have widespread hematogenous dissemination of pathogens. Nonoliguric (high output) renal dysfunction should be supported with fluids and electrolytes. When oliguric renal failure occurs, prompt initiation of dialysis can be life saving. Elevated bilirubin levels are due to hepatocellular damage and disruption of intercellular junctions between hepatocytes, resulting in leaking of bilirubin out of bile caniliculi. Hemorrhagic complications are common and are associated with coagulation abnormalities. Severe pulmonary hemorrhage syndrome due to extensive alveolar hemorrhage has a fatality rate of >50 %. Readers are referred to earlier, excellent summaries related to this subject (Adler and de la Pena-Moctezuma 2010; Bharti et al. 2003; Hartskeerl et al. 2011; Ko et al. 2009; Levett 2001; McBride et al. 2005).

/pdf/leptospirosis-in-humans-53isr2cjcx.pdf

Leptospirosis in Humans

Investing in Animal Health Research to Alleviate Poverty

The title of this book does not adequately reflect the comprehensive treatment of a complex and important parasitic disease of domestic cattle. Despite the passing of 100 years, East Coast fever (ECF) remains an economically and environmentally important disease in a continent desperate to increase food production in response to modest expectations from a growing population. The 13 chapters embrace a wide range of subjects, each of which is pertinent to understanding why the disease still remains a constraint and a challenge to livestock production in Africa. Chapters I, 2, 7 and 10 give a historical overview of the study of the disease. Chapters I and 2 provide detailed historical backgrounds to the spread and control of the disease in Southern, Central and Eastem Africa. These chapters are written with great clarity and are rich in detail that might have become lost had they not been wisely commissioned for inclusion in the book. Although Chapter 7 is intended to be a discussion of the host population dynamics, it inevitably becomes a historical review of the pattern of trends in selection of cattle breeds for increased productivity in a continent that was targeted for agricultural exploitation. Chapter 10, under the theme of epidemiological states, revisits the historical pattern of disease by examination of reported case his tones of outbreaks in cattle populations in different geographical loci. In contrast, Chapter II l ists the crucial armour/ of control methods which have been pursued. These methods range from early attempts to eradicate the tick population using arsenical acaricides, to modem-day usage of drugs and the future potential for large-scale vaccination. The contents of these chapters, therefore, span from the fascinating 'whodunit' detective work of early investigators in the 1900s (and, in particular, the pioneering work of Theiler and Koch) to the control methods listed in Chapter II that offer the potential to 'undo it'. Chapters 3, 8 and 9 are targeted primarily at readers with a capacity for absorbing scientific and technical detail. An early chapter on origins, classification and nomenclature lists in tedious scientific format the various taxonomical properties of the many theilerial species. The content of this chapter represents the labour of investigations over many years, and portrays the classical difficulties in obtaining agreement on taxonomical issues. The chapter on parasite population dynamics, in contrast, relates with great simplicity what is a complex relationship between the theilerial parasite and the cattle host; and a chapter on reporting, diagnosis and surveillance reports on the current techniques available for monitoring the effects of the disease under laboratory and field conditions. This chapter should be of interest to those workers interested in measuring the impact of potential control methods on other vector-transmitted diseases. The remaining chapters are written at a general level, and each gives a good overview to the non-specialist. The chapter on tick vectors of theileriosis was fragmented. The Boophilus life cycle seemed out of place and there was undue attention given to the use of the Climex model for the distribution of Amblyomma. This material would have been better placed in the modeling chapter where Climex is discussed in detail. These deviations serve to emphasize that the content of the book is not confined to theileriosis epidemiology in Africa but has wide-reaching implications for all such diseases. The two final chapters on modeling and economic impact acknowledge the broad perspective in which efforts to control the disease are now set. This is an important book on two accounts: (I) it provides a competent and accurate record of scientific achievements in the control of a ticktransmitted disease, and (2) it provides a record of the historical events which have affected the transmission of a disease across national boundaries. Since the conception of the book at a scientific meeting in Lilongwe in 1988, a combination of events has led it towards successful completion. Over the years, aid agencies have remained committed to finding solutions to ECF and their support has sustained a small community of dedicated scientific workers. The collaboration of the authors and the use of other expert contributors has provided a successful formula for the presentation of the material. The authors have produced an accurate and balanced perspective of the epidemiology of theileriosis. The text has already become an important handbook for ECF research workers and will be of value to anyone with an interest in the control of parasitic diseases. To list minor points of criticism would be misleading. Although other contributions could have enhanced the book, this is a first-class volume which has provided a useful service not only for ECF workers, but also for students of tropical diseases, epidemiology, preventive animal health practice and planning. What is interesting is that the end is yet to be written. The control of ECF has come to a crossroads. Recent progress in the development of molecular vaccines and the prospect of models to predict the efficacy and impact of control point to new horizons. Perhaps by the year 2020, ECF will no longer plague African cattle.

The epidemiology of theileriosis in Africa

A Handbook Jørgen Hansen, DVM, PhD Animal Production and Health Division Food and Agriculture Organization Rome, Italy Brian Perry, BVM&S, DTVM, MSc, DVM&S, MRCVS International Laboratory for Research on Animal Diseases Nairobi, Kenya © ILRAD 1994 Published by the International Laboratory for Research on Animal Diseases, P.O. Box 30709, Nairobi, Kenya Cover Design by Dynamic Advertising Ltd. Printed by the International Livestock Centre for Africa Addis Ababa, Ethiopia ISBN 92-9055-703-1 This electronic document has been scanned using optical character recognition (OCR) software and careful manual recorrection. Even if the quality of digitalisation is high, the FAO declines all responsibility for any discrepancies that may exist between the present document and its original printed version.

The epidemiology, diagnosis and control of helminth parasites of ruminants

Improving the assessment of the economic impact of parasitic diseases and of their control in production animals

Poverty is now at the heart of development discourse; we discuss how it is measured and understood. We next consider the negative and positive impacts of livestock on pro-poor development. Taking a value-chain approach that includes keepers, users and eaters of livestock, we identify diseases that are road blocks on the ‘three livestock pathways out of poverty’. We discuss livestock impacts on poverty reduction and review attempts to prioritize the livestock diseases relevant to the poor. We make suggestions for metrics that better measure disease impact and show the benefits of more rigorous evaluation before reviewing recent attempts to measure the importance of disease to the poor. High impact of a disease does not guarantee high benefits from its control; other factors must be taken into consideration, including technical feasibility and political desirability. We conclude by considering how we might better understand and exploit the roles of livestock and improved animal health by posing three speculative questions on the impact of livestock diseases and their control on global poverty: how can understanding livestock and poverty links help disease control?; if global poverty reduction was the aim of livestock disease control, how would it differ from the current model?; and how much of the impact of livestock disease on poverty is due to disease control policy rather than disease itself?

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Brian D. Perry

Papers

Investing in Animal Health Research to Alleviate Poverty

The epidemiology of theileriosis in Africa

The epidemiology, diagnosis and control of helminth parasites of ruminants

Improving the assessment of the economic impact of parasitic diseases and of their control in production animals

The impacts of livestock diseases and their control on growth and development processes that are pro-poor.