The efficacy of T1 strain broth vaccine against contagious bovine pleuropneumonia: in-contact trials carried out six and twelve months after primary vaccination

Gilbert, F. R.; Davies, Gareth; Read, W. C. S.; Turner, G. R. J.

doi:10.1136/vr.86.2.29

Cited by 20 publications

(13 citation statements)

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“…As controls exhibit more severe signs of infection, the percent protection calculated by these methods is usually greater than the percent of vaccinates that actually remain free of disease. For example, in the 6 month post-vaccination experiment reported by Gilbert et al (1970) 3 of 16 vaccinates (18.8%) exhibited lesions and 2 of 16 (12.5%) had CFT titres yet the E p score was 94.5%. In the case of a 2-year post-vaccination experiment 5 of 16 vaccinates (31.3%) possessed infected sequestra but the E p score was 80.0%.…”

Section: Discussionmentioning

confidence: 97%

“…Naturally immune animals could lose their immunity at the rate v n and return to the susceptible state. Wesonga and Thiaucourt, 2000;Gilbert et al, 1970;Windsor et al, 1972 c Rate of sequestrum resolution 0.0068 0.0075 0.0079 Bygrave et al, 1968 The model utilized an open population design where animals are born into the susceptible (S) state at each time step at rate b. Non-specific mortality occurred at the rate m and resulted in losses from all six states. The non-specific mortality rate and the estimated birth rate were set equal.…”

Section: Stochastic Model Structurementioning

confidence: 99%

“…The observations of Turner and Etheridge (1963) and Bygrave et al (1968) indicated that the majority of survivors develop sequestra. With the exception of one study that found only 1 of 80 survivors developed a sequestra (Parker, 1960), other studies reported between 56.6 and 76.1% of survivor developed sequestra (Gourlay, 1965;Davies et al, 1968;Stone and Bygrave, 1969;Gilbert et al, 1970;Windsor et al, 1972). Bygrave et al (1968) published a very detailed analysis of the lesions encountered in a pastoral outbreak of CBPP in Northeastern Kenya.…”

Section: Duration Of Acute and Persistent Infectionsmentioning

confidence: 99%

“…A review of the T1/44 vaccine strain efficacy trials found seven papers that had evaluated the vaccine at 3-6 months post vaccination (Davies et al, 1968;Gilbert et al, 1970;Karst, 1971;Masiga and Read, 1972;Masiga et al, 1978;Wesonga and Thiaucourt, 2000;Thiaucourt et al, 2000). The reported efficacy scores for protection against macroscopic pathologic lesions (E p ) ranged between 33 and 95%.…”

Section: Vaccine Efficacy and Duration Of Immunitymentioning

confidence: 99%

“…The reported efficacy scores for protection against macroscopic pathologic lesions (E p ) ranged between 33 and 95%. Three articles reported E p values between 66 and 75% from challenge experiments conducted at 12-15 months post vaccination (Gilbert et al, 1970;Masiga et al, 1978;Wesonga and Thiaucourt, 2000). Finally, Windsor et al (1972) found an E p of 80% for the T1/44 strain in cattle challenged 2 years post vaccination, although 5 of 16 vaccinates (31.3%) developed infected sequestra as a result of in-contact challenge.…”

Section: Vaccine Efficacy and Duration Of Immunitymentioning

confidence: 99%

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A model of contagious bovine pleuropneumonia transmission dynamics in East Africa

Mariner¹,

McDermott

Heesterbeek

et al. 2006

Preventive Veterinary Medicine

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The dynamics of contagious bovine pleuropneumonia (CBPP) transmission vary widely between livestock production systems. This paper describes the development of a homogeneous, stochastic, compartmental model for CBPP transmission in pastoral herds of East Africa. The model was built using parameter estimates based on data published in the literature and on observations of livestock owners obtained through participatory research. The basic reproduction number for CBPP in southern Sudan was estimated to range from 3.2 to 4.6. The homogeneous model indicates that the critical community size for the persistence of CBPP falls within the typical herd sizes for pastoral communities in East Africa suggesting that individual isolated herds are capable of maintaining infection indefinitely. Vaccination alone with currently available vaccines was unlikely to eradicate the disease. # 2005 Published by Elsevier B.V.

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Section: Discussionmentioning

confidence: 97%

Section: Stochastic Model Structurementioning

confidence: 99%

Section: Duration Of Acute and Persistent Infectionsmentioning

confidence: 99%

Section: Vaccine Efficacy and Duration Of Immunitymentioning

confidence: 99%

Section: Vaccine Efficacy and Duration Of Immunitymentioning

confidence: 99%

See 3 more Smart Citations

A model of contagious bovine pleuropneumonia transmission dynamics in East Africa

Mariner¹,

McDermott

Heesterbeek

et al. 2006

Preventive Veterinary Medicine

View full text Add to dashboard Cite

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Contagious Bovine Pleuropneumonia

Thiaucourt¹,

Nwankpa²,

Amanfu³

2021

Veterinary Vaccines

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The protection rate of T1/44 and T1sr vaccines assessed in two independent vaccine trials varied between 33 and 67% (Thiaucourt et al., 2000). Animals were challenged against local pathogenic strains, 3 months after single vaccination. Further experiments demonstrated that T1/44 confers longer immunity than T1sr after a single dose, while a booster vaccination received 12 months after initial immunisation increased the efficacy of both vaccines (> 80%; Wesongaet al., 2000). In order to be effective vaccines must contain at least 10 7 CFU/dose of live Mmm (WOAH, 2021).Both vaccines confer low efficacy at primo-vaccination and short-term immunity, requiring re-vaccinations every 6 and 12 months respectively for T1sr and T1/44. T1/44 has residual virulence, which results in occasional cases of severe inflammation at the site of injection called Willems' reactions. These local reactions can evolve into systemic disease and may even result in death of the animals in the absence of antibiotic treatments, which can discourage vaccine acceptance by farmers . Willems' reactions are observed mainly upon first vaccination and with low occurrence after re-vaccination (Muuka et al., 2014). No side effects have been reported for T1sr.Both T1/44 and T1sr are currently produced as freeze-dried live vaccines with cold chain requirements until delivery. After reconstitution, delivery time is restricted to 30 min -2 hrs. In field conditions and with hot temperatures, viability rapidly drops below the minimum recommended titre affecting vaccine efficacy.The quality of CBPP vaccines is known to differ among producers / batches, which may result in variable vaccine efficacy. Due to the potential side effects and cold chain requirements, vaccine delivery should be restricted to fully trained veterinary personnel. GAPS :Vaccine safety: Side effects associated with the T1/44 strain are perceived as an important issue. For example, T1/44 is not accepted in some countries due to reported adverse reactions and T1sr is used instead, although the frequency of vaccination campaigns is normally once per year. Vaccine delivery can exacerbate side effects, since applying inappropriate administration routes (intradermal or intramuscular instead of subcutaneous) or using inappropriate needle gauge, etc. can result in increased adverse reactions and, thus, reduced acceptability by farmers.Vaccine efficacy: The true efficacy of T1 vaccines in the field is not well known. Control programs based on vaccination alone are not sufficient for CBPP eradication in the absence of additional countermeasures such as animal movement control. For ex.: Northern Namibia and Western Zambia, where CBPP mass vaccination campaigns are delivered annually, are still struggling to control the disease, with many outbreaks declared in 2021 and 2022.Vaccine delivery: Fully trained personnel is needed to manage vaccination, since administration problems such as use of wrong diluents and vial sizes, inappropriate number of doses per vial, etc. can result in reduced viability a...

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Serological response to T1 strainMycoplasma mycoides in calves born of previously vaccinated dams

Gilbert

Stone

1970

Trop Anim Health Prod

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The efficacy of T1 strain broth vaccine against contagious bovine pleuropneumonia: in-contact trials carried out six and twelve months after primary vaccination

Cited by 20 publications

References 0 publications

A model of contagious bovine pleuropneumonia transmission dynamics in East Africa

A model of contagious bovine pleuropneumonia transmission dynamics in East Africa

Contagious Bovine Pleuropneumonia

Serological response to T1 strainMycoplasma mycoides in calves born of previously vaccinated dams

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