Molecular Detection and Phylogenetic Analysis of Anaplasma phagocytophilum and Related Strains in Cattle from Henan, China
by
and
Yaqun Yan
1,2,
Yongli Wang
1,2,
Yanyan Cui
3,
Jin Wang
1,2,
Shuhua Fan
1,2,* and
Changshen Ning
4,* 1
College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou 466000, China
2
Field Observation and Research Station of Green Agriculture in Dancheng County, Dancheng 477150, China
3
School of Biotechnology and Food, Shangqiu Normal University, Shangqiu 476000, China
4
College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
*
Authors to whom correspondence should be addressed.
Vet. Sci. 2025, 12(3), 252; https://doi.org/10.3390/vetsci12030252
Submission received: 4 December 2024
/
Revised: 27 February 2025
/
Accepted: 4 March 2025
/
Published: 6 March 2025
Simple Summary
Anaplasma phagocytophilum exhibits significant genetic diversity, and studies have identified several variants of A. phagocytophilum across various geographic regions. In this investigation, 662 blood samples from cattle in Henan Province, China, were examined for A. phagocytophilum and related strains. The overall infection rate was 11.33%, with some cattle carrying two strains simultaneously. This study highlights the importance of including A. phagocytophilum-like strains in the diagnosis of anaplasmosis in cattle. Despite existing research on these bacteria, further large-scale studies are necessary to enhance our understanding of their dissemination, clinical manifestations in animals, and genetic variations.
Abstract
Anaplasma phagocytophilum is a zoonotic pathogen transmitted by arthropod vectors. The pathogen infects various vertebrate hosts, causing mild to severe illness. Molecular studies have demonstrated that A. phagocytophilum exhibits a high level of genetic diversity, with two A. phagocytophilum-related variants identified in several countries. This study represents the first application of PCR amplification and restriction fragment length polymorphism (PCR-RFLP) in conjunction with DNA sequencing to investigate the frequency and phylogenetic relationships of A. phagocytophilum and its related strains in cattle from China. A total of 662 bovine blood samples were collected from diverse regions within Henan Province, China, and pathogen DNA was detected in 75 samples, comprising 11.33% of the total. PCR-RFLP analysis identified three strains with frequency rates of 2.87% (19/662) for A. phagocytophilum, 11.33% (75/662) for A. phagocytophilum-like 1, and 3.22% (22/662) for A. phagocytophilum-like 2. Additionally, co-infections involving A. phagocytophilum and A. phagocytophilum-like 1 were observed as well as between A. phagocytophilum-like 1 and A. phagocytophilum-like 2. Anaplasma phagocytophilum-like strains 1 and 2 should be considered when diagnosing bovine anaplasmosis. Despite recent molecular studies of A. phagocytophilum-related strains, there remains a shortage of data concerning vector capability, the epidemiology of the disease, clinical signs, and genetic diversity of the pathogens. Thus, large-scale investigations involving animals and tick vectors are necessary to obtain more detailed information concerning the etiology of anaplasmosis.
