Epidemiology, genetic variants and clinical course of natural infections with Anaplasma phagocytophilum in a dairy cattle herd

Abstract Background Anaplasma phagocytophilum is an obligate intracellular, tick-transmitted bacterium that causes granulocytic anaplasmosis in humans and several mammalian species including domestic ruminants where it is called tick-borne fever (TBF). Different genetic variants exist but their impa...

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Main Authors: Cornelia Silaghi, Marion Nieder, Carola Sauter-Louis, Gabriela Knubben-Schweizer, Kurt Pfister, Martin Pfeffer
Format: Article
Language:English
Published: BMC 2018-01-01
Series:Parasites & Vectors
Subjects:
Online Access:http://link.springer.com/article/10.1186/s13071-017-2570-1
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author Cornelia Silaghi
Marion Nieder
Carola Sauter-Louis
Gabriela Knubben-Schweizer
Kurt Pfister
Martin Pfeffer
author_facet Cornelia Silaghi
Marion Nieder
Carola Sauter-Louis
Gabriela Knubben-Schweizer
Kurt Pfister
Martin Pfeffer
author_sort Cornelia Silaghi
collection DOAJ
description Abstract Background Anaplasma phagocytophilum is an obligate intracellular, tick-transmitted bacterium that causes granulocytic anaplasmosis in humans and several mammalian species including domestic ruminants where it is called tick-borne fever (TBF). Different genetic variants exist but their impact with regard to putative differences in host associations and pathogenicity are not yet completely understood. Methods Natural infections with A. phagocytophilum in a dairy cattle herd in Germany were investigated over one pasture season by using serology, haematology, blood chemistry and polymerase chain reaction (PCR). Sequence analysis of partial 16S rRNA, groEL, msp2 and msp4 genes of A. phagocytophilum was carried out in order to trace possible genetic variants and their relations between cattle, roe deer (Capreolus capreolus) and ticks (Ixodes ricinus) in this area. Results In total 533 samples from 58 cattle, 310 ticks, three roe deer and one wild boar were examined. Our results show (i) typical clinical symptoms of TBF in first-time infected heifers, such as high fever, reduced milk yield, lower limb oedema and typical haematological and biochemical findings such as severe leukopenia, erythropenia, neutropenia, lymphocytopenia, monocytopenia, a significant increase in creatinine and bilirubin and a significant decrease in serum albumin, γ-GT, GLDH, magnesium and calcium; (ii) a high overall prevalence of A. phagocytophilum infections in this herd as 78.9% (15/19) of the naïve heifers were real-time PCR-positive and 75.9% (44/58) of the entire herd seroconverted; and (iii) a high level of sequence variation in the analysed genes with five variants of the 16S rRNA gene, two variants of the groEL gene, three variants of the msp2 gene and four variants in the msp4 gene with certain combinations of these variants. Conclusions In cattle particular combinations of the genetic variants of A. phagocytophilum occurred, whereas three roe deer showed different variants altogether. This is indicative for a sympatric circulation of variants in this small geographical region (< 1 km2). Both re- and superinfections with A. phagocytophilum were observed in five cattle showing that infection does not result in sterile immunity. For prevention of clinical cases we suggest pasturing of young, not pregnant heifers to reduce economical losses.
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spelling doaj.art-ae1b25199ef24f2e8fab3a05995cd5282022-12-22T00:32:43ZengBMCParasites & Vectors1756-33052018-01-0111111310.1186/s13071-017-2570-1Epidemiology, genetic variants and clinical course of natural infections with Anaplasma phagocytophilum in a dairy cattle herdCornelia Silaghi0Marion Nieder1Carola Sauter-Louis2Gabriela Knubben-Schweizer3Kurt Pfister4Martin Pfeffer5Comparative Tropical Medicine and Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-University MunichInstitute for Animal Hygiene and Veterinary Public Health, Faculty of Veterinary Medicine, University of LeipzigClinic for Ruminants with Ambulatory and Herd Health Services at the Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University MunichClinic for Ruminants with Ambulatory and Herd Health Services at the Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University MunichComparative Tropical Medicine and Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-University MunichInstitute for Animal Hygiene and Veterinary Public Health, Faculty of Veterinary Medicine, University of LeipzigAbstract Background Anaplasma phagocytophilum is an obligate intracellular, tick-transmitted bacterium that causes granulocytic anaplasmosis in humans and several mammalian species including domestic ruminants where it is called tick-borne fever (TBF). Different genetic variants exist but their impact with regard to putative differences in host associations and pathogenicity are not yet completely understood. Methods Natural infections with A. phagocytophilum in a dairy cattle herd in Germany were investigated over one pasture season by using serology, haematology, blood chemistry and polymerase chain reaction (PCR). Sequence analysis of partial 16S rRNA, groEL, msp2 and msp4 genes of A. phagocytophilum was carried out in order to trace possible genetic variants and their relations between cattle, roe deer (Capreolus capreolus) and ticks (Ixodes ricinus) in this area. Results In total 533 samples from 58 cattle, 310 ticks, three roe deer and one wild boar were examined. Our results show (i) typical clinical symptoms of TBF in first-time infected heifers, such as high fever, reduced milk yield, lower limb oedema and typical haematological and biochemical findings such as severe leukopenia, erythropenia, neutropenia, lymphocytopenia, monocytopenia, a significant increase in creatinine and bilirubin and a significant decrease in serum albumin, γ-GT, GLDH, magnesium and calcium; (ii) a high overall prevalence of A. phagocytophilum infections in this herd as 78.9% (15/19) of the naïve heifers were real-time PCR-positive and 75.9% (44/58) of the entire herd seroconverted; and (iii) a high level of sequence variation in the analysed genes with five variants of the 16S rRNA gene, two variants of the groEL gene, three variants of the msp2 gene and four variants in the msp4 gene with certain combinations of these variants. Conclusions In cattle particular combinations of the genetic variants of A. phagocytophilum occurred, whereas three roe deer showed different variants altogether. This is indicative for a sympatric circulation of variants in this small geographical region (< 1 km2). Both re- and superinfections with A. phagocytophilum were observed in five cattle showing that infection does not result in sterile immunity. For prevention of clinical cases we suggest pasturing of young, not pregnant heifers to reduce economical losses.http://link.springer.com/article/10.1186/s13071-017-2570-1Anaplasma phagocytophilumCattleTick-borne feverIxodes ricinus16S rRNA genegroEL gene
spellingShingle Cornelia Silaghi
Marion Nieder
Carola Sauter-Louis
Gabriela Knubben-Schweizer
Kurt Pfister
Martin Pfeffer
Epidemiology, genetic variants and clinical course of natural infections with Anaplasma phagocytophilum in a dairy cattle herd
Parasites & Vectors
Anaplasma phagocytophilum
Cattle
Tick-borne fever
Ixodes ricinus
16S rRNA gene
groEL gene
title Epidemiology, genetic variants and clinical course of natural infections with Anaplasma phagocytophilum in a dairy cattle herd
title_full Epidemiology, genetic variants and clinical course of natural infections with Anaplasma phagocytophilum in a dairy cattle herd
title_fullStr Epidemiology, genetic variants and clinical course of natural infections with Anaplasma phagocytophilum in a dairy cattle herd
title_full_unstemmed Epidemiology, genetic variants and clinical course of natural infections with Anaplasma phagocytophilum in a dairy cattle herd
title_short Epidemiology, genetic variants and clinical course of natural infections with Anaplasma phagocytophilum in a dairy cattle herd
title_sort epidemiology genetic variants and clinical course of natural infections with anaplasma phagocytophilum in a dairy cattle herd
topic Anaplasma phagocytophilum
Cattle
Tick-borne fever
Ixodes ricinus
16S rRNA gene
groEL gene
url http://link.springer.com/article/10.1186/s13071-017-2570-1
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