| Preface |
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| Section 1 Introduction of African Animal Trypanosomosis (AAT) |
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Chapter 1 Introduction of African Animal Trypanosomosis (AAT)/Nagana |
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1 | (23) |
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African animal trypanosomosis (AAT), a livestock disease, also known as Nagana, tsetse fly disease, or tsetse disease, is a widespread tsetse-borne disease complex caused by unicellular protozoan parasites belonging to the genus Trypanosoma. |
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It is one of the major constraints to the expansion of livestock rearing and livestock-based industries in Africa. |
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It also constrains mixed farming, human health, and livelihood in tropical Africa. |
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The tsetse fly is the major vector of the disease. |
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Acute disease is characterized by marked depression, intermittent fever, anorexia, anemia, blood-tinged diarrhea, and adenopathy, sometimes petechiae on mucosa, abortion, and death if not treated. |
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Diagnosis is made by observing trypanosome parasites by direct microscopic examination of blood, lymph nodes, edema fluid, or tissues. |
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Treatment is by chemotherapy and chemoprophylaxis. |
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Control is achieved through vector control treatment using available molecules and use of a few available trypanotolerant breeds of animals. |
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Chapter 2 Epidemiology and Economic Importance of African Animal Trypanosomiasis |
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24 | (29) |
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African animal trypanosomiasis (AAT), also called Nagana, is a vector-borne parasitic disease caused by an extracellular protozoan belonging to the genus Trypanosoma. |
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It has serious effects on the health status and welfare of domestic mammals which considerably results in a reduction in their productivity. |
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In this review, a comprehensive overview of the epidemiology of AAT was provided with a special focus on its general clinical aspects (the clinical signs and pathogenesis as well as its transmission cycle), the parasite (Trypanosoma spp.), the parasite life cycle and transmission, its vector (Glossina spp.), tsetse fly lifecycle and reproduction, risk factors of AAT, and economic importance of AAT in the affected countries. |
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The present work gave a detailed account of epidemiology in the context of infestation patterns, the parasite causing it, its vector, and the economic impacts of the disease on different livestock species. |
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Chapter 3 Overview of the Vectors and Their Role in Transmission of African Animal Trypanosomiasis |
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53 | (20) |
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African animal trypanosomiasis (AAT) is a major constraint to livestock productivity, particularly in cattle and in camels. |
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This chapter covers some general aspects of the arthropod vectors of animal trypanosomiasis, the tsetse flies Glossina spp., and to a lesser extent the biting flies. |
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This chapter covers the classification, morphology, basic biology, and the eco-distribution of tsetse flies. |
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The role of tsetse flies in disease epidemiology has also been reviewed. |
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The elementary biology of these vectors is quite well known and elucidated. |
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However, with advances in molecular and other biological techniques, new insights related to tsetse biology have been obtained. |
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This chapter will revisit these basics and include some updated information emanating from research done in the recent past. |
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The final part of the chapter is devoted to a brief discussion on biting flies, the vectors of T. evansi, which causes camel trypanosomiasis. |
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Chapter 4 Role of Kenya Tsetse and Trypanosomiasis Eradication Council (KENTTEC) in Control of African Animal Trypanosomiasis (AAT)/Nagana |
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73 | (22) |
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The role of the Kenya Tsetse and Trypanosomiasis Eradication Council (KENTTEC) in the control of animal trypanosomiasis is premised on the fact that a large proportion of animal trypanosomiasis in Kenya is tsetse transmitted. |
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Tsetse distribution in Kenya is characterized by eight discontinuous belts defined by topographical, environmental and land-use. |
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KENTTEC's strategy for control of African animal trypanosomiasis is based on use of community-based organizations for spraying of livestock, control of the vector using various devices such as targets and traps, and development of strategies and policies for use of land after the intervention. |
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The council has developed linkage with research institutions for adaptive and operational research. |
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The council has initiated the development of national atlas by mapping tsetse and animal trypanosomiasis distribution in collaboration with stakeholders at the national, regional, and international levels. |
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Chapter 5 Use of Trypanotolerant Breeds: The Case of the Orma Boran |
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95 | (27) |
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This chapter describes the meaning of trypanotolerance and its implication as used with trypanotolerant livestock that are known and studied for many years in West Africa. |
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This trait is observed in many West African breeds of cattle that survive in areas of tsetse fly challenge where the humped zebu cannot. |
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Small ruminants and wildlife also exhibit increased resistance to infection with trypanosomes. |
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Trypanotolerance is viewed as a more sustainable and environmentally friendly approach to control of trypanosomiasis given the limitations of the present methods of control and lack of vaccine. |
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Little work has been conducted with East African cattle breeds. |
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The Kenyan Orma Boran (OB) has been studied since 1983 to enhance its conservation and utilization in East African region. |
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Nucleus breeding herd of superior genotypes was multiplied in Galana Agricultural Development Corporation (ADC) and disseminated to trypanosomosis endemic areas of Kenya. |
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On evaluation, performance of the crosses was comparable to that of other Borans. |
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Challenges of adoption in pastoral area are presented. |
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Chapter 6 Non-Tsetse-Transmitted Animal Trypanosomosis (NTT): Trypanosomosis Due to Trypanosoma evansi (Surra), T vivax (Duttonella), and T. equiperdum |
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122 | (22) |
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The non-tsetse-transmitted animal trypanosomoses are infections caused by three main mammalian trypanosome species, namely Trypanosoma evansi, T. equiprdum, and T. vivax. |
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Their global distribution is much wider than tsetse-transmitted trypanosomoses and includes Africa and Latin America, Asia, and Euro-Asia. |
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These trypanosomoses affect a very wide range of domestic animals and game and negatively impact on the development of the animal industry, thus directly affecting national economies and people's livelihoods. |
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| Section 2 Tick-Borne Diseases (TBDs) |
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Chapter 7 Epidemiology and Economic Importance of Tick-Borne Diseases of Cattle in Africa |
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144 | (22) |
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The tropical and sub-tropical climate in Africa favours multiplication and maintenance of tick vectors and transmission of various pathogens to cattle. |
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Key challenges including acaricide resistance, policy issues, transboundary animal movements, and inadequate veterinary services compromise effective control of tick-borne diseases (TBDs). |
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This chapter discusses important host, pathogen, climatic, and management factors that impact the control of TBDs among cattle in Africa, and which affect the productivity and overall contribution to economic development. |
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The economic losses in cattle production attributed to tick infestation and TBDs in Africa are also reviewed. |
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The use of a sustainable integrated control approach, including vaccination, strategic tick control, surveillance for acaricide resistance, and multi-stakeholder involvement is also evaluated. |
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Chapter 8 An Overview of Hard and Soft Ticks and Their Control Methods |
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166 | (29) |
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Ticks are important ectoparasites of livestock in tropical and sub-tropical countries. |
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They are responsible for the enormous economic losses both through the direct effects of blood sucking and indirectly as vectors of disease pathogens and toxins. |
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Morphologically, ticks are classified into two families known as Ixodidae (hard ticks) and Argasidae (soft ticks). |
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In this chapter, the authors provide a description of the soft and hard ticks. |
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Emphasis is laid on the genera morphology, species, mammalian hosts, and distribution and the diseases transmitted by the ticks species. |
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Various methods for controlling ticks and tick-borne diseases using chemicals are described. |
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A broad range of chemical acaricides used for the control of ticks on livestock are described. |
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Conventional methods and unconventional methods for applying acaricides to protect livestock against ticks are described. |
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Alternative methods for tick control are described. |
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Only the most important hard and soft ticks and associated diseases are discussed within the limits of this review. |
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Chapter 9 East Coast Fever: Theileria Parva Infection of Cattle |
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195 | (26) |
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East coast fever, a disease of cattle caused by the protozoan parasite Theileria parva and transmitted by the three-host tick Rhipicephalus appendiculatus (the brown ear tick), is a major constraint to cattle production in Eastern, Central, and Southern Africa. |
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In Kenya it is the most important tick-borne disease and a major constraint in cattle productivity. |
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This is due to the high morbidity and mortality it causes in susceptible herds, the cost of control of the vector ticks, and the cost of treatment of clinical cases. |
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Animals that recover from the disease also suffer from reduced productivity which can be long term. |
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The limited distribution of the tick and the disease to only East, Central and Southern Africa also means that the market for therapeutic drugs and acaricides is small. |
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Therefore, drug companies are not keen on funding research and development of new drug and acaricide molecules when resistance occurs. |
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Chapter 10 Bovine Anaplasmosis and Control |
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221 | (22) |
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Bovine anaplasmosis is one of the most important tick borne diseases of ruminants worldwide causing significant economic losses in the livestock industries due to the high morbidity and mortality in susceptible cattle herds. |
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Bovine anaplasmosis, caused by Anaplasma marginale, is an infectious but non-contagious disease. |
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The mode of transmission of bovine anaplasmosis includes mechanical (blood contaminated fomites (needles, ear tagging, dehorning and castration equipment), biological (tick bites) and transplacental (mother to fetus). |
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Bovine Anaplasmosis occurs in tropical and subtropical regions worldwide. |
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Cattle of all ages are susceptible to infection with A. marginale, but the severity of disease increases with age. |
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The common clinical sign of bovine anaplsmosis includes; fever, anorexia, rapid loss of body condition, severe decrease in milk production, pale and icteric mucous membranes, increased heart and respiratory rates, muscle weakness and depression. |
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Diagnosis of bovine anaplasmosis can be made by demonstration of A. marginale on stained blood smears from clinically infected animals during the acute phase of the disease, but it is not reliable for detecting infection in pre-symptomatic or carrier animals. |
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Instead, serological demonstration of antibodies and confirmation of antigen with molecular detection tools are used for diagnosis. |
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Anaplasmosis can be treated by administration of oxytetracyclines, however oxytetracyclines do not clear the parasite from carrier animals. |
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Control measures for bovine anaplasmosis vary with geographical location and include maintenance of Anaplasma free herds, vector control, administration of antibiotics and vaccination. |
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Intensive acaridae application to control ticks has a number of limitations, therefore, immunization together with strategic tick control is recommended for exotic and crossbred cattle. |
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Further studies on epidemiology of bovine anaplasmosis is needed. |
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Chapter 11 Heartwater and Control |
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243 | (20) |
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Leonard Muchenditsi Khaluhi |
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Heartwater (HW) is an acute, febrile, tick-borne disease of cattle, sheep, goats, and wild ruminants characterized by nervous signs and high mortality. |
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The disease is caused by a rickettsia agent, Erlichia ruminantium, formally classified as Cowdria ruminantium. |
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The disease is transmitted by several ixodid ticks of the genus Ambylomma. |
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Chemoprophylaxis has been used as a method to facilitate the movement of heartwater susceptible stock into heartwater endemic areas while allowing them to acquire immunity by limited tick exposure. |
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Chapter 12 Bovine Babesioses and Control |
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263 | (25) |
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Leonard Muchenditsi Khaluhi |
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Bovine babesiosis is considered one of the most economically important tick-borne diseases in tropical and subtropical areas. |
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Thus, it is important to understand the disease in terms causative agent, vectors, hosts, and distribution. |
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Babesia is the causative agent of the disease and has a life cycle both in the invertebrate and vertebrate hosts. |
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The major bovine species are B. bovis, B. bigemina, found in the tropics and sub tropics while B. divergens and B. major are found in the temperate regions. |
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Bovine babesiosis is transmitted by the one-host cattle ticks, formerly in the genus Boophilus and now Rhipicephalus. |
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In endemic areas are tick management, immunization, and anti-babesia drugs or by a combination. |
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Chemotherapy is important for controlling the disease either to treat field cases or to control artificially induced infections. |
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Conventional drugs for treating bovine babesiosis are Imidocarb dipropionate and Diminazene aceturate. |
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Ticks are controlled by application of acaricides, but tick resistance and environmental pollution are drawbacks. |
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Chapter 13 Canine Ehrlichiosis in Africa: Epidemiology, Diagnosis, and Control |
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288 | (23) |
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Canine ehrlichiosis is an infection of canids causing a clinical disease in domestic dogs and asymptomatic infections in wild canids. |
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Currently, the disease assumes a cosmopolitan distribution. |
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This chapter summarises published information on the disease from across Africa. |
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Some studies were able to demonstrate experimental infections in these canids. |
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Different diagnostic methods, cell culture, direct microscopy, serology, hematology, and molecular methods were employed in different studies for detection of ehrlichiosis. |
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Treatment of the disease mainly involved use of oxytetracycline, doxycycline, imidocarb disproportionate, and levamisole. |
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In severe cases, management has involved administration of supportive therapy such as blood transfusion. |
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Generally, though available, the information on different aspects of the disease in the Africa is scant and fragmented. |
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There is still a need to generate more information on the epidemiology, diagnosis, clinical aspects, and treatment of the disease. |
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Chapter 14 Tick Borne Viruses: Nairobi Sheep Disease/Ganjam Disease |
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311 | (18) |
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Michael Kiraithe Muthamia |
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Nairobi sheep disease virus (NSDV) is a one of the viruses transmitted by tick vectors and causes Nairobi sheep disease (NSD) - a disease of small ruminants. |
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The disease was first identified as a problem in sheep and goats in Kenya in 1910. |
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The virus belongs to the genus Nairovirus and family Bunyaviridae. |
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An equally pathogenic variant of NSDV is Ganjam virus, which is found in India and Sri Lanka. |
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Both viruses are closely related to the human pathogen Crimean-Congo haemorrhagic fever virus (CCHFV), a fever transmitted through infected tick bites or through contact with infected animal blood or tissues during and immediately after slaughter. |
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Other members of the genus include Dugbe virus, Hazara virus, and Kupe virus, isolated from cattle ticks in East Africa. |
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The virus is spread by hard (Ixodid) ticks and appears to be dependent on the tick vector for dissemination, with no direct transmission between animals. |
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The transmission of tick-borne viruses (TBV) occurs primarily during tick feeding and is a complex process, known to be promoted by tick saliva constituents. |
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Chapter 15 Control of African Swine Fever and Avian Spirochaetosis |
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329 | (25) |
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Ticks are distributed worldwide and have an enormous medical and veterinary importance owing to the direct damage they cause and indirectly as vectors of a large variety of human and animal pathogens. |
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The family Argasidae (soft ticks) comprises five genera and with about 193 species. |
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Among all the argasid ticks, only four Argas and two Ornithodoros species are competent to transmit diseases. |
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This chapter describes the various ticks of the argasidae family, diseases they transmit, and strategies for their control. |
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A description of the two important genera, Ornithodorus and Argas, that belong to the family argasidae are provided. |
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Emphasis is on the mammalian hosts affected, tick species involved, morphological features (with relevant pictorials), geographic distribution, life cycle, and economic importance. |
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A detailed description of the two most important diseases transmitted by argasidae ticks namely African swine fever (ASF) and avian spirochaetosis is given. |
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Emphasis is laid on the historical background, epidemiology, clinical signs, and strategies for their control. |
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| Compilation of References |
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354 | (76) |
| About the Contributors |
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430 | (7) |
| Index |
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437 | |
