Epidemiological analysis of an outbreak of foot-and-mouth disease (serotype SAT2) on a large dairy farm in Kenya using regular vaccination

Lyons, Nicholas A.; Stärk, K. D. C.; Maanen, C. van; Thomas, S; Chepkwony, Eunice C.; Sangula, Abraham; Dulu, Thomas D.; Fine, Paul E. M.

doi:10.1016/j.actatropica.2014.09.010

Cited by 28 publications

(34 citation statements)

References 41 publications

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“…No association was found between age and number of lactations with the presence of clinical signs, which is similar to results reported by Lyons et al. (). However, non‐pregnant animals were more likely to be clinically affected by FMDV despite being vaccinated.…”

Section: Discussionsupporting

confidence: 91%

Foot‐and‐mouth disease virus transmission dynamics and persistence in a herd of vaccinated dairy cattle in India

Hayer

VanderWaal

Ranjan

et al. 2017

Transbound Emerg Dis

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Foot-and-mouth disease (FMD) is an important transboundary disease with substantial economic impacts. Although between-herd transmission of the disease has been well studied, studies focusing on within-herd transmission using farm-level outbreak data are rare. The aim of this study was to estimate parameters associated with within-herd transmission, host physiological factors and FMD virus (FMDV) persistence using data collected from an outbreak that occurred at a large, organized dairy farm in India. Of 1,836 regularly vaccinated, adult dairy cattle, 222 had clinical signs of FMD over a 39-day period. Assuming homogenous mixing, a frequency-dependent compartmental model of disease transmission was built. The transmission coefficient and basic reproductive number were estimated to be between 16.2-18.4 and 67-88, respectively. Non-pregnant animals were more likely to manifest clinical signs of FMD as compared to pregnant cattle. Based on oropharyngeal fluid (probang) sampling and FMDV-specific RT-PCR, four of 36 longitudinally sampled animals (14%) were persistently infected carriers 10.5 months post-outbreak. There was no statistical difference between subclinical and clinically infected animals in the duration of the carrier state. However, prevalence of NSP-ELISA antibodies differed significantly between subclinical and clinically infected animals 12 months after the outbreak with 83% seroprevalence amongst clinically infected cattle compared to 69% of subclinical animals. This study further elucidates within-herd FMD transmission dynamics during the acute-phase and characterizes duration of FMDV persistence and seroprevalence of FMD under natural conditions in an endemic setting.

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Section: Discussionsupporting

confidence: 91%

Foot‐and‐mouth disease virus transmission dynamics and persistence in a herd of vaccinated dairy cattle in India

Hayer

VanderWaal

Ranjan

et al. 2017

Transbound Emerg Dis

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“…The animal level morbidity in the current study is higher than the 19.6% morbidity reported by Negussie et al () in Ethiopia. The 54.5% morbidity in the commercial dairy farms in the current study was lower than the 64.23% reported in central Ethiopia from commercial dairy farms ( (Beyi, ), 62% in a large dairy farm in Kenya (Lyons et al, ) and 100% overall morbidity in naive animals in Egypt (Abed El‐Rahman et al, ). This variation in morbidity may be due to the difference in breed of animals, strain of the virus circulating in these different outbreaks and also difference in background immunity due to previous outbreak or vaccination.…”

Section: Discussioncontrasting

confidence: 64%

“…There was no mortality in the commercial dairy farms in the current study, while a mortality of 4.01% was reported in central Ethiopia in commercial dairy farms (Beyi, ). In an outbreak of FMD in a large commercial dairy farm in Kenya, similarly, very low mortality rate of 0.4% was reported (Lyons et al, ). This wide difference in mortality could be due to differences in age composition of herds as the disease's mortality is known to be higher in young calves (OIE, ) and could also be due to factors mentioned above for morbidity differences.…”

Section: Discussionmentioning

confidence: 88%

Foot and mouth disease outbreak investigation and estimation of its economic impact in selected districts in northwest Ethiopia

Tadesse

Tesfahun

Molla

et al. 2019

Veterinary Medicine & Sci

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Foot and mouth disease (FMD), a highly contagious and economically important disease of cloven‐hoofed animals, is endemic in Ethiopia. Foot and mouth disease outbreak investigation and follow‐up studies were undertaken to identify the causative serotype, determine the morbidity and mortality, and estimate the economic impact of the outbreaks in selected districts of Northwest Ethiopia. The serotype of FMD virus involved in the outbreaks was identified by antigen detection ELISA from clinical samples. Morbidity, mortality and economic impact of the outbreaks were assessed based on data collected from 738 smallholder farmers in a mixed crop‐livestock (MCL) production system and from five dairy farms in the commercial dairy production system. The outbreaks were confirmed to be due to FMD virus serotype O. The animal level morbidity in clinically affected cattle herds was 68.1% for MCL production system and 54.5% for commercial dairy farms. The mortality in cattle in the MCL system was 0.4% and no mortality was recorded in the commercial dairy farms. The animal level morbidity in sheep and goats in the infected flocks was 35.7% but no mortality was seen in these species. The herd/flock level morbidity of FMD in outbreak affected kebeles of MCL system was 57.2% for cattle and 8% for sheep and goats. The economic losses due to milk loss, draught power loss, mortality and treatment cost were on average USD 34 (interquartile range: 9.4–44.4) per affected herd in the MCL system and this was statistically significantly lower than the USD 459.1 (interquartile range: 400.0–486.2) per affected farm in the commercial dairy farms (p < .05). These economic losses have significant impact in the livelihood and income of affected farmers in both production systems. Future work should focus on the implementation of control measures that mitigate the economic impact of the disease.

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“…An important over‐simplification of many studies predicting the benefits of control is a failure to incorporate the variable effectiveness of FMD control programmes (Knight‐Jones et al., , ; Knight‐Jones et al., a, Lyons et al., ; Elnekave et al., ; Woolhouse et al., ; Lyons et al., ). Two critical factors are (i) the variable potency and quality of vaccines used in endemic settings (Metwally et al., In press) and (ii) the limited application of biosecurity and sanitary control measures (Young et al., ).…”

Section: Fmd Smallholder Impact: What Do We Know and What Don't We Know?mentioning

confidence: 99%

Foot-and-Mouth Disease Impact on Smallholders - What Do We Know, What Don't We Know and How Can We Find Out More?

Knight-Jones

McLaws²,

Rushton

2016

Transbound Emerg Dis

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SummaryFoot‐and‐mouth disease (FMD) endemic regions contain three‐quarters of the world's FMD susceptible livestock and most of the world's poor livestock keepers. Yet FMD impact on smallholders in these regions is poorly understood. Diseases of low mortality can exert a large impact if incidence is high. Modelling and field studies commonly find high FMD incidence in endemic countries. Sero‐surveys typically find a third of young cattle are sero‐positive, however, the proportion of sero‐positive animals that developed disease, and resulting impact, are unknown. The few smallholder FMD impact studies that have been performed assessed different aspects of impact, using different approaches. They find that FMD impact can be high (>10% of annual household income). However, impact is highly variable, being a function of FMD incidence and dependency on activities affected by FMD. FMD restricts investment in productive but less FMD‐resilient farming methods, however, other barriers to efficient production may exist, reducing the benefits of FMD control. Applying control measures is costly and can have wide‐reaching negative impacts; veterinary‐cordon‐fences may damage wildlife populations, and livestock movement restrictions and trade bans damage farmer profits and the wider economy. When control measures are ineffective, farmers, society and wildlife may experience the burden of control without reducing disease burden. Foot‐and‐mouth disease control has benefitted smallholders in South America and elsewhere. Success takes decades of regional cooperation with effective veterinary services and widespread farmer participation. However, both the likelihood of success and the full cost of control measures must be considered. Controlling FMD in smallholder systems is challenging, particularly when movement restrictions are hard to enforce. In parts of Africa this is compounded by endemically infected wildlife and limited vaccine performance. This paper reviews FMD impact on smallholders in endemic countries. Significant evidence gaps exist and guidance on the design of FMD impact studies is provided.

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Epidemiological analysis of an outbreak of foot-and-mouth disease (serotype SAT2) on a large dairy farm in Kenya using regular vaccination

Cited by 28 publications

References 41 publications

Foot‐and‐mouth disease virus transmission dynamics and persistence in a herd of vaccinated dairy cattle in India

Foot‐and‐mouth disease virus transmission dynamics and persistence in a herd of vaccinated dairy cattle in India

Foot and mouth disease outbreak investigation and estimation of its economic impact in selected districts in northwest Ethiopia

Foot-and-Mouth Disease Impact on Smallholders - What Do We Know, What Don't We Know and How Can We Find Out More?

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