A multispecies model for the transmission and control of mastitis in dairy cows

White, Lisa J.; Schukken, Y.H.; Lam, T.J.G.M.; Medley, Graham; Chappell, Michael J.

doi:10.1017/s0950268801006100

Cited by 22 publications

(17 citation statements)

References 20 publications

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“…Infection with major pathogens generally results in clinical illness or strong inflammatory responses and reduced milk yields, whereas minor pathogen infection is usually subclinical (White et al, 2001). Pathogens can also be categorized, depending on their aetiology, into environmental or contagious (Fox and Gay, 1993): i) Environmental bacteria (found in the soil, faeces and bedding), which enter the teat duct from these sources and include both Gram-positive and Gramnegative bacteria such as Streptococcus non-agalactiae and coliform organisms (Escherichia coli, Klebsiella sp., Aerobacter aerogenes, Enterobacter sp.…”

Section: Mastitis and Mastitis-causing Pathogensmentioning

confidence: 99%

Genetic selection for reduced somatic cell counts in sheep milk: A review

Riggio

Portolano

2015

Small Ruminant Research

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a b s t r a c tMastitis is an inflammation of the udder, mainly caused by bacteria, and leads to economic loss, due to discarded milk, reduced milk production, reduced milk quality and increased health costs in both dairy sheep and cattle. Selecting for increased genetic resistance to mastitis can be done directly or indirectly, with the indirect selection corresponding to a prediction of the bacteriological status of the udder based on traits related to the infection. The most frequently used indirect method is currently milk somatic cell count (SCC) or somatic cell score (SCS). This review reports the state of the art relating to the genetic basis of mastitis resistance in sheep and explores the opportunities to use SCC as selection criterion in a breeding programme to improve resistance to mastitis in sheep, discussing the actual situation and prospects for improvement. It has been stressed, in particular, that although it is unlikely that selection for mastitis resistance by the farmers on their own will be successful, there is good prospect for genetic improvement if reliable pedigree and performance recording is implemented across flocks, combined with breeding value estimation. To achieve this, a strong and well-structured organization to implement and support the programme is essential.

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Section: Mastitis and Mastitis-causing Pathogensmentioning

confidence: 99%

Genetic selection for reduced somatic cell counts in sheep milk: A review

Riggio

Portolano

2015

Small Ruminant Research

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“…Models have also been used to consider the interaction between multiple strains or species and its effect on the behaviour of the whole biological system [22,23]. We consider a model with seasonal forcing as implemented previously [21], but extended to include groups A and B and their influence on each other via re-infection and crossimmunity.…”

Section: Introductionmentioning

confidence: 99%

The transmission dynamics of groups A and B human respiratory syncytial virus (hRSV) in England & Wales and Finland: seasonality and cross-protection

et al. 2005

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SUMMARYHuman respiratory syncytial virus (hRSV) transmission dynamics are inherently cyclical, and the observed genetic diversity (between groups A and B) also appears to have a repeating pattern. A key unknown is the extent to which genetic variants interact immunologically, and thus impact on epidemiology. We developed a novel mathematical model for hRSV transmission including seasonal forcing of incidence and temporary intra-and inter-group partial immunity. Simultaneous model fits to data from two locations (England & Wales, UK, and Turku, Finland) successfully reproduced the contrasting infection dynamics and group A/B dominance patterns. Parameter estimates are consistent with direct estimates. Differences in the magnitude and seasonal variation in contact rate between the two populations alone could account for the variation in dynamics between these populations. The A/B group dominance patterns are explained by reductions in susceptibility to and infectiousness of secondary homologous and heterologous infections. The consequences of the observed dynamic complexity are discussed.

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“…In this section, the local stability of boundary equilibria and the region of existence of the endemic equilibrium of system (2.2) are discussed by introducing the invasion reproduction numbers for the multi-strain or multi-species models [19,18,22,34,35], which are to be investigated by being partitioned into two cases.…”

Section: The Stability Of Boundary Equilibria and The Existence Of Thmentioning

confidence: 99%

“…Two M. tuberculosis strains can coexist if the drug-sensitive strain can invade the population when the drug-resistant strain is present at its boundary equilibrium P r [22,35]. We now assume the tuberculosis disease exactly reaches the boundary equilibrium P r .…”

Section: The Case Where Q 1 = Q 2 = 1 Does Not Holdmentioning

confidence: 99%

Qualitative Study for a Multi-Drug Resistant Tb Model With Exogenous Reinfection and Relapse

Liu

Xin-chun

2012

Int. J. Biomath.

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One tuberculosis transmission model is formulated by incorporating exogenous reinfection, relapse, and two treatment stages of infectious TB cases. The global stability of the unique disease-free equilibrium is obtained by applying the comparison principle if the effective reproduction number for the full model is less than unity. The existence and stability of the boundary equilibria are given by introducing the invasion reproduction numbers. Furthermore, the existence and local stability of the endemic equilibrium are addressed under some conditions. Keywords: Exogenous reinfection; relapse; the effective reproduction number; the invasion reproduction number; center manifold theory; stability. 1250031-1 Int. J. Biomath. 2012.05. Downloaded from www.worldscientific.com by NANYANG TECHNOLOGICAL UNIVERSITY on 08/25/15. For personal use only. L. Liu & X. Gaoamong patients in the 2007 cohort, 87% were successfully treated, which is the first time the target of 85% has been exceeded at the global level [36]. But, almost 30,000 cases of multidrug-resistant TB (MDR-TB) were notified in 2008, which is equivalent to 11% of the total number of cases of MDR-TB estimated to exist among cases notified in 2008 [36], which is currently a main threat to tuberculosis control programs and community health [31].MDR-TB is thought to be a formidable challenge to global TB control in several settings, but until now, the global burden is largely unknown [38]. It was roughly estimated that the number of the MDR-TB cases in India, China and Russia accounted for more than 62% of the global MDR-TB burden [6,38]. It was reported in China that the prevalence of MDR-TB among TB patients with diagnosis ranged from 4.5% in Zhejiang Province to 10.8% in Henan Province [15]. The main cause of developing MDR-TB is thought of as due to the incomplete treatment of infectious TB cases by adopting the Directly Observed Treatment, Short-Course (DOTS) strategy recommended by WHO. Actually, the failure treatment of infectious TB cases maybe result in the emergence of drug-resistant strains in the body and the relapse of recovered individuals. Furthermore, drug-resistant strains can cause much higher mortality rates, treatment failure, and relapse, and treatment is more toxic, expensive, and lengthy [8,12,14].Active tuberculosis in TB patients with previous tuberculosis infection can be due to either the endogenous reactivation by the same strain or the exogenous reinfection by a new strain. The issue of the role of exogenous reinfection has been debated for decades [1,4,33]. It is commonly thought that incomplete treatment, either regimen or treatment duration, is the very important cause for relapse. However, a study in Shanghai, China, indicated that exogenous reinfection accounted for 61.5% of the recurrent TB cases, which also indicated that high levels of transmission of M. tuberculosis were an important cause of TB in Shanghai, China [24]. Furthermore, in a 2003 review [13], one study supported that the exogenous reinfection in HIV-infected patien...

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A multispecies model for the transmission and control of mastitis in dairy cows

Cited by 22 publications

References 20 publications

Genetic selection for reduced somatic cell counts in sheep milk: A review

Genetic selection for reduced somatic cell counts in sheep milk: A review

The transmission dynamics of groups A and B human respiratory syncytial virus (hRSV) in England & Wales and Finland: seasonality and cross-protection

Qualitative Study for a Multi-Drug Resistant Tb Model With Exogenous Reinfection and Relapse

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