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A screening for Schmallenberg Virus among sheep and goats in Tanzania

Schmallenberg virus (SBV) is a novel arthropod-borne orthobunyavirus emerging in Europe in 2011 to 2012. Acute SBV infection causes diarrhoea, fever and reduced milk production in dairy cattle, but it is mainly the reproductive disorders (abortions, malformed foetuses and stillborn animals) in rumin...

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Main Author: Levin, Lovisa
Format: Second cycle, A2E
Language:Swedish
Inglés
Published: 2015
Subjects:
Animal diseases
Online Access:https://stud.epsilon.slu.se/7615/
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author Levin, Lovisa
author_browse Levin, Lovisa
author_facet Levin, Lovisa
author_sort Levin, Lovisa
collection Epsilon Archive for Student Projects
description Schmallenberg virus (SBV) is a novel arthropod-borne orthobunyavirus emerging in Europe in 2011 to 2012. Acute SBV infection causes diarrhoea, fever and reduced milk production in dairy cattle, but it is mainly the reproductive disorders (abortions, malformed foetuses and stillborn animals) in ruminants that have caused substantial economical losses. The prevalence of the virus outside of Europe is poorly investigated. SBV or SBV-like antibodies were detected in Mozambique in 2013, which raised interest for a similar study in Tanzania. In this study in Tanzania, blood samples were collected from 478 sheep and goats from 39 herds in 15 different villages in three districts, covering areas in the north, south and east of Tanzania. The epidemiology of the virus was investigated by tracing antibodies by ELISA and mapping of the virus by PCR was started. In total 309 serum samples were analysed by a competitive ELISA. The overall seroprevalence was 43% by this test. Seropositive herds were found in all areas. In Mikumi in the east, all herds were positive for SBV antibodies, in Ngorongoro in the north, 64% were positive and in Mahenge in the south were 85% positive. In total 127 of the tested samples were additionally analysed by an indirect ELISA. The results between the two ELISAs differed more than expected. The overall seroprevalence was 21% by the indirect ELISA. This divergent result is not supported by other studies comparing different SBV ELISAs, and the fact that the sensitivity and specificity are similar for both tests contradicts the result. In total 68 buffy coats from herds seropositive by both ELISAs were analysed by PCR. All analysed samples were negative in the Pan-Simbu RT-PCR. The findings in this study indicate that SBV is endemic in Tanzania. However cross-reactivity with viruses related to SBV cannot be ruled out as cause of the positive ELISA results.
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Inglés
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spelling RepoSLU76152015-02-16T16:13:15Z https://stud.epsilon.slu.se/7615/ A screening for Schmallenberg Virus among sheep and goats in Tanzania Levin, Lovisa Animal diseases Schmallenberg virus (SBV) is a novel arthropod-borne orthobunyavirus emerging in Europe in 2011 to 2012. Acute SBV infection causes diarrhoea, fever and reduced milk production in dairy cattle, but it is mainly the reproductive disorders (abortions, malformed foetuses and stillborn animals) in ruminants that have caused substantial economical losses. The prevalence of the virus outside of Europe is poorly investigated. SBV or SBV-like antibodies were detected in Mozambique in 2013, which raised interest for a similar study in Tanzania. In this study in Tanzania, blood samples were collected from 478 sheep and goats from 39 herds in 15 different villages in three districts, covering areas in the north, south and east of Tanzania. The epidemiology of the virus was investigated by tracing antibodies by ELISA and mapping of the virus by PCR was started. In total 309 serum samples were analysed by a competitive ELISA. The overall seroprevalence was 43% by this test. Seropositive herds were found in all areas. In Mikumi in the east, all herds were positive for SBV antibodies, in Ngorongoro in the north, 64% were positive and in Mahenge in the south were 85% positive. In total 127 of the tested samples were additionally analysed by an indirect ELISA. The results between the two ELISAs differed more than expected. The overall seroprevalence was 21% by the indirect ELISA. This divergent result is not supported by other studies comparing different SBV ELISAs, and the fact that the sensitivity and specificity are similar for both tests contradicts the result. In total 68 buffy coats from herds seropositive by both ELISAs were analysed by PCR. All analysed samples were negative in the Pan-Simbu RT-PCR. The findings in this study indicate that SBV is endemic in Tanzania. However cross-reactivity with viruses related to SBV cannot be ruled out as cause of the positive ELISA results. Schmallenberg virus (SBV) är ett nytt vektorburet virus som upptäcktes och spred över Europa 2011-2012. Akut infektion med SBV orsakar diarré, feber och sänkt mjölkproduktion hos mjölkkor. Det är dock främst reproduktionsstörningarna (abort, missbildade och dödfödda avkommor) hos idisslare som har orsakat stora ekonomiska förluster. Förekomsten av viruset utanför Europa har studerats i mycket liten utsträckning. År 2013 upptäcktes antikroppar mot SBV eller ett SBV liknade virus i Mozambique, vilket väckte intresse för genoförandet av en liknande studie i Tanzania. I denna studie i Tanzania samlades blodprov från 478 får och getter från 39 flockar, i 15 olika byar i tre olika distrikt, från norra, södra och östra Tanzania. Viruset undersöktes epidemiologiskt genom spårning av antikroppar med ELISA och en kartläggning av viruset med PCR påbörjades. Totalt analyserades 309 serumprover med en kompetitiv ELISA. Den totala seroprevalensen var 43 % med detta test. Seropositiva flockar fanns i alla provtagna områden. I Mikumi i öst, var samtliga flockar seropositiva, I Ngorongoro i norr, var 64 % av flockarna positiva och i Mahenge i söder, var 85 % positiva. Av de analyserade proverna analyserades 127 även med en indirekt ELISA. Resultatet mellan de två ELISorna skiljde sig mer än väntat. Den totala seroprevalensen var 21 % med den indirekta ELISAn. Denna skillnad mellan olika ELISor har inte setts i tidigare studier. Båda testerna har liknande sensitivitet och specificitet vilket gör resultatet än mer motsägelsefullt. Från flockar som var seropositiva med både den kompetitiva och den indirekta ELISAn analyserades 68 buffy coats med PCR. Alla prover var negativa med Pan-Simbu RT-PCR. Fynden i denna studie indikerar att SBV finns endemiskt i Tanzania. Dock kan korsreaktivitet med virus som är närbesläktade med SBV inte uteslutas som orsak till de positiva ELISA resultaten. 2015-02-16 Second cycle, A2E NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/7615/7/levin_l_150128.pdf Levin, Lovisa, 2015. A screening for Schmallenberg Virus among sheep and goats in Tanzania. Second cycle, A2E. Uppsala: (VH) > Dept. of Clinical Sciences (until 231231) <https://stud.epsilon.slu.se/view/divisions/OID-715.html> urn:nbn:se:slu:epsilon-s-4111 eng
spellingShingle Animal diseases
Levin, Lovisa
A screening for Schmallenberg Virus among sheep and goats in Tanzania
title A screening for Schmallenberg Virus among sheep and goats in Tanzania
title_full A screening for Schmallenberg Virus among sheep and goats in Tanzania
title_fullStr A screening for Schmallenberg Virus among sheep and goats in Tanzania
title_full_unstemmed A screening for Schmallenberg Virus among sheep and goats in Tanzania
title_short A screening for Schmallenberg Virus among sheep and goats in Tanzania
title_sort screening for schmallenberg virus among sheep and goats in tanzania
topic Animal diseases
url https://stud.epsilon.slu.se/7615/
https://stud.epsilon.slu.se/7615/

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