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Survey for filarial helminth infections of domestic dogs in Mahikeng North West Province South AfricaVoigts, Bianca January 2018 (has links)
There is a dearth of information pertaining to the occurrence and prevalence of filarial helminth infections of dogs and cats in several provinces in South Africa. In this context the dissertation is a pilot survey that was conducted to determine the occurrence and prevalence of filarial helminth infections of dogs in the greater Mahikeng Local Municipality of North West province. The incentive for the choice of this location in the North West province was a reported high overall prevalence of 18 % of canine filariosis in the town of Gaborone in neighbouring Botswana. EDTA blood samples were collected from 100 live dogs between the ages of 1-11 years (53 males and 47 females). Only dogs that had not received treatment with macrocyclic lactone actives during the previous 12 months were included in the survey. A total of 13 different dog breeds were involved in the survey and the crossbreed animals were the most abundant (59 %) followed by the Boerboel (9 %). Blood samples were screened for the presence of microfilariae by means of the membrane filtration technique. There was no evidence of filarial infections in the 100 dogs sampled. / Dissertation (MSc)--University of Pretoria, 2018. / Veterinary Tropical Diseases / MSc / Unrestricted
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Spatio-temporal analysis of dog ecology and rabies epidemiology at a wildlife interface in the Lowveld Region of South AfricaGrover, Michael January 2015 (has links)
It is estimated that free-roaming dogs comprise on average 75% of dog populations. Interactions between free-roaming dogs and wildlife occur across the globe but little is known about these interactions in the Lowveld region of South Africa, where wildlife areas are fenced off from surrounding communities. Even with extensive fences dogs are still entering the reserves. The study site, a private reserve in eastern Mpumalanga Province on the western boundary of the Greater Limpopo Transfrontier Park, has a high density of human settlements on its boundary. These communities own dogs, many of which are free-roaming. Between January 2009 and March 2014, 170 stray dogs were destroyed inside the reserve and 65.3% of the samples returned a positive result for rabies. Dogs are not limited to the reserve edges and have been documented several kilometres into the reserve.
Eleven geographical factors were used in the spatial analysis: (i) camps or lodges in the reserve, (ii) fence line of the reserve, (iii) water points within the reserve, both natural and man-made (excluding rivers but including pans, dams and waterholes which hold water for most of the year), (iv) access roads from gates to camps and lodges, (v) access gates into the reserve, (vi) pickets (field ranger accommodation) and general staff accommodation, (vii) rivers in stream order from 1 to 6, (viii) vulnerable points for erosion along the fence line, and (ix) villages bordering the reserve. GPS locations of dogs shot were used to obtain nearest distance to each factor. Generalized linear models (GLM) were then used to analyse the spatial data of distance of dogs shot to the nearest factor.
Dogs were significantly more likely to be shot further away from pickets and closer to minor rivers. There was a significant interaction between these two factors (p < 0.0001). Dogs that were shot further from villages (odds ratio 1.42, 95% confidence intervals 1.18 1.71, p = 0.0002) and closer to water (odds ratio 0.41, 95% confidence intervals 0.21 0.81, p = 0.009) were more likely to test positive for rabies. A univariate GLM, with distance to fence as the only explanatory variable, showed a significant association between this and rabies test result: for every 1 km further away from the fence the odds of a dog testing rabies positive increases by 1.68 (95% confidence intervals 1.20 2.36, p = 0.002). However the fence is likely not to be the influencing factor but rather other factors close to the fence. To remove the effect of the fence an analysis of the subset of dogs found further than 200m into the reserve found a positive association between distance from a village and a positive rabies test result (odds ratio 1.58, 95% confidence intervals 1.18-2.32, p = 0.007).
Temporal analysis of the data shows a higher average monthly number of dogs shot during the wet season (Oct-Mar) as well as a higher variance although the cycle is not strictly seasonal. An upgrade of the reserve fence for security reasons coincided with a decrease in number of dogs destroyed in the reserve in 2012-1014. Home range analysis of most susceptible predators was collected from daily sightings data and overlaid with rabies hotspots, which gives management an indication of the need to vaccinate predators with home ranges in close proximity to the fence. The spatial results gives management an indication to increase efforts to destroy free-roaming domestic dogs further into the reserve as the likelihood of a positive rabies result is greater. Ultimately efforts should be focused outside the reserve in the communities to eradicate rabies from the host (domestic dogs) before there is a significant transfer of rabies to wildlife. / Dissertation (MSc)--University of Pretoria, 2015. / tm2016 / Veterinary Tropical Diseases / MSc
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Seroprevalence and factors associated with Q fever and Rift Valley fever in goats in Moretele municipality, South AfricaMagadu, Rungano January 2019 (has links)
Q fever is a zoonotic disease caused by Coxiella burnetii which infects humans and a wide range of hosts including birds, mammals, ticks, fish and reptiles. Rift Valley fever (RVF) virus (RVFV) is a mosquito-borne pathogen of livestock, wildlife and humans and is found throughout much of sub-Saharan Africa, occasionally causing large scale abortions and mortality. There is little detailed knowledge of the distribution and level of occurrence of these two pathogens in South Africa. The aim of this study was to estimate the prevalence of antibodies against C. burnetii and RVFV in goats in Moretele municipality, and to identify factors associated with seropositivity to the two zoonotic pathogens.
Multi-stage random sampling was conducted and sera were collected from 216 goats in 32 goat herds. A questionnaire was completed for each participating goat owner to collect information on potential animal, management and environmental risk factors, as well as potential animal health consequences of the two infections. Rift Valley fever virus antibody testing was done by ID Screen® Rift Valley Fever Competition ELISA test kit (IDVet, Grabels, France) and C. burnetii antibody testing was done by LSIVETTM Ruminant Q Fever - Serum/Milk ELISA test kit (Life Technologies, Carlsbad, California, USA) with confirmation using a virus neutralisation test (VNT).
32/216 goats tested positive for C. burnetii antibodies and the overall seroprevalence, adjusted for clustering and sampling weights was 16% (95% CI: 10.6-23.5%). The intraclass correlation co-efficient (ICC) was 0.06, indicating low to moderate clustering within herds. Multiple logistic regression revealed age as the only factor that was significantly associated with seropositivity to C. burnetii, with a higher seroprevalence in animals ≥2 years of age (26%) than in animals ≤6 months of age (6%) (odds ratio (OR) = 6.6; 95% CI: 1.6-26.7; P = 0.010). Regarding potential consequences of infection, females with a history of abortion were more likely to be seropositive (OR = 4.6; 95% CI: 1.1-20.2; P = 0.043). Goats in herds that reported >2 abortions in the 12 months prior to sampling tended to have a higher odds of seropositivity than animals in herds with no reported abortions (OR = 2.5; 95% CI: 0.9-6.8; P = 0.071). 1/216 goats tested ELISA-positive for RVF virus antibodies and 3 samples were “doubtful”; however, they all tested VNT-negative. The estimated seroprevalence of RVFV was therefore 0% (95% CI: 0.0-1.4%).
In this study, the herd seroprevalence of C. burnetii was high at 51% and there was possibility that C. burnetii is a likely cause of abortions in goats in Moretele municipality of South Africa. Seropositivity to RVFV could not be demonstrated in this study; but if present, the virus is likely to be circulating at very low levels. / Dissertation (MMedVet)--University of Pretoria, 2019. / Production Animal Studies / MMedVet / Unrestricted
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A scoping review of viral diseases in African ungulatesSwanepoel, Hendrik Johannes January 2020 (has links)
Rationale: Viral diseases are important in the African context as they cause significant clinical disease in both wild and domestic animals, as well as in humans. Viral diseases make up a large proportion of emerging infectious diseases. The management and prevention of these diseases have proven to be challenging due to the large population of reservoir hosts consisting of African wildlife. There is no comprehensive publication investigating viruses in African ungulates. Hence, this research study will provide comprehensive analyses to add to the current global knowledge base and provide guidance about areas where there is little information.
Aim of the study: Provide a scoping review of viral diseases, which occur in free-ranging African ungulates and identify knowledge gaps with regards to these diseases.
Objectives:
1. List and describe viruses diagnosed in free-ranging African ungulates
2. Identify ungulates affected by viruses
3. Describe the geographical distribution of viruses
4. Identify viruses which appear to be “under-studied”
Study design: This is a scoping review of peer reviewed publications pertaining to viruses and viral diseases in African ungulates. The methodology for this scoping review was based on the guidelines set out in the PRISMA extension for scoping reviews. A search string was developed and run in three major databases, namely Scopus, Web of Science and Wildlife and Ecology Worldwide, to obtain publications relevant to the research topic. Publications were screened using predetermined inclusion and exclusion criteria to obtain a final set of publications to undergo data extraction and analysis. Results: The final set of publications consisted of 145 publications. A total of 32 viruses were identified in the publications. The range of the publication dates were from 1957 to 2018. Nine out of 32 viruses accounted for 74% of the total reports of viruses detected by antigen/antibody testing in African ungulates. African elephant polyomavirus 1 was the only virus that was solely detected in captive animals according to published literature using antigen/antibody detection. A total of 50 African ungulates were reported/diagnosed with viral infections. The four most frequently mentioned African ungulates in publications reporting on viruses or viral diseases, in descending order, were the African buffalo, blue wildebeest, impala and warthog (common and desert). Of the 52 countries on the African continent, only 18 countries (35%) had viruses diagnosed in wild ungulates reported in the literature. All the publications in this study reported on viruses or viral diseases in ungulates from only sub-Saharan Africa. Foot-and-mouth disease, African swine fever, Rift Valley fever, bluetongue and rabies were frequently reported in the literature. On the contrary, lumpy skin disease, peste des petits ruminants, African horse sickness, enzootic hemorrhagic disease, bovine viral diarrhoea, infectious bovine rhinotracheitis/infectious pustular vulvovaginitis, equine influenza, equine viral arteritis, equine viral rhinopneumonitis and classical swine fever were infrequently reported on.
Conclusion: There are a variety of viruses which have been diagnosed in African ungulates and all African ungulates identified have had one or more viruses or viral diseases associated with them. The findings will be valuable to policymakers, funding bodies, researchers and other stakeholders who need an understanding of viral diseases in African ungulates. Research opportunities in this field will allow them to make informed decisions about investment in future research projects and animal health policies and protocols. It is recommended that governments and research institutions offer more funding to investigate and report viral diseases of greater clinical and zoonotic significance, such as rabies and Rift Valley fever. This is especially important in the current climate of emerging diseases and the related overflow of disease from wild to domestic animals and from animals, both wild and domestic, to humans. A further recommendation is for appropriate One Health approaches to be adopted for investigating, controlling, managing and preventing diseases (Cunningham et al., 2017). This is especially true for diseases such as African swine fever and Rift Valley fever where human actions, poor biosecurity and natural weather changes play a major role in the transmission of diseases (Cunningham et al., 2017, Penrith et al., 2019a, Swanepoel and Coetzer, 2004). Diseases which may threaten the conservation of certain wildlife species also require focused attention. In order to keep track of these diseases it may be necessary to consider adding a “wildlife” category to the OIE-listed diseases.
Viral diseases, as a whole, are of great significance and require extra attention in the future as they make up a large proportion of emerging infectious diseases and can often infect multiple hosts (Bengis et al., 2004, Cleaveland et al., 2001). Hence, the viruses and viral diseases diagnosed in African ungulates are of significance, particularly at the wildlife/livestock interface and many of them have the potential of becoming emerging wildlife diseases. / Dissertation (MSc (Tropical Animal Health))--University of Pretoria, 2020. / Veterinary Tropical Diseases / MSc (Tropical Animal Health) / Restricted
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The epidemiology of tuberculosis in cattle and humans living in the wildlife-livestock-human interface in the rural Mnisi community Mpumalanga province South AfricaMusoke, Jolly January 2016 (has links)
The aim of this study was to investigate the prevalence and epidemiological significance of tuberculosis (TB) in bovine and humans living at a wildlife/livestock/human interface, as well as the risk factors associated with TB transmission at that interface. The Mnisi community was chosen as it is located at the western border of the Kruger National park (KNP) and enables research at the wildlife/livestock/human interface. The first objective of the study entailed investigating the presence of bovine tuberculosis (BTB) in 10% of Mnisi?s livestock, using the comparative intradermal skin test. A low individual prevalence of 0.33 % (95% CI.0.14 ? -0.79) was detected. Further investigations into the causative agent in livestock, using genotyping techniques identified the KNP parental strain, M. bovis KNP VNTR -1 strain.1 Supporting records from the provisional Mpumalanga Veterinary Services and the physical location of dip-tanks where BTB was detected, it was established the infection was a result of spillback infection from wildlife in the neighbouring KNP. The epidemiological significance of BTB in human TB was investigated through the isolation and genetic characterisation of the Mycobacterium tuberculosis complex (MTBC) strain population in the Mnisi community. Mycobacterium bovis was not detected in the human population. However, a high genetic diversity of M. tuberculosis was observed among the 13 isolates obtained.The M. tuberculosis isolates were identified as the following eight families: T; Beijing; LAM 11_ZWE; EAI5; MANU1; X1; X2; and S families. The predominant lineage was as T family, sub-lineage ST53. Based on the high diversity (8 clusters/13isolates) and the predominance of the T family, it was concluded that the TB population structure within the Mnisi community was largely impacted by human migration from urban towns and neighbouring Mozambique. A questionnaire was administered to investigate BTB transmission risk factors at the livestock/human interface. It was established that there were low risk levels of BTB transmission at the human/livestock interface mainly based on the fact that the majority of the households in the community obtained pasteurised milk commercially, and although undercooked/raw meat and organs were preferred, the majority of respondents reported that they discarded the meat if changes in meat quality were observed. / Thesis (PhD)--University of Pretoria, 2016. / tm2016 / Veterinary Tropical Diseases / PhD
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Descriptive human health risk assessment of informal slaughter by small scale farmers of Gauteng focussing on Brucella abortusDeclercq, Gillian January 2018 (has links)
This study is a questionnaire-based, descriptive assessment of informal livestock slaughter practices by small scale farmers in Gauteng. This study aims to assess if the practice of informal slaughter poses a potential risk to public health specifically to brucellosis exposure, a disease of high seroprevalence in Gauteng and South Africa. Informal livestock slaughter from antemortem selection to carcass dressing, butchering and product preparation were descriptively assessed for potential disease exposure and resultant public health risk. This study assessed the frequency of brucellosis testing and the occurrence of livestock abortions as a possible disease indicator. Farmers were asked on the particulars of informal slaughter to ascertain if disease exposure could occur through this practice.
The study made use of a questionnaire where 109 study participants were interviewed individually. Questionnaire results were compiled in Microsoft® Excel where data was analysed through descriptive statistics to identify trends and frequency data from the results. The study found that the majority of small-scale farmers participating in the study were older individuals, the majority of whom were not earning an income. It was found that study participants would slaughter livestock informally themselves or with a family member. This would occur only once or twice a year, usually for cultural or religious purposes or for a special occasion.
Livestock most commonly owned and slaughtered by small-scale farmers were cattle, carriers of Brucella abortus. Participants rarely made use of adequate protective personal protective equipment (PPE) when slaughtering informally. The use of PPE and the adequacy thereof was however found to increase in frequency with participant age group. Older individuals, elders in their communities were often given the responsibility of livestock slaughter, thus providing some risk mitigation to disease exposure during the process. High risk structures such as lymph nodes and reproductive organs were handled during slaughter, the former frequently consumed with the tripe due to lack of recognition. While some organs previously found to harbour Brucella organisms were consumed raw or only exposed to short cooking times, the majority of slaughter products were exposed to prolonged cooking times, sufficient to reduce bacterial loads, reducing risk through consumption. While many participants recognised brucellosis as a zoonotic disease, the routes of transmission were poorly recognised.
Exposure to Brucella spp. through informal slaughter is likely in the current environment of high brucellosis seroprevalence, poor disease control and the unreliable disease history of animals sourced for slaughter, posing a risk to public health. Should a brucella infected animal be slaughtered informally, exposure of those performing the slaughter, dressing the carcass and those involved in food preparation is likely and may lead to brucellosis. / Dissertation (MSc)--University of Pretoria, 2018. / Veterinary Tropical Diseases / MSc / Unrestricted
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Investigating Rickettsia africae infection in Amblyomma hebraeum ticks in Mnisi, Bushbuckridge Municipality, South AfricaMazhetese, Estere January 2019 (has links)
Rickettsia africae is a gram-negative bacterium which causes African tick bite fever (ATBF) in humans. ATBF is a febrile disease mainly affecting travellers to Southern Africa. This bacterium is known to be transmitted by Amblyomma hebraeum and Amblyomma variegatum ticks. In Southern Africa, the principal vector is A. hebraeum. This project was performed in a rural community in Mpumalanga province and aimed at addressing knowledge gaps of R. africae infection in A. hebraeum ticks. Infection rates in adult ticks and larvae as well as transovarial transmission efficiency of R. africae from the tick to its offspring were determined. To accomplish this, 106 adult A. hebraeum ticks were collected from cattle from Utah A and 106 from Welverdiend A. Larvae (n=1060) were collected by dragging at each of the two targeted dip tanks. Engorged female A. hebraeum ticks (n=53) were also collected from cattle from each of the two dip tanks and they were incubated in a humidity tank to oviposit and egg masses were collected from each tick.
DNA was extracted from the engorged ticks and the egg masses as well as from the adult ticks and the larvae. After DNA quantification, a real-time quantitative PCR targeting Rickettsia gltA gene was performed to screen all samples for Rickettsia DNA. The gltA gene is common in all Rickettsia species. Samples positive for the gltA gene were subjected to conventional PCR targeting the ompA gene, which is specific for the Spotted Fever Group to which R. africae belongs.
The samples positive for amplicons of ompA gene were sequenced and all the sequenced samples were found to be 99.98% identical to R. africae sequences from GenBank. From the sampled adult ticks, 13.43% tested positive for R. africae and 13.20% of the larvae also tested positive. The infection rate for larvae and adult ticks collected from Utah A was 15.09% and those from Welverdiend A was 11.79%. From these results, there were no notable differences in the infection rates of ticks at different stages of development. R. africae infection rates for the two study sites were found to be similar which can be an indication of even distribution of R. africae in this area. Transovarial transmission was found to be 100% in engorged female ticks collected from Utah and 71.43% in ticks from Welverdiend, which indicates a high transmission rate of the pathogen to the offspring of the vector. The presence of R. africae in A. hebraeum ticks from this area is a cause of concern since there are chances of people getting ATBF after bites by these ticks. / Dissertation (MSc)--University of Pretoria, 2019. / Veterinary Tropical Diseases / MSc / Unrestricted
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Rift Valley fever virus circulation in livestock and wildlife, and population dynamics of potential vectors, in northern KwaZulu-Natal, South AfricaVan den Bergh, Carien January 2019 (has links)
Rift Valley fever virus (RVFV) is a mosquito-borne virus and a member of the family Phenuiviridae and genus Phlebovirus. The single stranded RNA genome consists of three segments, Large (L), Medium (M) and Small (S). Rift Valley fever (RVF) is a mosquito-borne zoonotic disease that may cause large epidemics in ruminants and humans. Infection in humans causes influenza-like symptoms but the disease can also be more severe and fatal. Outbreaks in livestock are classified by abortion storms and young and newborn animals are severely affected with a high mortality rate. Rift Valley fever causes severe health and economic consequences in the areas where it occurs.
Since the first recorded incidence of RVF in Kenya in 1930, South Africa has had three major countrywide outbreaks: in 1950-1951, 1973-1975 and 2008-2011. The disease is characterized in southern Africa by large epidemics at long, irregular intervals. The epidemics are usually associated with conditions favourable for proliferation of mosquito populations, such as high rainfall and flooding. Rift Valley fever has previously been isolated from 12 different mosquito species in South Africa including 5 Aedes spp., 3 Culex spp., 3 Anopheles spp. and 1 Eretmapodites sp. The presence of the virus and patterns of occurrence of the disease in the eastern parts of South Africa are poorly understood.
Multiple studies were conducted; the aim of the first study was to detect the presence of RVFV in far northern KwaZulu-Natal Province, South Africa and to estimate the incidence rate of seroconversion. Cross-sectional studies were performed in communally farmed cattle (n=423) and goats (n=104), followed by longitudinal follow-up of seronegative livestock (n=253) 14 times over 24 months, representing 160.3 animal-years at risk. Exposure to RVFV was assessed using an IgG sandwich ELISA and a serum neutralization test (SNT) and seroconversion was assessed using SNT. Initial overall seroprevalence was 34.0% (95%CI: 29.5-38.8%) in cattle and 31.7% (95%CI: 22.9-41.6%) in goats, varying by locality from 18-54%. Overall seroconversion rate in cattle was 0.59 per animal-year (95% CI: 0.46-0.75) and in goats 0.41 per animal-year (95% CI: 0.25-0.64), varying significantly over short distances. The high seroprevalence in all age groups and evidence of year-round viral circulation provide evidence for a hyperendemic situation in the study area. The second study investigated the seroprevalence and associated risk factors of RVFV in antelope in the Tembe Elephant Park (TEP) and the Ndumo Game Reserve (NGR), using 326 sera from nyala (Tragelaphus angasii) and impala (Aepyceros melampus) routinely culled over a two-year period. The overall seroprevalence of RVFV was 35.0% (114/326; 95% CI 29.8-40.4%); the presence of antibodies in juveniles (6/21; 28.6%; 95% CI 11.3-52.2%) and sub-adults (13/65; 20.0%; 95% CI 11.1-37.8%) confirmed that infections had occurred subsequent to the 2008-2011 RVF outbreaks in South Africa. Seroprevalence was highest in adults and inversely associated with distance from a swamp or floodplain.
The third study aimed to investigate the diversity, abundance, and seasonal dynamics of mosquitoes in the study area, and to screen mosquitoes for RVFV. Monthly collections of adult mosquitoes were carried out from January 2017 to June 2018 at three sites using CO2-baited tent traps. Mosquitoes were identified, pooled and screened for RVFV by quantitative reverse transcriptase (RT)-polymerase chain reaction (PCR) directed toward amplification of a 217-bp fragment of the L segment. A total of 34,848 mosquitoes of 7 genera and 48 species, were captured; Culex (Cux.) tritaeniorhynchus (31%), Cx. (Cux.) antennatus (29%), Aedes (Adm.) durbanensis (12%) and Cx. (Cux.) neavei (10%) were the most abundant species collected. Genera differences were noted between the collection sites. Cumulative rainfall and average minimum temperatures 30 days prior to collection were positively associated with the number of mosquitoes collected while maximum temperatures were only associated with the number of Culex mosquitoes caught.
A single pool of Ae. durbanensis was found to be positive for RVFV genomic RNA. The same pool was also positive for Chikungunya virus (Family Togaviridae, genus Alphavirus) (CHIKV) and Sindbis virus (Family Togaviridae, genus Alphavirus) (SINV). The RVFV isolate was closely related to one obtained from Ae. (Neo.) circumluteolus at Simbu pan in 1955, ±20 km from the collection sites for this study. Further investigation should be done on the human health implications of the presence of these three zoonotic arboviruses. It is possible that these viruses are causing disease among the communities in the area and that the diseases are under-reported.
The results of this study show that RVFV is circulating in the area in domestic ruminants and wildlife, in the absence of apparent clinical disease, at a rate that varies by location, season and year. It appears that, under similar ecological conditions, domestic and wild ruminants may play a similar role in maintenance of viral circulation, and either or both may serve as the mammalian host in a vector-host maintenance system. The study also demonstrates the presence of a wide variety of mosquito species, several of which are known to be competent RVFV vectors. / Thesis (PhD)--University of Pretoria, 2019. / Veterinary Tropical Diseases / PhD / Unrestricted
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Bacterial microbiome of Rhipicephalus sanguineus ticks collected from dogs in the Mnisi community, South AfricaAckermann, Rebecca January 2019 (has links)
In Mnisi, a rural community in South Africa, Rhipicephalus sanguineus is one of the most prevalent ticks found on dogs. The community lies at the wildlife/livestock/human interface where humans are at risk of tick-borne diseases. The aim of this study was to investigate the diversity of the bacterial microbiome in R. sanguineus that may impact human health. Over a 12-month period, R. sanguineus (n=1,788), Rhipicephalus simus (n=61), Rhipicephalus turanicus (n=73), Amblyomma hebraeum (n=68), Haemaphysalis leachi (n=219) and Hyalomma truncatum (n=1) ticks were collected from 64 dogs. Genomic DNA was extracted from salivary gland and midgut tissues of 62 R. sanguineus tick pools (1 pool = 10 ticks); identifications were confirmed using Cytochrome c oxidase I barcoding. The 16S rRNA gene was amplified using barcoded primers and sent for Pacific Bioscience’s circular consensus sequencing. Characterisation of the bacterial microbiome of midgut and salivary gland pools revealed a total of 260,312 sequences with Proteobacteria (85.44%) being the most prevalent phylum found; with Anaplasma (21.69%), Coxiella (12.12%) and Ehrlichia (19.94%) species dominating the microbiome. Further classification of Ehrlichia revealed 95.46% Ehrlichia canis and 4.54% Ehrlichia species Anaplasma consisted of 15.36% Anaplasma centrale, 75.82% Anaplasma platys and 8.82% Anaplasma species Phylogenetic analysis indicated that the A. centrale and A. platys clustered with various other published A. centrale and A. platys sequences, respectively. It also confirmed that all Ehrlichia species sequences detected in this study are E. canis sequences (94.46%). Furthermore, we determined that the Coxiella sequences detected in the study belong to the R. sanguineus Coxiella-like endosymbionts group. Assessment of risk factors for R. sanguineus infestation indicates that higher average monthly temperatures have a significant association with an increased risk of R. sanguineus tick infestations on dogs. Additionally, rearing chickens at the household was significantly associated with a decreased risk of R. sanguineus tick infestations on dogs. Our study indicated that R. sanguineus could be a potential reservoir for important bacterial pathogens of zoonotic importance. / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2019. / Veterinary Tropical Diseases / MSc (Veterinary Science) / Unrestricted
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Tick species composition and associated haemoparasites of cattle in a semi-arid area of Karamoja, UgandaAkure, Christine Patience January 2019 (has links)
Ticks and tick-borne diseases (TBDs) cause significant losses, through their effects on health, production of animals and humans worldwide. Notably, the countries located within the tropics and subtropics such as Uganda are the most affected due to abundance and distribution of the tick vector. Unfortunately, there is little data in Karamoja Region regarding tick species and the pathogens they transmit. Therefore, a cross-sectional study was undertaken to determine the various tick species, and to detect the tick-borne pathogens within the ticks collected from cattle in Karamoja Region, northeastern Uganda. Between June 2017 and early September 2017 (wet season), a total of 4,897 ixodid ticks were collected from 100 cattle in 20 purposively-selected herds. Three genera of ticks, namely Amblyomma (96.8%), Hyalomma (0.6%) and Rhipicephalus (2.6%) were identified. From the ticks collected, the most dominant species was A. lepidum (93.85%), followed by A. variegatum (2.0%), R. evertsi evertsi (1.0%) and A. gemma (0.98%). Tick species that have not been reported in recent studies in Uganda were found amongst cattle in Karamoja, and these were R. pravus, R. praetextatus and R. turanicus. A representative number of ticks, from each tick species identified in the present study were placed in pools of 1 to 10. Subsequently, a reverse line blot (RLB) hybridization assay was performed to screen for the presence of tick-borne pathogens. Out of the 40 tick pools, 30 (75%) were positive for tick-borne pathogens of the genera Ehrlichia, Anaplasma, Babesia and Theileria. The RLB assay results showed that 57% (n=17) of the tick pools were positive for single infections, while 43% (n=13) had mixed infections. The most frequently detected tick-borne pathogens were
T. parva (10 pools), T. velifera (10 pools), T. mutans (9 pools) and Theileria sp. (sable) (5 pools). Other pathogens detected were E. ruminantium, B. microti, B. rossi, T. separata and B. bigemina. The tick-borne species B. microti, B. rossi, Theileria sp. (sable) and T. separata are not common in cattle, or not known to infect cattle, but were detected from the ticks collected. The detection of B. microti in this study may point to incidental infections with implications for human health. There could have also been a possibility of cross reactions during the RLB analysis leading to the detection of B. microti in this study. These findings provide knowledge of the distribution of ticks and epidemiology of tick-borne pathogens in cattle and may provide support for control of TBDs and improve cattle productivity. / Mini Dissertation (MSc (Tropical Animal Health))--University of Pretoria, 2019. / Veterinary Tropical Diseases / MSc (Tropical Animal Health) / Unrestricted
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