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Fathi A, Nabavi R, Noaman V, Sarani A, Saadati D, Ben Said M, Ghafar A, Jabbar A, Sazmand A. Molecular identification, risk factor assessment, and phylogenetic analysis of tick-borne pathogens in symptomatic and asymptomatic cattle from South-Eastern Iran. EXPERIMENTAL & APPLIED ACAROLOGY 2024; 92:479-506. [PMID: 38457048 DOI: 10.1007/s10493-023-00886-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 12/29/2023] [Indexed: 03/09/2024]
Abstract
Tick-borne pathogens (TBPs) represent a substantial threat to cattle globally, exerting adverse impacts on production, health, and economic viability. This study delves into the prevalence and implications of TTBPs in cattle sourced from resource-limited smallholder livestock farms situated in southeastern Iran, proximate to Afghanistan and Pakistan. Blood and tick specimens were systematically collected from a cohort of 230 cattle, comprising 150 asymptomatic and 80 symptomatic individuals. Genomic DNA isolated from blood samples underwent rigorous examination for the presence of key TBPs, including Anaplasma marginale, A. phagocytophilum, A. bovis, A. centrale, Babesia bigemina, and Theileria annulata, utilizing multiple genetic markers. Nucleotide sequence analysis facilitated the reconstruction of phylogenetic relationships. The study also evaluated various potential risk factors, such as clinical status, gender, age, breed, tick infestation, and management practices, to elucidate their associations with TTBPs. Among the cattle cohort, a staggering 87.8% (202/230) tested positive for at least one pathogen. Prevalence statistics encompassed A. marginale (72.2%), T. annulata (68.3%), A. phagocytophilum/A. platys-like complex (66.1%), A. centrale (16.7%), B. bigemina (10.0%), and A. bovis (6.1%). Remarkably, mixed infections involving two, three, and four pathogens were detected in 23%, 52.1%, and 2.2% of animals, respectively. Notably, all asymptomatic cattle were positive for at least one TBP. Tick infestation was observed in 62.2% (143/230) of cattle, predominantly caused by Hyalomma anatolicum (82.5%), Rhipicephalus (Boophilus) annulatus (13.1%), and R. sanguineus sensu lato (4.4%). Risk factors linked to TBPs encompassed tick infestation, older age, and crossbred animals. Clinical presentations among symptomatic cattle encompassed fever, anemia, weight loss, anorexia, jaundice, and enlarged superficial lymph nodes. This study underscores the pivotal role of asymptomatic carriers in the propagation of TTBPs within endemic regions. Furthermore, it emphasizes the potential for the implementation of molecular diagnostics to unmask subclinical infections, thereby affording the opportunity for targeted interventions aimed at ameliorating the burden of TTBPs in resource-constrained smallholder dairy farms.
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Affiliation(s)
- Atefeh Fathi
- Department of Pathobiology, Faculty of Veterinary Medicine, University of Zabol, Zabol, Iran
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Reza Nabavi
- Department of Pathobiology, Faculty of Veterinary Medicine, Bu-Ali Sina University, Hamedan, 6517658978, Iran.
| | - Vahid Noaman
- Department of Parasitic Disease Research, Agricultural Research, Education and Extension Organization (AREEO), Razi Vaccine and Serum Research Institute, Karaj, Iran
| | - Ali Sarani
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Zabol, Bonjar Road, Zabol, 9861335856, Iran
| | - Dariush Saadati
- Department of Food Hygiene, Faculty of Veterinary Medicine, University of Zabol, Bonjar Road, Zabol, 9861335856, Iran
| | - Mourad Ben Said
- Department of Basic Sciences, Higher Institute of Biotechnology of Sidi Thabet, University of Manouba, 2010, Manouba, Tunisia
- Laboratory of Microbiology, National School of Veterinary Medicine of Sidi Thabet, University of Manouba, 2010, Manouba, Tunisia
| | - Abdul Ghafar
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Werribee, VIC, 3030, Australia
| | - Abdul Jabbar
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Werribee, VIC, 3030, Australia
| | - Alireza Sazmand
- Department of Pathobiology, Faculty of Veterinary Medicine, Bu-Ali Sina University, Hamedan, 6517658978, Iran
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Elati K, Tajeri S, Mugo RM, Obara I, Darghouth MA, Zweygarth E, Nijhof AM. In vitro infection of bovine erythrocytes with Theileria annulata merozoites as a key step in completing the T. annulata life cycle in vitro. Sci Rep 2024; 14:3647. [PMID: 38351295 PMCID: PMC10864261 DOI: 10.1038/s41598-024-54327-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 02/11/2024] [Indexed: 02/16/2024] Open
Abstract
Theileria annulata is a protozoan parasite with a complex life cycle involving a bovine host and a tick vector. It is transmitted by Hyalomma ticks and is the causative agent of tropical theileriosis, a debilitating and often fatal disease in southern Europe, northern Africa and large parts of Asia. Understanding the biology of different life cycle stages is critical for the control of tropical theileriosis and requires the use of experimental animals which poses an ethical concern. We present for the first time the in vitro infection of red blood cells (RBCs) with T. annulata differentiated schizonts. The Ankara cell line of T. annulata was cultured at 41 °C for nine days to induce merogony and subsequently incubated with purified RBCs for one to three days. Percentage of parasitized erythrocyte (PPE) over the short culture period was estimated by Giemsa staining (0.007-0.01%), Flow cytometry activated sorting (FACS) (0.02-1.1%) and observation of FACS sorted cells by confocal microscopy (0.05-0.4%). There was a significant difference in the PPE between FACS and the two other techniques (one-way ANOVA followed by Tukey test, P = 0.004) but no significant difference was observed between the confocal imaging and Giemsa staining methods (ANOVA one-way followed by Tukey test, P = 0.06). Importantly, all three complementary methods confirmed the invasion of RBCs by T. annulata merozoites in vitro. Although the experimental conditions will require further optimization to increase the PPE, the in vitro infection of RBCs by T. annulata merozoites is pivotal in paving the way for the eventual completion of the T. annulata life cycle in vitro when combined with artificial tick feeding.
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Affiliation(s)
- Khawla Elati
- Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-Von-Ostertag-Str. 7, 14163, Berlin, Germany.
- Veterinary Centre for Resistance Research, Freie Universität Berlin, Robert-Von-Ostertag-Str. 8, 14163, Berlin, Germany.
- Laboratoire de Parasitologie, École Nationale de Médecine Vétérinaire de Sidi Thabet, Institution de la Recherche et de l'Enseignement Supérieur Agricoles, Université de la Manouba, 2020, Sidi Thabet, Tunisia.
| | - Shahin Tajeri
- Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-Von-Ostertag-Str. 7, 14163, Berlin, Germany
- Veterinary Centre for Resistance Research, Freie Universität Berlin, Robert-Von-Ostertag-Str. 8, 14163, Berlin, Germany
| | - Robert M Mugo
- Institute of Immunology, Center for Infection Medicine, Freie Universtät Berlin, 14163, Berlin, Germany
| | - Isaiah Obara
- Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-Von-Ostertag-Str. 7, 14163, Berlin, Germany
- Veterinary Centre for Resistance Research, Freie Universität Berlin, Robert-Von-Ostertag-Str. 8, 14163, Berlin, Germany
| | - Mohamed Aziz Darghouth
- Laboratoire de Parasitologie, École Nationale de Médecine Vétérinaire de Sidi Thabet, Institution de la Recherche et de l'Enseignement Supérieur Agricoles, Université de la Manouba, 2020, Sidi Thabet, Tunisia
| | - Erich Zweygarth
- Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-Von-Ostertag-Str. 7, 14163, Berlin, Germany
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Ard Menzo Nijhof
- Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-Von-Ostertag-Str. 7, 14163, Berlin, Germany.
- Veterinary Centre for Resistance Research, Freie Universität Berlin, Robert-Von-Ostertag-Str. 8, 14163, Berlin, Germany.
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Ramzan MS, Suleman M, Rashid MI, Akbar H, Avais M. Comparative evaluation of cell-mediated immune response in calves immunized with live-attenuated and killed Theileria annulata vaccines. Parasitol Res 2023; 122:2135-2145. [PMID: 37466666 DOI: 10.1007/s00436-023-07912-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 06/20/2023] [Indexed: 07/20/2023]
Abstract
Tropical theileriosis is a tick-borne disease caused by the protozoan Theileria annulata and transmitted by numerous species of Ixodid ticks of the genus Hyalomma. The main clinical signs are fever, lymphadenopathy, and anemia responsible for heavy economic losses, including mortality, morbidity, vaccination failure, and treatment cost. Development of poor cell-mediated immunity (CMI) has been observed in the case of many bovine pathogens (bacteria, viruses, and parasites). Quantification of CMI is a prerequisite for evaluating vaccine efficacy against theileriosis caused by T. annulata. The current study evaluated the CMI in calves administered with two types of T. annulata vaccine (live attenuated and killed). We prepared a live attenuated T. annulata vaccine by attenuation in a rabbit model and also prepared killed vaccine from non-attenuated T. annulata. For the evaluation of immune response in experimental groups including control, 20 calves were divided into four different groups (A, B, C, and D). They were either inoculated subcutaneously with live rabbit-propagated-Theileria-infected RBCs (5 × 106) (group A) or with killed T. annulata vaccine (2 × 109 schizonts) with Freund's adjuvant (group B), along with an infected group (group C) and a healthy control group (group D). The protection of vaccinated calves was estimated with challenge infection. Our results showed that with a single shot of live-attenuated and killed vaccine with a booster dose elicited cell-mediated immune responses in immunized calves. We observed a significant elevation in CD4 + and CD8 + T cells in immunized calves. A significant difference in the CD8 + T cell response between the post-challenge stage of killed and live vaccine (p < 0.0001) was observed, whereas no other difference was found at both pre- and post-immunization stages. A similar finding was recorded for the CD4 + T cells at a post-challenge stage, where a significant difference was seen between killed and live vaccine (p < 0.0001). Another significant difference was observed between the CD8 + T cells and CD4 + T cells at the post-challenge stage in the live vaccine group, where there was a significantly higher induction of CD4 + T cell response (p < 0.0001).
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Affiliation(s)
- Muhammad Sajid Ramzan
- Department of Parasitology, University of Veterinary and Animal Sciences, Lahore, 54200, Pakistan
| | - Muhammad Suleman
- Institute of Microbiology, University of Veterinary and Animal Sciences, Lahore, 54000, Pakistan.
| | - Muhammad Imran Rashid
- Department of Parasitology, University of Veterinary and Animal Sciences, Lahore, 54200, Pakistan.
| | - Haroon Akbar
- Department of Parasitology, University of Veterinary and Animal Sciences, Lahore, 54200, Pakistan
| | - Muhammad Avais
- Department of Veterinary Medicine, Faculty of Veterinary Science, University of Veterinary and Animal Sciences, Lahore, 54000, Pakistan
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Hossain MJ, Raut S, Singh RP, Mishra P, Hossain MS, Dey AR, Kabir A, Anisuzzaman, Talukder MH, Shahiduzzaman M. Molecular detection of Babesia and Theileria from crossbred cattle in Sirajganj and Rangpur districts of Bangladesh. Vet Med Sci 2023; 9:899-906. [PMID: 36331989 PMCID: PMC10029904 DOI: 10.1002/vms3.989] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Babesia and Theileria are potential threats to the livestock industry, causing considerable economic losses. These tick-borne blood parasites are more prevalent in crossbred cattle than local cattle in Bangladesh. OBJECTIVES To confirm the species of Babesia and Theileria in crossbred cattle from the northern part of Bangladesh using conventional and molecular tools. METHODS A total of 385 crossbred cattle blood samples were subjected to DNA extraction and PCR. For molecular detection, B. bigemina rhoptry-associated protein 1a, B. bovis spherical body protein-4, and Theileria spp. 18S rRNA were used as the marker genes. RESULTS Using PCR, only 72 (18.7%) samples were found piroplasm positive, of which 12.2% Theileria, 4.7% Babesia, and 1.8% mixed infections. Both Babesia (7.3%), Theileria (7.7%) and mixed (2.8%) infections were detected in Sirajganj, and only Theileria (20.4%) was detected in Rangpur district. By PCR and nPCR we detected B. bigemina and T. annulata in Sirajganj district, and Theileria sp. in Rangpur district. The target gene sequences of isolated pathogens confirmed B. bigemina and T. annulata, and Theileria sp from these samples. Blood smears of all samples were also examined microscopically for Babesia and/or Theileria spp. and 14.3% of samples were found positive, of which 5.9% Babesia and 8.3% Theileria. Generally, the pathogens detected in Sirajgang and Rangpur were genetically related to South Asia, particularly South East Asian isolates. CONCLUSIONS These findings provide information for a better understanding of the epidemiology of Babesia and Theileria as well as to improve the approaches for diagnosis and control of tick-borne diseases in Bangladesh.
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Affiliation(s)
- Md Jakir Hossain
- Department of Parasitology, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Sanjana Raut
- Department of Parasitology, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Rahul Pratap Singh
- Department of Parasitology, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Pravin Mishra
- Department of Parasitology, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Md Shahadat Hossain
- Department of Parasitology, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Anita Rani Dey
- Department of Parasitology, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Ajran Kabir
- Department of Microbiology & Hygiene, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Anisuzzaman
- Department of Parasitology, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | | | - Md Shahiduzzaman
- Department of Parasitology, Bangladesh Agricultural University, Mymensingh, Bangladesh
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Comparative Degradome Analysis of the Bovine Piroplasmid Pathogens Babesia bovis and Theileria annulata. Pathogens 2023; 12:pathogens12020237. [PMID: 36839509 PMCID: PMC9965338 DOI: 10.3390/pathogens12020237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 01/30/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023] Open
Abstract
Babesia bovis and Theileria annulata are tick-borne hemoprotozoans that impact bovine health and are responsible for considerable fatalities in tropical and subtropical regions around the world. Both pathogens infect the same vertebrate host, are closely related, and contain similar-sized genomes; however, they differ in invertebrate host specificity, absence vs. presence of a schizont stage, erythrocyte invasion mechanism, and transovarial vs. transstadial transmission. Phylogenetic analysis and bidirectional best hit (BBH) identified a similar number of aspartic, metallo, and threonine proteinases and nonproteinase homologs. In contrast, a considerably increased number of S54 serine rhomboid proteinases and S9 nonproteinase homologs were identified in B. bovis, whereas C1A cysteine proteinases and A1 aspartic nonproteinase homologs were found to be expanded in T. annulata. Furthermore, a single proteinase of families S8 (subtilisin-like protein) and C12 (ubiquitin carboxyl-terminal hydrolase), as well as four nonproteinase homologs, one with dual domains M23-M23 and three with S9-S9, were exclusively present in B. bovis. Finally, a pronounced difference in species-specific ancillary domains was observed between both species. We hypothesize that the observed degradome differences represent functional correlates of the dissimilar life history features of B. bovis and T. annulata. The presented improved classification of piroplasmid proteinases will facilitate an informed choice for future in-depth functional studies.
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Valente D, Gomes J, Coelho AC, Carolino I. Genetic Resistance of Bovines to Theileriosis. Animals (Basel) 2022; 12:2903. [PMID: 36359026 PMCID: PMC9657666 DOI: 10.3390/ani12212903] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 10/15/2022] [Accepted: 10/20/2022] [Indexed: 04/07/2024] Open
Abstract
Diseases caused by ticks have a high impact on the health, welfare, and productivity of livestock species. They are also an important cause of economic losses in farms worldwide. An example of such diseases is theileriosis, which can be controlled by drugs or vaccines, although these are not fully efficient. Therefore, there is a need to develop alternative and more sustainable and efficient complementary strategies. These may involve the identification and selection of animals more resistant to the disease. Several previous studies have identified significant differences in resistance between different breeds, with resistant breeds typically identified as those native to the region where they are being studied, and susceptible as those from exotic breeds. These studies have indicated that resistance traits are intrinsically related to the modulation of the immune response to infection. This review aims to systematize the general knowledge about theileriosis, emphasize resistance to this disease as a sustainable control strategy, and identify which traits of resistance to the disease are already known in cattle.
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Affiliation(s)
- Diana Valente
- CIVG—Vasco da Gama Research Center, EUVG—Vasco da Gama University School, 3020-210 Coimbra, Portugal
- Escola de Ciências Agrárias e Veterinárias, Universidade de Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal
| | - Jacinto Gomes
- Escola Superior Agrária de Elvas, Instituto Politécnico de Portalegre, 7350-092 Elvas, Portugal
- CIISA—Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1300-477 Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Faculty of Veterinary Medicine, University of Lisbon, 1300-477 Lisbon, Portugal
| | - Ana Cláudia Coelho
- Escola de Ciências Agrárias e Veterinárias, Universidade de Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Faculty of Veterinary Medicine, University of Lisbon, 1300-477 Lisbon, Portugal
| | - Inês Carolino
- CIVG—Vasco da Gama Research Center, EUVG—Vasco da Gama University School, 3020-210 Coimbra, Portugal
- Polo de Inovação da Fonte Boa—Estação Zootécnica Nacional, Instituto Nacional de Investigação Agrária e Veterinária, 2005-424 Santarém, Portugal
- ISA—Instituto Superior de Agronomia, Universidade de Lisboa, 1349-017 Lisboa, Portugal
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Molecular detection and phylogenetic characterization of Theileria equi in horses (Equus caballus) from a peri-urban area of Argentina. Ticks Tick Borne Dis 2021; 12:101810. [PMID: 34416568 DOI: 10.1016/j.ttbdis.2021.101810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 07/16/2021] [Accepted: 07/26/2021] [Indexed: 11/21/2022]
Abstract
To investigate the presence of Theileria equi in an endemic area of equine piroplasmosis 42 horses (Equus caballus) from Corrientes City, Argentina were sampled. Eighty-one percent (34 blood samples) of the analyzed horses were tested positive to the presence of piroplasmid 18S rDNA. All these samples could be identified as T. equi by amplifying the specific EMA-1 (merozoite antigen 1) gene of this species. Phylogenetic analysis of an obtained 18S rDNA complete sequence from one strain resulted in the identification of this sample as T. equi sensu stricto (genotype A). This study presents the first molecular detection and characterization of T. equi by the complete 18S rDNA sequence in Argentina. Based on these results further studies should be carried out to investigate the distribution and heterogeneity of presented genotypes of T. equi in Argentina, which is essential for the diagnosis, prevention and treatment of equine piroplasmosis.
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Ceylan O, Xuan X, Sevinc F. Primary Tick-Borne Protozoan and Rickettsial Infections of Animals in Turkey. Pathogens 2021; 10:pathogens10020231. [PMID: 33669573 PMCID: PMC7923091 DOI: 10.3390/pathogens10020231] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/30/2021] [Accepted: 02/17/2021] [Indexed: 01/13/2023] Open
Abstract
Parasitic diseases caused by ticks constitute a barrier on global animal production, mainly in tropical and subtropical regions. As a country with a temperate and subtropical climate, Turkey has topography, climate, and pasture resources, and these resources are suitable for animal breeding and parasite–host–vector relationships throughout the country. This geography restricts the regulations on animal movements in the southeastern and eastern Anatolia because of the close contact with the neighboring states. The livestock resources in Turkey are regulated by strong foundations. Almost 30% of the agriculture-based gross domestic product is provided by the livestock industry. Parasitic diseases arising from ticks are endemic in Turkey, and they have a significant impact on the economy and animal health, particularly for ruminants. The main and economically-important tick-borne diseases (TBDs) suffered by animals include theileriosis, babesiosis, hepatozoonosis, and cytauxzoonosis caused by protozoa, and anaplasmosis and ehrlichiosis caused by rickettsiae. The most common hemoprotozoan and rickettsial agents are Anaplasma marginale, Anaplasma ovis, Anaplasma phagocytophilum, Anaplasma platys, Babesia bigemina, Babesia caballi, Babesia ovis, Cytauxzoon felis, Ehrlichia canis, Hepatozoon canis, Theileria annulata and Theileria equi. These diseases are basically controlled through treatment and measures for tick control. Vaccination can be performed for only tropical theileriosis caused in Turkey. We reviewed the studies published in domestic and international journals to gather epidemiological data regarding the major TBDs suffered by animals in Turkey.
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Affiliation(s)
- Onur Ceylan
- Department of Parasitology, Faculty of Veterinary Medicine, Selcuk University, 42250 Konya, Turkey;
| | - Xuenan Xuan
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan;
| | - Ferda Sevinc
- Department of Parasitology, Faculty of Veterinary Medicine, Selcuk University, 42250 Konya, Turkey;
- Correspondence: ; Tel.: +90-332-223-2687
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Bovine Babesiosis in Turkey: Impact, Current Gaps, and Opportunities for Intervention. Pathogens 2020; 9:pathogens9121041. [PMID: 33322637 PMCID: PMC7763958 DOI: 10.3390/pathogens9121041] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 12/11/2022] Open
Abstract
Bovine babesiosis is a global tick-borne disease that causes important cattle losses and has potential zoonotic implications. The impact of bovine babesiosis in Turkey remains poorly characterized, but several Babesia spp., including B. bovis, B. bigemina, and B. divergens, among others and competent tick vectors, except Rhipicephalus microplus, have been recently identified in the country. Bovine babesiosis has been reported in all provinces but is more prevalent in central and highly humid areas in low and medium altitude regions of the country housing approximately 70% of the cattle population. Current control measures include acaricides and babesicidal drugs, but not live vaccines. Despite the perceived relevant impact of bovine babesiosis in Turkey, basic research programs focused on developing in vitro cultures of parasites, point-of-care diagnostic methods, vaccine development, “omics” analysis, and gene manipulation techniques of local Babesia strains are scarce. Additionally, no effective and coordinated control efforts managed by a central animal health authority have been established to date. Development of state-of-the-art research programs in bovine babesiosis to address current gaps in knowledge and implementation of long-term plans to control the disease will surely result in important economic, nutritional, and public health benefits for the country and the region.
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Gharbi M, Darghouth MA, Elati K, Al-Hosary AAT, Ayadi O, Salih DA, El Hussein AM, Mhadhbi M, Khamassi Khbou M, Hassan SM, Obara I, Ahmed LS, Ahmed J. Current status of tropical theileriosis in Northern Africa: A review of recent epidemiological investigations and implications for control. Transbound Emerg Dis 2020; 67 Suppl 1:8-25. [PMID: 32174036 DOI: 10.1111/tbed.13312] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 07/18/2019] [Accepted: 07/22/2019] [Indexed: 11/29/2022]
Abstract
Tropical theileriosis caused by the apicomplexan hemoparasite Theileria annulata is a tick-borne disease that constraints livestock production in parts of Europe, Asia and Africa. Four Hyalomma tick species transmit T. annulata in at least eight Africa countries (Mauritania, Morocco, Algeria, Tunisia, Egypt, Sudan, South Sudan and Ethiopia). The two dominant T. annulata vector ticks present in Africa, H. scupense and H. anatolicum, underlie two different patterns of transmission, which in turn greatly influence the epidemiology of tropical theileriosis. H. dromedarii and H. lusitanicum are also capable of transmitting T. annulata in North Africa, but their roles are associated with specific production systems and agro-ecological contexts. The emergence of resistance to the most widely used theilericidal compound, buparvaquone, continues to limit the effectiveness of chemotherapy. In addition, acaricide use is increasingly becoming unsustainable. Deployable T. annulata attenuated live vaccines established from local strains in Tunisia, Sudan and Egypt are available, and recent work has indicated that these vaccines can be protective under conditions of natural transmission. However, vaccination programmes may vary over space and time due to differences in the prevalence of disease amongst cattle populations, as well seasonal variation in vector activity. We review recent descriptive and analytical surveys on the epidemiology of T. annulata infection with reference to (a) demographic aspects such as breeds and ages of cattle herds previously exposed to distinct T. annulata infection pressures and (b) seasonal dynamics of tick activity and disease transmission. We then discuss how the wider endemic patterns that we delineate can underpin the development and execution of future vaccination programmes. We also outline options for integrated control measures targeting tick vectors and husbandry practices.
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Affiliation(s)
- Mohamed Gharbi
- Laboratoire de Parasitologie, Institution de la Recherche et de l'Enseignement Supérieur Agricoles and Univ. Manouba, École Nationale de Médecine Vétérinaire de Sidi Thabet, Sidi Thabet, Tunisia
| | - Mohamed Aziz Darghouth
- Laboratoire de Parasitologie, Institution de la Recherche et de l'Enseignement Supérieur Agricoles and Univ. Manouba, École Nationale de Médecine Vétérinaire de Sidi Thabet, Sidi Thabet, Tunisia
| | - Khawla Elati
- Laboratoire de Parasitologie, Institution de la Recherche et de l'Enseignement Supérieur Agricoles and Univ. Manouba, École Nationale de Médecine Vétérinaire de Sidi Thabet, Sidi Thabet, Tunisia
| | - Amira A T Al-Hosary
- Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt
| | - Ouarda Ayadi
- Laboratoire de Parasitologie, Institut des Sciences Vétérinaire El Khroub, Université Frères Mentouri, Constantine I, Algeria
| | | | | | - Moez Mhadhbi
- Laboratoire de Parasitologie, Institution de la Recherche et de l'Enseignement Supérieur Agricoles and Univ. Manouba, École Nationale de Médecine Vétérinaire de Sidi Thabet, Sidi Thabet, Tunisia
| | - Médiha Khamassi Khbou
- Laboratoire de Maladies Contagieuses, Zoonoses et Législation Sanitaire, Institution de la Recherche et de l'Enseignement Supérieur Agricoles and Univ Manouba, École Nationale de Médecine Vétérinaire de Sidi Thabet, Sidi Thabet, Tunisia
| | | | - Isaiah Obara
- Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Laila S Ahmed
- Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt
| | - Jabbar Ahmed
- Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
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Discovery of a new Theileria sp. closely related to Theileria annulata in cattle from Sri Lanka. Sci Rep 2019; 9:16132. [PMID: 31695080 PMCID: PMC6834563 DOI: 10.1038/s41598-019-52512-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 10/18/2019] [Indexed: 01/23/2023] Open
Abstract
Theileria annulata is a haemoprotozoan parasite that causes a cancer-like illness known as tropical theileriosis in cattle. In the course of analyzing the genetic diversity of T. annulata in Sri Lanka, we observed that merozoite-piroplasm surface antigen (tams1) and surface protein (tasp)-like gene sequences obtained from bovine blood DNA samples, which were PCR-positive for T. annulata, were conserved but shared low identity with T. annulata GenBank sequences. Moreover, the 18S rRNA sequences from the Sri Lankan samples contained ten unique single-nucleotide polymorphisms compared with all known T. annulata sequences. The cytochrome b (cob) gene sequences isolated from the Sri Lankan samples were highly conserved and shared low identity scores with similarly conserved T. annulata sequences from GenBank. Phylogenetic analysis showed that the Sri Lankan tams1-like, tasp-like, 18S rRNA, and cob sequences clustered together and formed sister clades to the common ancestors of all known T. annulata and Theileria lestoquardi sequences. These findings demonstrated that the Sri Lankan cattle were not infected with T. annulata but with a new Theileria sp. (designated as Theileria sp. Yokoyama) closely related to T. annulata.
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A systematic review on modelling approaches for economic losses studies caused by parasites and their associated diseases in cattle. Parasitology 2018; 146:129-141. [PMID: 30068403 DOI: 10.1017/s0031182018001282] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Parasites reside inside or outside their hosts and get host nutrition and blood. Here, we have emphasized economic losses in cattle caused by parasitic diseases due to ecto- and endo- parasites (flies, ticks, mites and helminths). We have outlined different methods/models including economic evaluation techniques and dynamic analysis as a major class, used for the calculation of economic losses caused by parasites in cattle. According to already conducted studies, a decrease in production is mentioned in quantity and percentage while financial losses are expressed in the form of account with respect to per head, herd or for the specific study area. The parasites cause the reduced production and financial losses due to control, treatment and mortality costs. We calculated the average decrease in milk production and organ condemnation as 1.16 L animal-1 day-1 and 12.95%, respectively, from overall cattle parasitic infections. Moreover, the average calculated financial and percentage losses were US$ 50.67 animal-1 year-1 and 17.94%, respectively. Economically important parasitic diseases mentioned here are caused by specific spp. of protozoans and helminths according to data collected from the literature. Protozoan diseases include tick-borne diseases, coccidiosis, neosporosis, trypanosomiasis and cryptosporidiosis. Losses due to tick-borne infections were encountered for decreased milk production, mortality, treatment and control. Losses from coccidiosis were due to decreased weight gain, treatment costs and mortality. While abortion losses were encountered in neosporosis. Trypanosomiasis caused losses due to a decrease in milk yield. Moreover, only diagnostic (conventional or molecular techniques) cost was taken into account for cryptosporidiosis. Economically important nematode parasites are Oesophagostomum spp., Cooperia spp., Trichostrongylus spp., Strongyloides spp., Ostertagia spp. and Haemonchus placei. Due to the zoonotic importance of echinococcosis, Echinococcus granulosus is the most economically important cestode parasite. Losses caused by echinococcosis were due to organ condemnation, carcass weight loss and decreases hide value, milk production and fecundity. While, fascioliasis is one of the most economically important trematodal disease, which causes cirrhosis of the liver due to parasite migration, and thus, the organ becomes inedible. So, it would be helpful for farmers and researchers to approach these methods/models for calculation of parasitic losses and should adopt suitable measures to avoid long-term economic losses.
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Rashid M, Akbar H, Rashid I, Saeed K, Ahmad L, Ahmad AS, Shehzad W, Islam S, Farooqi S. Economic Significance of Tropical Theileriosis on a Holstein Friesian Dairy Farm in Pakistan. J Parasitol 2018; 104:310-312. [PMID: 29485311 DOI: 10.1645/16-179] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The dairy industry in Pakistan is booming, and investors are anxious to fund dairy farms that are using high-milk-producing (exotic) cattle breeds such as Holstein Friesians that are not native to the country. Unfortunately, the benefits of increased milk production do not provide resistance to pathogens present in regions where the exotic breeds are introduced. Therefore, the current study was conducted to evaluate the economic impact of Theileria annulata on a commercial Holstein Friesian dairy farm in the District of Ranjanpur, in the Province of Punjab, Pakistan. The economic impact of T. annulata infection was calculated for cattle with subclinical and clinical theileriosis. Losses were estimated based on milk production, morbidity, mortality, and tick control costs (organophosphate sprays). Animals were classified into groups after screening for mastitis, teat abnormality, abnormal parturition, intestinal parasites, and hemoparasites ( T. annulata, Babesia spp., and Anaplasma spp.). Microscopy was done for hemoparasites and intestinal parasites. PCR was used to confirm microscopic identification of T. annulata. Animals were classified into 3 groups: group A (normal), group B (subclinical theileriosis), and group C (acute theileriosis). Hemoparasites were observed microscopically in 28.7% of cows. Theileria annulata was found in 8%, and the herd incidence (new cases) of T. annulata was 2.8%. Milk production, animal rectal temperature, and body condition scores between group A and groups B and C were significantly different ( P < 0.05). But the enlargement of sub-scapular lymph node and interval of body condition score of the 3 groups were not significant ( P > 0.05). The total expenditure incurred due to theileriosis was US $74.98 per animal and 13.83% of total farm costs. Hence theileriosis caused significant economic loss of US $18,743.76 (0.02 million) on this Holstein Friesian dairy.
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Affiliation(s)
- Muhammad Rashid
- 1 Department of Parasitology, University of Veterinary and Animal Sciences, Lahore 54200, Pakistan
| | - Haroon Akbar
- 1 Department of Parasitology, University of Veterinary and Animal Sciences, Lahore 54200, Pakistan
| | - Imran Rashid
- 1 Department of Parasitology, University of Veterinary and Animal Sciences, Lahore 54200, Pakistan
| | - Khalid Saeed
- 1 Department of Parasitology, University of Veterinary and Animal Sciences, Lahore 54200, Pakistan
| | - Liaquat Ahmad
- 2 Department of Statistics, University of Veterinary and Animal Sciences, Lahore 54200, Pakistan
| | - Abdullah Saghir Ahmad
- 1 Department of Parasitology, University of Veterinary and Animal Sciences, Lahore 54200, Pakistan
| | - Wasim Shehzad
- 3 Institute of Biotechnology and Biochemistry, University of Veterinary and Animal Sciences, Lahore 54200, Pakistan
| | - Saher Islam
- 3 Institute of Biotechnology and Biochemistry, University of Veterinary and Animal Sciences, Lahore 54200, Pakistan
| | - Shahid Farooqi
- 4 Department of Clinical Medicine and Surgery, University of Veterinary and Animal Sciences, Lahore 54200, Pakistan
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14
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Inci A, Yildirim A, Duzlu O, Doganay M, Aksoy S. Tick-Borne Diseases in Turkey: A Review Based on One Health Perspective. PLoS Negl Trop Dis 2016; 10:e0005021. [PMID: 27977689 PMCID: PMC5158090 DOI: 10.1371/journal.pntd.0005021] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The importance of tick-borne diseases is increasing all over the world, including Turkey. Global warming, environmental and ecological changes and the existence of suitable habitats increase the impact of ticks and result in frequent emergence or re-emergence of tick-borne diseases (TBDs) with zoonotic characteristics. In Turkey, almost 19 TBDs have been reported in animals and men, involving four protozoa (babesiosis, theileriosis, cytauxzoonosis, hepatozoonosis), one filarial nematode (acanthocheilonemasis), ten bacterial agents (anaplasmosis, ehrlichiosis, aegyptianellosis, tick-borne typhus, Candidatus Rickettsia vini, Lyme borreliosis, tick-borne relapsing fever [TBRF], tularaemia, bartonellosis, and hemoplasmosis), and four viral infections (tick-borne encephalitis [TBE], Crimean-Congo Haemorrhagic Fever [CCHF], louping-ill [LI], and lumpy skin disease [LSD]). The growing number of TBD cases, in particular the fatal viral epidemics in humans, have led to increased public awareness and concern against TBDs in recent years. The World Health Organization (WHO) has developed a new political concept, called the "One Health" initiative, which is especially relevant for developing strategies against tick infestations and TBD control in humans and animals. It would be beneficial for Turkey to adopt this new strategy and establish specific research and control programs in coordination with international organizations like WHO, the World Organization for Animal Health (OIE), the Food and Agriculture Organization (FAO), the Centers for Disease Control and Prevention (CDC), and the European Center for Disease Prevention and Control (ECDC) to combat TBDs based on the "One Health Initiative" concept. In this article, we review the occurrence of primary TBDs in man and animals in Turkey in light of the "One Health" perspective.
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Affiliation(s)
- Abdullah Inci
- Department of Parasitology, Faculty of Veterinary Medicine, Erciyes University, Kayseri, Turkey
- Vectors and Vector-Borne Diseases Implementation and Research Centre, University of Erciyes, Kayseri, Turkey
| | - Alparslan Yildirim
- Department of Parasitology, Faculty of Veterinary Medicine, Erciyes University, Kayseri, Turkey
- Vectors and Vector-Borne Diseases Implementation and Research Centre, University of Erciyes, Kayseri, Turkey
| | - Onder Duzlu
- Department of Parasitology, Faculty of Veterinary Medicine, Erciyes University, Kayseri, Turkey
- Vectors and Vector-Borne Diseases Implementation and Research Centre, University of Erciyes, Kayseri, Turkey
| | - Mehmet Doganay
- Vectors and Vector-Borne Diseases Implementation and Research Centre, University of Erciyes, Kayseri, Turkey
- Department of Infection Diseases and Clinical Microbiology, Faculty of Medicine, Erciyes University, Kayseri, Turkey
| | - Serap Aksoy
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
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Al-Hamidhi S, H. Tageldin M, Weir W, Al-Fahdi A, Johnson EH, Bobade P, Alqamashoui B, Beja-Pereira A, Thompson J, Kinnaird J, Shiels B, Tait A, Babiker H. Genetic Diversity and Population Structure of Theileria annulata in Oman. PLoS One 2015; 10:e0139581. [PMID: 26469349 PMCID: PMC4607491 DOI: 10.1371/journal.pone.0139581] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/15/2015] [Indexed: 12/04/2022] Open
Abstract
Background Theileriosis, caused by a number of species within the genus Theileria, is a common disease of livestock in Oman. It is a major constraint to the development of the livestock industry due to a high rate of morbidity and mortality in both cattle and sheep. Since little is currently known about the genetic diversity of the parasites causing theileriosis in Oman, the present study was designed to address this issue with specific regard to T. annulata in cattle. Methods Blood samples were collected from cattle from four geographically distinct regions in Oman for genetic analysis of the Theileria annulata population. Ten genetic markers (micro- and mini-satellites) representing all four chromosomes of T. annulata were applied to these samples using a combination of PCR amplification and fragment analysis. The resultant genetic data was analysed to provide a first insight into the structure of the T. annulata population in Oman. Results We applied ten micro- and mini-satellite markers to a total of 310 samples obtained from different regions (174 [56%] from Dhofar, 68 [22%] from Dhira, 44 [14.5%] from Batinah and 24 [8%] from Sharqia). A high degree of allelic diversity was observed among the four parasite populations. Expected heterozygosity for each site ranged from 0.816 to 0.854. A high multiplicity of infection was observed in individual hosts, with an average of 3.3 to 3.4 alleles per locus, in samples derived from Batinah, Dhofar and Sharqia regions. In samples from Dhira region, an average of 2.9 alleles per locus was observed. Mild but statistically significant linkage disequilibrium between pairs of markers was observed in populations from three of the four regions. In contrast, when the analysis was performed at farm level, no significant linkage disequilibrium was observed. Finally, no significant genetic differentiation was seen between the four populations, with most pair-wise FST values being less than 0.03. Slightly higher FST values (GST’ = 0.075, θ = 0.07) were detected when the data for T. annulata parasites in Oman was compared with that previously generated for Turkey and Tunisia. Conclusion Genetic analyses of T. annulata samples representing four geographical regions in Oman revealed a high level of genetic diversity in the parasite population. There was little evidence of genetic differentiation between parasites from different regions, and a high level of genetic diversity was maintained within each sub-population. These findings are consistent with a high parasite transmission rate and frequent movement of animals between different regions in Oman.
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Affiliation(s)
- Salama Al-Hamidhi
- Department of Biochemistry, College of Medicine and Health Sciences, Sultan Qaboos University, P.O Box 35 Postal Code 123, Al-Khod, Sultanate of Oman
| | - Mohammed. H. Tageldin
- Department of Animal and Veterinary Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, P.O Box 34 Postal Code 123, Al-Khod, Sultanate of Oman
| | - William Weir
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Amira Al-Fahdi
- Department of Biochemistry, College of Medicine and Health Sciences, Sultan Qaboos University, P.O Box 35 Postal Code 123, Al-Khod, Sultanate of Oman
| | - Eugene H. Johnson
- Department of Animal and Veterinary Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, P.O Box 34 Postal Code 123, Al-Khod, Sultanate of Oman
| | - Patrick Bobade
- Department of Animal and Veterinary Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, P.O Box 34 Postal Code 123, Al-Khod, Sultanate of Oman
| | | | - Albano Beja-Pereira
- Research Centre in Biodiversity and Genetic Resources (CIBIO), University of Porto, Rua Padre Armando Quintas 7, Vairão, 4485–661, Portugal
| | - Joanne Thompson
- Centre for Immunity, Infection & Evolution. Institutes of Evolution, Immunology and Infection Research, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
| | - Jane Kinnaird
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Brian Shiels
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Andy Tait
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Hamza Babiker
- Department of Biochemistry, College of Medicine and Health Sciences, Sultan Qaboos University, P.O Box 35 Postal Code 123, Al-Khod, Sultanate of Oman
- Centre for Immunity, Infection & Evolution. Institutes of Evolution, Immunology and Infection Research, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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16
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Perera PK, Gasser RB, Firestone SM, Anderson GA, Malmo J, Davis G, Beggs DS, Jabbar A. Oriental theileriosis in dairy cows causes a significant milk production loss. Parasit Vectors 2014; 7:73. [PMID: 24552213 PMCID: PMC3937217 DOI: 10.1186/1756-3305-7-73] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Accepted: 02/10/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Oriental theileriosis is a tick-borne, protozoan disease of cattle caused by members of the Theileria orientalis-complex. Recent outbreaks of this disease in eastern Australia have caused major concerns to the dairy and beef farming communities, but there are no published studies of the economic impact of this disease. On a farm in Victoria, Australia, we assessed whether oriental theileriosis has an impact on milk production and reproductive performance in dairy cows. METHODS Blood samples collected from all 662 cows on the farm were tested using an established molecular test. For individual cows, milk production and reproductive performance data were collected. A clinical assessment of individual cows was performed. Based on clinical findings and molecular test results, the following groups of cows were classified: group 1, with cardinal clinical signs of oriental theileriosis and molecular test-positive for T. orientalis; group 2, with mild or suspected signs of theileriosis and test-positive; group 3, with no clinical signs and test-positive; and group 4, with no clinical signs and test-negative. Milk production and reproductive performance data for groups 1, 2 and 3 were each compared with those for group 4 using linear and logistic regression analyses, respectively. RESULTS At 100 days of lactation, group 1 cows produced significantly less milk (288 l; P = 0.001), milk fat (16.8 kg; P < 0.001) and milk protein (12.6 kg; P < 0.001) compared with group 4. At this lactation point, group 2 also produced significantly less milk fat (13.6 kg; P = 0.002) and milk protein (8.6 kg; P = 0.005) than group 4. At 305 days of lactation, group 1 cows produced significantly less milk (624 l; P = 0.004), milk fat (42.9 kg; P < 0.001) and milk protein (26.0 kg; P < 0.001) compared with group 4 cows. Group 2 cows also produced significantly less milk fat (21.2 kg; P = 0.033) at this lactation point. No statistically significant difference in reproductive performance was found upon pairwise comparisons of groups 1-3 with group 4 cows. CONCLUSIONS The present findings demonstrate that clinical oriental theileriosis can cause significant milk production losses in dairy cattle.
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Affiliation(s)
| | - Robin B Gasser
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia.
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Speybroeck N, Williams CJ, Lafia KB, Devleesschauwer B, Berkvens D. Estimating the prevalence of infections in vector populations using pools of samples. MEDICAL AND VETERINARY ENTOMOLOGY 2012; 26:361-371. [PMID: 22486773 DOI: 10.1111/j.1365-2915.2012.01015.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Several statistical methods have been proposed for estimating the infection prevalence based on pooled samples, but these methods generally presume the application of perfect diagnostic tests, which in practice do not exist. To optimize prevalence estimation based on pooled samples, currently available and new statistical models were described and compared. Three groups were tested: (a) Frequentist models, (b) Monte Carlo Markov-Chain (MCMC) Bayesian models, and (c) Exact Bayesian Computation (EBC) models. Simulated data allowed the comparison of the models, including testing the performance under complex situations such as imperfect tests with a sensitivity varying according to the pool weight. In addition, all models were applied to data derived from the literature, to demonstrate the influence of the model on real-prevalence estimates. All models were implemented in the freely available R and OpenBUGS software and are presented in Appendix S1. Bayesian models can flexibly take into account the imperfect sensitivity and specificity of the diagnostic test (as well as the influence of pool-related or external variables) and are therefore the method of choice for calculating population prevalence based on pooled samples. However, when using such complex models, very precise information on test characteristics is needed, which may in general not be available.
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Affiliation(s)
- N Speybroeck
- Institut de Recherche Santé et Société (IRSS), Université catholique de Louvain, Brussels, Belgium.
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