RESUMO
Anaplasma centrale (A. centrale) is an obligate red blood cell residing tick transmitted rickettsiae that has not been studied extensively for its prevalence in cattle along with its epidemiology. Aim of this investigation was to report the seasonal prevalence, phylogeny and epidemiological parameters associated with the prevalence of A. centrale in cattle breeds enrolled from District Layyah in Punjab, Pakistan. A total of 844 blood samples [Cross breed = 300, Holstein Friesian = 244, Sahiwal breed = 300)] were collected from apparently healthy cattle along with epidemiological data during 2017-18. PCR amplified 426 base pair fragment from 16S rRNA gene of A. centrale in 14.4% (122/844) of cattle. Amplified 16S rRNA partial gene sequence of A. centrale were confirmed by DNA sequencing and deposited to GenBank. Highest A. centrale prevalence was observed in spring (24%) followed by autumn (12.4%) summer (10%) and winter (7.1%) seasons. Sahiwal breed (18.3%) was most susceptible to A. centrale infection followed by cross (12.3%) and Holstein Friesian breed (12.3%). 69/844 (8.2%) of Giemsa stained cattle blood smears were also found positive for Anaplasma spp. Farms where animal use to drink pool water and farms where dogs and other dairy animals were living with cattle had higher A. centrale prevalence. Female cattle and dogs having tick burden were found associated with A. centrale infection. Hematological profile was severely disturbed in A. centrale positive cattle. It is recommended that A. centrale should be screened in cattle, in addition to A. marginale, for the effective control of tick born diseases in Pakistan.
RESUMO
Anaplasmosis is a tick-borne disease caused by obligate intercellular gram-negative bacteria, Anaplasma (A.) marginale. The present study reports on seasonal prevalence, epidemiology, and phylogeny of A. marginale in three cattle breeds from District Layyah, Southern Punjab, Pakistan. A total of 844 blood samples (Cross = 300, Holstein Friesian = 244, Sahiwal breed = 300) from apparently healthy cattle on seasonal basis were collected along with epidemiological data during May 2018 till April 2019. Polymerase chain reaction generated 265 base-pair amplicon specific for major surface protein-1b encoding gene of A. marginale in 8.6% (73/844) of enrolled cattle. The highest prevalence was observed during autumn (18.3%) followed by summer (9.7%) and winter season (7.1%). Holstein Friesian breed was most susceptible to A. marginale infection (13.1%) followed by Sahiwal (7.6%) and cross breed (6%). Representative amplified partial gene sequences of A. marginale were submitted to GenBank (Accession numbers MK032842 and MK032843). 37/844 (4.3%) Giemsa-stained blood smears were found positive for Anaplasma spp. Small number of ticks including Hyalomma anatolicum, Hyalomma excavatum, Rhipicephalus microplus, Haemaphysalis punctata were identified from cattle but none of them was found PCR positive for the presence of A. marginale. Analysis of epidemiological factors revealed that female cattle and farm with water supply from pool, farms where other dairy animals and dogs were living with cattle and dogs having ticks load on them had significant association with A. marginale prevalence. It was observed that white blood cell, lymphocytes (%), monocytes (%) hematocrit, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were significantly disturbed in A. marginale-positive than negative cattle.
