Cross-sectional study of Anaplasma spp. in goats and sheep in Mongolia : a comparison between species in relationship to pasture conditions
Anaplasma ovis, the main aetiology behind of ovine and caprine anaplasmosis, is a vector-borne bacterium of the order Rickettsiales, capable of infecting erythrocytes of small ruminants. The infection is generally a subclinical or mild condition, but stress-factors as co-infections, vaccinations,...
| Autor principal: | |
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| Formato: | H3 |
| Lenguaje: | Inglés |
| Publicado: |
SLU/Dept. of Clinical Sciences (until 231231)
2017
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| Materias: |
| _version_ | 1855571638004744192 |
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| author | Jansson Lagerkvist, Malin |
| author_browse | Jansson Lagerkvist, Malin |
| author_facet | Jansson Lagerkvist, Malin |
| author_sort | Jansson Lagerkvist, Malin |
| collection | Epsilon Archive for Student Projects |
| description | Anaplasma ovis, the main aetiology behind of ovine and caprine anaplasmosis, is a vector-borne
bacterium of the order Rickettsiales, capable of infecting erythrocytes of small ruminants. The
infection is generally a subclinical or mild condition, but stress-factors as co-infections,
vaccinations, or transports may aggravate the disease. Severe cases of A. ovis infection may
involve anaemia, abortion, and mortality. The pathogen is widely distributed, and is endemic
in several tropical and subtropical areas. In addition to goat and sheep, several species of wild
ruminants are known to be susceptible to infection, but their importance as reservoirs in the
epidemiology of A. ovis is yet uncertain.
The aim of this cross-sectional study was to investigate the prevalence of A. ovis in goats and
sheep in Mongolia and to analyse the occurrences of changes in body condition, colours of
mucous membranes and blood parameters due to infection. In addition, goats and sheep’s
tendency of developing clinical signs was compared between different pasture conditions,
analysing whether their species-related pasture adoptions as browser respective grazers may
contribute as a stress-factor in insufficient pasture. Although a third of Mongolian population
relies on small ruminant-dominated livestock for subsistence, few previous studies of A. ovis
have been undertaken. Three regions were selected for the study, based on their respective
pasture conditions. Samples from 80 sheep and 88 goats were collected and analysed by
microscopic examination of stained blood smears, polymerase chain reaction (PCR) for the 16s
RNA gene of Anaplasma spp. (IVM Ulaanbaatar, Mongolia) and msp4 PCR (IVM Ulaanbaatar,
Mongolia) specific for detection of A. ovis. In addition, haemoglobin (Hb), haematocrit (HCT),
Body Condition Score (BCS) and FAMACHA© (i.e. method for detecting anaemia by grading
the colour of the lower inner eyelid) was recorded for each animal.
The overall PCR-based prevalence of Anaplasma spp. in the study was 82.4 % with no
significant difference between goats and sheep in any of the regions. The proportion of positive
animals in South Gobi was significantly lower than in other regions. Typing of anaplasma
subspecies was unsuccessful due to complications in the msp4 PCR, and A. ovis could therefore
not be confirmed. There was a disagreement between the microscopic results and 16S rRNA
PCR results, but all individuals with findings of more than eight inclusion-like structures during
six minutes of microscopy were PCR-positive. Using this criterion, 34.2 % of PCR-positive
individuals could be identified. Goats were generally over-represented compared to sheep
regarding the occurrence of clinical parameters diverging from normal values. Neither low Hbvalues
nor low BCS occurred to a higher extent in anaplasma-positive animals but there was a
significant correlation between the occurrence of pale mucous membranes (FAMACHA©scores
below 3) and anaplasma-positivity among goats in the South Gobi. In addition, goats were
slightly paler than sheep in general, suggesting that FAMACHA© scale might be less accurate
for goats. An interesting finding was the high occurrence of Hb values below reference among
anaplasma-negative goats with in South Gobi. The aetiology behind this is still unknown.
Regional comparisons between the infected and non-infected population were limited by the
low occurrence of PCR-negative individuals in two of the regions. For the same reason,
assessments about pasture influence on disease development were not possible. |
| format | H3 |
| id | RepoSLU10103 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés |
| publishDate | 2017 |
| publishDateSort | 2017 |
| publisher | SLU/Dept. of Clinical Sciences (until 231231) |
| publisherStr | SLU/Dept. of Clinical Sciences (until 231231) |
| record_format | eprints |
| spelling | RepoSLU101032017-04-12T10:30:14Z Cross-sectional study of Anaplasma spp. in goats and sheep in Mongolia : a comparison between species in relationship to pasture conditions Tvärsnittststudie av Anaplasma spp. bland får och getter I Mongoliet : en jämförelse mellan arter i relation till betesförhållanden Jansson Lagerkvist, Malin Anaplasma ovis ovine and caprine anaplasmosis Mongolia sheep goats Anaplasma ovis, the main aetiology behind of ovine and caprine anaplasmosis, is a vector-borne bacterium of the order Rickettsiales, capable of infecting erythrocytes of small ruminants. The infection is generally a subclinical or mild condition, but stress-factors as co-infections, vaccinations, or transports may aggravate the disease. Severe cases of A. ovis infection may involve anaemia, abortion, and mortality. The pathogen is widely distributed, and is endemic in several tropical and subtropical areas. In addition to goat and sheep, several species of wild ruminants are known to be susceptible to infection, but their importance as reservoirs in the epidemiology of A. ovis is yet uncertain. The aim of this cross-sectional study was to investigate the prevalence of A. ovis in goats and sheep in Mongolia and to analyse the occurrences of changes in body condition, colours of mucous membranes and blood parameters due to infection. In addition, goats and sheep’s tendency of developing clinical signs was compared between different pasture conditions, analysing whether their species-related pasture adoptions as browser respective grazers may contribute as a stress-factor in insufficient pasture. Although a third of Mongolian population relies on small ruminant-dominated livestock for subsistence, few previous studies of A. ovis have been undertaken. Three regions were selected for the study, based on their respective pasture conditions. Samples from 80 sheep and 88 goats were collected and analysed by microscopic examination of stained blood smears, polymerase chain reaction (PCR) for the 16s RNA gene of Anaplasma spp. (IVM Ulaanbaatar, Mongolia) and msp4 PCR (IVM Ulaanbaatar, Mongolia) specific for detection of A. ovis. In addition, haemoglobin (Hb), haematocrit (HCT), Body Condition Score (BCS) and FAMACHA© (i.e. method for detecting anaemia by grading the colour of the lower inner eyelid) was recorded for each animal. The overall PCR-based prevalence of Anaplasma spp. in the study was 82.4 % with no significant difference between goats and sheep in any of the regions. The proportion of positive animals in South Gobi was significantly lower than in other regions. Typing of anaplasma subspecies was unsuccessful due to complications in the msp4 PCR, and A. ovis could therefore not be confirmed. There was a disagreement between the microscopic results and 16S rRNA PCR results, but all individuals with findings of more than eight inclusion-like structures during six minutes of microscopy were PCR-positive. Using this criterion, 34.2 % of PCR-positive individuals could be identified. Goats were generally over-represented compared to sheep regarding the occurrence of clinical parameters diverging from normal values. Neither low Hbvalues nor low BCS occurred to a higher extent in anaplasma-positive animals but there was a significant correlation between the occurrence of pale mucous membranes (FAMACHA©scores below 3) and anaplasma-positivity among goats in the South Gobi. In addition, goats were slightly paler than sheep in general, suggesting that FAMACHA© scale might be less accurate for goats. An interesting finding was the high occurrence of Hb values below reference among anaplasma-negative goats with in South Gobi. The aetiology behind this is still unknown. Regional comparisons between the infected and non-infected population were limited by the low occurrence of PCR-negative individuals in two of the regions. For the same reason, assessments about pasture influence on disease development were not possible. Anaplasma ovis, den främsta etiologin bakom anaplasmos hos får och getter, är en vektorburen bakterie i ordningen Rickettsiales med förmågan att infektera erytrocyter hos små idisslare. Infektionen är oftast subklinisk till mild, men stressfaktorer som saminfektioner, vaccinationer eller transporter kan bidra till att sjukdomen förvärras, och allvarliga fall kan innebära anemi, aborter och dödsfall. A. ovis har en omfattande geografisk spridning och är endemisk i flera tropiska och subtropiska områden runtom i världen. Utöver getter och får har flertalet vilda idisslare visat sig vara mottagliga för infektionen, men huruvida de har en betydande roll som reservoarer i epidemiologin för A. ovis, är ännu inte klarlagt. Syftet med denna tvärsnittsstudie var att undersöka förekomsten av A. ovis hos får och getter i Mongoliet, samt att utvärdera förändringar av fett- och muskelansättning, slemhinnefärg och blodparametrar till följd av anaplasmainfektion. Vidare jämfördes tendensen att utveckla kliniska symtom hos getter och får mellan olika betesförhållanden för att utvärdera om deras artspecifika betesanpassningar som buskätare- respektive gräsätare kan bidra som stressfaktor vid otillfredsställande beten. Trots att en tredjedel av Mongoliets befolkning försörjer sig på get- och fårdominerad boskapshållning har få tidigare studier av A. ovis genomförts i landet. Tre regioner valdes ut för studien baserat på deras respektive betesförhållanden. Prover samlades från 80 får och 88 getter och analyserades genom mikroskopering av färgade blodutstryk, polymeraskedjereaktion (PCR) för 16S rRNA genen i Anaplasma spp (IVM Ulaanbaatar, Mongolia) sampt msp4 PCR (IVM Ulaanbaatar, Mongolia), specifik för detektion av A. ovis. Därtill analyserades hemoglobin (Hb), hematokrit (Hk), Body condition score (BCS) och FAMACHA© (gradering av färgen på inre nedre ögonlocket för detektion av anemi) för samtliga provtagna individer. Den totala PCR-baserade prevalensen av Anaplasma spp. var 82,4 %, där ingen signifikant skillnad kunde ses i förekomsten mellan får och getter i någon av regionerna. Andelen positiva djur var emellertid signifikant lägre i södra Gobi än i de övriga regionerna. Artbestämning av anaplasma-underarter misslyckades på grund av komplikationer i msp4-PCR:en och A. ovis kunde därmed ej med säkerhet fastställas som patogen bakom fynden i studien. Resultatet från mikroskoperingen skiljde sig något från 16S rRNA PCR-resultaten, men samtliga individer med fynd av fler än åtta inklusionskroppar under sex minuters mikroskopering var PCRpositiva. Om detta kriterium användes kunde 34,2 % av de PCR-positiva individerna identifieras genom mikroskopering. Getter var generellt överrepresenterade jämfört med får angående avvikelser från de kliniska parametrarnas normalvärden. Varken låga Hb-värden eller låga BCS förekom i större utsträckning hos anaplasma-positiva djur, men det fanns ett signifikant samband mellan bleka slemhinnor (FAMACHA© under 3) och anaplasmapositivitet bland getterna i South Gobi. Dessutom var getterna generellt något blekare än fåren vilket implicerar att FAMACHA©-skalan kan vara sämre anpassad för getter. Ett intressant fynd var den höga förekomsten av Hb-värden under referensintervall bland anaplasma-negativa getter i South Gobi. Etiologin bakom detta är fortfarande okänd. Regionala jämförelser mellan infekterade och icke-infekterade populationer begränsades av den låga förekomsten av PCRnegative individer i två av regionerna. Av samma skäl inskränktes bedömningen av betets inflytande över sjukdomsutvecklingen. SLU/Dept. of Clinical Sciences (until 231231) 2017 H3 eng https://stud.epsilon.slu.se/10103/ |
| spellingShingle | Anaplasma ovis ovine and caprine anaplasmosis Mongolia sheep goats Jansson Lagerkvist, Malin Cross-sectional study of Anaplasma spp. in goats and sheep in Mongolia : a comparison between species in relationship to pasture conditions |
| title | Cross-sectional study of Anaplasma spp. in goats and sheep in Mongolia : a comparison between species in relationship to pasture conditions |
| title_full | Cross-sectional study of Anaplasma spp. in goats and sheep in Mongolia : a comparison between species in relationship to pasture conditions |
| title_fullStr | Cross-sectional study of Anaplasma spp. in goats and sheep in Mongolia : a comparison between species in relationship to pasture conditions |
| title_full_unstemmed | Cross-sectional study of Anaplasma spp. in goats and sheep in Mongolia : a comparison between species in relationship to pasture conditions |
| title_short | Cross-sectional study of Anaplasma spp. in goats and sheep in Mongolia : a comparison between species in relationship to pasture conditions |
| title_sort | cross-sectional study of anaplasma spp. in goats and sheep in mongolia : a comparison between species in relationship to pasture conditions |
| topic | Anaplasma ovis ovine and caprine anaplasmosis Mongolia sheep goats |