3.1. TBP infection rates
One hundred fifty-nine (72.3%) samples showed amplicons for at least 2 of the 9 TBPs. In this study, the following pathogens were identified: A. marginale (23.2%; 51/220), A. phagocytophilum (22.3%; 49/220), A. bovis (9.6%; 21/220), B. bigemina (34.5%; 76/220), B. naoakii (2.7%; 6/220) and B. bovis (7.3%; 16/220), T. parva (15.5%; 34/220), T. taurotragi (22.3%; 49/220), and T. mutans (4.1%; 9/220) (Table 2). In terms of infection rate by sex, 41 males (47.7%) and 118 females (88.1%) were infected with at least one of the examined pathogens. Females exhibited significantly higher detection rates for T. taurotragi (26.9%; p = 0.047) and B. bovis (10.4%; p = 0.031) (Table 3). Eighteen calves (48.6%) and 141 adults (77.1%) were infected with at least one pathogen. Age was strongly linked with infection rates for T. taurotragi (26.8%; p<0.001), B. bigemina (37.7%; p = 0.036), and A. bovis (11.5%; p = 0.029) (Table 3). As denoted in Table 2, substantial variances among six locations for cattle positive for T. parva (p = 0.009), B. bigemina (p=0.026), A. phagocytophilum (p=0.031) were observed. In this study, samples were also analyzed for E. ruminantium, Coxiella burnetii, A. platys, T. orientalis, and Rickettsia spp., but all samples were negative.
3.2. Co-infection of TBP-positive samples
In this study, two or more pathogen species (co-infections) were found in all positive samples (159/220; 72.3%). Up to seven pathogens were detected in one host, including two pathogens (64.2%; 102/159) in the majority of the positive samples. This was followed by three mixed infections (21.4%; 34/159), four mixed infections (8.2%; 13/159), and five mixed infections (4.6%; 7/159). Two animals had six mixed infections (1.3%; 2/159) and one animal had seven mixed infections (0.6%) (Table 4). B. bigemina-T. parva combination was the most common co-infection detected (n=16), followed by B. bigemina-A. phagocytophilum (n=11), B. bigemina-A. marginale (n=8), and B. bigemina-T. mutans (n=6) (Supplementary Table 1).
3.3. Gene sequence analysis
The groEL gene sequences of A. marginale (OP868837–OP868840) were well conserved among themselves, with high identity values of 97.2–99.6%. The identity values of these sequences ranged from 99.1–100% when compared with sequences KX685362–KX685365 of cattle from Benin and MG700525 of cattle from Tanzania. The 16S rRNA nucleotide sequences for A. phagocytophilum (OP824619 and OP824620) and A. bovis (OP824766) showed sequence identity of 99.3% with sequences reported in cattle from Poland (GQ450278) and tick from South Korea (AF470699) and 100% with MZ148472 of cattle from China.
Moreover, the percent sequence identity values of B. bigemina (OP866967–OP866971) in this study ranged from 88.2–99.8%. In addition, the sequences had similarity scores ranging from 98.4–100% with the bovine sequences KP347559 and MK481015, which were obtained from past studies in Kenya and South Africa, respectively. Sequences (n=2; OP839189–OP839190) of B. bovis sbp-4 shared identity values ranging from 94.4–99.2% and showed higher identities of up to 99.8–100% with sequences ON012668 and KF626632, which were previously isolated from cattle in Kenya and South Africa, respectively. Additionally, two B. naoakii ama-1 sequences (OP854628 and OP854629) showed identity values of 99.5–100%. The sequences were identical with sequences LC385892 and LC653109, which were previously isolated from cattle in Sri Lanka and camel in Egypt, respectively.
In contrast, T. parva sequences (OP866888–OP866892) varied between 83.4% and 99.6%, indicating genetic variability among themselves. The sequences showed 96.3% and 100% identity with sequences of Cameroonian cattle (MK568804) and Tanzanian cattle (MG700531), respectively. In addition, the percent identity arrangements of T. taurotragi (n=7; OP824492–OP824498) and T. mutans (n=2; OP821414–OP821415) ranged between 94.5–99.6% and 99.2–100%, respectively. The sequences exhibited between 97.7% and 100% identity with MN726650 of Tanzanian cattle and MH751463 of South African cattle.
3.4. Phylogenetic analyses
Assessing the evolutionary relationship of herein identified pathogens alongside those described elsewhere, phylogenetic trees were generated (Fig. 2–4 and Supplementary Fig. 1–4). Phylogenetic trees were generated using sequences from the databank of NCBI. Three of the A. marginale sequences from this study (OP868837, OP868838, and OP868840) clustered in the same subclade with available homologous sequences in the databank, whereas OP868839 formed an independent branch, a sister subclade to the first subclade (Fig 2). The alignments of A. phagocytophilum and for A. bovis grouped with other GenBank-obtained homologous sequences (Supplementary Fig 4).
Babesia bigemina rap-1a sequences OP866967 and OP866970 clustered in a different subclade, diverging from the main clade where OP866968, OP866969, and OP866971 grouped with isolates from Benin (KX685386), Tanzania (MG210824), Burkina Faso (OK323209), Kenya (KP347559), Bangladesh (MH790974), Uganda (MG426202), and Turkey (KT220512) (Figure 3). The B. naoakii ama-1 sequences (OP854628 and OP854629) from this study clustered with previously reported isolates and were most closely related to LC506533 from Mongolia and LC653109 from Egypt (Supplementary Fig 2). In addition, the B. bovis sbp-4 sequences (OP839189 and OP839190) of this study clustered with sequences LC611418 reported in ticks from Sudan, AB569302 in cattle from Mongolia, AB617641 in cattle from Syria, MZ197893 in cattle and MZ197894 in goat from Egypt, ON012668 in cattle from Kenya, KX685399 in cattle from Benin, and KF626632 in cattle from South Africa (Supplementary Fig 3).
Theileria parva p104 sequences showed some degree of diversity, with OP866888–OP866890 located in the major subclades, while OP866891 and OP866892 grouped in a well-supported and distinct clade (Fig 4). The sequences obtained in this study for T. mutans (OP821414 and OP821415) and T. taurotragi (OP824492–OP824498) were conserved and clustered together with T. mutans sequences from South Africa (MH751463), Angola (MT898574), and Mozambique (FJ869899) and T. taurotragi sequences previously obtained from South Africa (L19082), and Tanzania (OP380380) (Supplementary Fig 1).