Molecular detection of zoonotic tick-borne pathogens from ticks collected from ruminants in four South African provinces

Comparison of test performance of a conventional PCR and two field-friendly tests to detect Coxiella burnetii DNA in ticks using Bayesian latent class analysis

Introduction

Coxiella burnetii (C. burnetii)-infected livestock and wildlife have been epidemiologically linked to human Q fever outbreaks. Despite this growing zoonotic threat, knowledge of coxiellosis in wild animals remains limited, and studies to understand their epidemiologic role are needed. In C. burnetii-endemic areas, ticks have been reported to harbor and spread C. burnetii and may serve as indicators of risk of infection in wild animal habitats. Therefore, the aim of this study was to compare molecular techniques for detecting C. burnetii DNA in ticks.

Methods

In total, 169 ticks from wild animals and cattle in wildlife conservancies in northern Kenya were screened for C. burnetii DNA using a conventional PCR (cPCR) and two field-friendly techniques: Biomeme's C. burnetii qPCR Go-strips (Biomeme) and a new C. burnetii PCR high-resolution melt (PCR-HRM) analysis assay. Results were evaluated, in the absence of a gold standard test, using Bayesian latent class analysis (BLCA) to characterize the proportion of C. burnetii positive ticks and estimate sensitivity (Se) and specificity (Sp) of the three tests.

Results

The final BLCA model included main effects and estimated that PCR-HRM had the highest Se (86%; 95% credible interval: 56-99%), followed by the Biomeme (Se = 57%; 95% credible interval: 34-90%), with the estimated Se of the cPCR being the lowest (24%, 95% credible interval: 10-47%). Specificity estimates for all three assays ranged from 94 to 98%. Based on the model, an estimated 16% of ticks had C. burnetii DNA present.

Discussion

These results reflect the endemicity of C. burnetii in northern Kenya and show the promise of the PCR-HRM assay for C. burnetii surveillance in ticks. Further studies using ticks and wild animal samples will enhance understanding of the epidemiological role of ticks in Q fever.

Molecular detection and phylogenetic analysis of tick-borne pathogens in cattle from southern Malawi

INTRODUCTION

Tick-borne diseases (TBDs) pose a major hindrance to livestock production in countries with limited resources. Effective prevention and management of TBDs require a thorough understanding of disease vectors and pathogens. However, there is limited information on studies of bovine tick-borne pathogens (TBPs) using molecular methods in Malawi. This study aimed to detect TBPs of cattle populations in southern Malawi, which has the largest cattle population in the country.

METHODOLOGY

A total of 220 blood samples from apparently healthy cattle were collected in six districts, and were screened for selected TBPs using polymerase chain reaction (PCR).

RESULTS

The overall detection rate of TBPs was 72.3%. Among the detected pathogens, Babesia bigemina had the highest detection rate (34.5%), followed by Anaplasma marginale (23.2%), Anaplasma phagocytophilum (22.3%), Theileria taurotragi (22.3%), Theileria parva (15.5%), Anaplasma bovis (9.6%), Babesia bovis (7.3%), Theileria mutans (4.1%), and Babesia naoakii (2.7%). Among the positive samples, 64.2% were found to be co-infected with two or more TBPs, with the highest number of seven pathogens detected in a single sample. The study documents the existence of A. phagocytophilum, B. bovis, and B. naoakii in Malawian cattle for the first time.

CONCLUSION

The findings herein demonstrate a significant burden of TBPs on cattle in Malawi, which gives a challenge in combating TBDs. The high TBP burden, along with the high co-infection frequencies in Malawian cattle necessitates the urgency to implement effective control strategies to enhance cattle production in the country.

First report of dog ticks and tick-borne pathogens they are carrying in Malawi

Ticks are vectors for transmitting tick-borne pathogens (TBPs) in animals and humans. Therefore, tick identification is necessary to understand the distribution of tick species and the pathogens they carry. Unfortunately, data on dog ticks and the TBPs they harbor in Malawi are incomplete. This study aimed to identify dog ticks and the TBPs they transmit in Malawi. One hundred thirty-two ticks were collected from 87 apparently healthy but infested domestic dogs in four districts of Malawi, which were pooled into 128 tick samples. The ticks were morphologically identified under a stereomicroscope using identification keys, and species identification was authenticated by polymerase chain reaction (PCR) through the amplification and sequencing of 12S rRNA and cytochrome c oxidase subunit I (CO1) genes. The tick species identified were Rhipicephalus sanguineus sensu lato (58.3%), Haemaphysalis elliptica (32.6%), and Hyalomma truncatum (9.1%). Screening for TBPs using species-specific PCR assays revealed that 48.4% of the ticks were infected with at least one TBP. The TBP detection rates were 13.3% for Anaplasma platys, 10.2% for Babesia rossi, 8.6% for B. vogeli, 6.3% for Ehrlichia canis, 3.9% for A. phagocytophilum, 3.1% for B. gibsoni, 2.3% for B. canis and 0.8% for Hepatozoon canis. Co-infections of up to three pathogens were observed in 48.4% of the positive samples. This is the first study to identify dog ticks and the TBPs they harbor in Malawi. These findings provide the basis for understanding dog tick distribution and pathogens they carry in Malawi. This study necessitates the examination of ticks from more study locations to have a better picture of tick challenge, and the development of ticks and tick-borne disease control methods in Malawi.

Coxiella burnetii infections from animals and ticks in South Africa: a systematic review

Coxiella burnetii is a zoonotic intracellular bacterium that is widely distributed and affects domestic animals, wildlife, humans and non-mammalian species. This systematic review was aimed at synthesizing research findings on C. burnetii in both domestic and wild animals of South Africa. The systematic review protocol was registered with Open Society Foundations of systematic reviews ( https://doi.org/10.17605/OSF.IO/8WS ). PRISMA guidelines were followed to collect and evaluate relevant scientific articles published on C. burnetii infecting domestic and wild animals in South Africa. Published articles were sourced from five electronic databases, namely, Google Scholar, PubMed and ScienceDirect, EBSCO and Scopus. Results showed 11 eligible studies involving four domestic animals, three wild animals and one ectoparasite species from seven provinces across South Africa. The occurrence of C. burnetii infection was high in Ceratotherium simum (white rhinoceros) (53.9%), medium in sheep (29.0%) and low in pigs (0.9%). Limpopo province (26%) had the most recorded infections followed by KwaZulu-Natal (19%) and Free State (3%) had the least reported occurrence of C. burnetii. The current study discovered that there is scarcity of published research on prevalence and distribution of C. burnetii infecting domestic and wild animals in South Africa, and this is of concern as this bacterium is an important zoonotic pathogen of "One Health" importance.

Characterisation of South African field Ehrlichia ruminantium using multilocus sequence typing

Heartwater, one of the major tick-borne diseases of some domestic and wild ruminants in Africa, is caused by Ehrlichia ruminantium. The genetic diversity of E. ruminantium isolates renders the available vaccine ineffective against certain virulent isolates. To better understand the E. ruminantium genotypes in South Africa, a total of 1004 Amblyomma hebraeum tick deoxyribonucleic acid (DNA) samples from cattle in three South African provinces were tested by pCS20 Sol1 real-time polymerase chain reaction (qPCR) and characterised by multilocus sequence typing (MLST) using five housekeeping genes. Out of 1004 samples tested, 222 (22%) were positive for E. ruminantium. The occurrence of E. ruminantium in Mpumalanga, KwaZulu-Natal and Limpopo provinces was 19%, 22% and 27%, respectively. The E. ruminantium positive samples were screened for housekeeping genes and sequenced. Phylogenetic analysis revealed three main lineages: clade 1 made up of worldwide isolates (eastern, southern Africa, and Caribbean isolates), clade 2 comprised only West African isolates and clade 3 consisted of Omatjenne, Kümm2 and Riverside. Some study sample sequences were not identical to any of the reference isolates. However, they could all be grouped into the worldwide clade. Genetic variation in the sequenced regions was observed in the form of single nucleotide polymorphisms (SNPs). Using MLST to characterise E. ruminantium field isolates allowed the South African genotypes to be clearly distinguished from the distinct West African isolates.Contribution: Characterisation of E. ruminantium field isolates is important for the control of heartwater and contributes to preliminary knowledge required for the development of a more practical vaccine against heartwater.

Molecular detection of Rickettsia africae from Amblyomma hebraeum ticks in Mafikeng city of North West Province, South Africa

Rickettsia africae causes zoonotic African tick bite fever, which is a disease of "One Health" importance. There have been reported cases of tourists from Europe and Asia who have been bitten by ticks whilst visiting South Africa's nature reserves, and on their return to their countries, the display African Tick Bite Fever sickness. Hence, the aim of this study was to determine the occurrence of Rickettsia africae in Amblyomma hebraeum ticks infesting livestock in the North West Province. A total of 358 A. hebraeum ticks were collected from 60 ruminants (cattle, sheep and goats) in Mafikeng City of North West Province, South Africa. Ticks were identified morphologically and further confirmed by sequencing of their ITS2 gene. DNA was extracted from 60 pools of ticks which consisted of 5-6 adult ticks that were from the same ruminant host. Infections with Rickettsia spp. were found in 48%, 40%, and 32% of cattle, sheep, and goats, respectively, in amplification by PCR using the ompA gene. The ompA gene sequences showed that the Rickettsia spp. were identified as R. africae. Although the animals from whom the ticks were collected did not exhibit any clinical symptoms, it is well recognised that R. africae is a disease with significant zoonotic potential. Thus, it is important to use the "One Health" approach to formulate prevention and control measures for this pathogen for animal and human health as well as the tourism sector due to the ecotourism importance of the resultant disease.

Molecular detection of Coxiella burnetii and Coxiella species in rats and chickens from poultry farms in North West Province, South Africa

BACKGROUND

Coxiella burnetii is a bacterial pathogen that causes query fever and coxiellosis in humans and animals, respectively. There is a scarcity of studies on the prevalence of C. burnetii infections in rats and chickens in South Africa.

OBJECTIVE

The aim of this study was to determine the occurrence of C. burnetii in rats and chickens sampled from poultry farms in the North West Province of South Africa.

METHODS

DNA was extracted from rodent kidneys (n = 68) and chicken faeces (n = 52). Two rodent pest species, namely Rattus rattus and Rattus tanezumi, were identified by analysis of CO1 gene sequences. Detection of C. burnetii was carried out using polymerase chain reaction assays targeting 23S rRNA, 16S rRNA and IS111 markers.

RESULTS

C. burnetii was detected in 16.2%, 8.8% and 25% of R. rattus, R. tanezumi and chickens, respectively.

CONCLUSIONS

The findings in this study demonstrate that rodents and chickens are harbouring C. burnetii at sampled poultry farms. There should be frequent screening for C. burnetii in poultry operations. The likelihood of future transmission between rodents and chickens, including humans, also needs to be investigated.

Low genetic diversity and population structuring of Amblyomma hebraeum and Rickettsia africae from coastal and inland regions in the Eastern Cape Province of South Africa

Amblyomma hebraeum is the main vector of Rickettsia africae, the causative agent of African tick bite fever in southern Africa. Because pathogen dispersal is known to be influenced by tick adaptations to climate or host species, this study aimed to analyse the genetic diversity of A. hebraeum and R. africae infection of ticks collected from cattle in the Eastern Cape province of South Africa. DNA was extracted, amplified, and sequenced for the COI and ITS2 markers from A. hebraeum samples and the 17 kDa and ompA genes for rickettsial detection. Between six and ten haplotypes were identified from 40 COI and 31 ITS2 sequences; however, no population structuring was observed among sites (ΦST = 0.22, p < 0.05). All A. hebraeum isolates clustered with southern Africa GenBank isolates. Rickettsia africae was detected in 46.92% (95% CI = 41%-53%, n = 260) of ticks. All R. africae isolates clustered with strain PELE and Chucks, which were reported previously from South Africa. These results confirm that A. hebraeum populations are undergoing a recent population expansion driven by cattle movement, facilitating local and long dispersal events across the Eastern Cape province.

Anaplasma Species in Africa-A Century of Discovery: A Review on Molecular Epidemiology, Genetic Diversity, and Control

Anaplasma species, belonging to the family Anaplasmataceae in the order Rickettsiales, are obligate intracellular bacteria responsible for various tick-borne diseases of veterinary and human significance worldwide. With advancements in molecular techniques, seven formal species of Anaplasma and numerous unclassified species have been described. In Africa, several Anaplasma species and strains have been identified in different animals and tick species. This review aims to provide an overview of the current understanding of the molecular epidemiology and genetic diversity of classified and unclassified Anaplasma species detected in animals and ticks across Africa. The review also covers control measures that have been taken to prevent anaplasmosis transmission on the continent. This information is critical when developing anaplasmosis management and control programs in Africa.

Distribution and Prevalence of Anaplasmataceae, Rickettsiaceae and Coxiellaceae in African Ticks: A Systematic Review and Meta-Analysis

In Africa, ticks continue to be a major hindrance to the improvement of the livestock industry due to tick-borne pathogens that include Anaplasma, Ehrlichia, Rickettsia and Coxiella species. A systemic review and meta-analysis were conducted here and highlighted the distribution and prevalence of these tick-borne pathogens in African ticks. Relevant publications were searched in five electronic databases and selected using inclusion/exclusion criteria, resulting in 138 and 78 papers included in the qualitative and quantitative analysis, respectively. Most of the studies focused on Rickettsia africae (38 studies), followed by Ehrlichia ruminantium (27 studies), Coxiella burnetii (20 studies) and Anaplasma marginale (17 studies). A meta-analysis of proportions was performed using the random-effects model. The highest prevalence was obtained for Rickettsia spp. (18.39%; 95% CI: 14.23–22.85%), R. africae (13.47%; 95% CI: 2.76–28.69%), R. conorii (11.28%; 95% CI: 1.77–25.89%), A. marginale (12.75%; 95% CI: 4.06–24.35%), E. ruminantium (6.37%; 95% CI: 3.97–9.16%) and E. canis (4.3%; 95% CI: 0.04–12.66%). The prevalence of C. burnetii was low (0%; 95% CI: 0–0.25%), with higher prevalence for Coxiella spp. (27.02%; 95% CI: 10.83–46.03%) and Coxiella-like endosymbionts (70.47%; 95% CI: 27–99.82%). The effect of the tick genera, tick species, country and other variables were identified and highlighted the epidemiology of Rhipicephalus ticks in the heartwater; affinity of each Rickettsia species for different tick genera; dominant distribution of A. marginale, R. africae and Coxiella-like endosymbionts in ticks and a low distribution of C. burnetii in African hard ticks.

Rickettsia spp. in Ticks of South Luangwa Valley, Eastern Province, Zambia

Ticks are important vectors for Rickettsia spp. belonging to the Spotted Fever Group responsible for causing Rickettsiosis worldwide. Rickettsioses pose an underestimated health risk to tourists and local inhabitants. There is evidence of the presence of Rickettsia spp. in Zambia, however there is limited data. A total of 1465 ticks were collected in 20 different locations from dogs and cattle including one cat. Ticks were identified by morphological features or by sequencing of the 16S mitochondrial rRNA gene. Individual ticks were further tested for rickettsiae using a pan-Rickettsia real-time-PCR. Rickettsia species in PCR-positive ticks were identified by sequencing the 23S-5S intergenic spacer region or partial ompA gene, respectively. Seven tick species belonging to three different tick genera were found, namely: Amblyomma variegatum, Rhipicephalus appendiculatus, Rhipicephalus (Boophilus) microplus, Rhipicephalus simus, Rhipicephalus sanguineus, Rhipicephalus zambesiensis and Haemaphysalis elliptica. Out of the 1465 ticks collected, 67 (4.6%) tested positive in the pan-Rickettsia PCR. This study provides detailed data about the presence of Rickettsia species in South Luangwa Valley, Eastern Province, Zambia for the first time. High prevalence of Rickettsia africae in Amblyomma variegatum was found, which indicates the potential risk of infection in the investigated area. Furthermore, to our best knowledge, this is the first time Rickettsia massiliae, a human pathogen causing spotted fever, has been detected in Zambia.

Unraveling the epidemiological relationship between ticks and rickettsial infection in Africa

Tick-borne rickettsioses are emerging and re-emerging diseases of public health concern caused by over 30 species of Rickettsia. Ticks are obligate hematophagous arthropods with over 700 species of Ixodid ticks known worldwide. The escalating geographical dispersal of tick vectors and concomitant increase in the incidences of tick-borne diseases have fueled interest in the ecology of tick-borne pathogens. This review focuses on aspects of the Rickettsia pathogen, including biology, taxonomy, phylogeny, genetic diversity, epidemiology of the disease, and the role of vertebrate host in the perpetuation of rickettsioses in Africa. Our review also highlights some of the species of Rickettsia that are responsible for disease, the role of tick vectors (both hard and soft ticks) and the species of Rickettsia associated with diverse tick species across the continent. Additionally, this article emphasizes the evolutionary perspective of rickettsiae perpetuation and the possible role of amplifying vertebrate host and other small mammals, domestic animals and wildlife in the epidemiology of Rickettsia species. We also specifically, discussed the role of avian population in the epidemiology of SFG rickettsiae. Furthermore, we highlighted tick-borne rickettsioses among travelers due to African tick-bite fever (ATBF) and the challenges to surveillance of rickettsial infection, and research on rickettsiology in Africa. Our review canvasses the need for more rickettsiologists of African origin based within the continent to further research towards understanding the biology, characterization, and species distribution, including the competent tick vectors involved in their transmission of rickettsiae across the continent in collaboration with established researchers in western countries. We further highlighted the need for proper funding to encourage research despite competing demands for resources across the various sectors. We finalize by discussing the similarities between rickettsial diseases around the world and which steps need to be taken to help foster our understanding on the eco-epidemiology of rickettsioses by bridging the gap between the growing epidemiological data and the molecular characterization of Rickettsia species.

Detection of Ticks and Tick-Borne Pathogens of Urban Stray Dogs in South Africa

This study aimed to identify ticks infesting dogs admitted to the Potchefstroom Animal Welfare Society (PAWS) and to detect tick-borne pathogens they are harbouring. A total of 592 ticks were collected from 61 stray dogs admitted to PAWS originating from several suburbs in and near Potchefstroom, South Africa. The dog ticks were identified as Haemaphysalis elliptica (39%) and Rhipicephalus sanguineus (61%) by both morphological and DNA analyses. Of these ticks, H. elliptica consisted of 67.5% (156/231) and 32.5% (75/231) female and male ticks, respectively, whilst R. sanguineus consisted of 48.5% (175/361) and 51.5% (186/361) female and male ticks, respectively. Microscopic examination of blood smears from engorged female ticks indicated overall occurrences of 0.5% (1/204) for Babesia spp. from R. sanguineus, 1% (2/204) of Anaplasma spp. from H. elliptica, and 22% (45/204) of Rickettsia spp. from both H. elliptica and R. sanguineus. Using pooled samples molecular detection of tick-borne pathogens indicated overall occurrences of 1% (1/104) for A. phagocytophilum in H. elliptica, 9.6% (10/104) of Rickettsia spp. in H. elliptica and R. sanguineus, 5.8% (6/104) of Ehrlichia canis in H. elliptica and R. sanguineus, and 13.5% (14/104) of Coxiella spp. in both H. elliptica and R. sanguineus. Additionally, PCR detected 6.5% (2/31) of Coxiella spp. DNA from H. elliptica eggs. Our data indicate that urban stray dogs admitted at PAWS are infested by H. elliptica and R. sanguineus ticks which are harbouring several pathogenic organisms known to cause tick-borne diseases.

Detection of Tick-Borne Bacterial and Protozoan Pathogens in Ticks from the Zambia–Angola Border

Tick-borne diseases (TBDs), including emerging and re-emerging zoonoses, are of public health importance worldwide; however, TBDs tend to be overlooked, especially in countries with fewer resources, such as Zambia and Angola. Here, we investigated Rickettsia, Anaplasmataceae, and Apicomplexan pathogens in 59 and 96 adult ticks collected from dogs and cattle, respectively, in Shangombo, a town at the Zambia–Angola border. We detected Richkettsia africae and Rickettsia aeschilimannii in 15.6% of Amblyomma variegatum and 41.7% of Hyalomma truncatum ticks, respectively. Ehrlichia minasensis was detected in 18.8% of H. truncatum, and Candidatus Midichloria mitochondrii was determined in Hyalomma marginatum. We also detected Babesia caballi and Theileria velifera in A. variegatum ticks with a 4.4% and 6.7% prevalence, respectively. In addition, Hepatozoon canis was detected in 6.5% of Rhipicephalus lunulatus and 4.3% of Rhipicephalus sanguineus. Coinfection of R. aeshilimannii and E. minasensis were observed in 4.2% of H. truncatum. This is the first report of Ca. M. mitochondrii and E. minasensis, and the second report of B. caballi, in the country. Rickettsia africae and R. aeschlimannii are pathogenic to humans, and E. minasensis, B. caballi, T. velifera, and H. canis are pathogenic to animals. Therefore, individuals, clinicians, veterinarians, and pet owners should be aware of the distribution of these pathogens in the area.

Protozoan and Rickettsial Pathogens in Ticks Collected from Infested Cattle from Turkey

Diseases caused by tick-transmitted pathogens including bacteria, viruses, and protozoa are of veterinary and medical importance, especially in tropical and subtropical regions including Turkey. Hence, molecular surveillance of tick-borne diseases will improve the understanding of their distribution towards effective control. This study aimed to investigate the presence and perform molecular characterization of Babesia sp., Theileria sp., Anaplasma sp., Ehrlichia sp., and Rickettsia sp. in tick species collected from cattle in five provinces of Turkey. A total of 277 adult ticks (males and females) were collected. After microscopic identification, tick pools were generated according to tick species, host animal, and sampling sites prior to DNA extraction. Molecular identification of the tick species was conducted through PCR assays. Out of 90 DNA pools, 57.8% (52/90) were detected to harbor at least 1 pathogen. The most frequently-detected pathogens were Babesia bovis, with a minimum detection rate of 7.9%, followed by Ehrlichia sp. (7.2%), Theileria annulata (5.8%), Coxiella sp. (3.3%), Anaplasma marginale (2.5%), Rickettsia sp. (2.5%), and B. occultans (0.7%). Rickettsia sp. identified in this study include Candidatus Rickettsia barbariae, R. aeschlimannii, and Rickettsia sp. Chad. All sequences obtained from this study showed 99.05−100% nucleotide identity with those deposited in GenBank (query cover range: 89−100%). This is the first molecular detection of Rickettsia sp. Chad, a variant of Astrakhan fever rickettsia, in Turkey. Results from this survey provide a reference for the distribution of ticks and tick-borne pathogens in cattle and expand the knowledge of tick-borne diseases in Turkey.

Distribution and prevalence of ticks and tick-borne pathogens of wild animals in South Africa: A systematic review

Ticks are significant ectoparasites of animals and humans. Published data indicate that most vectors that transmit livestock and human pathogens in sub-Saharan Africa, are native to the region and originate from wild animals. Currently, there is a paucity of information on the role of wild animals on the epidemiology of zoonotic tick-borne pathogens in South Africa. This systematic review focuses on the distribution of ticks and prevalence of tick-borne pathogens in different wild animals in South Africa to identify potential reservoir hosts and possible hotspots for emergence of novel tick-borne pathogens. Following several screening processes, 38 peer-reviewed studies published from 1970 to 2021, were deemed eligible. The studies reported on ticks collected from 63 host species of 21 host families, mostly Canidae, Felidae, Bovidae and Muridae. A total of 49 tick species of nine genera, i.e. Amblyomma, Dermacentor, Haemaphysalis, Hyalomma, Ixodes, Margaropus, Nuttalliella, Rhipicentor and Rhipicephalus, were reported. Nine tick species, i.e. Amblyomma marmoreum, Am. hebraeum, Haemaphysalis elliptica, Hyalomma truncatum, I. rubicundus, Rh. appendiculatus, Rh. (B.) decoloratus, Rh. evertsi evertsi and Rh. simus were the most commonly reported. Pathogens of the genera Anaplasma, Babesia, Hepatozoon and Theileria were identified in the wild animals. This review provides more insight on the ecology of ticks and tick-borne pathogens of wild animals in South Africa and gives useful information for predicting their future spread. It also demonstrates that wild animals habour a diverse range of tick species. This level of diversity entails a similarly high potential for emergence of novel tick-borne pathogens. The review further indicates that wild animals in South Africa are sentinels of tick-borne protozoans of veterinary importance and some bacterial pathogens as most ticks they habour are known vectors of pathogens of domestic animals and humans. However, studies on potential tick-borne zoonoses are under-represented and should be included in future epidemiological surveys, especially in the light of climate change and other anthropogenic threats which might result in the emergence of novel tick-borne pathogens.

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Wild animals in South Africa harbor a wide range of tick species of veterinary and medical importance.

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Forty-nine tick species belonging to 9 genera were reported from 63 wild host species of 21 families.

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Majority of the ticks occur throughout all nine provinces of South Africa.

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Wildlife in South Africa are sentinels of tick-borne protozoans and some bacterial pathogens of veterinary importance.

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The review also emphasizes the host preference of the ticks and the pathogens they transmit.

Molecular Detection of Coxiella burnetii, Rickettsia africae and Anaplasma Species in Ticks from Domestic Animals in Lesotho

Tick-borne diseases (TBDs) hamper the growth of the livestock sector and impose major constraints for the health and management of domestic animals in the tropic and subtropical regions globally. Currently, there is no scientific report on the presence of zoonotic pathogens transmitted by tick species in Lesotho. This study aimed to identify zoonotic tick-borne pathogens of economic importance from ticks infesting domestic animals in Lesotho using molecular techniques. A total of 322 tick DNA pools were subjected to PCR screening for the presence of zoonotic pathogens and sequenced. The overall prevalence of Anaplasma spp. was 35% (113/322), with a 100% infection rate in Rhipicephalus microplus, followed by R. evertsi evertsi (92%), Hyalomma rufipes and Otobius megnini sharing 50% and the lowest infection rate was observed in R. decoloratus with 40%. The prevalence of Coxiella burnetii, a gram-negative pleomorphic etiological agent of Query fever (Q fever), was 1% (2/322) for all screened samples, with 20% of R. decoloratus and 1% of R. e. evertsi infected. Rickettsia africae was detected from Hyalomma rufipes with a 70% prevalence. This study provides a baseline knowledge of tick-borne pathogens of medical and veterinary importance in Lesotho and raises awareness of the prevalence of such diseases within the tourism sector as they are mostly affected.

A Pilot Study on the Microbiome of Amblyomma hebraeum Tick Stages Infected and Non-Infected with Rickettsia africae

Variation in tick microbiota may affect pathogen acquisition and transmission but for many vector species, including Amblyomma hebraeum, components and determinants of the microbiome are unidentified. This pilot study aimed to determine baseline microbial community within A. hebraeum nymphs infected- and non-infected with Rickettsia africae from the environment, and within adult ticks infected- and non-infected with R. africae collected from cattle sampled from two locations in the Eastern Cape province of South Africa. Adult A. hebraeum ticks (N = 13) and A. hebraeum nymph (N = 15) preliminary screened for R. africae were randomly selected and subjected to Illumina sequencing targeting the v3–v4 hypervariable regions of the 16S rRNA gene. No significant difference in microbial community composition, as well as rarefied OTU richness and diversity were detected between adults and nymphs. Nymphs showed a higher richness of bacterial taxa indicating blood-feeding could have resulted in loss of microbial diversity during the moulting stage from nymph to adult. Core OTUs that were in at least 50% of nymphs and adults negative and positive for Rickettsia at 1% minimum relative abundance were Rickettsia, Coxiella and Ruminococcaceae UCG-005 with a single genus Arsenophonus occurring only in nymphs negative for Rickettsia. Ehrlichia spp. was present in only four nymphal ticks positive for Rickettsia. Interestingly, Rickettsia aeschlimannii was found in one nymph and one adult, indicating the first ever detection of the species in A. hebraeum. Furthermore, A. hebraeum harboured a Coxiella-like endosymbiont, which should be investigated further as Coxiella may affect the viability and transmission of other organisms.

The epidemiology of bacterial zoonoses in pastoral and dairy cattle in Cameroon, Central Africa

Previous work identified that bacterial zoonoses (Brucella species, Coxiella burnetii and Leptospira hardjo) were present in Cameroonian pastoral cattle. To assess the characteristics of this zoonotic risk, we analyse seroprevalence of each pathogen and the associated management, herd and environmental factors in Cameroonian pastoral and dairy cattle. Cross-sectional samples included pastoralist herds in the Northwest Region (NWR n = 750) and Vina Division (VD n = 748) and small holder dairy herds in the NWR (n = 60). Exposure to Brucella spp., C. burnetii and L. hardjo were screened for using commercial ELISAs and population adjusted estimates made. In addition, individual, herd and ecological metadata were collected and used to identify risk factors associated with animal-level seropositivity. In the pastoral cattle, seroprevalence to Brucella spp. was relatively low but was higher in the NWR (4.2%, CI: 2.5%-7.0%) than the VD (1.1%: CI 0.5%-2.4%), while L. hardjo seroprevalence was much higher though similar in the NWR (30.7%, CI 26.3%-35.5%) and VD (35.9%, CI 31.3%-40.7%). No differences were noted in C. burnetii seroprevalence between the two study sites (NWR: 14.6%, CI 11.8%-18.0%. VD: 12.4%, 9.6%-15.9%). Compared to pastoral, dairy cattle had lower seroprevalences for L. hardjo (1.7%, CI: 0.0%-4.9%), C. burnetii (0.0%, CI 0.0%-6.0%) but similar for Brucella spp. (5.0%, CI 0.0%-10.6%). Increased odds of Brucella spp. seropositivity were associated with owning sheep or rearing sheep and fencing cattle in at night. Adult cattle had increased odds of being seropositive for both C. burnetii and L. hardjo. Additionally, exposure to C. burnetii was associated with local ecological conditions and L. hardjo was negatively associated with cattle undertaking transhumance. This work highlights that exposure to these 3 important production diseases and occupational zoonoses are widespread in Cameroonian cattle. Further work is required to understand transmission dynamics between humans and livestock to inform implementation of effective control measures.

Molecular Detection and Characterization of Rickettsia Species in Ixodid Ticks Collected From Cattle in Southern Zambia

Tick-borne zoonotic pathogens are increasingly becoming important across the world. In sub-Saharan Africa, tick-borne pathogens identified include viruses, bacteria and protozoa, with Rickettsia being the most frequently reported. This study was conducted to screen and identify Rickettsia species in ticks (Family Ixodidae) infesting livestock in selected districts of southern Zambia. A total of 236 ticks from three different genera (Amblyomma, Hyalomma, and Rhipicephalus) were collected over 14 months (May 2018-July 2019) and were subsequently screened for the presence of Rickettsia pathogens based on PCR amplification targeting the outer membrane protein B (ompB). An overall Rickettsia prevalence of 18.6% (44/236) was recorded. Multi-locus sequencing and phylogenetic characterization based on the ompB, ompA, 16S rRNA and citrate synthase (gltA) genes revealed the presence of Rickettsia africae (R. africae), R. aeschlimannii-like species and unidentified Rickettsia species. While R. aeschlimannii-like species are being reported for the first time in Zambia, R. africae has been reported previously, with our results showing a wider distribution of the bacteria in the country. Our study reveals the potential risk of human infection by zoonotic Rickettsia species and highlights the need for increased awareness of these infections in Zambia's public health systems.

Molecular Characterization of Ticks and Tick-Borne Pathogens in Cattle from Khartoum State and East Darfur State, Sudan

Ticks transmit many pathogens with public health and veterinary importance. Despite the wide distribution of tick-borne pathogens in Sudan, the information on the tick–pathogen relationship needs to be updated, particularly using modern molecular techniques. This cross-sectional study, conducted between September and November 2019, used morphology, PCR, and sequencing to confirm the identity of adult cattle ticks (male and female; n = 536) from Khartoum State (n = 417) and East Darfur State (n = 119). Moreover, the presence of Theileria annulata, Babesia bigemina, B. bovis, Anaplasma marginale, and Ehrlichia ruminantium was detected and confirmed in each tick using species-specific PCR or nested PCR and sequencing. The most economically important tick genera, Rhipicephalus, Hyalomma, and Amblyomma, were prevalent in the study area, and 13 different tick species were identified. The most prevalent tick species were Rhipicephalusevertsi evertsi (34.3%) and Hyalomma anatolicum (57.3%) in Khartoum State, and Rhipicephalus annulatus (27%), Rhipicephalus decoloratus (25%), and Hyalomma rufipes (29%) in East Darfur State. We detected all five pathogens in both states. To the best of our knowledge, this is the first study to report the presence of E. ruminantium, its vector Amblyomma variegatum, and B. bovis in Khartoum State. Further, this is the first report on most tick and pathogen species identified in East Darfur State. Our findings indicate the migration of some tick and pathogen species beyond their distribution areas in the country, and this consideration is necessary to develop future control strategies.

Q Fever: Seroprevalence, Risk Factors in Slaughter Livestock and Genotypes of Coxiella burnetii in South Africa

Q fever is a neglected zoonosis in South Africa, causing significant losses in livestock and game animals through reproductive disorders. However, there are limited studies on the extent of Coxiella burnetii infections in livestock in South Africa. Further, there is also lack of knowledge about the types of C. burnetii strains that are currently circulating in the country. Therefore, a cross-sectional, abattoir-based study was conducted to determine the seroprevalence of C. burnetii and associated risk factors, and to characterize C. burnetii strains from slaughter livestock at red meat abattoirs in Gauteng, South Africa. Of the 507 animals tested, 6.9% (95% CI: 4.9-9.5%) were positive for antibodies against C. burnetii. The seroprevalence was 9.4% (31/331) in cattle, 4.3% (3/69) in sheep, and 0.9% (1/107) in pigs. Out of the 63 tissue samples from 35 seropositive animals including material from two sheep aborted fetuses from Mangaung district (Free State province), 12.7% (8/63) tested positive by IS1111 PCR. Genotyping of the eight PCR-positive tissues from eight animals by MLVA revealed two novel genotypes, not available in Coxiella MLVA databases. It is concluded that slaughter animals pose a risk of exposing abattoir and farm workers to C. burnetii in South Africa.

Genetic diversity of Rickettsia africae isolates from Amblyomma hebraeum and blood from cattle in the Eastern Cape province of South Africa

Rickettsia africae is a re-emerging tick-borne pathogen causing African tick bite fever (ATBF) in humans. Amblyomma variegatum is the principal vector in most sub-Sahara African countries, whereas in South Africa it is A. hebraeum. Reports of high genetic heterogeneity among R. africae isolates in southern Africa have prompted the need for molecular investigations of isolates form South Africa. Therefore, this study aimed to determine the prevalence and genetic diversity of R. africae in A. hebraeum collected from cattle, grazing pasture, as well as from blood of cattle in the Eastern Cape Province of South Africa. Amblyomma hebraeum and blood from cattle were screened by PCR and the gltA, ompA, ompB, sca4, and 17kDa genes were sequenced for R. africae from samples collected from Caquba in Port St. Johns along the coastal region in the Eastern Cape province of South Africa. The overall proportion of adult A. hebraeum that were positive for the gltA and ompA genes was 0.63 (108/180). The overall proportion of nymphs positive for the gltA and ompA genes was 0.62 (23/37) and 0.22 (20/90) from cattle blood. A positive R. africae infection was inferred by analysis of 26 sequences of the ompA, gltA, ompB, 17kDa and sca4 genes. Neighbour-joining and Maximum Likelihood analysis revealed that the study isolates were closely related to R. africae isolates from South Africa deposited in GenBank, forming a clade that was separate from north, east and west African strains. This study provides new information on the epidemiology and phylogeny of R. africae isolated from A. hebraeum ticks in the Eastern Cape province of South Africa. The heterogeneity observed between R. africae isolates from South Africa deposited in GenBank and R. africae isolates from Africa retrieved from Genbank highlight the importance of differentiation and tracking of the genetic movement among R. africae isolates in southern Africa for the better characterisation of ATBF cases, especially in rural communities and travellers visiting the region.

Wentzel J, Wills-Berriman S, Boni LD, Weyer J, Rossouw J, Oosthuizen MC. Anaplasma phagocytophilum and Other Anaplasma spp. in Various Hosts in the Mnisi Community, Mpumalanga Province, South Africa

DNA samples from 74 patients with non-malarial acute febrile illness (AFI), 282 rodents, 100 cattle, 56 dogs and 160 Rhipicephalus sanguineus ticks were screened for the presence of Anaplasma phagocytophilum DNA using a quantitative PCR (qPCR) assay targeting the msp2 gene. The test detected both A. phagocytophilum and Anaplasma sp. SA/ZAM dog DNA. Microbiome sequencing confirmed the presence of low levels of A. phagocytophilum DNA in the blood of rodents, dogs and cattle, while high levels of A. platys and Anaplasma sp. SA/ZAM dog were detected in dogs. Directed sequencing of the 16S rRNA and gltA genes in selected samples revealed the presence of A. phagocytophilum DNA in humans, dogs and rodents and highlighted its importance as a possible contributing cause of AFI in South Africa. A number of recently described Anaplasma species and A. platys were also detected in the study. Phylogenetic analyses grouped Anaplasma sp. SA/ZAM dog into a distinct clade, with sufficient divergence from other Anaplasma species to warrant classification as a separate species. Until appropriate type-material can be deposited and the species is formally described, we will refer to this novel organism as Anaplasma sp. SA dog.

Development of a practical framework for sustainable surveillance and control of ticks and tick-borne diseases in Africa

A workshop on ticks and tick-borne diseases (T&TBDs) was held on June 25 and 26, 2019, at the Tropical Pesticides Research Institute, Division of Livestock and Human Diseases Vector Control, Arusha, Tanzania. The objectives of the workshop were to discuss the current situation and to formulate actionable strategies to improve surveillance and control of T&TBDs in Africa. The workshop was funded by the National Research Foundation and the Cape Peninsula University of Technology and attended by livestock health providers, farmers, and researchers from East, West, and Southern African countries. During the workshop, experts presented recent surveillance data focused on T&TBDs; participants discussed research opportunities and community engagement. The primary outcome of the workshop was the creation of a new research consortium known as The African Consortium for T&TBDs. The consortium is intended to function as a community for researchers, students, farmers, policymakers, extension workers, and community members who are interested in the advancement of T&TBD control. The consortium will engage in research activities that focus on comprehensive surveillance of T&TBDs, developing tick acaricide resistance, alternative tick control programs, and policy development and education. These areas were identified as top priorities to be developed to improve T&TBD control on the continent.

Parasites of veterinary importance from domestic animals in uMkhanyakude district of KwaZulu-Natal province

This study investigated the occurrence and phylogenetic relationship of protozoan parasites and Ehrlichia infecting domestic animals from three municipalities in uMkhanyakude district of KwaZulu-Natal province, South Africa. A total of 208 blood samples collected from clinically healthy cattle, sheep, goats and dogs from uMkhanyakude district were examined by polymerase chain reaction (PCR) assays, using either genus or species-specific primers to determine the occurrence and phylogenetic relationship of various protozoan parasites and Ehrlichia of veterinary importance. A total of 5/109 (4.6%) cattle were PCR-positive for the presence of Toxoplasma gondii, 33/109 (30.3%) for Babesia bovis, 24/109 (22.02%) for Babesia bigemina and 20/109 (18.3%) for Trypanosoma sp., while 3/10 (30%) of sheep were PCR-positive for Theileria ovis and none of the goats were positive for any of the detected pathogens. The co-infection of 4/109 (3.7%) B. bovis and B. bigemina was detected in cattle. Only Ehrlichia canis was detected in dogs with infection rate of 20/48 (41.7%). Sequences of PCR-positive isolates (B. bovis, B. bigemina, E. canis, T. ovis and T. gondii) showed that they were closely related to their relevant species from various countries. These findings have expanded our knowledge about the prevalence and phylogenetic similarity between protozoan parasites and Ehrlichia isolates of South African origin. To date, this is the first study in South Africa to detect T. gondii infections from cattle blood using PCR.

Genetic Diversity and Sequence Polymorphism of Two Genes Encoding Theileria parva Antigens Recognized by CD8+ T Cells among Vaccinated and Unvaccinated Cattle in Malawi

East Coast fever (ECF) is an acute fatal tick-borne disease of cattle caused by Theileria parva. It causes major losses in exotic and crossbreed cattle, but this could be prevented by a vaccine of T. parva if the vaccine is selected properly based on information from molecular epidemiology studies. The Muguga cocktail (MC) vaccine (Muguga, Kiambu 5 and Serengeti-transformed strains) has been used on exotic and crossbreed cattle. A total of 254 T. parva samples from vaccinated and unvaccinated cattle were used to understand the genetic diversity of T. parva in Malawi using partial sequences of the Tp1 and Tp2 genes encoding T. parva CD8⁺ antigens, known to be immunodominant and current candidate antigens for a subunit vaccine. Single nucleotide polymorphisms were observed at 14 positions (3.65%) in Tp1 and 156 positions (33.12%) in Tp2, plus short deletions in Tp1, resulting in 6 and 10 amino acid variants in the Tp1 and Tp2 genes, respectively. Most sequences were either identical or similar to T. parva Muguga and Kiambu 5 strains. This may suggest the possible expansion of vaccine components into unvaccinated cattle, or that a very similar genotype already existed in Malawi. This study provides information that support the use of MC to control ECF in Malawi.

Amblyomma hebraeum is the predominant tick species on goats in the Mnisi Community Area of Mpumalanga Province South Africa and is co-infected with Ehrlichia ruminantium and Rickettsia africae

Background

In sub-Saharan Africa, Amblyomma ticks are vectors of heartwater disease in domestic ruminants, caused by the rickettsial pathogen Ehrlichia ruminantium. Immature tick stages often bite humans, whereby they act as vectors of tick-bite fever caused by Rickettsia africae. Moreover, Amblyomma ticks cause damage to livestock due to their feeding behaviour. In South Africa, we studied the abundance of Amblyomma hebraeum ticks on goats of emerging farmers in Mpumalanga Province. A selected number of A. hebraeum nymphs and adult ticks was tested for co-infection with E. ruminantium and R. africae.

Methods

A total of 630 indigenous goats, belonging to farmers in the Mnisi Community area, were examined for ticks in 2013 and 2014. All ticks were identified, and a selected number was tested by PCR with reverse line blot hybridisation.

Results

In total, 13,132 ticks were collected from goats distributed over 17 different households. Amblyomma hebraeum was the predominant species, followed by R. microplus. Rhipicephalus appendiculatus, R. simus and R. zambeziensis were also identified. Amblyomma hebraeum was present throughout the year, with peak activity of adults in summer (November) and nymphs in winter (July). The ratio between adults and nymphs ranged from 1:2.7 in summer to 1:55.1 in winter. The mean prevalence of infection for E. ruminantium by PCR/RLB in adult ticks was 17.4% (31/178), whereas 15.7% (28/178) were infected with R. africae. In pooled nymphs, 28.4% were infected with E. ruminantium and 38.8% carried R. africae infection. Co-infections of E. ruminantium and R. africae in adult and pooled nymphal ticks were 3.9% (7/178) and 10% (14.9), respectively. Lameness of goats due to predilection of ticks for the interdigital space of their feet was observed in 89% of the households.

Conclusions

Goats act as important alternative hosts for cattle ticks, which underscored the necessity to include goats in control programs. It is suggested to use acaricide-impregnated leg-bands as a sustainable method to kill ticks and prevent lameness in goats. The challenge of goats by considerable numbers of E. ruminantium-infected ticks is a major obstacle for upgrading the indigenous goat breeds. Humans may be at risk to contract tick-bite fever in this area.

Molecular investigation and phylogeny of species of the Anaplasmataceae infecting animals and ticks in Senegal

BACKGROUND

Our study aimed to assess the diversity of the species of Anaplasmataceae in Senegal that infect animals and ticks in three areas: near Keur Momar Sarr (northern region), Dielmo and Diop (Sine Saloum, central region of Senegal), and in Casamance (southern region of Senegal).

METHODS

A total of 204 ticks and 433 blood samples were collected from ruminants, horses, donkeys and dogs. Ticks were identified morphologically and by molecular characterization targeting the 12S rRNA gene. Molecular characterization of species of Anaplasmataceae infecting Senegalese ticks and animals was conducted using the 23S rRNA, 16S rRNA, rpoB and groEL genes.

RESULTS

Ticks were identified as Rhipicephalus evertsi evertsi (84.3%), Hyalomma rufipes (8.3%), Hyalomma impeltatum (4.9%), R. bursa (1.5%) and R. muhsamae (0.9%). The overall prevalence of Anaplasmataceae infection in ticks was 0.9%, whereas 41.1% of the sampled animals were found infected by one of the species belonging to this family. We identified the pathogen Anaplasma ovis in 55.9% of sheep, A. marginale and A. centrale in 19.4% and 8.1%, respectively, of cattle, as well as a putative new species of Anaplasmataceae. Two Anaplasma species commonly infecting ruminants were identified. Anaplasma cf. platys, closely related to A. platys was identified in 19.8% of sheep, 27.7% of goats and 22.6% of cattle, whereas a putative new species, named here provisionally "Candidatus Anaplasma africae", was identified in 3.7% of sheep, 10.3% of goats and 8.1% of cattle. Ehrlichia canis and Anaplasma platys were identified only from dogs sampled in the Keur Momar Sarr area. Ehrlichia canis was identified in 18.8% of dogs and two R. e. evertsi ticks removed from the same sheep. Anaplasma platys was identified in 15.6% of dogs. Neither of the dogs sampled from Casamance region nor the horses and donkeys sampled from Keur Momar Sarr area were found infected by an Anaplasmataceae species.

CONCLUSIONS

This study presents a summary of Anaplasmataceae species that infect animals and ticks in three areas from the northern, central and southern regions of Senegal. To our knowledge, our findings demonstrate for the first time the presence of multiple Anaplasmataceae species that infect ticks and domestic animals in Senegal. We recorded two potentially new species commonly infecting ruminants named here provisionally as Anaplasma cf. platys and "Candidatus Anaplasma africae". However, E. canis was the only species identified and amplified from ticks. None of the other Anaplasmataceae species identified in animals were identified in the tick species collected from animals.

Molecular detection and genetic characterisation of pathogenic Theileria, Anaplasma and Ehrlichia species among apparently healthy sheep in central and western Kenya

Tick-borne diseases (TBDs) caused by Theileria, Babesia, Anaplasma and Ehrlichia species are common in tropical and subtropical regions. In this study, we investigated the presence and genetic diversity of Theileria spp., Anaplasma ovis, B. ovis, E. ruminantium and Anaplasma spp. in sheep from the Machakos and Homa Bay counties of Kenya. In order to improve the diagnosis and control of ovine TBDs, a total of 76 blood samples from apparently healthy sheep were screened using a polymerase chain reaction (PCR). The assays were conducted using primers based on Theileria spp. 18S rRNA, Anaplasma ovis Major surface protein-4 (AoMSP4), B. ovis 18S rRNA, E. ruminantium pCS20 and Anaplasma spp. 16S rRNA. The overall infection rates for Theileria spp., A. ovis, E. ruminantium and Anaplasma spp. were 39/76 (51.3%), 26/76 (34.2%), 6/76 (7.9%) and 31/76 (40.8%), respectively. The overall co-infection was 47/76 (61.8%). All Theileria spp. positive samples were confirmed to be of Theileria ovis on sequencing. A phylogenetic analysis of the 18S rRNA gene sequences of T. ovis revealed that all isolates of this study clustered with T. ovis sequences extracted from the GenBank suggesting this gene is highly conserved. E. ruminantium pCS20 sequences were in the same clade on the phylogenetic tree. However, three AoMSP4 sequences from this study appeared in the same clade, while one sequence formed a separate branch revealing genetic divergence. The 16S rRNA sequencing revealed uncharacterised Anaplasma spp. and A. ovis. The phylogenetic analyses of the uncharacterised Anaplasma spp. revealed that the two sequences from this study appear in an independent clade from other sequences extracted from the GenBank. This study provides important information regarding the occurrence of tick-borne pathogens and their degree of genetic diversity among sheep in Kenya, which is useful for the diagnosis and control of TBDs.

Genetic characterization of tick-borne pathogens in ticks infesting cattle and sheep from three South African provinces

Ticks are involved in the transmission of many public health and veterinary important pathogens. Although tick-borne pathogens are widely distributed in South Africa, information on tick-pathogen relationship needs to be updated particularly using modern molecular techniques. This study used PCR and sequencing to confirm the identity of the tick species collected from cattle and sheep from KwaZulu-Natal, Free State and Eastern Cape. Furthermore, presence of Babesia spp., Theileria spp., Anaplasma marginale, Rickettsia spp., Ehrlichia ruminantium and Coxiella burnetii was detected from tick DNA using species-specific PCR or nested PCRs. The study samples consisted of 390 adult ticks (male and female) which were pooled according to species, host animal and sampling site (three ticks per pool) for DNA extraction. The PCR results revealed that out of 130 tick DNA pools, 30 (23.1%) were positive for at least one pathogen. The most frequent pathogen was C. burnetii (9.2%), followed by Rickettsia spp. (7.7%), A. marginale (3.8%), T. mutans (3.1%), T. taurotragi (2.3%) and E. ruminantium (1.5%). The highest prevalence of pathogens was observed in ticks collected from cattle in Eastern Cape (16/42) and the lowest was in ticks obtained from sheep in Free State (1/21). Infected ticks were identified as Rhipicephalus evertsi evertsi (n = 13), R. appendiculatus (n = 3), R. decoloratus (n = 7) and Amblyomma hebraeum (n = 7). Coinfection with two pathogens was found in 21% of pathogen-positive pools. Analysis of Theileria taurotragi 18S rRNA, T. mutans 18S rRNA, C. burnetii htpB, Rickettsia spp. gltA, Rickettsia spp. ompA, E. ruminantium pCS20 and A. marginale Msp5 sequences showed that the pathogens detected in this study were genetically related to isolates previously reported in Africa. These findings provide important information on distribution of ticks and tick-borne pathogens of ruminants and will contribute in the formulation of future control strategies in South Africa.

Detection of zoonotic agents and a new Rickettsia strain in ticks from donkeys from South Africa: Implications for travel medicine

BACKGROUND

In rural South Africa, people are in close contact with tick-infested donkeys. This study aimed to investigate the presence of spotted fever group Rickettsia, Anaplasma, Ehrlichia and Coxiella species in these arthropods.

METHOD

376 ticks (7 species) from donkeys from Limpopo Province (South Africa) were pooled and analyzed using PCR assays for the bacterium detection.

RESULTS

Rickettsia africae was amplified in 6 Amblyomma hebraeum, 1 Rhipicephalus appendiculatus and 5 Rhipicephalus evertsi evertsi pools. Rickettsia aeschlimannii was found in 1 Hyalomma rufipes, 1 Rh. appendiculatus and 2 Rh. e. evertsi pools. Three Rhipicephalus simus specimens were infected with a new Rickettsia strain that showed low identity with any validated Rickettsia species. Ehrlichia canis was detected in 2 Rh. e. evertsi pools and in one of them Anaplasma bovis was amplified. An Am. hebraeum pool showed infection with Anaplasma ovis and another with Coxiella burnetii.

CONCLUSION

South African donkeys are involved in the epidemiology of tick-borne pathogens and other associated agents such as C. burnetii with Health importance. A potential new Rickettsia species, with unknown pathogenic potential, has been detected in the anthropophilic Rh. simus.

A review of wildlife tourism and meta-analysis of parasitism in Africa's national parks and game reserves

The recent increase of parasitic diseases associated with wildlife tourism can be traced to human contact with wildlife and intense modification of wildlife habitat. The continental estimates of parasitic diseases among visited wildlife-tourists and mammalian wildlife present in conservation areas are lacking; therefore, a general review was necessary to provide insights into Africa's parasitic disease burden and transmission between humans and wildlife. A two-step analysis was conducted with searches in Ovid MEDLINE, EMBASE, PubMed, Web of Science and Global Health. All diseases reported without prevalence were grouped and analysed as categorical data while meta-analysis of prevalence rates of parasitic diseases in wildlife from national parks and reserves in Africa was conducted. Only 4.7% of the tourist centres reported routine wildlife diagnosis for parasitic diseases. Disease intensity shows that cryptosporidiosis and seven other parasitic diseases were observed in both human and wildlife; however, no significant difference in intensity between human and wildlife hosts was observed. Schistosomiasis intensity reports showed a significant increase (P < 0.05) while entamoebiasis showed a significant decrease (P < 0.05) in humans as compared to wildlife. Visiting tourists were more infected with malaria, while wildlife was more infected with parasitic gastroenteritis (PGE). The meta-analysis of wildlife revealed the highest prevalence of PGE with mixed parasites and lowest prevalence of Giardia spp. at 99.9 and 5.7%, respectively. The zoonotic and socioeconomic impact of some of these parasites could pose a severe public threat to tourism. Pre- and post-travel clinical examinations are important for tourists while routine examination, treatment and rational surveillance are important for these animals to improve wildlife tourism.

A rapid bio-optical sensor for diagnosing Q fever in clinical specimens

Recent zoonotic outbreaks, such as Zika, Middle East respiratory syndrome and Ebola, have highlighted the need for rapid and accurate diagnostic assays that can be used to aid pathogen control. Q fever is a zoonotic disease caused by the transmission of Coxiella burnetii that can cause serious illness in humans through aerosols and is considered a potential bioterrorism agent. However, the existing assays are not suitable for the detection of this pathogen due to its low levels in real samples. We here describe a rapid bio-optical sensor for the accurate detection of Q fever and validate its clinical utility. By combining a bio-optical sensor, that transduces the presence of the target DNA based on binding-induced changes in the refractive index on the waveguide surface in a label-free and real-time manner, with isothermal DNA amplification, this new diagnostic tool offers a rapid (<20 min), 1-step DNA amplification/detection method. We confirmed the clinical sensitivity (>90%) of the bio-optical sensor by detecting C. burnetii in 11 formalin-fixed, paraffin-embedded liver biopsy samples from acute Q fever hepatitis patients and in 16 blood plasma samples from patients in which Q fever is the cause of fever of unknown origin.

Molecular analysis of tick-borne protozoan and rickettsial pathogens in small ruminants from two South African provinces

Tick-borne protozoan and rickettsial diseases are a major threat to livestock in tropical and sub-tropical regions of Africa. In this study we investigated the presence and distribution of Theileria spp., Babesia ovis, Anaplasma ovis, Anaplasma phagocytophilum, Ehrlichia ruminantium and SFG Rickettsia in sheep and goats from Free State and KwaZulu-Natal provinces. A total of 91 blood samples were screened in this study, 61 from goats and 30 from sheep. PCR assay was conducted using primers based on Theileria spp. 18S rRNA, Babesia ovis (BoSSU rRNA), Anaplasma ovis (AoMSP4), Anaplasma phagocytophilum epank1, Ehrlichia ruminantium pCS20 and SFG Rickettsia OmpA. Overall infection rates of Theileria spp., Anaplasma ovis and Ehrlichia ruminantium were 18 (19.8%), 33 (36.3%) and 13 (14.3%), respectively. The co-infection of two pathogens were detected in 17/91 (18.7%) of all samples, goats having higher rates of co-infection compared to sheep. Phylogenetic tree analysis sequence of pCS20 gene of E. ruminantium of this study was found to be in the same clade with Kumm2 and Riverside strains both from South Africa. The phylogram of SSU rRNA of Theileria ovis had longer branch length compared to all other sequences most of which were from Asia and Middle East. This study provides important data for understanding the tick-borne diseases occurrence in the study area and it is expected to improve the approach for the diagnosis and control of these diseases.

Bacterial arthropod-borne diseases in West Africa

Arthropods such as ticks, lice, fleas and mites are excellent vectors for many pathogenic agents including bacteria, protozoa and viruses to animals. Moreover, many of these pathogens can also be accidentally transmitted to humans throughout the world. Bacterial vector-borne diseases seem to be numerous and very important in human pathology, however, they are often ignored and are not well known. Yet they are in a phase of geographic expansion and play an important role in the etiology of febrile episodes in regions of Africa. Since the introduction of molecular techniques, the presence of these pathogens has been confirmed in various samples from arthropods and animals, and more rarely from human samples in West Africa. In this review, the aim is to summarize the latest information about vector-borne bacteria, focusing on West Africa from 2000 until today in order to better understand the epidemiological risks associated with these arthropods. This will allow health and veterinary authorities to develop a strategy for surveillance of arthropods and bacterial disease in order to protect people and animals.

Occurrence of <i>Coxiella burnetii</i>, <i>Ehrlichia canis</i>, <i>Rickettsia</i> species and <i>Anaplasma phagocytophilum</i>-like bacterium in ticks collected from dogs and cats in South Africa

Ticks are major vectors of arthropod-borne infections and transmit a wide variety of zoonotic pathogens. This study was conducted mainly to determine the occurrence of canine tick-borne bacterial and rickettsial pathogens especially those with zoonotic potential. We examined 276 Rhipicephalus sanguineus, 38 Haemaphysalis elliptica and 4 Amblyomma hebraeum ticks from 90 dogs and 4 cats from the Free State, KwaZulu-Natal, North West and Mpumalanga provinces. DNA of Coxiella burnetii (41%), Ehrlichia or Anaplasma (18%), Rickettsia spp. (37%), Anaplasma phagocytophilum-like bacterium (18%) and Ehrlichia canis (19%) was detected by polymerase chain reaction (PCR) from a total of 147 pooled DNA samples. All samples were negative for the presence of Borrelia burgdorferi DNA. Ehrlichia canis was detected in samples from all the provinces except the North West; A. phagocytophilum was absent in KwaZulu-Natal samples, whereas Rickettsia species and C. burnetii were detected in all sampled provinces. The PCR-positive samples were confirmed by direct sequencing of the product. Data from this study calls for a joint effort by both veterinary and medical sectors to conduct epidemiological studies of the zoonotic pathogens in both animals and humans.

Molecular epidemiological surveillance to assess emergence and re-emergence of tick-borne infections in tick samples from China evaluated by nested PCRs

An investigation was performed to detect eight pathogens in ticks collected from grass tips or animals in the southern, central and northeast regions of China. DNA samples extracted from ticks were collected from ten different locations in eight provinces of China and subjected to screening for tick-borne pathogens, including Borrelia burgdorferi sensu lato, Ehrlichia spp., Rickettsia spp., Babesia/Theileria spp., Ehrlichia ruminantium, Coxiella burnetii, and Francisella tularensis, using nested PCR assays and sequencing analysis. The results indicated that Borrelia spp., Rickettsia spp., and Babesia/Theileria spp. were detected in all of the investigated provinces. Ehrlichia spp. was also found in all of the surveyed areas, except Guangxi, Luobei and Tonghe counties in Heilongjiang province. The average prevalence of these pathogens was 18.4% (95% CI=12.8-42.5), 60.3% (95% CI=18.2-65.3), 26.0% (95% CI=25.8-65.1), and 28.7% (95% CI=5.6-35.2), respectively. A sequencing analysis of the pCS20 gene of E. ruminantium revealed an E. ruminantium-like organism (1/849, 0.1%, 95% CI=0-0.3) in one tick DNA sample extracted from Rhipicephalus (Boophilus) microplus in Hunan. In addition, Borrelia americana in Ixodes persulcatus, Babesia occultans in Haemaphysalis qinghaiensis and both Rhipicephalus sanguineus and an Ehrlichia muris-like organism in R. (B.) microplus was detected, possibly for the first time in China. Four DNA sequences closely related to Borrelia carolinensis and/or Borrelia bissettii from Haemaphysalis longicornis, Candidatus Rickettsia principis from H. qinghaiensis, and I. persulcatus and Ehrlichia canis (named E. canis-like) from Haemaphysalis bispinosa were also detected in this work.

Investigation of Rickettsia, Coxiella burnetii and Bartonella in ticks from animals in South Africa

Ticks are involved in the epidemiology of several human pathogens including spotted fever group (SFG) Rickettsia spp., Coxiella burnetii and Bartonella spp. Human diseases caused by these microorganisms have been reported from South Africa. The presence of SFG Rickettsia spp., C. burnetii and Bartonella spp. was investigated in 205 ticks collected from domestic and wild animals from Western Cape and Limpopo provinces (South Africa). Rickettsia massiliae was detected in 10 Amblyomma sylvaticum and 1 Rhipicephalus simus whereas Rickettsia africae was amplified in 7 Amblyomma hebraeum. Neither C. burnetii nor Bartonella spp. was found in the examined ticks. This study demonstrates the presence of the tick borne pathogen R. massiliae in South Africa (Western Cape and Limpopo provinces), and corroborates the presence of the African tick-bite fever agent (R. africae) in this country (Limpopo province).