Occurrence and transplacental transmission of Anaplasma marginale in dairy cattle: a comprehensive report on the comparative susceptibility of local and exotic cattle breeds

Bovine anaplasmosis, caused by Anaplasma marginale , is a non-contagious tick borne disease. The main objective of the current study was to investigate comparative frequency of anaplasmosis in three different cattle breeds (European breed/ Holstein Friesian and Jersey breed, indigenous breed and cross breed (1st and 2nd pedigree) and transplacental transmission using real time polymerase chain reaction for detection. Of the total 96 blood samples analyzed, our results indicated an overall incidence 45.83% (44/96) of A. marginale with highest incidence 62.5% (20/32) in European breed, followed by 42.4% (14/33) in cross breed and 35.4% (11/31) in indigenous breed. Most importantly, our results indicated that 13.7% (4/29) calves were found positive for the presence of A. marginale indicating transplacental transmission. Furthermore, indirect ELISA revealed an overall incidence rate of 34.3% (33/96) more likely indicating current or previous exposure. Finally, Giemsa staining determined that 15% (15/96) animals were found positive by examining red blood cells. Statistical analysis showed significantly higher (P 0.05) difference was found among the crossbred and indigenous breed of cattle. Moreover, non significant (P> 0.05) effect of age group was observed on the incidence of A. marginale . White blood cell count and mean corpuscular volume were significantly (P<0.05) higher in infected cattle, while, red blood cells, packed cell volume hemoglobin concentration, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration (MCHC) were significantly (P<0.05) higher in non-infected as compare to infected animals. Key words: Anaplasma marginale ; cattle breeds; enzyme linked immuno sorbent assay; real-time polymerase chain reaction; transplacental transmission POJAVNOST IN PRENOS Anaplasma marginale PREKO POSTELJICE PRI MLECNEM GOVEDU Povzetek: Goveja anaplazmoza, ki jo povzroca Anaplasma marginale , je bolezen, ki ni kužna in jo prenasajo klopi. Glavni namen studije je bil raziskati in primerjati pogostost anaplazmoze pri razlicnih pasmah goveda in sicer dveh evropskih pasmah (holstein-frizijske pasma in pasma jersey) pri avtohtoni pasmi ter pri križancih med evropskimi pasmami in avtohtonimi pasmami (1. In 2. generacija križancev) ter prenos preko posteljice z uporabo verižne rekacije s polimerazo v realnem casu (PCR). Od skupno 96 pregledanih vzorcev krvi so rezultati pokazali skupno incidenco 45,83 % (44/96) A. marginale z najvecjo incidenco 62,5 % (20/32) pri evropskih pasmah, nato 42,4 % (14/33) pri križanih živalih in 35,4 % (11/31) pri avtohtonih pasmah. Rezultati so tudi pokazali pozitivno rekacijo na prisotnost A. marginale pri 13,7 % (4/29) telet, kar kaže na prenos anaplazmoze preko posteljice. Metoda posrednega testa ELISA, ki pokaže na trenutno ali predhodno izpostavljenost, je pokazala 34,3-odstotno pojavnost pri vseh živalih skupaj (33/96 živali). Proucitev rdecih krvnick z barvanjem Giemsa je pokazalo 15 % (15/96) pozitivnih živali. Statisticna analiza je pokazala statisticno znacilno razliko v pojavnosti anaplazmoze med evropskima pasmama v primerjavi s križanci in avtohtono pasmo (p < 0,05), razlika med križanci in avtohtono pasmo goveda pa ni bila statisticno znacilna. Poleg tega je bil pri pojavnosti A. marginale opazen neznaten (statisticno neznacilen) ucinek starosti proucevanih živali. Stevilo belih krvnih celic in povprecni volumen telesne mase sta bila pri okuženih govedih statisticno znacilno povecana (p < 0,05), medtem ko so bile rdece krvne celice, koncentracija hemoglobina v celicah in povprecna kolicina hemoglobina v posameznem eritrocitu (MCHC) v neokuženi skupini visja kot v skupini z okuženimi živalmi (p <0,05). Kljucne besede: Anaplasma marginale ; pasme goveda; test ELISA; verižna reakcija s polimerazo v realnem casu; prenos preko posteljice