Molecular epidemiology of bovine anaplasmosis with a particular focus in Mexico

The replication rate of Anaplasma marginale is temperature-mediated in ticks

Anaplasma marginale , the cause of bovine anaplasmosis, a serious production-limiting disease of cattle found worldwide, is biologically transmitted by adult male Dermacentor spp. ticks in the United States. We tested the impact of 9 temperatures on infected D. andersoni and found that the replication of A. marginale in tick midguts and salivary glands is temperature dependent. There were higher bacterial levels between 32°C and 37°C than between 4°C to 26°C. We observed 100% mortality in ticks at 42°C. Future research should explore the mechanisms of temperature-dependent replication in A. marginale and possible links to transmission rates under climate change.

Molecular Detection of Anaplasma marginale in Amblyomma mixtum Infesting Cattle in the Major Livestock-Producing States of Mexico

Bovine anaplasmosis is a tick-borne disease caused by Anaplasma marginale, although mechanical transmission by biting flies also occurs. Infection with A. marginale can reach 26% mortality and morbidity is associated with reduced beef and milk production, causing economic losses for livestock producers. Between March 2022 and July 2023, 1920 ticks were collected from 52 cattle production units in major cattle-producing states in Mexico, including Chiapas, Jalisco, Michoacán, Tabasco, and Veracruz. Of all the ticks collected, 35.57% were morphologically identified as Amblyomma mixtum. Samples of A. mixtum from each state, totaling 271, were tested for A. marginale via polymerase chain reaction (PCR). A. marginale was detected molecularly in 15.3% of A. mixtum samples. A. mixtum from Chiapas had the highest prevalence of A. marginale (24.0%), followed by Tabasco and Veracruz (20.0% each), Jalisco (15.2%), and Michoacán (6.6%). Phylogenetic analysis supported the morphological identification of A. mixtum and confirmed the genetic identity of A. marginale. This research is the first report on the molecular detection of A. marginale in A. mixtum ticks in Mexico. Results suggest that this 3-host tick species might be a potential vector. A. mixtum is Mexico's second most economically significant tick feeding on cattle after Rhipicephalus microplus. This information about A. marginale prevalence in A. mixtum expands our understanding of bovine anaplasmosis epidemiology in Mexico. Further research is needed to assess the role of A. mixtum as a vector of A. marginale.

Bovine anaplasmosis in Zimbabwe: spatio-temporal distribution and environmental drivers

Understanding the spatial and temporal distribution of Bovine anaplasmosis is crucial for identifying areas of high prevalence for targeted disease control. This research was aimed at modelling and mapping the B. anaplasmosis potential distribution, and identify hotspots as well as significant variables explaining the occurrence of the disease. The Getis Ord Gi* statistic for Hotspot analysis was used as well as MaxEnt ecological niche modelling. The effects of time, land-use, and agro-ecological regions on B. anaplasmosis occurrence were tested using Analysis of Variance (ANOVA). Results showed that several districts in Zimbabwe are suitable for the occurence of the disease for example Binga, Seke, Buhera, Kwekwe, Gweru, Mhondoro, Chegutu, Sanyati, and in the North: Mbire, Muzarabani, Mt Darwin, Shamva, Bindura, Zvimba and Makonde. Morbidity and mortality hotspots were detected in Gokwe-south, Kwekwe, and Chirumhanzu districts. Binga, Gokwe-south, Gutu, Hurungwe, Mazoe, Nkayi, Shamva, and Kwekwe districts also experienced high disease incidences. Temperature seasonality, precipitation seasonality, mean diurnal range, and isothermality were the most important variables in explaining 93% of B. anaplasmosis distribution. Unlike land-use and agro-ecological regions, time (months) had a significant effect on B. anaplasmosis occurrence with July and September having significantly (p < 0.05) higher cases and deaths than the rest of the months. The results of this study provide insights into the management strategies and control of B. anaplasmosis in Zimbabwe. It is thus concluded that geo-spatial techniques, combined with ecological niche modelling can provide useful insights into disease prevalence and distribution and hence can contribute to effective management and control of B. anaplasmosis in Zimbabwe.

In Situ Localization of Staphylococcus shinii and Staphylococcus succinus in Infected Rhipicephalus microplus Ticks: Implications for Biocontrol Strategies

Rhipicephalus microplus is a blood-sucking parasite that causes heavy infestations on cattle and is a vector for severe tick-borne diseases, such as anaplasmosis and babesiosis, and poses a significant threat to the cattle industry. Cattle ticks show increasing acaricide resistance, which creates an additional problem concerning the inefficient chemical control of tick populations in cattle-grazing areas, necessitating the exploration of alternative tick biocontrol methods. Our study aimed to demonstrate the acaropathogenic efficacy of two bacterial species during experimental infections on R. microplus. Our experimental data confirmed that S. shinii and S. succinus exhibited significant acaropathogenic properties against R. microplus, as demonstrated by the tracking of fluorescent-labeled bacteria within the engorged-tick body. Our experiments revealed that both bacterial species could infect the hemolymph, salivary glands, and vestibular vagina of the tick, inducing histological changes in the affected organs that may impair feeding as well as reproductive capabilities. Gené's organ infection was detected only in S. succinus. Our findings offer valuable insights for developing biocontrol strategies to manage Rhipicephalus microplus populations effectively.

Dynamic nesting of Anaplasma marginale in the microbial communities of Rhipicephalus microplus

Interactions within the tick microbiome involving symbionts, commensals, and tick-borne pathogens (TBPs) play a pivotal role in disease ecology. This study explored temporal changes in the microbiome of Rhipicephalus microplus, an important cattle tick vector, focusing on its interaction with Anaplasma marginale. To overcome limitations inherent in sampling methods relying on questing ticks, which may not consistently reflect pathogen presence due to variations in exposure to infected hosts in nature, our study focused on ticks fed on chronically infected cattle. This approach ensures continuous pathogen exposure, providing a more comprehensive understanding of the nesting patterns of A. marginale in the R. microplus microbiome. Using next-generation sequencing, microbiome dynamics were characterized over 2 years, revealing significant shifts in diversity, composition, and abundance. Anaplasma marginale exhibited varying associations, with its increased abundance correlating with reduced microbial diversity. Co-occurrence networks demonstrated Anaplasma's evolving role, transitioning from diverse connections to keystone taxa status. An integrative approach involving in silico node removal unveils the impact of Anaplasma on network stability, highlighting its role in conferring robustness to the microbial community. This study provides insights into the intricate interplay between the tick microbiome and A. marginale, shedding light on potential avenues for controlling bovine anaplasmosis through microbiome manipulation.

Molecular detection of Rickettsiales and a potential novel Ehrlichia species closely related to Ehrlichia chaffeensis in ticks (Acari: Ixodidae) from Shaanxi Province, China, in 2022 to 2023

Important tick-borne diseases include spotted fever group Rickettsia (SFGR), Anaplasma, and Ehrlichia, which cause harm to animal and human health. Ixodidae are the primary vectors of these pathogens. We aimed to analyze the prevalence and genetic diversity of SFGR, Anaplasma, and Ehrlichia species in the Ixodidae in Shaanxi Province, China. Herein, 1,113 adult Ixodidae ticks were collected from domestic cattle and goats, and detected using nested PCR. A total of four Ixodidae species were collected and Ca. R. jingxinensis (20.58%, 229/1113), A. bovis (3.05%, 34/1113), A. capra (3.32%, 37/1113), A. marginale (0.18%, 2/1113), E. sp. Yonaguni138 (0.18%, 2/1113), and a potent novel Ehrlichia species named E. sp. Baoji96 (0.09%, 1/1113) were detected. A. marginale was detected for the first time in Rhipicephalus microplus. E. sp. Baoji96 was closely related to E. chaffeensis and was first identified in Haemaphysalis longicornis. In addition, co-infection with two Rickettsiales pathogens within an individual tick was detected in 10 (1.54%) ticks. This study provides a reference for the formulation of biological control strategies for ticks and tick-borne diseases in Shaanxi Province, and could lead to an improved control effect.

Perception of Ticks and Tick-Borne Diseases Worldwide

In this comprehensive review study, we addressed the challenge posed by ticks and tick-borne diseases (TBDs) with growing incidence affecting human and animal health worldwide. Data and perspectives were collected from different countries and regions worldwide, including America, Europe, Africa, Asia, and Oceania. The results updated the current situation with ticks and TBD and how it is perceived by society with information bias and gaps. The study reinforces the importance of multidisciplinary and international collaborations to advance in the surveillance, communication and proposed future directions to address these challenges.

Microorganisms associated with hedgehog arthropods

Hedgehogs are small synanthropic mammals that live in rural areas as well as in urban and suburban areas. They can be reservoirs of several microorganisms, including certain pathogenic agents that cause human and animal public health issues. Hedgehogs are often parasitized by blood-sucking arthropods, mainly hard ticks and fleas, which in turn can also carry various vector-born microorganisms of zoonotic importance. Many biotic factors, such as urbanization and agricultural mechanization, have resulted in the destruction of the hedgehog's natural habitats, leading these animals to take refuge near human dwellings, seeking food and shelter in parks and gardens and exposing humans to zoonotic agents that can be transmitted either directly by them or indirectly by their ectoparasites. In this review, we focus on the microorganisms detected in arthropods sampled from hedgehogs worldwide. Several microorganisms have been reported in ticks collected from these animals, including various Borrelia spp., Anaplasma spp., Ehrlichia spp., and Rickettsia spp. species as well as Coxiella burnetii and Leptospira spp. As for fleas, C. burnetii, Rickettsia spp., Wolbachia spp., Mycobacterium spp. and various Bartonella species have been reported. The detection of these microorganisms in arthropods does not necessarily mean that they can be transmitted to humans and animals. While the vector capacity and competence of fleas and ticks for some of these microorganisms has been proven, in other cases the microorganisms may have simply been ingested with blood taken from an infected host. Further investigations are needed to clarify this issue. As hedgehogs are protected animals, handling them is highly regulated, making it difficult to conduct epidemiological studies on them. Their ectoparasites represent a very interesting source of information on microorganisms circulating in populations of these animals, especially vector-born ones.

Molecular and Serological Identification of Anaplasma marginale and Borrelia burgdorferi in Cattle and Ticks from Nuevo Leon, Northern Mexico

Ticks and tick-borne diseases affect livestock productivity and cause significant economic losses. Therefore, surveillance of these pathogens and vectors is paramount to reducing these effects in livestock. This study aimed to identify Anaplasma marginale and Borrelia burgdorferi sensu lato in ticks collected from cattle. Molecular biology techniques were utilized to identify A. marginale for both types of samples, i.e., ticks and bovine blood. Serology of cattle using indirect immunofluorescence assay (IFA) was conducted to determine antibodies to B. burgdorferi s.l. from seven locations in Nuevo Leon, Mexico, between 2015 and 2017. From 404 bovines, 2880 ticks were collected: Rhipicephalus microplus (2391 females and 395 males), Amblyomma spp. (51 females and 42 males) and Dermacentor variabilis (1 female). Rhipicephalus microplus represented the largest specimens captured, with 96.7% within the seven study sites. PCR processed only 15% (442) of tick samples to identify A. marginale. Field genera proportions were followed to select testing tick numbers. Results showed that 9.9% (44/442) of A. maginale infected the pooled tick species, whereas the highest percent corresponded to 9.4% (38/404) in R. microplus. Regarding the molecular analysis of blood samples, 214 of 337 (63.5%) were positive for A. maginale. In each of the seven locations, at least one bovine sample tested positive for A. maginale. Borrelia burgdorferi s.l. was not found either in the ticks or serum samples. Two A.marginale DNA nucleotide sequences obtained in this study were deposited in the GenBank with the following accession numbers OR050501 cattle, and OR050500 R.microplus tick. Results of this work point to current distribution of bovine anaplasmosis in northern Mexico.

Molecular detection of Tick-Borne Pathogens in Ovaries and a Mummified Foetus of three cows with Historical Reproductive Problems in Northern Veracruz, Mexico

The aim of this study was to identify the presence of tick-borne pathogens as the probable cause of reproductive problems in cows in a commercial dual-purpose cow operation living in tropical conditions in Northern Veracruz, Mexico. As part of the reproductive control of the herd, ultrasonography was performed periodically, and the presence of three open (non-pregnant) cows with historical infertility problems was detected. The ovaries from the two open cows and the mummified foetus of a third one were removed, and two sets of tissue samples were collected. Histopathology analysis revealed the presence of follicular abnormalities. The DNA tests revealed the presence of Anaplasma marginale, Babesia bigemina and/or Babesia bovis. In conclusion, the present work represents the first report of tick-borne pathogens in ovarian tissue samples and a mummified foetus of infertile cows in tropical conditions in Northern Veracruz, Mexico, highlighting the possibility that many reproductive problems in tropical conditions could be caused by tick-borne pathogens.

Bovine Anaplasmosis: Will there ever be an almighty effective vaccine?

Bovine anaplasmosis is a tick-borne bacterial disease with a worldwide distribution and the cause of severe economic losses in the livestock industry in many countries, including México. In the present work, we first review the elements of the immune response of the bovine, which allows ameliorating the clinical signs while eliminating the majority of the blood forms and generating an immunologic memory such that future confrontations with the pathogen will not end in disease. On the other hand, many vaccine candidates have been evaluated for the control of bovine anaplasmosis yet without no commercial worldwide effective vaccine. Lastly, the diversity of the pathogen and how this diversity has impaired the many efforts to control the disease are reviewed.

Gut and faecal bacterial community of the terrestrial isopod Porcellionides pruinosus: potential use for monitoring exposure scenarios

This work aimed to characterize the gut and faeces bacterial communities (BC) of Porcellionides pruinosus using high-throughput sequencing. Isopods were collected from the field and kept in laboratory conditions similar to those normally applied in ecotoxicology tests. Faeces and purged guts of isopods (n = 3 × 30) were analysed by pyrosequencing the V3-V4 region of 16 S rRNA encoding gene. Results showed that gut and faecal BCs were dominated by Proteobacteria, particularly by an OTU (Operational Taxonomic Unit) affiliated to genus Coxiella. Diversity and richness values were statistically higher for faecal BC, mainly due to the occurrence of several low-abundance phylotypes. These results may reflect faecal carriage of bacterial groups that cannot settle in the gut. BCs of P. pruinosus comprised: (1) common members of the soil microbiota, (2) bacterial symbionts, (3) bacteria related to host metabolic/ecological features, and (4) bacterial etiological agents. Comparison of BC of this isopod species with the BC from other invertebrates revealed common bacterial groups across taxa. The baseline information provided by this work will assist the design and data interpretation of future ecotoxicological or biomonitoring assays where the analysis of P. pruinosus BC should be included as an additional indicator. CAPSULE: Terrestrial isopods bacterial communities might support ecotoxicological assays and biomonitoring processes as a valuable tool.

Molecular Prevalence of Anaplasma marginale and Ehrlichia in Domestic Large Ruminants and Rhipicephalus (Boophilus) microplus Ticks From Southern Luzon, Philippines

Anaplasmosis and ehrlichiosis are tick-borne rickettsial diseases that cause significant economic losses in the livestock industry worldwide. Although bovine anaplasmosis is known to be endemic in the Philippines, epidemiological data is fragmented. Moreover, little is known about bovine ehrlichiosis in the country. In this study, the prevalence of Anaplasma marginale and Ehrlichia in cattle and water buffalo from provinces in the southern part of Luzon, Philippines, was investigated through PCR. Blood samples from 620 animals comprised of 512 cattle and 108 water buffalo and 195 tick samples were subjected to nested PCR targeting the groESL gene of Anaplasmataceae. Positive samples were further subjected to another nested PCR and conventional PCR to amplify the A. marginale groEL gene and the Ehrlichia dsbA gene, respectively. Selected A. marginale-positive samples were also subjected to nested PCR targeting the msp5 gene. Regardless of the animal host, the overall prevalence in blood samples obtained was 51.9% for Anaplasmataceae, 43% for A. marginale, and 1.1% for Ehrlichia. No water buffalo were positive for Ehrlichia. Meanwhile, 15.9, 6.7, and 2% of the tick samples, all morphologically identified as Rhipicephalus (Boophilus) microplus, were positive for Anaplasmataceae, A. marginale, and Ehrlichia, respectively. Sequence analysis of selected A. marginale msp5 amplicons showed that the isolates from the region share 94–98% identity to reported A. marginale from other countries. The phylogenetic tree showed clustering of isolates in the region and a close relationship with A. marginale isolates from other countries. Sequences of Ehrlichia amplicons from cattle and ticks were 97–100% similar to reported Ehrlichia minasensis isolates. This study showed the high prevalence of A. marginale in Luzon, Philippines, and provided the first molecular evidence of E. minasensis in the country.

Recombinase polymerase amplification (RPA) with lateral flow detection for three Anaplasma species of importance to livestock health

Anaplasma marginale, A. ovis, and A. phagocytophilum are the causative agents of bovine anaplasmosis, ovine anaplasmosis, and granulocytic anaplasmosis, respectively. The gold standard for diagnosis of post-acute and long-term persistent infections is the serological cELISA, which does not discriminate between Anaplasma species and requires highly equipped laboratories and trained personnel. This study addresses the development of a rapid, isothermal, sensitive, species-specific RPA assays to detect three Anaplasma species in blood and cELISA A. marginale-positive serum samples. Three RPA primer and probe sets were designed targeting msp4 genes of each Anaplasma species and the internal control (GAPDH gene) for each assay. The limit of detection of gel-based or RPA-basic assays is 8.99 × 10⁴ copies/µl = A. marginale, 5.04 × 10⁶ copies/µl = A. ovis, and 4.58 × 10³ copies/µl = A. phagocytophilum, and for each multiplex lateral flow or RPA-nfo assays is 8.99 × 10³ copies/µl of A. marginale, 5.04 × 10³ copies/µl of A. ovis, 4.58 × 10³ copies/µl of A. phagocytophilum, and 5.51 × 10³ copies/µl of internal control (GAPDH). Although none of the 80 blood samples collected from Oklahoma cattle were positive, the RPA-nfo assays detected all A. marginale cattle blood samples with varying prevalence rates of infection, 83% of the 24 cELISA A. marginale-positive serum samples, and all A. phagocytophilum cell culture samples. Overall, although early detection of three Anaplasma species was not specifically addressed, the described RPA technique represents an improvement for detection of three Anaplasma in regions where access to laboratory equipment is limited.

Relationship between certain serum biochemical values and serostatus against Anaplasma marginale in dairy cows

Aim:

This study was conducted to evaluate the possible association between values of certain serum biochemical parameters and seropositivity against Anaplasma marginale in dairy cows.

Materials and Methods:

Serum samples from 60 seropositive and 40 seronegative cows were used to determine the values of beta-hydroxybutyrate (BHB), glucose, creatinine, blood urea nitrogen, total protein, albumin, alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine transaminase (ALT), lactate dehydrogenase (LDH), and gamma-glutamyl transferase (GGT) using commercially available kits and reagents. The serostatus of cows against A. marginale was determined using a commercially available cellular enzyme-linked immunosorbent assay kit according to the manufacturer’s recommendations. Significant differences in serum biochemical values between seropositive and seronegative groups were evaluated using independent Student’s t-test. Possible associations between the serostatus of the cows and different biochemical parameters were evaluated using univariate followed by multivariate logistic regression analyses.

Results:

There was a statistically significant increase (p≤0.05) in values of total protein, BHB, LDH, and AST in seropositive cows compared to seronegative cows while a non-significant increase in values of ALP, ALT, and GGT was detected in seropositive cows. A strong correlation (R=0.69) between serum levels of BHB, LDH, and AST and seropositivity against A. marginale was detected.

Conclusion:

There is evidence of a possible association between A. marginale infection and liver damage/hepatic fatty degeneration in dairy cows. Further studies, however, are required to elucidate the exact pathophysiological mechanisms of this relationship.

Draft Genome Sequences of Anaplasma marginale Strains MEX-15-099-01 and MEX-31-096-01, Two Mexican Isolates with Different Degrees of Virulence

Anaplasma marginale is an intraerythrocytic bacterium that causes bovine anaplasmosis and is endemic in Mexico. In this work, we report two draft genome sequences of Mexican isolates from different geographical regions and with different degrees of virulence.

Anaplasma marginale is an intraerythrocytic bacterium that causes bovine anaplasmosis and is endemic in Mexico. In this work, we report two draft genome sequences of Mexican isolates from different geographical regions and with different degrees of virulence.

First Molecular Evidence of Anaplasma bovis and Anaplasma phagocytophilum in Bovine from Central Punjab, Pakistan

Obligate intracellular bacteria belonging to the genus Anaplasma spp. are responsible for causing a hemolytic disease called anaplasmosis in animals, as well as in humans. This study was aimed at the molecular identification and genetic analysis of responsible causative agents of anaplasmosis beyond those already reported. A survey was performed during July and August 2018 in the Jhang District, Punjab, Pakistan. Four hundred and fifty blood samples from asymptomatic, tick-infested cattle were collected on FTA cards and tested for the Anaplasma spp. presence using nested-polymerase chain reaction (PCR) methods. The 16S ribosomal RNA gene sequences generated from the positive samples were used for genetic analysis of Anaplasma spp. The nested-PCR results showed the presence of two Anaplasma spp. with an overall prevalence rate of 10.44%, where the prevalence of A. bovis and A. phagocytophilum was 7.78% and 2.66%, respectively. The study portrayed new molecular data on the prevalence of Anaplasma spp. in the studied cattle population, indicating a potential threat to the human population as well.

Molecular evidence of the reservoir competence of water buffalo (Bubalus bubalis) for Anaplasma marginale in Cuba

Water buffalo (Bubalus bubalis) is a potential reservoir for Anaplasma marginale in livestock ecosystems of tropical countries. However, their participation in the epidemiological process of bovine anaplasmosis in endemic areas remains unclear. In the present study, the reservoir competence of water buffalo for A. marginale was explored by focusing on the analysis of rickettsemia levels in carrier animals, and the genetic characterization of A. marginale strains from cattle and buffalo. Eight groups of cattle and water buffaloes were randomly selected from cohabiting herds in four livestock ecosystems of Cuba, together with two control groups from unrelated cattle and buffalo herds. A total of 180 adult animals (88 water buffalo and 92 cattle) were sampled. Rickettsemia in carrier animals was determined by quantitative real-time PCR. The rickettsemia (parasitemia) levels in cattle were higher than in buffaloes, however the rickettsemia in buffalo may be enough to infect R. microplus ticks. The genetic diversity of A. marginale was assessed by strain characterization and phylogenetic analysis of 27 msp1α gene sequences. The results showed genetic similarity among strains from cattle and water buffalo, suggesting the occurrence of cross-species transmission.

Molecular epidemiology of bovine anaplasmosis in Khyber Pakhtunkhwa, Pakistan

Bovine anaplasmosis is endemic in Pakistan where it reduces livestock productivity and leads to high mortality, especially in young animals. This study was aimed to identify the potential risk factors responsible for the occurrence and spread of anaplasmosis in cattle and buffaloes for the first time in Pakistan. A total of 900 (cattle = 479, buffalo = 421) blood samples were collected irrespective of age and sex from three distinct zones of Khyber Pakhtunkhhwa (KP) province of Pakistan. Polymerase chain reaction (PCR) technique was used for the molecular detection of anaplasmosis. Data collected on a piloted questionnaire including 11 predicting variables which were analyzed using R-statistical software, and association between the dependent and independent variables was assessed using univariable analysis. Automated and manual approaches were exercised, producing comparable models. Key risk factors identified in all the approaches included species of the animal, breed of animal, sex of animal, tick infestation status, previous tick history, tick control status, and acaricides used (odds ratio > 1). The 611 bp DNA fragment specific for 16S rRNA gene of Anaplasma spp. was produced from 165 samples. The samples were confirmed for anaplasmosis through sequencing and BLAST queries. The findings of the current study conclude that by enhancing the protective measures to control the identified risk factors can reduce the spread of anaplasmosis in Pakistan.

Transmission Dynamics of Bovine Anaplasmosis in a Cattle Herd

Bovine anaplasmosis is an infectious disease of cattle caused by the obligate intercellular bacterium, Anaplasma marginale, and it primarily occurs in tropical and subtropical regions of the world. In this study, an age-structured deterministic model for the transmission dynamics of bovine anaplasmosis was developed; the model incorporates symptomatic and asymptomatic cattle classes. Sensitivity analysis was carried out to determine the parameters with the highest impact on the reproduction number. The dominant parameters were the bovine natural and disease-induced death rates, disease progression rate in adult cattle, the mechanical devices transmission probability and contact rates, the pathogen contamination, and decay rates on the mechanical devices. The result of the sensitivity analysis suggests that control strategies to effectively prevent/control the spread of bovine anaplasmosis should focus on these parameters according to their positive or negative effect as seen from the sensitivity index. Following the results of the sensitivity analysis, three control strategies were investigated, namely, bovine-culling, safety-control, and universal. In addition to these strategies, three effectiveness levels (low, medium, and high) were considered for each control strategy using the cumulative number of newly infected cases in both juvenile and adult cattle as measure function. The universal strategy (comprising both cattle-culling and safety-control strategies) is only marginally better at reducing the number of infected cattle compare to the safety-control strategy. This result suggests that efforts should be aimed at improving and maintaining good hygiene practices; furthermore, the added benefit of culling infected cows is only minimal and not cost-efficient.

Molecular diagnosis and genetic diversity of tick-borne Anaplasmataceae agents infecting the African buffalo Syncerus caffer from Marromeu Reserve in Mozambique

Background

Tick-borne diseases (TBDs) are very important in relation to domestic ruminants, but their occurrence among wild ruminants, mainly in the African buffalo Syncerus caffer, remains little known.

Methods

Molecular diagnostic methods were applied to detect Anaplasma marginale, Anaplasma centrale, Anaplasma phagocytophilum, Ehrlichia ruminantium and Ehrlichia chaffeensis in 97 blood samples of African buffalo captured at the Marromeu Reserve in Mozambique. Molecular detection of agents belonging to the family Anaplasmataceae were based on conventional and qPCR assays based on msp5, groEL, 16S rRNA, msp2, pCS20 and vlpt genes. Phylogenetic reconstruction of new Anaplasma isolates detected in African buffalo was evaluated based on msp5, groEL and 16S rRNA genes.

Results

All the animals evaluated were negative for specific PCR assays for A. phagocytophilum, E. ruminantium and E. chaffeensis, but 70 animals were positive for A. marginale, showing 2.69 × 10⁰ up to 2.00 × 10⁵msp1β copies/μl. This result overcomes the conventional PCR for A. marginale based on msp5 gene that detected only 65 positive samples. Sequencing and phylogenetic analyses were performed for selected positive samples based on the genes msp5, groEL and 16S rRNA. Trees inferred using different methods separated the 29 msp5 sequences from buffalo in two distinct groups, assigned to A. centrale and A. marginale. The groEL sequences determined for African buffalo samples revealed to be more heterogeneous and inferred trees could not assign them to any species of Anaplasma despite being more related to A. marginale and A. centrale. The highly conserved 16S rRNA gene sequences suggested a close relationship of the new 16 sequences with A. centrale/A. marginale, A. platys and A. phagocytophilum.

Conclusions

Our analysis suggests that different species of Anaplasma are simultaneously present in the African buffalo. To the best of our knowledge, this is the first study that diagnosed Anaplasma spp. in the African buffalo and inferred the taxonomic status of new isolates with different gene sequences. The small fragment of msp5 sequences revealed to be a good target for phylogenetic positioning of new Anaplasma spp. isolates.

Emerging status of anaplasmosis in cattle in Hisar

Aim:

Anaplasma marginale is a rickettsial pathogen responsible for progressive anemia in ruminants leading to huge economic losses. The objectives of this cross-sectional study were to determine the prevalence of anaplasmosis and therapeutic evaluation of traditional line of treatment.

Materials and Methods:

A total of 168 cattle presented to Teaching Veterinary Clinical Complex, Lala Lajpat Rai University of Veterinary & Animal Sciences, Hisar during the period of 3 months (July-September, 2014) with history of fever, anorexia, reduced milk yield and tick infestation were analyzed for prevalence of hemoprotozoan diseases using classical giemsa stained thin blood smear parasitological method.

Results:

Out of these 168 animals, 7 (4.17%) were found to be suffering from anaplasmosis on the basis of presence of dense, rounded, intra-erythrocytic bodies situated on or near the margin of the erythrocytes. Overall prevalence of theileriosis and babesiosis were found to be 42.9% and 1.8%, respectively. Level of parasitemia was noticed to be 1.2%, 0.8% and 0.9% in babesiosis, theileriosis, and anaplasmosis, respectively. The most marked and common clinical signs reported in all the cases were severe anemia (hemoglobin=3-6 g/dl) and history of fever, followed by normal body temperature. Following treatment with oxytetracycline parenterally along with supportive therapy out of seven cases six got recovered without any side-effects.

Conclusion:

The current study indicates the emerging status of anaplasmosis in this part of the country as during the past few years there are very few reports showing the prevalence of clinical cases of anaplasmosis. Treatment with oxytetracycline yielded excellent result showing recovery in most of the clinical cases.

Association of Anaplasma marginale strain superinfection with infection prevalence within tropical regions

Strain superinfection occurs when a second strain infects a host already infected with and having mounted an immune response to a primary strain. The incidence of superinfection with Anaplasma marginale, a tick-borne rickettsial pathogen of domestic and wild ruminants, has been shown to be higher in tropical versus temperate regions. This has been attributed to the higher prevalence of infection, with consequent immunity against primary strains and thus greater selective pressure for superinfection with antigenically distinct strains. However an alternative explanation would be the differences in the transmitting vector, Dermacentor andersoni in the studied temperate regions and Rhipicephalus microplus in the studied tropical regions. To address this question, we examined two tropical populations sharing the same vector, R. microplus, but with significantly different infection prevalence. Using two separate markers, msp1α (one allele per genome) and msp2 (multiple alleles per genome), there were higher levels of multiple strain infections in the high infection prevalence as compared to the low prevalence population. The association of higher strain diversity with infection prevalence supports the hypothesis that high levels of infection prevalence and consequent population immunity is the predominant driver of strain superinfection.

A report on the high prevalence of Anaplasma sp. in buffaloes from two provinces in Pakistan

The present study was designed to use a PCR-RFLP protocol for the molecular detection of Anaplasma sp. and to compare its prevalence in blood samples from buffaloes (Bubalus bubalis) from 2 provinces of Pakistan and to determine the risk factors associated with the spread of Anaplasma infection. A total of 281 blood samples were collected from adults and calves of buffaloes from 4 sampling sites in Southern Punjab (Bahawalnagar, Burewala, Layyah, and Multan districts) and 2 in Khyber Pukhtoon Khwa (Peshawer and Kohat districts) from randomly selected herds. Data on the characteristics of the animals (gender, age, tick presence or absence, prior treatment for Anaplasma infection) and the herd (location, size, dogs associated with the herds, tick burden of dogs associated with the herds) were collected through questionnaires. One hundred and sixteen blood samples (41% of total) produced the 577-base pairs DNA fragment specific for the 16S rRNA gene of Anaplasma sp. by PCR amplification. Twenty of the 116 Anaplasma sp.-positive PCR products were confirmed to be Anaplasma marginale upon restriction with BssNa1, specific to cut A. marginale sequences. ANOVA results revealed a highly significant association between sampling sites and prevalence of Anaplasma sp. (P<0.001) indicating that Anaplasma sp. prevalence was variable among all 6 sampling sites. Risk factor analysis indicated that the association of dogs with the herd was the only significant (P=0.029) risk factor associated with the spread of Anaplasma sp. in buffaloes while sex, age, presence of ticks on animals or herd size showed no association with Anaplasma infection.

Pyrosequencing-based analysis of the microbiome associated with the horn fly, Haematobia irritans

The horn fly, Haematobia irritans, is one of the most economically important pests of cattle. Insecticides have been a major element of horn fly management programs. Growing concerns with insecticide resistance, insecticide residues on farm products, and non-availability of new generation insecticides, are serious issues for the livestock industry. Alternative horn fly control methods offer the promise to decrease the use of insecticides and reduce the amount of insecticide residues on livestock products and give an impetus to the organic livestock farming segment. The horn fly, an obligatory blood feeder, requires the help of microflora to supply additional nutrients and metabolize the blood meal. Recent advancements in DNA sequencing methodologies enable researchers to examine the microflora diversity independent of culture methods. We used the bacterial 16S tag-encoded FLX-titanium amplicon pyrosequencing (bTEFAP) method to carry out the classification analysis of bacterial flora in adult female and male horn flies and horn fly eggs. The bTEFAP method identified 16S rDNA sequences in our samples which allowed the identification of various prokaryotic taxa associated with the life stage examined. This is the first comprehensive report of bacterial flora associated with the horn fly using a culture-independent method. Several rumen, environmental, symbiotic and pathogenic bacteria associated with the horn fly were identified and quantified. This is the first report of the presence of Wolbachia in horn flies of USA origin and is the first report of the presence of Rikenella in an obligatory blood feeding insect.

Functional genomics of the horn fly, Haematobia irritans (Linnaeus, 1758)

Background

The horn fly, Haematobia irritans (Linnaeus, 1758) (Diptera: Muscidae) is one of the most important ectoparasites of pastured cattle. Horn flies infestations reduce cattle weight gain and milk production. Additionally, horn flies are mechanical vectors of different pathogens that cause disease in cattle. The aim of this study was to conduct a functional genomics study in female horn flies using Expressed Sequence Tags (EST) analysis and RNA interference (RNAi).

Results

A cDNA library was made from whole abdominal tissues collected from partially fed adult female horn flies. High quality horn fly ESTs (2,160) were sequenced and assembled into 992 unigenes (178 contigs and 814 singlets) representing molecular functions such as serine proteases, cell metabolism, mitochondrial function, transcription and translation, transport, chromatin structure, vitellogenesis, cytoskeleton, DNA replication, cell response to stress and infection, cell proliferation and cell-cell interactions, intracellular trafficking and secretion, and development. Functional analyses were conducted using RNAi for the first time in horn flies. Gene knockdown by RNAi resulted in higher horn fly mortality (protease inhibitor functional group), reduced oviposition (vitellogenin, ferritin and vATPase groups) or both (immune response and 5'-NUC groups) when compared to controls. Silencing of ubiquitination ESTs did not affect horn fly mortality and ovisposition while gene knockdown in the ferritin and vATPse functional groups reduced mortality when compared to controls.

Conclusions

These results advanced the molecular characterization of this important ectoparasite and suggested candidate protective antigens for the development of vaccines for the control of horn fly infestations.