Molecular prevalence of Anaplasma spp. in cattle and assessment of associated risk factors in Northeast Thailand

Molecular Detection and Phylogenetic Analysis of Anaplasma phagocytophilum and Related Strains in Cattle from Henan, China

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.

Molecular Detection of Hemoparasites in Hematophagous Insects Collected from Livestock Farms in Northeastern Thailand

Vector-borne parasitic diseases (VBPDs) are diseases that have a major impact on the health and productivity of livestock. VBPDs, including trypanosomosis, theileriosis, and anaplasmosis, are caused by blood parasites and Rickettsiales infections that can be transmitted by biting insects. The control and elimination of VBPDs is difficult and challenging. This study contributed to better understanding the impact of hematophagous insects on carrying pathogens to livestock by investigating the detection of Trypanosoma evansi, Theileria spp. and Anaplasma spp. in hematophagous insects collected from five livestock farms in Northeastern Thailand using polymerase chain reaction (PCR). The Stomoxys and Tabanus samples were collected using Nzi and Vavoua traps. Morphological and molecular identifications of hematophagous insects were performed. The Stomoxys samples were dissected into head and abdomen parts, while the Tabanus samples were dissected into head, salivary glands, and abdomen parts before DNA extraction individually. The host blood meal in the DNA of each part of the hematophagous insects was identified using PCR targeting the prepronociceptin (PNOC) gene. PCR detection of T. evansi, Theileria spp., and Anaplasma spp. were performed by targeting the ITS2, 18s rRNA, and msp4 genes, respectively. In total, 131 insect samples were collected, with Stomoxys calcitrans being the most common species at 40 (30.53%), followed by Tabanus spp. at 14 (10.69%) and the other Stomoxys spp. at 7 (5.34%), respectively. The hemoparasite detection results identified Theileria spp. in the abdomen (21.43%; 3/14) of three Tabanus samples. Neither Anaplasma spp. nor T. evansi were detected in this study. Additionally, host blood meal DNA was found in the abdomen of Stomoxys calcitrans (4.17%; 1/24) and Stomoxys spp. (20%; 1/5). For the Tabanus spp., host blood meal DNA was detected in the head (7.14%; 1/14), salivary glands (7.14%; 1/14), and abdomen (14.29%; 2/14). These results highlighted that Tabanus spp. might play an important role in Theileria transmission.

Prevalence and Risk Factors of Anaplasmosis in Simmental Cattle in the Peruvian Amazon

Anaplasmosis, transmitted biologically and mechanically, is one of the most prevalent diseases responsible for high production costs worldwide. In this research, the prevalence and risk factors of anaplasmosis in Simmental cattle raised in the Peruvian Amazon were evaluated. 266 blood samples were collected from bovines of different categories such as calves male, calves females, heifers <1.3 years, heifers >1.3 years, steers, bulls, and cows from the districts of Omia and Molinopampa. The enzyme-linked immunosorbent assay (ELISA) technique was used to detect antibodies against Anaplasma marginale. Of the 266 animals sampled, 67% were positive for A. marginale. A higher prevalence was determined in the district of Omia (99.3%), while in the district of Molinopampa, 28.7% was obtained. A prevalence of A. marginale was recorded in females (67.7%) and in males (64.8%) (p > 0.05). There is a significant association of the disease with the category of cattle, verifying the highest prevalence of A. marginale in calves male, heifer >1.3 years, and bull. The multiple correspondence analysis shows that San Mateo, Puma Marca, Mashuyacu, Primavera, and Los Olivos have a higher prevalence of anaplasmosis, associated with altitude of 1701-2000 m, spray baths and paddock rotation. Anaplasmosis is prevalent in Simmental cattle from the Peruvian Amazon, with a higher incidence in Omia and in females, considering May to August the critical months and the altitude less than 2000 meters above sea level.

RPA-CRISPR/Cas12a assay for the diagnosis of bovine Anaplasma marginale infection

Anaplasma marginale infection is one of the most common tick-borne diseases, causing a substantial loss in the beef and dairy production industries. Once infected, the pathogen remains in the cattle for life, allowing the parasites to spread to healthy animals. Since clinical manifestations of anaplasmosis occur late in the disease, a sensitive, accurate, and affordable pathogen identification is crucial in preventing and controlling the infection. To this end, we developed an RPA-CRISPR/Cas12a assay specific to A. marginale infection in bovines targeting the msp4 gene. Our assay is performed at one moderately high temperature, producing fluorescent signals or positive readout of a lateral flow dipstick, which is as sensitive as conventional PCR-based DNA amplification. This RPA-CRISPR/Cas12a assay can detect as few as 4 copies/μl of Anaplasma using msp4 marker without cross-reactivity to other common bovine pathogens. Lyophilized components of the assay can be stored at room temperature for an extended period, indicating its potential for field diagnosis and low-resource settings of anaplasmosis in bovines.

Seasonal dynamics and genetic characterization of bovine arthropod-borne parasites in Nan Province, Thailand with molecular identification of Anaplasma platys and Trypanosoma theileri

Virulent species or strains of hematophagous borne pathogens such as Anaplasma spp., Babesia spp., Theileria spp., and Trypanosoma spp., are lethal to susceptible animals or reduce their productivity on a global scale. Nonetheless, efforts to diagnose the causative agents and assess the genotypic profiles as well as quantify the parasite burden of aforementioned parasites across seasons remain limited. Therefore, the present investigation sought to elucidate the genotypic composition of Anaplasma spp., Babesia spp., Theileria spp., and Trypanosoma spp. The findings revealed heightened infection rates during the summer, manifesting a correlation between Trypanosoma spp. infection and seasonal fluctuations. Among the identified pathogens, Anaplasma marginale emerged as the most dominant species, while the occurrence of Anaplasma platys in Thai cattle was confirmed via the sequencing of the groEL gene. Moreover, the study successfully identified two lineages of Trypanosoma theileri. The findings of this investigation offer valuable insights that can inform the development of preventive strategies for vector-borne diseases, such as considering the appropriate use of insect repellent, mosquito or insect nets, or eliminating breeding places for insects in each season.