Molecular epidemiology and risk factors of Anaplasma spp., Babesia spp. and Theileria spp. infection in cattle in Chongqing, China

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.

Global Prevalence of Anaplasma phagocytophilum in Cattle: A One Health Perspective, Meta-Analysis and Future Predictions (up to 2035)

Anaplasma phagocytophilum is an emerging tick-borne zoonotic bacterium, which is considered a significant risk to the health and industry of cattle in tropical and sub-tropical regions worldwide. This research focuses on examining the worldwide occurrence of A. phagocytophilum in cattle. Several databases, including Scopus, PubMed, ProQuest, Web of Science, ScienceDirect, and Google Scholar, were searched for publications spanning October 2004 to November 2024. The pooled prevalence was calculated with a 95% confidence interval (CI) using a random-effects model based on the Freeman-Tukey double arcsine transformation. A total of 72 studies satisfied the inclusion criteria, revealing a global prevalence of A. phagocytophilum in cattle estimated at 8.5% (5.9%-11.5%). Mongolia (51.9%, 45.9%-56.2%) and Guatemala (51%, 41.2%-60.7%) were countries that accounted for the highest prevalence. Moreover, the infection was most prevalent in African region with prevalence of 11.3% (3.9%-21.5%). The highest prevalence rate was observed in hot-summer Mediterranean climate (13.7%, 4.7%-26.2%). The analysis indicated that immunological techniques were associated with the highest prevalence rate (14.2%, 6.5%-24.3%). The findings of the present research highlighted important geographical and environmental factors that affect the prevalence of disease. In the fields of veterinary medicine and public health, these findings enhance disease management plans and preventative initiatives.

Molecular Characterization of Anaplasma spp. in Cattle from Kazakhstan

Bovine anaplasmosis is an infectious vector-borne disease caused by bacteria of the genus Anaplasma, which have a wide global distribution and represent a high economic burden for agriculture. The use of molecular genetic techniques has increased our knowledge of the species diversity of Anaplasma spp. and naturally susceptible animals. Monitoring studies allow us to assess the level of infection in herds, as well as the involvement of natural vectors in the processes of maintaining and spreading infection. Despite the high prevalence of Theileria and Babesia in cattle in Kazakhstan, there is no information on the distribution and species diversity of Anaplasma spp in this country. As part of this work, 7027 DNA samples isolated from the whole blood of cattle from 175 settlements in all 17 Kazakhstan regions were PCR-tested for the presence of Anaplasma spp. Anaplasma carriers were found in 1.3% (90 out of 7027) of the tested animals in 9 of the 17 regions of Kazakhstan. The highest percentage of infected animals was recorded in Turkistan (South Kazakhstan) and North Kazakhstan with 4.46% and 2.48% positive samples, respectively. The partial sequencing of 16S rRNA and the groEL gene allowed us to identify five species of Anaplasma: A. centrale, A. marginale, Candidatus Anaplasma Mongolica, A. ovis, and Unknown Anaplasma with infection rates of 0.63%, 0.44%, 0.13%, 0.01%, and 0.01%, respectively.

Babesia bigemina and Theileria annulata infections in cattle: molecular detection, phylogenetic analysis, and assessment of risk factors

Babesia bigemina and Theileria annulata are tick-borne protozoans that cause piroplasmosis in cattle, resulting in huge damages to the livestock industry. The prevalence of these infections depends on various intrinsic and extrinsic risk factors. In Pakistan, there is no information regarding the molecular characterization of Babesia bigemina and the risk factors associated with piroplasmosis. This study aimed to molecularly characterize Babesia spp. and Theileria spp. infecting various cattle breeds in Khyber Pakhtunkhwa, Pakistan, and to shed light on risk factors associated with these infections. Altogether, 219 blood samples were collected from various symptomatic cattle breeds, including Holstein Friesian (65.3%; 143/219), Jersey (21.5%; 47/219) and Sahiwal (13.2%; 29/219). Isolated genomic DNA from these blood samples was used in PCR for the amplification of the 18S rRNA fragment of apicomplexan parasites. Obtained 18S rDNA sequences from cattle hosts showed 99.5% identity with B. bigemina, or 100% with T. annulata. Having an overall infection rate of 61.6% (135/219), the highest infection rate was recorded for T. annulata (43.8%; 95/219), followed by B. bigemina (18.3%; 40/219). Phylogenetic analysis of 18S rDNA sequences revealed that B. bigemina clustered with corresponding species reported from Bolivia, and South Africa, while T. annulata grouped with same species from Italy, India, and Turkey. Among the different risk factors, the breed, season, and tick infestation were found to have a significant (P < 0.05) association with the piroplasmid infections. The information obtained in this study can be employed for effective surveillance and control of babesiosis and theileriosis in Pakistan. In addition to confirming our previous molecular detection of T. annulata in cattle, this study provides the first molecular surveillance and phylogenetic position of B. bigemina and associated risk factors in the study region.

Molecular detection of tick-borne piroplasmids in camel blood samples collected from Cairo and Giza governorates, Egypt

Piroplasmosis, a tick-borne disease affecting livestock, including camels, is caused by intracellular apicomplexan parasites belonging to the order Piroplasmida. Despite its importance, there's limited research on piroplasmosis among Egyptian camels. This study aimed to fill this gap by investigating tick-borne piroplasmids in camels from Cairo and Giza Governorates. Out of 181 blood samples collected between October 2021 and March 2022 from apparently healthy one-humped camels (Camelus dromedarius), PCR assays revealed a 41.4 % infection rate with various piroplasmids. Detected species included B. bovis (17.7 %), B. bigemina (12.2 %), B. caballi (8.3 %), B. naoakii (11.6 %), B. microti (1.7 %), T. equi (4.4 %), and Theileria spp. (28.7 %). Phylogenetic analysis revealed the first detection of T. equi genotype E in Egypt and identified a novel B. caballi genotype. Additionally, B. microti isolates were identified as the US-type. These findings shed lights on piroplasmosis among Egyptian camels, and provide valuable information for devising effective control strategies, especially B. microti, a pathogen with potential human health risks.

Epidemiology of Anaplasma species amongst cattle in Africa from 1970 to 2022: A systematic review and meta-analysis

Tick-borne pathogens of the genus Anaplasma cause anaplasmosis in livestock and humans, impacting health and livelihoods, particularly in Africa. A comprehensive review on the epidemiology of Anaplasma species is important to guide further research and for implementation of control approaches. We reviewed observational studies concerning Anaplasma species amongst cattle in Africa. Peer-reviewed studies published in PubMed, Google Scholar, and Web of Science - from database inception to 2022 - were searched. The quality of individual studies was assessed using the Joanna Briggs Institute Critical Appraisal Tool and the pooled prevalences by diagnostic method were estimated using random-effects models. Heterogeneity across the studies was tested and quantified using the Cochran's Q statistic and the I2 statistic. Potential sources of heterogeneity were investigated by subgroup analysis. A total of 1117 records were retrieved and at the end of the screening, 149 records (155 studies) were eligible for this meta-analysis. The occurrence of Anaplasma species was reported in 31/54 countries in all regions. Seven recognised species (A. marginale, A. centrale, A. phagocytophilum, A. platys, A. capra, A. bovis, A. ovis) and nine uncharacterised genotypes (Anaplasma sp. Hadesa; Anaplasma sp. Saso; Anaplasma sp. Dedessa; Anaplasma sp. Mymensingh; Anaplasma sp. Lambwe-1; Candidatus Anaplasma africae; Anaplasma sp.; Candidatus Anaplasma boleense) were reported in African cattle. Anaplasma marginale was the most frequently reported (n=144/155 studies) and the most prevalent species (serology methods 56.1%, 45.9-66.1; direct detection methods 19.9%, 15.4-24.7), followed by A. centrale (n=26 studies) with a prevalence of 8.0% (95% CI: 4.8-11.9) and A. platys (n=19 studies) with prevalence of 9.7% (95% CI: 5.4-15.2). Anaplasma marginale, A. centrale and A. platys were reported in all Africa's regions, while A. ovis and A. capra were reported only in the northern and central regions. The uncharacterised Anaplasma taxa were mostly detected in the eastern and southern regions. Subgroup analysis showed that significant determinants for A. marginale exposure (serology) were geographical region (p=0.0219), and longitude (p=0.0336), while the technique employed influenced (p<0.0001) prevalence in direct detection approaches. Temperature was the only significant variable (p=0.0269) for A. centrale. These findings show that various Anaplasma species, including those that are zoonotic, circulate in African cattle. There is need for more genetic and genome data, especially for unrecognised species, to facilitate effective identification, improve livestock and minimise the health risk in human populations. Additional epidemiological data including pathogen occurrence, tick vectors and host range, as well as pathogenicity are essential.

Leading report of molecular prevalence of tick borne Anaplasma marginale and Theileria ovis in yaks (Bos grunniens) from Pakistan

Domestic yak (Bos grunniens) is an economically important feature of the mountainous region of Gilgit-Baltistan in Pakistan where agriculture is restricted and yaks play multiple roles which includes being a source of milk, meat, hides, fuel and power. However little is known about the parasitic infections in Pakistani yaks. Aim of this research was to report the prevalence and genetic diversity of protozoa parasite (Theileria ovis, 18 S rDNA gene was targeted) and an obligate bacterium (Anaplasma marginale, msp-1 gene was amplified) in the blood that was sampled from 202 yaks collected from four districts in Gilgit-Baltistan during January 2023 till January 2024. Results revealed that 6/202 (3%) yaks were of Theileria ovis while 8/202 (4%) were Anaplasma marginale infected. Positive PCR products of both parasites were confirmed by DNA sequencing and their similarity with previously available pathogen sequences was determined by BLAST analysis. Phylogenetic tree indicated that isolates of both parasites displayed genetic. Anaplasma marginale infection varied with the sampling districts and Shigar district had the highest rate of bacterial infection. Cows were significantly more prone to Theileria ovis infection than bulls. Calf and hybrid yaks were more prone to Anaplasma marginale infection. In conclusion, this is the first report that yaks residing the Gilgit-Baltistan region in Pakistan are infected with Theileria ovis and Anaplasma marginale. Similar larger scales studies are recommended in various regions of Gilgit-Baltistan to document the infection rates of these parasites to formulate strategies that will lead to the effective control of these pathogens.

Effects of cattle on vector-borne disease risk to humans: A systematic review

Vector-borne pathogens (VBPs) causing vector-borne diseases (VBDs) can circulate among humans, domestic animals, and wildlife, with cattle in particular serving as an important source of exposure risk to humans. The close associations between humans and cattle can facilitate the transmission of numerous VBPs, impacting public health and economic security. Published studies demonstrate that cattle can influence human exposure risk positively, negatively, or have no effect. There is a critical need to synthesize the information in the scientific literature on this subject, in order to illuminate the various ecological mechanisms that can affect VBP exposure risk in humans. Therefore, the aim of this systematic review was to review the scientific literature, provide a synthesis of the possible effects of cattle on VBP risk to humans, and propose future directions for research. This study was performed according to the PRISMA 2020 extension guidelines for systematic review. After screening 470 peer-reviewed articles published between 1999-2019 using the databases Web of Science Core Collection, PubMed Central, CABI Global Health, and Google Scholar, and utilizing forward and backward search techniques, we identified 127 papers that met inclusion criteria. Results of the systematic review indicate that cattle can be beneficial or harmful to human health with respect to VBDs depending on vector and pathogen ecology and livestock management practices. Cattle can increase risk of exposure to infections spread by tsetse flies and ticks, followed by sandflies and mosquitoes, through a variety of mechanisms. However, cattle can have a protective effect when the vector prefers to feed on cattle instead of humans and when chemical control measures (e.g., acaricides/insecticides), semio-chemicals, and other integrated vector control measures are utilized in the community. We highlight that further research is needed to determine ways in which these mechanisms may be exploited to reduce VBD risk in humans.

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

Background and Aim

Anaplasma spp. are common rickettsia species described in ruminant hosts, including cattle. The clinical signs of anaplasmosis range from asymptomatic to mortality. However, there are insufficient studies on epidemiology surveys of this blood pathogen. This study aimed to estimate the prevalence and risk factors of anaplasmosis in beef and dairy cattle in Northeast, Thailand.

Materials and Methods

A total of 187 blood samples of beef and dairy cattle were collected from five provinces in Northeast Thailand. Anaplasma spp. infections were screened by microscopic examination and polymerase chain reaction targeting specific genes (msp4 gene for Anaplasma marginale and 16S rRNA gene for Anaplasma platys and Anaplasma bovis). Moreover, the associated risk factors for the infections were evaluated.

Results

Overall, blood samples from cattle revealed that 17.6% (33/187) were positive for Anaplasma spp. by microscopic examination and 20.8% (39/187) were positive by DNA amplification. Of these 20.8%, 17.6% were A. marginale and 3.2% were A. platys. However, A. bovis infection was not detected. Infection with Anaplasma spp. and A. marginale showed a significant association with breed and gender (p < 0.05) while age and packed cell volume levels showed no significant statistical relationship between Anaplasma spp. infected and uninfected animals.

Conclusion

This study indicated that anaplasmosis is distributed in beef and dairy cattle in Thailand; therefore, prevention and control strategies for these pathogens should be improved. This information will benefit veterinarians and cowherds by avoiding vector exposure and eliminating tick breeding sites.

Dynamics of Infections in Cattle and Rhipicephalus microplus: A Preliminary Study

Tick-borne pathogens (TBPs) pose a significant threat to livestock, including bovine species. This study aimed to investigate TBPs in cattle and ticks across four sampling points, utilizing real-time microfluidic PCR. The results revealed that Rhipicephalus microplus ticks were found infesting all animals. Among the detected TBPs in cattle, Anaplasma marginale was the most frequently identified, often as a single infection, although mixed infections involving Rickettsia felis, uncharacterized Rickettsia sp., and Anaplasma sp. were also observed. In ticks, A. marginale was predominant, along with R. felis, Rickettsia sp., and Ehrlichia sp. It is noteworthy that although A. marginale consistently infected all cattle during various sampling times, this pathogen was not detected in all ticks. This suggests a complex dynamic of pathogen acquisition by ticks. A phylogenetic analysis focused on the identification of Anaplasma species using amplified 16S rDNA gene fragments revealed the presence of A. marginale and Anaplasma platys strains in bovines. These findings underscore the presence of multiple TBPs in both cattle and ticks, with A. marginale being the most prevalent. Understanding the dynamics and phylogenetics of TBPs is crucial for developing effective control strategies to mitigate tick-borne diseases in livestock.

Seroprevalence and risk factors of tropical theileriosis in smallholder asymptomatic large ruminants in Egypt

Knowledge of the prevalence and epidemiological determinants of tropical theileriosis in large ruminants, particularly in the asymptomatic carrier, is crucial for designing and implementing effective host-specific control measures. This study aimed to estimate the seroprevalence of tropical theileriosis in asymptomatic cattle and water buffaloes and identify the potential risk factors of theileriosis in large ruminants raised under smallholder-production system in Egypt. A cross-sectional study was conducted in five districts of the Sharkia governorate from March 2019 to February 2020. In total, 350 serum samples were collected from cattle and water buffaloes under smallholder-production system and tested for Theileria annulata antibodies using the indirect antibody fluorescence test (IFAT). Data on species, host characteristics, presence of ticks, season, and districts were collected at sampling using a questionnaire. A multivariable mixed-effects logistic regression model was built to determine the potential risk factors associated with T. annulate seropositivity of the animals. The overall apparent seroprevalence of T. annulata in 350 tested animals was 70%. In the univariable analyses, cattle compared to buffaloes, younger animals compared to older ones, animals with ticks on their bodies, and warmer seasons were all associated with a higher likelihood of seropositive results in the study population while sex of the animals was not associated with seropositivity. The final multivariable model showed that animals with ticks on their bodies had 3.5× higher odds of seropositivity than those with no ticks (P < 0.001), and warmer seasons were associated with the higher odds of infection compared to winter (P = 0.003). The high seroprevalence of tropical theileriosis in the study region indicates that the disease is endemic among smallholders of large ruminants. The identified risk factors of T. annulata-seropositivity in asymptomatic carrier animals provides evidence-based guidance for adopting effective intervention measures.

Incidence of hemoparasitic infections in cattle from central and northern Thailand

Background

Hemoparasites, such as Babesia spp., Theileria spp. and Anaplasma spp., can negatively affect the health of farm animals resulting in significant losses in production. These losses inherently affect the economics of the livestock industry. Since increases in the severity of vector-borne diseases in the southeast Asian region have been reported, investigations of parasitic epidemiology in Thailand will be necessary to improve the existing parasite control strategies for blood parasitic infections. This study aims to investigate incidences of bovine hemoparasites throughout central and northern Thailand by focusing on areas of high-density cattle populations.

Methods

Blood parasitic infections among cattle were screened and identified by microscopic examination. Anemia status was then determined by evaluation of the packed cell volume (PCV) of each animal. Furthermore, blood parasites were detected and identified by genus and species-specific primers through the polymerase chain reaction method. Amplicons were subjected to DNA sequencing; thereafter, phylogenetic trees were constructed to determine the genetic diversity and relationships of the parasite in each area.

Results

A total of 1,066 blood samples were found to be positive for blood parasitic infections as follows: 13 (1.22%), 389 (36.50%), and 364 (34.15%) for Babesia bovis, Theileria orientalis, and Anaplasma marginale, respectively. Furthermore, multiple hemoparasitic infections in the cattle were detected. The hematocrit results revealed 161 hemoparasitic infected samples from 965 blood samples, all of which exhibiting indications of anemia with no significant differences. Sequence analysis of the identified isolates in this study revealed that B. bovis rap-1, four separate clades of T. orientalis msps, and A. marginale msp4 exhibited considerable sequence similarity to homologous sequences from isolates obtained from other countries. Sequence similarity ranged between 98.57-100%, 83.96-100%, and 97.60-100% for B. bovis rap-1, T. orientalis msps, and A. marginale msp4, respectively.

Conclusion

In this study, the analyzed incidence data of cattle hemoparasitic infection in Thailand has provided valuable and basic information for the adaptation of blood-borne parasitic infections control strategies. Moreover, the data obtained from this study would be useful for future effective parasitic disease prevention and surveillance among cattle.

Molecular epidemiology and genetic characterization of Theileria orientalis in cattle

Theileria orientalis (T. orientalis) is a benign species of Theileria that is found all throughout the world, including Egypt. The purpose of this work was to determine the current status of T. orientalis infection in cattle, as well as to define T. orientalis genetic diversity using the major piroplasm surface protein (MPSP) genes. In 2020, blood samples from 500 asymptomatic cattle were collected, which live in four different governorates at northern Egypt and examined using PCR assay based on MPSP gene. Overall, 44 blood samples (8.8%, 44/500) were positive for T. orientalis, and the highest prevalence rate was observed in Kafer ElSheikh while it was relatively low in Gharbia governorate. Moreover, based on multivariable analysis, the risk of infection with T. orientalis infection was higher in mixed breed cattle and in animals of age group more than 3 years compared to other. Additionally, absence of acaricide application, infestation with ticks, and communal grazing system were identified as potential risk factors for T. orientalis infection. Phylogenetic analysis revealed that the isolates studied belonged to two MPSP genotypes, types 1 and 2. These findings reveal that the MPSP genotypes discovered in the present work displayed genetic variation that was linked to geographic area. Therefore, further research should be focused on developing an effective T. orientalis monitoring and preventive program.

Molecular detection of Anaplasma spp., Babesia spp. and Theileria spp. in yaks (Bos grunniens) and Tibetan sheep (Ovis aries) on the Qinghai-Tibetan Plateau, China

BACKGROUND

Anaplasma, Babesia and Theileria are tick-borne pathogens (TBPs) that affect livestock worldwide. However, information on these pathogens in yaks (Bos grunniens) and Tibetan sheep (Ovis aries) on the Qinghai-Tibet Plateau (QTP), China, is limited. In this study, Anaplasma spp., Babesia spp. and Theileria spp. infections were assessed in yaks and Tibetan sheep from Qinghai Province.

METHODS

A total of 734 blood samples were collected from 425 yaks and 309 Tibetan sheep at nine sampling sites. Standard or nested polymerase chain reaction was employed to screen all the blood samples using species- or genus-specific primers.

RESULTS

The results showed that 14.1% (60/425) of yaks and 79.9% (247/309) of Tibetan sheep were infected with at least one pathogen. Anaplasma ovis, Anaplasma bovis, Anaplasma capra, Anaplasma phagocytophilum, Babesia bovis and Theileria spp. were detected in this study, with total infection rates for all the assessed animals of 22.1% (162/734), 16.3% (120/734), 23.6% (173/734), 8.2% (60/734), 2.7% (20/734) and 19.3% (142/734), respectively. For yaks, the infection rate of A. bovis was 6.4% (27/425), that of B. bovis was 4.7% (20/425) and that of Theileria spp. was 3.3% (14/425). Moreover, 52.4% (162/309) of the Tibetan sheep samples were infected with A. ovis, 30.1% (93/309) with A. bovis, 56.0% (173/309) with A. capra, 19.4% (60/309) with A. phagocytophilum and 41.4% (128/309) with Theileria spp.

CONCLUSIONS

This study revealed the prevalence of Anaplasma spp., Babesia spp. and Theileria spp. in yaks and Tibetan sheep in Qinghai Province, China, and provides new data for a better understanding of the epidemiology of TBPs in these animals in this area of the QTP, China.

Prevalence of Theileria in cattle in China: A systematic review and meta-analysis

Theileria, one of the causative agents of blood protozoan, has brought a huge economic loss to the cattle industry worldwide. However, the epidemiology of Theileria in Chinese cattle has not been systematically investigated. This comprehensive review aimed at investigating the prevalence of Theileria infection in cattle in China. A total of 48 published papers on Theileria infection in cattle in China (including data from 21,366 animals) from inception to October 8, 2021 met the inclusion standard after searching in five databases (Technology Periodical Database, Wan Fang Database, China National Knowledge Infrastructure, PubMed, and ScienceDirect). The pooled prevalence of Theileria in cattle in China was 32.4% identified by using a random effects model. The prevalence in Northeastern China (45.3%) was higher than that in other regions. In the sex subgroup, the prevalence of Theileria was higher in females (48.9%) than that in males (45.8%). The prevalence of Theileria was higher in cattle of free range (34.4%) compared with that of intensive farming (22.3%). The prevalence prior to 2013 (36.1%) was higher than that after 2013 (33.6%). Among three cattle species, dairy cows had the lowest prevalence (21.5%). The prevalence of Theileria (T.) annulata (22.2%) and T. sergenti (26.2%) was higher than other species of Theileria (T. buffeli: 17.5%, T. luwenshuni: 0.9%, T. orientalis: 15.5%, T. ovis: 0.21%, T. sinensis: 20.2%, T. uilenbergi: 6.2%, Others: 0.9%). We also analyzed the impact of different geographic factor subgroups (longitude, latitude, precipitation, temperature, humidity, and altitude) on the prevalence of Theileria in cattle. Among them, climatic factors of longitude, latitude, precipitation, humidity, temperature were associated with the prevalence of Theileria. These analyses suggested that Theileria was common in cattle in China. Targeted prevention programs based on geographic and climatic conditions in different areas may play an important role in reducing Theileria infection among cattle.

Molecular prevalence and risk factors associated with tick-borne pathogens in cattle in western Kenya

Background

Tick-borne pathogens (TBPs) are of global importance, especially in sub-Saharan Africa where they represent a major constraint to livestock production. Their association with human disease is also increasingly recognized, signalling their zoonotic importance. It is therefore crucial to investigate TBPs prevalence in livestock populations and the factors associated with their presence. We set out to identify TBPs present in cattle and to determine associated risk factors in western Kenya, where smallholder livestock production is important for subsistence and market-driven income.

Results

Tick-borne pathogen infections in blood samples collected from cattle at livestock markets and slaughterhouses between May 2017 and January 2019 were identified by high-resolution melting analysis and sequencing of PCR products of genus-specific primers. Of the 422 cattle sampled, 30.1% (127/422) were infected with at least one TBP, while 8.8% (37/422) had dual infections. Anaplasma spp. (19.7%) were the most prevalent, followed by Theileria (12.3%), Ehrlichia (6.6%), and Babesia (0.2%) spp. Sequence analysis of the TBPs revealed them to be Anaplasma platys-like organisms (13.5%), Theileria velifera (7.4%), Anaplasma marginale (4.9%), Theileria mutans (3.1%), Theileria parva (1.6%), and Babesia bigemina (0.2%). Ehrlichia ruminantium, Rickettsia spp., and arboviruses were not detected. Exotic breeds of cattle were more likely to be infected with A. marginale compared to local breeds (OR: 7.99, 95% CI: 3.04–22.02, p <  0.001). Presence of ticks was a significant predictor for Anaplasma spp. (OR: 2.18, 95% CI: 1.32–3.69, p = 0.003) and Ehrlichia spp. (OR: 2.79, 95% CI: 1.22–7.23, p = 0.022) infection. Cattle sampled at slaughterhouses were more likely to be positive for Anaplasma spp. (OR: 1.64, 95% CI: 1.01–2.70, p = 0.048) and A. marginale (OR: 3.84, 95% CI: 1.43–12.21, p = 0.012), compared to those sampled at livestock markets.

Conclusion

This study reports TBP prevalence and associated risk factors in western Kenya, factors which are key to informing surveillance and control measures.

Molecular survey on prevalence and risk factors of Anaplasma spp. infection in cattle and sheep in West of Iran

Tick-borne pathogens (TBPs) in general and Anaplasma spp. in particular are known as economically important agents of diseases of domestic ruminants worldwide. Little information exists regarding the prevalence and the role of various factors affecting the occurrence of anaplasmosis in the west of Iran. The present study was carried out to determine the prevalence and risk factors associated with Anaplasma pathogens in Kurdistan province, west of Iran. During spring and summer 2016, blood samples were collected from a total of 401 livestock animals from different farms distributed in the Kurdistan province. Furthermore, data on general husbandry traits and management practices were recorded. PCR examination showed an overall prevalence of 37.3 and 10% in cattle and sheep, respectively. Cattle were infected with A. phagocytophilum (23.8%), A. bovis (15.4%), and A. marginale (13.9%) while sheep were infected with A. ovis (10%) and A. phagocytophilum (3.5%). The occurrence of anaplasmosis was considerably higher in cattle compared to sheep (P < 0.0001). Based on results of logistic regression models, risk of Anaplasma infection was significantly higher in crossbreeds (odds ratio (OR) = 1.93, 95% confidence interval (CI) = 1.025-3.65, P = 0.042) compared with local cattle breeds. Furthermore, being older than 1 year was associated with increased risk of Anaplasma infection in cattle (OR = 2.18, 95%, CI = 1.022-4.68, P = 0.044) and sheep (OR = 2.86, 95%, CI = 1.006-8.22, P = 0.049) compared to younger individuals. No difference was observed between the counties. Identifying potential risk factors and potential vectors and reservoirs contribute to the successful control and prevention of tick-borne diseases.

Seasonal dynamics of Anaplasma spp. in goats in warm-temperate zone of China

Anaplasma are tick-borne obligate intracellular bacteria that can endanger human and animal health, and until now, there have been few reports on the seasonal dynamics of Anaplasma species in China. In this study, a total of 491 goat blood samples were collected in spring (n = 124), summer (n = 135), autumn (n = 110), and winter (n = 122) from Shaanxi provinces. Single and mixed infections of Anaplasma spp. from warm-temperate regions of China were analyzed according to seasons using a nested PCR method. Positive samples were sequenced to observe the molecular and phylogenetic characteristics of the Anaplasma species, and we determined the co-infection rates of Anaplasma spp. for each season. A molecular survey of Anaplasma phagocytophilum, A. bovis, A. ovis, and A. capra in goats showed average prevalences of 71.6 % (maximum 86.7 % in summer and minimum 48.4 % in winter), 62.2 % (minimum 38.7 % in spring and maximum 94.1 % in summer), 25.5 % (minimum 0% in summer and maximum 51.6 % in spring), and 26.6 % (minimum 8.2 % in winter and maximum 55.6 % in summer), respectively. In the phylogenetic analysis, A. phagocytophilum and A. capra occupied two separate groups, Chinese A. bovis and foreign isolates appeared to be geographically isolated, and all A. ovis isolates were in the same branch as the previously described sequences. The survey indicated that goats in warm-temperate regions of China are frequently exposed to Anaplasma spp. all year round, and thus prevention and treatment efforts for anaplasmosis in the region should be strengthened.

Anaplasma and Theileria Pathogens in Cattle of Lambwe Valley, Kenya: A Case for Pro-Active Surveillance in the Wildlife-Livestock Interface

Tick-borne pathogens (TBPs) are major constraints to livestock production and a threat to public health in Africa. This cross-sectional study investigated the risk of infection with TBPs in cattle of Lambwe Valley, Kenya. Blood samples of 680 zebu cattle from 95 herds in six geospatial clusters within 5 km of Ruma National Park were screened for bacterial and protozoan TBPs by high-resolution melting analysis and sequencing of PCR products. We detected Anaplasma bovis (17.4%), Anaplasma platys (16.9%), Anaplasma marginale (0.6%), Theileria velifera (40%), and Theileria mutans (25.7%), as well as an Anaplasma sp. (11.6%) that matched recently reported Anaplasma sp. sequences from Ethiopia. Babesia, Rickettsia, and Ehrlichia spp. were not detected. The animal and herd-level prevalences for TBPs were 78.5% (95% confidence intervals (CI): 75.3, 81.5) and 95.8% (95% CI: 91.8, 99.8), respectively. About 31.6% of cattle were co-infected with 13 combinations of TBPs. The prevalence of TBPs differed between clusters and age, but the risk of infection was not associated with sex, herd size, or the distance of homesteads from Ruma. This study adds insight into the epidemiology of TBPs around Ruma and highlights the need for proactive surveillance of TBPs in livestock–wildlife interfaces.

Bovines Harbor a Diverse Array of Vector-Borne Pathogens in Northeast Algeria

Arthropod-borne hemoparasites represent a serious health problem in livestock, causing significant production losses. Currently, the evidence of Anaplasma spp., Theileria spp., Babesia spp., and hemotropic Mycoplasma spp. in Algeria remains limited to a few scattered geographical regions. In this work, our objectives were to study the prevalence of these vector-borne pathogens and to search other agents not yet described in Algeria as well as the identification of statistical associations with various risk factors in cattle in the northeast of Algeria. Among the 205 cattle blood samples tested by PCR analysis, 42.4% positive results were obtained for at least one pathogen. The overall rates of Anaplasma spp., Theileria/Babesia spp., and Mycoplasma spp. in the cattle sampled were respectively 30.7%, 18.5%, and 2.9%; co-infections with multiple species was also detected. Anaplasma spp. and Theileria/Babesia spp. were detected at a higher rate in cattle under 3 years old, according to univariate analysis. Anaplasma spp. DNA was detected more frequently in our sample in cattle living in semi extensive farming. Our study provides additional data about Anaplasma spp., Theileria/Babesia spp. and reveals for the first time that Mycoplasma wenyonii and 'Candidatus Mycoplasma hemobos are present in cattle in Northeast Algeria.

Epidemiology and genotyping of Anaplasma marginale and co-infection with piroplasms and other Anaplasmataceae in cattle and buffaloes from Egypt

BACKGROUND

Anaplasma marginale is an obligate intracellular bacterium and the main cause of bovine anaplasmosis in tropical and subtropical regions. In Egypt, data regarding the prevalence of A. marginale in ruminant hosts and of the circulating genotypes is lacking. This study therefore aimed to (i) investigate the presence, epidemiology and genotypes of A. marginale in cattle and buffaloes in Egypt, (ii) to evaluate suitable diagnostic tools and (iii) to identify co-infections of A. marginale with other selected tick-borne pathogens.

METHODS

Blood samples were collected from 394 animals (309 cattle and 85 buffaloes) from three different areas in Egypt. For the detection of A. marginale infection, several tests were compared for their sensitivity and specificity: blood smear analysis, enzyme-linked immunosorbent assay (ELISA), PCR, real-time PCR and reverse line blot (RLB) assay. Co-infections with A. marginale, piroplasms and other Anaplasmataceae were surveyed by RLB while A. marginale genotypes were identified by amplifying and sequencing the partial msp1α gene.

RESULTS

Anaplasma marginale DNA was amplified by qPCR in 68.3% of cattle and 29.4% of buffaloes. RLB showed infection with A. marginale in 50.2% of cattle and 42.5% of buffaloes. Blood smear analysis detected this agent in 16.2% of cattle and 2.4% of buffaloes. ELISA showed specific antibodies against A. marginale in 54.9% of cattle. Anaplasma marginale was associated, in cattle and buffaloes, with several tick-borne pathogens (Theileria annulata, Babesia bovis, Babesia bigemina, Babesia occultans and Anaplasma platys). A significant difference of A. marginale infection level was noticed in cattle, where animals between 3-5-years-old had a higher prevalence (79.2%) compared to those older than 5 years (36.4%) and younger than 3 years (59.7%) and one year (64.5%), respectively (P = 0.002281). Microsatellite analysis identified 15 different genotypes.

CONCLUSIONS

The epidemiological findings revealed high prevalence of A. marginale in cattle and buffaloes in all the investigated areas. The circulation of diverse genotypes was observed, most of these A. marginale genotypes being specific for Egypt. The qPCR assay was confirmed to be the most sensitive tool for detection of A. marginale in cattle and buffaloes even in the carrier state, highlighting the importance of using suitable diagnostic tests.

Molecular Detection and Identification of Babesia spp., Theileria spp., and Anaplasma spp. in Sheep From Border Regions, Northwestern China

Babesia, Theileria, and Anaplasma are important causative agents of tick-borne diseases that severely affect sheep. However, there is paucity in the occurrence genetic diversity of the infections of tick-borne diseases in sheep in border regions, northwestern China. In this study, nested polymerase chain reaction (nPCR) assays and gene sequencing were used to identify tick-borne Babesia spp., Theileria spp., and Anaplasma spp. infections in border regions, northwestern China. Out of 323 samples tested in this study, 225 (69.7%) sheep were infected with Babesia spp., Theileria spp., and Anaplasma spp. Two hundred six (63.8%), 60 (18.6%), 54 (16.7%), 51 (15.8%), 32 (9.9%), 19 (5.9%), and 16 (5.0%) were positive for A. ovis, B. motasi-like, A. bovis, T. uilenbergi, A. phagocytophilum, T. luwenshuni, and B. motasi-like Xinjiang, respectively. The most common dual infection was with A. ovis and B. motasi-like while the most frequent triple coinfection was A. ovis, B. motasi-like, and T. uilenbergi with coinfection rates of 17.0% (55/323) and 5.0% (16/323), respectively. Sequencing analysis indicated that A. ovis MSP4, A. phagocytophilum epank1, A. bovis 16S rRNA, B. motasi-like rap1-b, B. motasi-like Xinjiang rap1-a, T. luwenshuni 18S rRNA, and T. uilenbergi 18S rRNA from border regions, northwestern China, showed 99–100% identity with documented isolates from other countries. To the best of the authors' knowledge, this is the first report of T. uilenbergi and T. luwenshuni infections of sheep in border regions, northwestern China. Furthermore, these findings provide important data for understanding the distribution of Babesia, Theileria, and Anaplasma in sheep between border countries and China.

The co-infection with Ehrlichia minasensis, Anaplasma marginale and Anaplasma platys is not associated with anemia in beef cattle in the Brazilian Pantanal

The Anaplasmataceae family is composed of obligatory intracellular Gram-negative bacteria transmitted by arthropod vectors. In Brazil, with the exception of Anaplasma marginale, little is known about the occurrence of other Anaplasma and Ehrlichia species infecting cattle. The present study aimed at investigating the occurrence of Anaplasma spp. and Ehrlichia spp. in beef cattle (Bos indicus) sampled in the Brazilian Pantanal, an area prone to periodic flooding and endemic for bovine trypanosomiasis. Blood samples from 400 cattle were collected and screened by PCR assays based on rrs and dsb genes from Anaplasma spp. and Ehrlichia spp., respectively. Positive samples for Anaplasma spp. were subjected to qPCR assays based on the msp-2 gene and nPCR based on the groEL gene. As a result, 4.75% (19/400) and 48.12% (167/347) were positive for Anaplasma platys and Ehrlichia minasensis, respectively. Besides, positivity of 56.75% (227/400) for A. marginale and seropositivity of 90.75% (363/400) for Trypanosoma vivax were found. A high rate of co-infection was observed (67.25%), from which the co-infection by A. marginale and E. minasensis was more frequently found in calves than cows. Interestingly, none of the animals presenting co-infection showed anemia or other clinical signs. The present study showed, for the first time, the occurrence of A. platys and E. minasensis in beef cattle in the southern Pantanal, as well as a high rate of co-infection by A. marginale, E. minasensis and T. vivax in the sampled animals.

Epidemiological Characteristics and Spatiotemporal Analysis of Acute Hemorrhagic Conjunctivitis from 2004 to 2018 in Chongqing, China

Chongqing is one of the five provinces in China that has the highest incidence of acute hemorrhagic conjunctivitis (AHC). Data of AHC cases from 2004 to 2018 were obtained from National Notifiable Diseases Reporting Information System (NNDRIS). Descriptive statistical methods were used to analyze the epidemiological characteristics; incidence maps were used to reflect incidence trends in each district; spatial autocorrelation was used to identify hotspot regions and spatiotemporal patterns of AHC outbreaks; spatiotemporal scan were conducted to identify AHC clusters. A total of 30,686 cases were reported with an annual incidence of 7.04 per 100,000. The incidence rates were high in 2007 and 2014, and large epidemics were observed in 2010 with the seasonal peak in September. Individuals aged 10–19 years, males, students and farmers were the prime high-risk groups. Except for 2012 and 2013, the spatial distribution of AHC did not exhibit significant global spatial autocorrelation. Local indicators of spatial association showed that the high-risk regions are Chengkou and Wuxi. The spatiotemporal scan indicated that all clusters occurred in September 2010, and the high-incidence clusters were mainly distributed in the northeast of Chongqing. The results could assist public health agencies to consider effective preventive measures based on epidemiological factors and spatiotemporal clusters in different regions.

Molecular characterization of tick-borne bacteria and protozoans in yaks (Bos grunniens), Tibetan sheep (Ovis aries) and Bactrian camels (Camelus bactrianus) in the Qinghai-Tibetan Plateau Area, China

Due to the specific plateau climate, a variety of unique animals live in the Qinghai-Tibetan Plateau Area (QTPA) including yaks (Bos grunniens), Tibetan sheep (Ovis aries) and Bactrian camels (Camelus bactrianus). However, information on tick-borne diseases (TBDs) in the QTPA and on the molecular characteristics of tick-borne pathogens (TBPs) in the area is limited. Therefore, the aim of this study was to investigate Anaplasma spp., Babesia spp., Theileria spp., Borrelia burgdorferi sensu lato and Rickettsia spp. infecting yaks, Tibetan sheep and camels in this area. A total of 276 animals were screened. Overall, 84.5% (164/194) of yaks, 58% (23/40) of Tibetan sheep, and 38% (16/42) of camels tested positive for at least one pathogen. Theileria spp., Anaplasma ovis and spotted fever group (SFG) Rickettsia spp. were detected as TBPs in the current study with overall infection rates of 10.9% (30/276), 8.3% (23/276) and 62.9% (171/276), respectively. Further study revealed that 1.5% (3/194) of the yaks were infected with Theileria sp. OT3, 1.5% (3/194) with T. luwenshuni, 6.2% (12/194) with T. uilenbergi, 1.1% (2/194) with T. ovis and 82% (159/194) with SFG Rickettsia spp. It was also shown that 58% (23/40) of the Tibetan sheep were infected with A. ovis and 15% (6/40) with T. ovis. Among the camels, 10% (4/42) were infected with T. equi, while 29% (12/42) were positive for Rickettsia spp. Sequence analysis revealed that the Rickettsia spp. infecting yaks and camels were Rickettsia raoultii and Rickettsia slovaca. To the best of our knowledge, this study reports the first detection and characterization of these pathogens in yaks, Tibetan sheep and camels in the country, except for T. luwenshuni infections in yaks.

Molecular detection, prevalence and risk factors of Theileria orientalis infection among cattle in Peninsular Malaysia

There is need to confirm the presence of Theileria orientalis among the cattle population in Peninsular Malaysia and to evaluate the risk factors associated with the infection. To this effect, blood samples were collected from 1045 cattle from 43 farms throughout the entire States of Peninsular Malaysia. The collected blood samples were subjected to DNA extraction and subsequent PCR amplification of the major piroplasm surface protein (MPSP) gene of the haemoprotozoan. Representative positive amplicons were purified, sequenced and compared with other sequences of the MPSP gene of T. orientalis curated from the GenBank. A well-structured questionnaire was used to get information about each cattle, it's demography, the bio-security, environmental and management factors. Univariate and multivariate analysis were used for the statistical evaluation, with significance set at p < 0.05. A total prevalence of 49.76% (520/1045; 95% CI: 46.73 - 52.79) was obtained. Types of breeds, age, production type, herd size, level of farm biosecurity, farm size, presence of other animal species in the farm, management systems and prophylaxis were significantly (p < 0.05) associated with the prevalence of T. orientalis. This study confirmed the presence of T. orientalis and establish that the haemoprotozoan is endemic among cattle in Peninsular Malaysia.

Molecular detection of Anaplasma spp. in dairy cattle in southern Xinjiang, China

Bovine anaplasmosis is caused by a group of obligate intracellular bacteria belonging to the genus Anaplasma, which are transmitted by ticks. This study was conducted to determine the prevalences and molecular characterization of Anaplasma spp. in dairy cattle in the upper reaches of the Tarim River in Xinjiang, China. Using polymerase chain reaction (PCR) and sequencing approaches, DNA of Anaplasma spp. was detected in 16 of 493 (3.2%) blood samples from dairy cattle. Positive rates were 0.2% (1/493), 0.4% (2/493), 0.2% (1/493), 2.4% (12/493) and 2.4% (12/493) for A. bovis, A. ovis, A. phagocytophilum like strain, A. phagocytophilum and A. platys like strain, respectively. Anaplasma phagocytophilum and A. platys like strain co-infection was detected in 12 samples. To our knowledge, this is the first report of A. ovis infection in dairy cattle in Xinjiang. This study provides new data on the prevalences of Anaplasma spp. in cattle in Xinjiang, which will help to formulate appropriate control strategies for these pathogens in this area.

Correction: Molecular epidemiology and risk factors of Anaplasma spp., Babesia spp. and Theileria spp. infection in cattle in Chongqing, China

[This corrects the article DOI: 10.1371/journal.pone.0215585.].