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Ticks and Tick-borne Diseases Sep 2021Herein we review the epidemiology of ticks and tick-borne diseases (TTBDs), their impact on livestock health and on the economy, control and associated challenges in... (Review)
Review
Herein we review the epidemiology of ticks and tick-borne diseases (TTBDs), their impact on livestock health and on the economy, control and associated challenges in Uganda. Ticks are leading vectors of economically important pathogens and are widespread in Uganda due to suitable climatic conditions. Besides the physical injury inflicted on the animal host, ticks transmit a number of pathogens that can cause morbidity and mortality of livestock if untreated, resulting in economic losses. Uganda suffers an aggregated annual loss (direct and indirect) of over USD 1.1 billion in the TTBDs complex. East Coast fever (ECF) caused by a protozoan haemoparasite, Theileria parva, is the most prevalent and economically important tick-borne disease (TBD) in Uganda and its vector, the brown ear tick (Rhipicephalus appendiculatus) widely distributed. Other prevalent TBDs in Uganda include anaplasmosis, babesiosis and heartwater. We highlight the role of agro-ecological zones (AEZs) and livestock management system in the distribution of TTBDs, citing warm and humid lowlands as being ideal habitats for ticks and endemic for TBDs. Control of TTBDs is a matter of great importance as far as animal health is concerned in Uganda. Indigenous cattle, which make up over 90% of the national herd are known to be more tolerant to TTBDs and most farms rely on endemic stability to TBDs for control. However, exotic cattle breeds are more capital intensive than indigenous breeds, but the increasing adoption of tick-susceptible exotic cattle breeds (especially dairy) in western and central Uganda demands intensive use of acaricides for tick control and prevention of TBDs. Such acaricide pressure has unfortunately led to selection of acaricide-resistant tick populations and the consequent acaricide resistance observed in the field. Vaccination against ECF, selective breeding for tick resistance and integrated tick control approaches that limit tick exposure, could be adopted to interrupt spread of acaricide resistance. We recommend increasing monitoring and surveillance for TTBDs and for emerging acaricide resistance, improved extension services and sensitization of farmers on tick control measures, appropriate acaricide use and the development and implementation of vaccines for the control of TTBDs as more sustainable and effective interventions. A tick control policy should be developed, taking into account variations of agro-ecological zones, farm circumstances and indigenous technical knowledge, and this should be incorporated into the overall animal health program.
Topics: Acaricides; Anaplasmosis; Animals; Antibodies, Protozoan; Babesiosis; Cattle; Cattle Diseases; Farmers; Protozoan Vaccines; Rhipicephalus; Seroepidemiologic Studies; Theileria parva; Theileriasis; Tick Control; Tick Infestations; Tick-Borne Diseases; Uganda
PubMed: 34134062
DOI: 10.1016/j.ttbdis.2021.101756 -
Revue Scientifique Et Technique... Aug 2015Summary The genus Anaplasmais one of four distinct genera in the family Anaplasmataceae, which are obligate intracellular pathogens vectored by ticks and found... (Review)
Review
Summary The genus Anaplasmais one of four distinct genera in the family Anaplasmataceae, which are obligate intracellular pathogens vectored by ticks and found exclusively within parasitophorous vacuoles in the host cell cytoplasm. The 2001 reclassification of the order Rickettsiales expanded the genus Anaplasma, which previously contained pathogens that were host specific for ruminants (A. marginale, A. centrale and A. bovis), by adding A. phagocytophilum, a unification of three organisms previously classified as Ehrlichia (E. equi, E. phagocytophila and the unnamed agent of human granulocytic ehrlichiosis). Also included in the genus Anaplasma were A. bovis (formerly E. bovis), A. platys (formerly E. platys) and Aegyptianella pullorum. Despite the genomic relatedness of the regrouped organisms, many aspects of their biology are diverse, including their host specificity, host cell preferences, major surface proteins (MSPs) and tick vectors. This review focuses on the two most important pathogens: A. marginale, which causes bovine anaplasmosis, and A. phagocytophilum, the aetiologic agent of tick-borne fever in sheep and human granulocytic anaplasmosis, an emerging tick-borne disease of humans. For both pathogens, strain diversity is much greater than previously recognised. While MSPs were found to be useful in phylogenetic studies and strain identification, highly conserved MSPs were found to affect the specificity of serologic tests. Comparison of these two important pathogens highlights the challenges and insight derived from reclassification and molecular analysis, both of which have implications for the development and evaluation of diagnosis and control strategies.
Topics: Anaplasma; Anaplasmosis; Animals; Antigens, Bacterial; Ehrlichiosis; Genetic Variation; Humans; Ticks
PubMed: 26601458
DOI: 10.20506/rst.34.2.2381 -
Veterinary Sciences Mar 2018Bovine anaplasmosis is endemic in South Africa and it has a negative economic impact on cattle farming. An improved understanding of and variety transmission,... (Review)
Review
Bovine anaplasmosis is endemic in South Africa and it has a negative economic impact on cattle farming. An improved understanding of and variety transmission, together with improved tools for pathogen detection and characterisation, are required to inform best management practices. Direct detection methods currently in use for and in South Africa are light microscopic examination of tissue and organ smears, conventional, nested, and quantitative real-time polymerase chain reaction (qPCR) assays, and a reverse line blot hybridisation assay. Of these, qPCR is the most sensitive for detection of and in South Africa. Serological assays also feature in routine diagnostics, but cross-reactions prevent accurate species identification. Recently, genetic characterisation has confirmed that and are separate species. Diversity studies targeting Msp1a repeats for and Msp1aS repeats for have revealed high genetic variation and point to correspondingly high levels of variation in outer membrane proteins (OMPs), which have been shown to be potential vaccine candidates in North American studies. Information on these OMPs is lacking for South African strains and should be considered in future recombinant vaccine development studies, ultimately informing the development of regional or global vaccines.
PubMed: 29510496
DOI: 10.3390/vetsci5010026 -
Parasite Epidemiology and Control Nov 2020species are tick-borne pathogens that are obligatory intracellular of ruminants and other mammalians. In this investigation, we systematically reviewed the distribution... (Review)
Review
species are tick-borne pathogens that are obligatory intracellular of ruminants and other mammalians. In this investigation, we systematically reviewed the distribution of anaplasmosis among domestic ruminants in Iran. Five and four English and Persian databases were studied, respectively, based on keywords and throughout 17 years (2001-2017). Thirty-eight articles were included in this systematic review and meta-analysis. Totally, 5093 cattle, 1958 sheep, and 1232 goats corresponding to prevalence of infection from different areas of Iran were examined. The total prevalence of infection was estimated to be 34% (95% CI 27%, 41%) in domestic ruminants. Based on our data, Khozestan (54%) and Khorasan Razavi (46%) provinces were the most prevalent areas in Iran and Kerman (3%) and Hamedan (1%) provinces are the lowest. The highest prevalence of spp. infection was belonged to (44%) and the lowest to (1%) with a significant difference among them ( < .001). In addition, the most common diagnostic tests were PCR (54%), microscopy (35%) and ELISA (7%) assays. The high prevalence of ovine and bovine anaplasmosis in Iran, confirms the stability situations of animal anaplasmosis in the studied regions particularly northeastern and southwestern parts of the country. Our data offer valuable and encouraging information as regards the current situation of anaplasmosis in domestic livestock in Iran, which might be useful for active and passive surveillance and preventing plans.
PubMed: 32875131
DOI: 10.1016/j.parepi.2020.e00173 -
Veterinary Sciences May 2022Ticks and tick-borne diseases such as babesiosis, anaplasmosis, ehrlichiosis, Lyme disease, Crimean Congo hemorrhagic fever, and Rocky Mountain spotted fever pose a... (Review)
Review
Ticks and tick-borne diseases such as babesiosis, anaplasmosis, ehrlichiosis, Lyme disease, Crimean Congo hemorrhagic fever, and Rocky Mountain spotted fever pose a significant threat to animal and human health. Tick-borne diseases cause billions of dollars of losses to livestock farmers annually. These losses are partially attributed to the lack of sensitive, robust, cost effective and efficient diagnostic approaches that could detect the infectious pathogen at the early stages of illness. The modern nucleic acid-based multiplex diagnostic approaches have been developed in human medicine but are still absent in veterinary medicine. These powerful assays can screen 384 patient samples at one time, simultaneously detect numerous infectious pathogens in each test sample and provide the diagnostic answer in a few hours. Development, commercialization, and wide use of such high throughput multiplex molecular assays in the cattle tick-borne disease surveillance will help in early detection and control of infectious pathogens in the animal reservoir before community spread and spillover to humans. Such approaches in veterinary medicine will save animal life, prevent billions of dollars of economic loss to cattle herders and reduce unwanted stress to both human and animal health care systems. This literature review provides recent updates on molecular diagnostics of tick-borne pathogens and discusses the importance of modern nucleic acid high throughput multiplex diagnostic approaches in the prevention of tick-borne infection to livestock.
PubMed: 35622769
DOI: 10.3390/vetsci9050241 -
Frontiers in Bioscience (Landmark... Mar 2018The cattle industry is one of the most important agroeconomic activities in Mexico. The national herd is estimated to include approximately 33.5. million head of cattle.... (Review)
Review
The cattle industry is one of the most important agroeconomic activities in Mexico. The national herd is estimated to include approximately 33.5. million head of cattle. Ticks and tick-borne diseases are principal factors with a negative impact on cattle health and production. The most economically important tick species parasitizing cattle in Mexico are , , and . Parasitism by ticks affects cattle health and production directly. Morbidity and mortality caused by tick-borne diseases augment the detrimental effect of tick infestation in cattle. Bovine babesiosis and anaplasmosis are the most important tick-borne diseases of cattle, which are caused by infectious agents transmitted by and . However, there are no prophylactic therapies to control bovine babesiosis and anaplasmosis. Chemical control is the most common way to treat animals against ticks, and the use of acaricides can also help manage tick-borne diseases. However, the evolution of resistance to acaricides among cattle tick populations renders chemical control ineffective; which represents a challenge for sustainable ticks and tick-borne diseases control. The only anti-tick vaccine commercially available globally is based on the recombinant antigen Bm86. Because of its mode of immunity against and , the Bm86-based vaccine also decreases the exposition of bovines to babesiosis and anaplasmosis. Research with Bm86-based vaccines documented high efficacy against , the efficacy levels against varies according to the geographic origin of tick populations, and there is not effect against other ticks species such as spp. The impact of ticks and tick-borne diseases, the problem of chemical control due to acaricide resistance, and progress with anti-tick vaccine research efforts in Mexico are reviewed herein.
Topics: Animals; Cattle; Cattle Diseases; Immunization; Membrane Glycoproteins; Recombinant Proteins; Rhipicephalus; Tick Control; Tick Infestations; Tick-Borne Diseases; Vaccines
PubMed: 29293449
DOI: 10.2741/4659 -
Interdisciplinary Perspectives on... 2018Bovine anaplasmosis is an infectious disease of cattle caused by the obligate intercellular bacterium, , and it primarily occurs in tropical and subtropical regions of...
Bovine anaplasmosis is an infectious disease of cattle caused by the obligate intercellular bacterium, , and it primarily occurs in tropical and subtropical regions of the world. In this study, an age-structured deterministic model for the transmission dynamics of bovine anaplasmosis was developed; the model incorporates symptomatic and asymptomatic cattle classes. Sensitivity analysis was carried out to determine the parameters with the highest impact on the reproduction number. The dominant parameters were the bovine natural and disease-induced death rates, disease progression rate in adult cattle, the mechanical devices transmission probability and contact rates, the pathogen contamination, and decay rates on the mechanical devices. The result of the sensitivity analysis suggests that control strategies to effectively prevent/control the spread of bovine anaplasmosis should focus on these parameters according to their positive or negative effect as seen from the sensitivity index. Following the results of the sensitivity analysis, three control strategies were investigated, namely, bovine-culling, safety-control, and universal. In addition to these strategies, three effectiveness levels (low, medium, and high) were considered for each control strategy using the cumulative number of newly infected cases in both juvenile and adult cattle as measure function. The universal strategy (comprising both cattle-culling and safety-control strategies) is only marginally better at reducing the number of infected cattle compare to the safety-control strategy. This result suggests that efforts should be aimed at improving and maintaining good hygiene practices; furthermore, the added benefit of culling infected cows is only minimal and not cost-efficient.
PubMed: 29853873
DOI: 10.1155/2018/4373981 -
Parasites & Vectors Feb 2022Ticks, which are ectoparasites of animals, may carry multiple pathogens. The cattle tick Rhipicephalus microplus is an important bovine parasite in China. However, the...
BACKGROUND
Ticks, which are ectoparasites of animals, may carry multiple pathogens. The cattle tick Rhipicephalus microplus is an important bovine parasite in China. However, the midgut microbiome of R. microplus from China has not been characterized via metagenomic methods.
METHODS
Rhipicephalus microplus were collected from cattle in the city of Changsha in Hunan province, China. The DNA of the midgut contents was extracted from fully engorged adult female R. microplus. A DNA library was constructed and sequenced using an Illumina HiSeq sequencing platform. SOAPdenovo software was used to assemble and analyze the clean data. The latent class analysis algorithm applied to system classification by MEGAN software was used to annotate the information on the species' sequences. DIAMOND software was used to compare unigenes with the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, and functional annotation was carried out based on the results of the comparison.
RESULTS
The dominant phyla in the five samples were Firmicutes, Proteobacteria, and Actinobacteria. Streptococcus, Mycobacterium, Anaplasma, Enterococcus, Shigella, Lactobacillus, Brachyspira, Pseudomonas, Enterobacter, Bacillus, and Lactococcus were the dominant genera in the five samples. The endosymbiotic bacterium Wolbachia was also detected in all of the samples. Mycobacterium malmesburyense, Streptococcus pneumoniae, Anaplasma phagocytophilum, Enterococcus faecium, Shigella sonnei, Enterococcus faecalis, Lactobacillus casei, Brachyspira hampsonii, Pseudomonas syringae, Enterobacter cloacae, and Lactococcus garvieae were the dominant species in the five samples. In addition to these bacterial species, we also detected some eukaryotes, such as Rhizophagus irregularis, Enterospora canceri, Smittium culicis, Zancudomyces culisetae, Trachipleistophora hominis, and viruses such as orf virus, human endogenous retrovirus type W, enzootic nasal tumor virus of goats, bovine retrovirus CH15, and galidia endogenous retrovirus in all of the samples at the species level. The results of the annotated KEGG pathway predictions for the gene functions of the midgut microflora of R. microplus indicated genes involved in lipid and amino acid metabolism, infectious diseases (e.g., Streptococcus pneumonia infection, human granulocytic anaplasmosis, Shigella sonnei infection, Salmonella enterica infection, and pathogenic Escherichia coli infection), and cancer.
CONCLUSIONS
Our study revealed that the midgut microbiome of R. microplus is not only composed of a large number of bacteria, but that a portion also comprises eukaryotes and viruses. The data presented here enhance our understanding of this tick's midgut microbiome and provide fundamental information for the control of ticks and tick-borne diseases.
Topics: Anaplasmosis; Animals; Cattle; Cattle Diseases; Female; Metagenomics; Microbiota; Rhipicephalus; Tick Infestations; Tick-Borne Diseases
PubMed: 35135613
DOI: 10.1186/s13071-022-05161-6 -
Journal of Dairy Science May 2022Bovine anaplasmosis causes considerable economic losses in dairy cattle production systems worldwide, ranging from $300 million to $900 million annually. It is commonly...
Bovine anaplasmosis causes considerable economic losses in dairy cattle production systems worldwide, ranging from $300 million to $900 million annually. It is commonly detected through rectal temperature, blood smear microscopy, and packed cell volume (PCV). Such methodologies are laborious, costly, and difficult to systematically implement in large-scale operations. The objectives of this study were to evaluate (1) rumination and activity data collected by Hr-Tag sensors (SCR Engineers Ltd.) in heifer calves exposed to anaplasmosis; and (2) the predictive ability of recurrent neural networks in early identification of anaplasmosis. Additionally, we aimed to investigate the effect of time series length before disease diagnosis (5, 7, 10, or 12 consecutive days) on the predictive performance of recurrent neural networks, and how early anaplasmosis disease can be detected in dairy calves (5, 3, and 1 d in advance). Twenty-three heifer calves aged 119 ± 15 (mean ± SD) d and weighing 148 ± 20 kg of body weight were challenged with 2 × 10 erythrocytes infected with UFMG1 strain (GenBank no. EU676176) isolated from Anaplasma marginale. After inoculation, animals were monitored daily by assessing PCV. The lowest PCV value (14 ± 1.8%) and the finding of rickettsia on blood smears were used as a criterion to classify an animal as sick (d 0). Rumination and activity data were collected continuously and automatically at 2-h intervals, using SCR Heatime Hr-Tag collars. Two time series were built including last sequence of -5, -7, -10, or -12 d preceding d 0 or a sequence of 5, 7, 10, or 12 d randomly selected in a window from -50 to -15 d before d 0 to ensure a sequence of days in which PCV was considered normal (32 ± 2.4%). Long short-term memory was used as a predictive approach, and a leave-one-animal-out cross-validation (LOAOCV) was used to assess prediction quality. Anaplasmosis disease reduced 34 and 11% of rumination and activity, respectively. The accuracy, sensitivity, and specificity of long short-term memory in detecting anaplasmosis ranged from 87 to 98%, 83 to 100%, and 83 to 100%, respectively, using rumination data. For activity data, the accuracy, sensitivity, and specificity varied from 70 to 98%, 61 to 100%, and 74 to 100%, respectively. Predictive performance did not improve when combining rumination and activity. The use of longer time-series did not improve the performance of models to predict anaplasmosis. The accuracy and sensitivity in predicting anaplasmosis up to 3 d before clinical diagnosis (d 0) were greater than 80%, confirming the possibility for early identification of anaplasmosis disease. These findings indicate the great potential of wearable sensors in early identification of anaplasmosis diseases. This could positively affect the profitability of dairy farmers and animal welfare.
Topics: Anaplasma marginale; Anaplasmosis; Animals; Cattle; Cattle Diseases; Erythrocytes; Female; Vaccination
PubMed: 35282915
DOI: 10.3168/jds.2021-20952 -
Seminars in Immunopathology May 2015Arthropod-borne obligately intracellular bacteria pose a difficult challenge to the immune system. The genera Rickettsia, Orientia, Ehrlichia, and Anaplasma evolved... (Review)
Review
Arthropod-borne obligately intracellular bacteria pose a difficult challenge to the immune system. The genera Rickettsia, Orientia, Ehrlichia, and Anaplasma evolved mechanisms of immune evasion, and each interacts differently with the immune system. The roles of CD8 T cells include protective immunity and immunopathology. In Rickettsia infections, CD8 T cells are protective mediated in part by cytotoxicity toward infected cells. In contrast, TNF-α overproduction by CD8 T cells is pathogenic in lethal ehrlichiosis by induction of apoptosis/necrosis in hepatocytes. Yet, CD8 T cells, along with CD4 T cells and antibodies, also contribute to protective immunity in ehrlichial infections. In granulocytic anaplasmosis, CD8 T cells impact pathogen control modestly but could contribute to immunopathology by virtue of their dysfunction. While preliminary evidence indicates that CD8 T cells are important in protection against Orientia tsutsugamushi, mechanistic studies have been neglected. Valid animal models will enable experiments to elucidate protective and pathologic immune mechanisms. The public health need for vaccines against these agents of human disease, most clearly O. tsutsugamushi, and the veterinary diseases, canine monocytotropic ehrlichiosis (Ehrlichia canis), heartwater (Ehrlichia ruminantium), and bovine anaplasmosis (A. marginale), requires detailed immunity and immunopathology investigations, including the roles of CD8 T lymphocytes.
Topics: Animals; CD8-Positive T-Lymphocytes; Host-Pathogen Interactions; Humans; Rickettsiaceae; Rickettsiaceae Infections; T-Lymphocyte Subsets
PubMed: 25823954
DOI: 10.1007/s00281-015-0480-x