The Tuberculin Test and Its Role in the Strategic Management And
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The Tuberculin Test and its Role in the Strategic Management and Eradication of Tuberculosis in Cattle Margaret Good Utrecht 2011 The Tuberculin Test and its Role in the Strategic Management and Eradication of Tuberculosis in Cattle Margaret Good ISBN : 978-90-393-5645-6 Printed by : Naas Printing Ltd., Naas, Co. Kildare, Ireland. Cover : Front: Photographs by P. Maher and M. Good Back: Arial map of Motobower, Gorey, Co. Wexford SICTT interpretation charts. The Tuberculin Test and its Role in the Strategic Management and Eradication of Tuberculosis in Cattle De tuberculinetest en zijn rol bij Strategisch Management en Uitroeiing van Tuberculose bij Runderen (met een samenvatting in het Nederlands) Proefschrift ter verkrijging van de graad van doctor aan de Universiteit Utrecht op gezag van de rector magnificus, prof.dr. G.J. van der Zwaan, ingevolge het besluit van het college voor promoties in het openbaar te verdedigen op vrijdag 28 oktober 2011 des middags te 2.30 uur door Margaret Good geboren op 25 oktober 1953 te Biggleswade, England Promotoren: Prof. dr. W. Gaastra Prof. dr. J.A. Wagenaar This thesis is published with the support of ERAD, The Eradication of Animal Diseases Division, Department of Agriculture, Fisheries and Food, Backweston, Young's Cross, Celbridge, Co. Kildare. Ireland. Chapters 2 to 8 inclusive have been reproduced with the permission of the original copyright holders. Contents Chapter 1 A perspective on the history of bovine TB and the role of 1 tuberculin in bovine TB eradication. Chapter 2 Bovine tuberculosis eradication in Ireland. 33 Chapter 3 The tuberculosis eradication programme in Ireland: A 51 review of scientific and policy advances since 1988. Chapter 4 The tuberculin test - A safe means to test a cattle 79 population for bovine tuberculosis. Chapter 5 The comparative performance of the single intradermal test 95 and the single intradermal comparative tuberculin test in Irish cattle, using tuberculin PPD combinations of differing potencies. Chapter 6 The comparative performance of the single intradermal 113 comparative tuberculin test in Irish cattle, using tuberculin PPD combinations from different manufacturers. Chapter 7 An evaluation of the Irish Single Reactor Breakdown 133 Protocol for 2005 to 2008 inclusive and its potential application as a monitor of tuberculin test performance. Chapter 8 The impact of the national full-herd depopulation policy 149 on the recurrence of bovine tuberculosis in Irish herds during 2003-2005. Chapter 9 General Discussion 169 Summary 183 Achoimre 191 Samenvatting 197 Acknowledgements 205 Curiculum vitae 207 List of publications 209 - Chapter 1- Perspectives on the History of Bovine TB and the Role of Tuberculin in Bovine TB Eradication. Margaret Good and Anthony Duignan Department of Agriculture, Fisheries and Food, Agriculture House, Kildare Street., Dublin 2. Ireland. Veterinary Medicine International, 2011. Volume 2011, Article ID 410470, 11 pages doi:10.4061/2011/410470 1 Chapter 1 – History. ________________________________________________________________ Tuberculosis remains a significant disease of animals and humans worldwide. Bovine tuberculosis is caused by Mycobacteria with an extremely wide host range and serious, although currently probably underdiagnosed, zoonotic potential. Where bovine tuberculosis controls are effective, human zoonotic TB, due to Mycobacterium bovis or M. caprae, is uncommon and clinical cases are infrequent in cattle. Therefore, the control and ultimate eradication of bovine tuberculosis is desirable. Tuberculin tests are the primary screening tool used in bovine eradication. The choice of tuberculin test is dependent on the environment in which it is to be used. Tuberculin potency is critical to test performance, and the accurate determination of potency is therefore particularly important. The design of a control or eradication programme should take into consideration the fundamental scientific knowledge, the epidemiological profile of disease, the experience of other eradication programmes, and the presence, in the same ecosystem, of maintenance hosts, in which infection is self-sustaining and which are capable of transmitting infection. A control or eradication programme will necessarily require modification as it progresses and must be under constant review to identify the optimal desirable goals, the efficacy of policy, and constraints to progress. 2 Chapter 1 – History. ________________________________________________________________ 1. Introduction All members of the closely related phylogenic grouping of Mycobacteria known collectively as the M. tuberculosis complex may cause tuberculosis in a range of species including man. Some members of this group are predominantly human (M. tuberculosis, M. africanum, M. canetti) or rodent pathogens (M. microti), whereas others have a wide host spectrum (M. bovis, M. caprae) (Brosch, et al., 2002; Prodinger, et al., 2005). Hewinson et al., (2006) recently expanded the ―phylogenetic analysis of strains of the M. tuberculosis complex to include single nucleotide mutations and deletions of spoligotype units‖ and concluded that ―this group of organisms might best be described as a series of host adapted ecotypes, each with a different host preference representing different niches‖. Originally M. caprae had been considered to be a subspecies of either M. tuberculosis or M. bovis; however, it is now apparent that phylogenetically it preceded M. bovis and it is only since the development of genotyping techniques allowing greater discrimination that its existence became apparent (Prodinger, et al., 2005). 2. Bovine Tuberculosis In cattle the most important causes of tuberculosis—bovine TB (bTB)—are M. bovis and M. caprae, both of which cause infectious disease that may result in significant productivity problems due to ill health (Prodinger, et al., 2005; Cvetnic et al., 2007; Javed et al., 2007; Duarte et al., 2008). M. bovis has one of the broadest host ranges of all known pathogens and has been diagnosed worldwide. O‘Reilly and Daborn (1995) citing various authors list the species in which the disease has been reported as domesticated and feral cattle, goat, pig, sheep, horse, cat, dog, fennec fox, deer, bison, buffalo, badger, possum, hare, ferret, wild and feral pig, antelope, Arabian Oryx, camel, llama, alpaca, man, humans, and nonhuman primates. M. bovis has also been detected in lion, hyena, kudu, baboon, leopard, cheetah, warthog and bushpig, elk, coyotes, meerkats, black rhinoceros, aoudad (Barbary sheep), and Lynx (Pérez et al., 2001; O'Brien et al., 2008; VerCauteren et al., 2008; Drewe et al., 2009; Espie et al., 2009; Michel, et al., 2009; Candela et al., 2009). Tuberculosis due to M. bovis or M. caprae is a zoonotic disease with a complex epidemiological 3 Chapter 1 – History. ________________________________________________________________ pattern which includes the transmission of infection within, and between, man, domestic animals, and wildlife. The occurrence of M. caprae has been reported in many European countries such as Austria, France, Germany, Hungary, Italy, Slovenia, and the Czech Republic but to date it has not been detected in Ireland (see Prodinger et al., 2005), Department of Agriculture, Fisheries and Food (DAFF) records unpublished). Disease caused by M. caprae is not considered to be substantially different from that caused by M. bovis and the same tests can be used for its diagnosis (World Organisation animal Health – OIE - 2009). 3. Zoonotic implications It is estimated that 1.5-2M people die each year from tuberculosis of the approximately 2 billion infected persons worldwide (Lo Bue et al., 2010). M. bovis infection currently accounts for only a small percentage of reported cases but it was a major public health problem in Europe and elsewhere, when this organism was transmitted to man in milk from infected cows, prior to the advent of pasteurization of milk and milk products (O‘Reilly and Daborn, 1995). Thoen et al. (2006) and de la Rua-Domenech (2006) provide several reasons why M. bovis in humans is underdiagnosed even in developed countries. The consumption of unpasteurised milk or milk products still remains a risk for infection in countries where bTB has not been eradicated where ethnic populations present significantly different epidemiological profile or where HIV is prevalent (Cosivie et al., 1998; Cicero et al., 2009; Doran et al., 2009; De Kantor et al., 2010). Zoonotic TB was originally considered primarily as a disease of children where the disease involved the cervical lymph nodes (scrofula), the intestinal tract, or the meninges. It is now increasingly being recognised that infection in childhood is the precursor of reactivated adult disease and that many infected children may remain asymptomatic, undiagnosed, and untreated (Amdekar, 2005; Evans et al., 2007). Thus zoonotic TB is of particular concern for developing countries, but where bTB controls are effective, human M. bovis or M. caprae isolates are uncommon and rare in countries where bTB has been eradicated (Davies, 1994; Cosivi et al., 1998; Prodinger, et al., 2005; De La Rua-Domenech, 2006; LoBue et al., 2010; Ingram, et al., 2010). M. bovis may affect humans of any age, and while the majority opinion is that human-to-human spread of M. bovis must be a very rare event, it does occur particularly amongst 4 Chapter 1 – History. ________________________________________________________________ immunocompromised individuals (Schönfeld, 1982; Evans et al., 2007; Bilal