scholarly journals Quantifying and Modeling the Acquisition and Retention of Lumpy Skin Disease Virus by Hematophagus Insects Reveals Clinically but Not Subclinically Affected Cattle Are Promoters of Viral Transmission and Key Targets for Control of Disease Outbreaks

2021 ◽  
Vol 95 (9) ◽  
Author(s):  
Beatriz Sanz-Bernardo ◽  
Ismar R. Haga ◽  
Najith Wijesiriwardana ◽  
Sanjay Basu ◽  
Will Larner ◽  
...  

ABSTRACT Lumpy skin disease virus (LSDV) is a vector-transmitted poxvirus that causes disease in cattle. Vector species involved in LSDV transmission and their ability to acquire and transmit the virus are poorly characterized. Using a highly representative bovine experimental model of lumpy skin disease, we fed four model vector species (Aedes aegypti, Culex quinquefasciatus, Stomoxys calcitrans, and Culicoides nubeculosus) on LSDV-inoculated cattle in order to examine their acquisition and retention of LSDV. Subclinical disease was a more common outcome than clinical disease in the inoculated cattle. Importantly, the probability of vectors acquiring LSDV from a subclinical animal (0.006) was very low compared with that from a clinical animal (0.23), meaning an insect feeding on a subclinical animal was 97% less likely to acquire LSDV than one feeding on a clinical animal. All four potential vector species studied acquired LSDV from the host at a similar rate, but Aedes aegypti and Stomoxys calcitrans retained the virus for a longer time, up to 8 days. There was no evidence of virus replication in the vector, consistent with mechanical rather than biological transmission. The parameters obtained in this study were combined with data from studies of LSDV transmission and vector life history parameters to determine the basic reproduction number of LSDV in cattle mediated by each of the model species. This reproduction number was highest for Stomoxys calcitrans (19.1), followed by C. nubeculosus (7.1) and Ae. aegypti (2.4), indicating that these three species are potentially efficient transmitters of LSDV; this information can be used to inform LSD control programs. IMPORTANCE Lumpy skin disease virus (LSDV) causes a severe systemic disease characterized by cutaneous nodules in cattle. LSDV is a rapidly emerging pathogen, having spread since 2012 into Europe and Russia and across Asia. The vector-borne nature of LSDV transmission is believed to have promoted this rapid geographic spread of the virus; however, a lack of quantitative evidence about LSDV transmission has hampered effective control of the disease during the current epidemic. Our research shows subclinical cattle play little part in virus transmission relative to clinical cattle and reveals a low probability of virus acquisition by insects at the preclinical stage. We have also calculated the reproductive number of different insect species, therefore identifying efficient transmitters of LSDV. This information is of utmost importance, as it will help to define epidemiological control measures during LSDV epidemics and of particular consequence in resource-poor regions where LSD vaccination may be less than adequate.

2020 ◽  
Author(s):  
Beatriz Sanz-Bernardo ◽  
Ismar R. Haga ◽  
Najith Wijesiriwardana ◽  
Sanjay Basu ◽  
Will Larner ◽  
...  

AbstractLumpy skin disease virus (LSDV), a poxvirus that causes severe disease in cattle, has in the last few years rapidly extended its distribution from Africa and the Middle East into Europe, Russia, and across Asia. LSDV is believed to be primarily spread mechanically by blood-feeding arthropods, however the exact mode of arthropod transmission, the relative ability of different arthropod species to acquire and retain the virus, as well as their comparative importance for LSDV transmission, remain poorly characterised. Since the vector-borne nature of LSDV transmission is believed to have enabled the rapid geographic expansion of this virus, the lack of quantitative evidence on LSDV transmission has impeded effective control of the disease during the current epidemic. Obtaining high quality data on virus transmission by arthropods is challenging, and practical limitations often result in inadequate arthropod numbers or model hosts, limiting the transferability of experimental findings to the natural transmission scenario.We have addressed these limitations in this study. Using a highly representative bovine experimental model of lumpy skin disease we allowed four representative vector species (Aedes aegypti, Culex quinquefasciatus, Stomoxys calcitrans and Culicoides nubeculosus) to blood-feed on LSDV-inoculated cattle in order to examine the acquisition and retention of LSDV by these species in unprecedented detail. We found the probability of LSDV transmission from clinical cattle to vector correlated with disease severity. Subclinical disease was more common than clinical disease in the inoculated cattle, however the probability of vectors acquiring LSDV from subclinical animals was very low.All four potential vector species studied had a similar rate of acquisition of LSDV after feeding on the host, but Aedes aegypti and Stomoxys calcitrans retained the virus for a longer time, up to 8 days. There was no evidence of virus replication in the vector, consistent with mechanical rather than biological transmission. The parameters obtained in the in-vivo transmission experiments subsequently enabled enhanced modelling approaches to determine the basic reproduction number of LSDV in cattle mediated by each of the insect species. This was highest for Stomoxys calcitrans (19.1), C. nubeculosus (7.4), and Ae. aegypti (2.4), surprisingly indicating these three species are all potentially efficient transmitters of LSDV. These results reveal that currently applied LSDV control measures such as stamping out of all cattle on affected premises or insect control measures targeting single species need to be urgently reconsidered. Overall our studies have highlighted that the combination of highly relevant in-vivo experiments and mathematical modelling can be directly applied to devise evidence-based proportionate and targeted control programmes.


2001 ◽  
Vol 126 (2) ◽  
pp. 317-321 ◽  
Author(s):  
C. M. CHIHOTA ◽  
L. F. RENNIE ◽  
R. P. KITCHING ◽  
P. S. MELLOR

Aedes aegypti female mosquitoes are capable of the mechanical transmission of lumpy skin disease virus (LSDV) from infected to susceptible cattle. Mosquitoes that had fed upon lesions of LSDV-infected cattle were able to transmit virus to susceptible cattle over a period of 2–6 days post-infective feeding. Virus was isolated from the recipient animals in 5 out of 7 cases. The clinical disease recorded in the animals exposed to infected mosquitoes was generally of a mild nature, with only one case being moderate. LSDV has long been suspected to be insect transmitted, but these findings are the first to demonstrate this unequivocally, and they suggest that mosquito species are competent vectors.


PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0238210
Author(s):  
Arman Issimov ◽  
David B. Taylor ◽  
Malik Shalmenov ◽  
Birzhan Nurgaliyev ◽  
Izimgali Zhubantayev ◽  
...  

Lumpy skin disease (LSD) is an emerging disease of cattle in Kazakhstan and the means of transmission remains uncertain. In the current study, retention of Lumpy Skin Disease Virus (LSDV) by three Stomoxys species following intrathoracic inoculation was demonstrated under laboratory conditions. A virulent LSDV strain was injected into the thorax of flies to bypass the midgut barrier. The fate of the pathogen in the hemolymph of the flies was examined using PCR and virus isolation tests. LSDV was isolated from all three Stomoxys species up to 24h post inoculation while virus DNA was detectable up to 7d post inoculation.


2019 ◽  
Author(s):  
Simon Gubbins

SummaryIn recent years, lumpy skin disease virus (LSDV) has emerged as a major threat to cattle outside Africa, where it is endemic. Although evidence suggests that LSDV is transmitted by the bites of blood sucking arthropods, few studies have assessed the risk of transmission posed by particular vector species. Here this risk is assessed by calculating the basic reproduction number (R0) for transmission of LSDV by five species of biting insect: the stable fly, Stomoxys calcitrans, the biting midge, Culicoides nubeculosus, and three mosquito species, Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. Parameters relating to mechanical transmission of LSDV were estimated using new analyses of previously-published data from transmission experiments, while vector life history parameters were derived from the published literature. Uncertainty and sensitivity analyses were used to compute R0 for each species and to identify those parameters which influence its magnitude. Results suggest that S. calcitrans is likely to be the most efficient at transmitting LSDV, with Ae. aegypti also an efficient vector. By contrast, C. nubeculosus, An. stephensi, and Cx. quinquefasciatus are likely to be inefficient vectors of LSDV. However, there is considerable uncertainty associated with the estimates of R0, reflecting uncertainty in most of the constituent parameters. Sensitivity analysis suggests that future experimental work should focus on estimating the probability of transmission from insect to bovine and on the virus inactivation rate in insects.


Vaccines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 473
Author(s):  
Andy Haegeman ◽  
Ilse De Leeuw ◽  
Laurent Mostin ◽  
Willem Van Campe ◽  
Laetitia Aerts ◽  
...  

Vaccines form the cornerstone of any control, eradication and preventative strategy and this is no different for lumpy skin disease. However, the usefulness of a vaccine is determined by a multiplicity of factors which include stability, efficiency, safety and ease of use, to name a few. Although the vaccination campaign in the Balkans against lumpy skin disease virus (LSDV) was successful and has been implemented with success in the past in other countries, data of vaccine failure have also been reported. It was therefore the purpose of this study to compare five homologous live attenuated LSDV vaccines (LSDV LAV) in a standardized setting. All five LSDV LAVs studied were able to protect against a challenge with virulent LSDV. Aside from small differences in serological responses, important differences were seen in side effects such as a local reaction and a Neethling response upon vaccination between the analyzed vaccines. These observations can have important implications in the applicability in the field for some of these LSDV LAVs.


2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Halima Rhazi ◽  
Najete Safini ◽  
Karima Mikou ◽  
Meryeme Alhyane ◽  
Khalid Omari Tadlaoui ◽  
...  

Abstract Background Animal vaccination is an important way to stop the spread of diseases causing immense damage to livestock and economic losses and the potential transmission to humans. Therefore effective method for vaccine production using simple and inexpensive bioprocessing solutions is very essential. Conventional culture systems currently in use, tend to be uneconomic in terms of labor and time involved. Besides, they offer a limited surface area for growth of cells. In this study, the CelCradle™-500A was evaluated as an alternative to replace conventional culture systems in use such as Cell factories for the production of viral vaccines against small ruminant morbillivirus (PPR), rift valley fever virus (RVF) and lumpy skin disease virus (LSD). Results Two types of cells Vero and primary Lamb Testis cells were used to produce these viruses. The study was done in 2 phases as a) optimization of cell growth and b) virus cultivation. Vero cells could be grown to significantly higher cell densities of 3.04 × 109 using the CelCradle™-500A with a shorter doubling time as compared to 9.45 × 108 cells in Cell factories. This represents a 19 fold increase in cell numbers as compared to seeding vs only 3.7 fold in Cell factories. LT cells achieved modestly higher cell densities of 6.7 × 108 as compared to 6.3 × 108 in Cell factories. The fold change in densities for these cells was 3 fold in the CelCradle™-500A vs 2.5 fold in Cell factories. The titers in the conventional system and the bioreactor were not significantly different. However, the Cell-specific virus yield for rift valley fever virus and lumpy skin disease virus are higher (25 virions/cell for rift valley fever virus, and 21.9 virions/cell for lumpy skin disease virus versus 19.9 virions/cell for rift valley fever virus and 10 virions/cell for lumpy skin disease virus). Conclusions This work represents a novel study for primary lamb testis cell culture in CellCradle™-500A bioreactors. In addition, on account of the high cell densities obtained and the linear scalability the titers could be further optimized using other culture process such us perfusion.


2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Mukhit B. Orynbayev ◽  
Raikhan K. Nissanova ◽  
Berik M. Khairullin ◽  
Arman Issimov ◽  
Kunsulu D. Zakarya ◽  
...  

AbstractThis study describes the registration of the first cases of lumpy skin disease in July 2016 in the Republic of Kazakhstan. In the rural district of Makash, Kurmangazinsky district of Atyrau region, 459 cattle fell ill and 34 died (morbidity 12.9% and mortality 0.96%). To determine the cause of the disease, samples were taken from sick and dead animals, as well as from insects and ticks. LSDV DNA was detected by PCR in all samples from dead animals and ticks (Dermacentor marginatus and Hyalomma asiaticum), in 14.29% of samples from horseflies (Tabanus bromius), and in one of the samples from two Stomoxys calcitrans flies. The reproductive LSD virus was isolated from organs of dead cattle and insects in the culture of LT and MDBK cells. The virus accumulated in cell cultures of LT and MDBK at the level of the third passage with titers in the range of 5.5–5.75 log 10 TCID50/cm3. Sequencing of the GPCR gene allowed us to identify this virus as a lumpy skin disease virus.


Author(s):  
Zeinab Hedayati ◽  
Hamid Reza Varshovi ◽  
Ali Mohammadi ◽  
Mohammad Tabatabaei

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