Risk factors affecting the feeding site predilection of ticks on cattle in Ghana.

Ticks are important disease vectors affecting animal health and causing substantial economic loss, especially in the tropics and subtropics. To examine the tick burden of cattle and associated risk factors for tick infestation, ticks were collected from 388 cattle within five regions in Ghana. Most of the cattle were males (50.3%) and generally older than 3 years (65%). Of the animals sampled, 2187 ticks were collected with a mean tick burden of 5.6 ticks per cattle, and the average tick burden on the udder/scrotum being significantly higher than in the anal region (Generalized Linear Mix Model [GLMM], p = 0.01197). The tick species identified were predominantly Amblyomma variegatum (42.6%) and Hyalomma rufipes (26.2%). High proportions of cattle examined were found to have A. variegatum infesting the udder/scrotum. Furthermore, H. rufipes infested mostly the anal region compared to other examined body parts (OR 14.8, 95% CI 8.6-25.4, p < 0.001). Using the GLMM, tick abundance was found to be significantly higher in cattle older than 3 years. The tick burden in the udder/scrotum was higher than that from the chest and leg/thigh of the cattle (GLMM, p < 0.05). The tick burden at the anal region was also significantly higher than the leg/thigh and chest. This study indicates that the preferred attachment sites of ticks on cattle are species-dependent and effective treatment with acaricides should take into consideration the udder/scrotum and anal regions as well as prioritizing older cattle.

Molecular identification of Crimean-Congo haemorrhagic fever virus in Hyalomma rufipes and Amblyomma variegatum in the Upper East Region of Ghana.

Sampled ticks were screened for Crimean-Congo haemorrhagic fever virus (CCHFV) using an assay that targets the nucleoprotein gene region of the S segment, a conserved region of the CCHFV genome. Minimum infection rates of 0.34% and 0.10% were obtained when testing pools of Hyalomma rufipes and Amblyomma variegatum, respectively. Next-generation sequencing and phylogenetic analysis showed that the S and L segments of the CCHFV isolate clustered with those of similar isolates of genotype III. However, analysis of the M segment showed that reassortment had occurred, causing this segment to cluster with those of isolates of genotype I, providing the first evidence of such an occurrence in Ghana.

First Molecular Identification of Rickettsia aeschlimannii and Rickettsia africae in Ticks from Ghana.

The threats from vector-borne pathogens transmitted by ticks place people (including deployed troops) at increased risk for infection, frequently contributing to undifferentiated febrile illness syndromes. Wild and domesticated animals are critical to the transmission cycle of many tick-borne diseases. Livestock can be infected by ticks, and serve as hosts to tick-borne diseases such as rickettsiosis. Thus, it is necessary to identify the tick species and determine their potential to transmit pathogens. A total of 1,493 adult ticks from three genera-Amblyomma, Hyalomma, and Rhipicephalus-were identified using available morphological keys and were pooled (n = 541) by sex and species. Rickettsia species were detected in 308 of 541 (56.9%) pools by genus-specific quantitative polymerase chain reaction assay (Rick17b). Furthermore, sequencing of the outer membrane protein A and B genes (ompA and ompB) of random samples of Rickettsia-positive samples led to the identification of Rickettsia aeschlimannii and Rickettsia africae with most R. africae DNA (80.2%) detected in pools of Amblyomma variegatum. We report the first molecular detection and identification of the rickettsial pathogens R. africae and R. aeschlimannii in ticks from Ghana. Our findings suggest there is a need to use control measures to prevent infections from occurring among human populations in endemic areas in Ghana. This study underscores the importance of determining which vector-borne pathogens are in circulation in Ghana. Further clinical and prevalence studies are needed to understand more comprehensively the clinical impact of these rickettsial pathogens contributing to human disease and morbidity in Ghana.

Spatial and Seasonal Patterns of Tick Infestations in Kassena-Nankana Livestock.

The ability of ticks to adapt to different ecological zones, coupled with the spread of infectious pathogens negatively affects livestock production and thus, there is a need for better control strategies. However, control measures within a geographical region can only be effective if there is available information on tick population dynamics and ecology. This study focused on ticks infesting livestock in the Kassena-Nankana Districts of the Upper East Region of Ghana. The ticks were morphologically identified, variables such as season, animal host, and predilection sites were recorded, and the data were analyzed using STATA version 13. Out of 448 livestock examined, tick infestation in cattle was (78.60%), followed by sheep (25%) and goats (5.88%). A total of 1,550 ticks including nymphs (303) and adults (1,247) were collected. Adult ticks were found to be significantly associated with season (p < 0.001), with a high burden in the wet season. The nymph burden and body parts of livestock hosts were significantly associated with more nymphs collected from male animals than females (p < 0.001). Three genera of ticks, Amblyomma (62.97%), Hyalomma (18.71%), and Rhipicephalus (18.32%) were morphologically identified with the most predominant tick species recorded as Amblyomma variegatum (62.97%). Matured A. variegatum was sampled primarily in the wet season with their predilection site as the udder/scrotum (p < 0.001). However, adult Hyalomma truncatum was observed to have a significant association with the anal region (p < 0.001). Findings from this study are essential for formulating tick control measures to prevent the spread of infectious pathogens.

Whole genome sequencing of outbreak strains from 2017 to 2018 reveals an endemic clade of dengue 1 virus in Cameroon.

Dengue fever is expanding as a global public health threat including countries within Africa. For the past few decades, Cameroon has experienced sporadic cases of arboviral infections including dengue fever. Here, we conducted genomic analyses to investigate the origin and phylogenetic profile of Cameroon DENV-1 outbreak strains and predict the impact of emerging therapeutics on these strains. Bayesian and maximum-likelihood phylogenetic inference approaches were employed in virus evolutionary analyses. An in silico analysis was performed to assess the divergence in immunotherapeutic and vaccine targets in the new genomes. Six complete DENV-1 genomes were generated from 50 samples that met a clinical definition for DENV infection. Phylogenetic analyses revealed that the strains from the current study belong to a sub-lineage of DENV-1 genotype V and form a monophyletic taxon with a 2012 strain from Gabon. The most recent common ancestor (TMRCA) of the Cameroon and Gabon strains was estimated to have existed around 2008. Comparing our sequences to the vaccine strains, 19 and 15 amino acid (aa) substitutions were observed in the immuno-protective prM-E protein segments of the Dengvaxia® and TetraVax-DV-TV003 vaccines, respectively. Epitope mapping revealed mismatches in aa residues at positions E155 and E161 located in the epitope of the human anti-DENV-1 monoclonal antibody HMAb 1F4. The new DENV strains constitute a conserved genomic pool of viruses endemic to the Central African region that needs prospective monitoring to track local viral evolution. Further work is needed to ascertain the performance of emerging therapeutics in DENV strains from the African region.

Detection of Leishmania DNA in Phlebotomine Sand Flies in Tsatee, a Community in the Volta Region, Ghana.

Leishmania parasites, which are spread by infected female sand flies, are the cause of the disease leishmaniasis. Although cutaneous leishmaniasis has been found to occur in the Volta Region, there is limited data on vector species and reservoirs. This study focused on the Tsatee community, in the South Dayi District of the Volta Region, and is aimed at identifying the sand fly fauna and detecting the presence of Leishmania DNA by the use of primers that target the conserved region of Leishmania spp. minicircle DNA of the parasite kinetoplast. The miniature light traps and hand aspirators provided by the Centers for Disease Control and Prevention (CDC) were used to collect outdoor and indoor sand flies for five months in a guinea woodland and semideciduous forest area. From the collections, 4,580 phlebotomine sand flies were obtained and identified, and females were examined for Leishmania DNA using PCR. The male flies were 1,202 (26.24%), non-blood-fed females were 3,321 (72.51%), and 57 (1.25%) were blood-fed females. It was observed that Sergentomyia species constituted 99.91% of the total collected sand flies with S. africana (76.77%) as the predominant species. Phlebotomus rodhaini (0.09%) was the only Phlebotomus species identified from the study area. From 283 non-blood-fed sand fly pools and 57 individual blood-fed species screened, Leishmania DNA was detected in 12 (4.24%) pools and 8 (14.04%) individuals, respectively. It was observed that Leishmania DNA was detected in all the sand fly species identified except S. collarti. This study reports the first detection of Leishmania DNA in P. rodhaini in Ghana, with an infection rate of 33.33% (95% CI, 1.23-88.32). The findings suggest that the role of Phlebotomus in disease transmission in the study area cannot be discounted. Future studies should include continuous surveillance, blood meal preferences, and vector competence of the various infected phlebotomine sand flies to create effective control measures.

First record of Babesia and Theileria parasites in ticks from Kassena-Nankana, Ghana.

Ticks are efficient vectors for transmitting pathogens that negatively affect livestock production and pose a risk to public health. In this study, Babesia and Theileria species were identified in ticks collected from cattle, sheep and goats from the Kassena-Nankana Districts of Ghana between February and December 2020. A total of 1550 ticks were collected, morphologically identified, pooled and screened for pathogens using primers that amplify a 560 bp fragment of the ssrRNA gene and Sanger sequencing. Amblyomma variegatum (62.98%) was the predominant tick species. From the 491 tick pools screened, 12/15 (2.44%) positive pools were successfully sequenced. The pathogen DNA identified were Theileria ovis in eight (15.38%) pools of Rhipicephalus evertsi evertsi, Theileria velifera in two (0.78%) pools of A. variegatum and Babesia occultans and Babesia sp. Xinjiang in one (1.72%) pool each of Hyalomma truncatum. It was further observed that T. ovis occurred in ticks collected from only sheep (p < 0.001) which were females (p = 0.023) and < =1 year old (p = 0.040). This study reports the first identification of these pathogens in ticks within Kassena-Nankana. With the constant trade of livestock, there is a need for effective tick control measures to prevent infection spread.

Ingested histamine and serotonin interact to alter Anopheles stephensi feeding and flight behavior and infection with Plasmodium parasites.

Blood levels of histamine and serotonin (5-HT) are altered in human malaria, and, at these levels, we have shown they have broad, independent effects on Anopheles stephensi following ingestion by this invasive mosquito. Given that histamine and 5-HT are ingested together under natural conditions and that histaminergic and serotonergic signaling are networked in other organisms, we examined effects of combinations of these biogenic amines provisioned to A. stephensi at healthy human levels (high 5-HT, low histamine) or levels associated with severe malaria (low 5-HT, high histamine). Treatments were delivered in water (priming) before feeding A. stephensi on Plasmodium yoelii-infected mice or via artificial blood meal. Relative to effects of histamine and 5-HT alone, effects of biogenic amine combinations were complex. Biogenic amine treatments had the greatest impact on the first oviposition cycle, with high histamine moderating low 5-HT effects in combination. In contrast, clutch sizes were similar across combination and individual treatments. While high histamine alone increased uninfected A. stephensi weekly lifetime blood feeding, neither combination altered this tendency relative to controls. The tendency to re-feed 2 weeks after the first blood meal was altered by combination treatments, but this depended on mode of delivery. For blood delivery, malaria-associated treatments yielded higher percentages of fed females relative to healthy-associated treatments, but the converse was true for priming. Female mosquitoes treated with the malaria-associated combination exhibited enhanced flight behavior and object inspection relative to controls and healthy combination treatment. Mosquitoes primed with the malaria-associated combination exhibited higher mean oocysts and sporozoite infection prevalence relative to the healthy combination, with high histamine having a dominant effect on these patterns. Compared with uninfected A. stephensi, the tendency of infected mosquitoes to take a second blood meal revealed an interaction of biogenic amines with infection. We used a mathematical model to project the impacts of different levels of biogenic amines and associated changes on outbreaks in human populations. While not all outbreak parameters were impacted the same, the sum of effects suggests that histamine and 5-HT alter the likelihood of transmission by mosquitoes that feed on hosts with symptomatic malaria versus a healthy host.

Occurrence of Rickettsia spp. and Coxiella burnetii in ixodid ticks in Kassena-Nankana, Ghana.

Ticks are arthropods of veterinary and medical importance which spread zoonotic pathogens that link animal and human health. In this study, ticks were collected from 448 livestock between February and December 2020 in the Kassena-Nankana Districts of Ghana and screened for the presence of zoonotic pathogens DNA using PCR and sequencing approaches. In total, 1550 ticks were collected and morphologically identified. Three tick genera were identified with Amblyomma variegatum (63%) as the predominant tick species collected. DNA was extracted from 491 tick pools and screened for the presence of DNA of Rickettsia spp. based on the 115 bp fragment of the 17 kDa surface protein and 639 bp of the Outer membrane protein A (ompA) gene and the 295 bp fragment of the transposase gene of Coxiella burnetii IS1111a element. From the 491 pools screened, the DNA of Rickettsia spp. and C. burnetii was detected in 56.8 and 3.7%, respectively. Coinfections were identified in 2.4% of the tick pools. Characterization of the Rickettsia spp. in this study based on the ompA gene showed that the DNA of Rickettsia africae and Rickettsia aeschlimannii accounted for 39.7 and 14.7%, respectively, and were 100% similar to sequences in GenBank. Most R. africae and C. burnetii infections occurred in ticks collected in the wet season, whereas R. aeschlimannii occurred mostly in the dry season. These pathogens are potential public health threats, thus there is a need to implement control measures to reduce the risk of infections in vulnerable populations.

First record of Rhipicephalus (Boophilus) microplus in Ghana, a potential risk to livestock production.

Ticks are a public health threat due to their tendency to spread pathogens that affect humans and animals. With reports of Rhipicephalus (Boophilus) microplus invasion in neighbouring countries, there is the risk of this species invading Ghana through livestock trade. Previous identification of tick species in Ghana has been based on morphological identification, which can be ineffective, especially with damaged tick specimens or engorged nymphs. This study focused on the Kassena-Nankana District, which serves as a trade route for cattle into Ghana, to determine the presence of R. microplus. Three genera of ticks were identified as Amblyomma (70.9%), Hyalomma (21.3%) and Rhipicephalus (7.8%). The engorged nymphs that could not be identified morphologically were analyzed using primers that target the mitochondrial 16S rRNA gene. This study reports the first record of R. (B.) microplus in Ghana. Furthermore, R. microplus constituted 54.8% of the Boophilus species collected in this study. This finding is an addition to the diverse tick species previously collected in Ghana, most of which are of veterinary and public health importance. With reports of acaricide resistance in R. microplus and its role in spreading infectious pathogens, the detection of this species in Ghana cannot be overlooked. Nationwide surveillance will be essential to ascertain its distribution, its effects on cattle production, and the control measures adopted.

Microbiological quality and antimicrobial resistance of Bacteria species recovered from ready-to-eat food, water samples, and palm swabs of food vendors in Accra, Ghana.

This study sought to investigate microbial quality and antimicrobial resistance of bacteria species from Ready-to-Eat (RTE) food, water, and vendor palm swab samples. Between 2019 and 2020, RTE food, water and vendor palm swab samples were collected from food vending sites in Accra, Ghana. Samples were cultured and confirmed using the Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF). Antimicrobial susceptibility testing (AST) was conducted using disk diffusion method. Beta-lactamase and Diarrheagenic Escherichia coli (DEC) genes were determined using Polymerase Chain Reaction (PCR). Total plate count (TPC) and Total coliform count (TCC) were performed on food and water samples. In total, 179 RTE food, 72 water and 10 vendor palm swab samples were collected. Enterobacter spp. (16.8 %), Citrobacter spp. (10.1 %), Enterococcus faecalis (7.8 %), Pseudomonas spp. (6.7 %) and Klebsiella pneumoniae (4.0 %) occurred in food. Isolates from water and palm were Klebsiella pneumoniae (20.8 %), Aeromonas spp. (16.7 %) and Enterobacter cloacae (11.1 %). Resistance to Amoxicillin-clavulanate, Tetracycline, Azithromycin, Sulfamethoxazole-trimethoprim, and Nitrofurantoin were common among Enterobacterales. High mean TPC and TCC showed in some RTE food and different water types used in vending depicting their unsafe condition for consumption and usage. The blaSHV and blaTEM genes were present in some Enterobacterales from food and water. The lt gene was identified in two food samples. AMR organisms associated with nosocomial infections in the samples investigated, calls for continuous surveillance in the food industry in Ghana. Also, the unsafe outcome of RTE food and water depicts the need for the enforcement of Ghana's food safety laws.

Molecular survey of Anaplasma and Ehrlichia species in livestock ticks from Kassena-Nankana, Ghana; with a first report of Anaplasma capra and Ehrlichia minasensis.

Tick-borne pathogens harm livestock production and pose a significant risk to public health. To combat these effects, it is necessary to identify the circulating pathogens to create effective control measures. This study identified Anaplasma and Ehrlichia species in ticks collected from livestock in the Kassena-Nankana Districts between February 2020 and December 2020. A total of 1550 ticks were collected from cattle, sheep and goats. The ticks were morphologically identified, pooled and screened for pathogens using primers that amplify a 345 bp fragment of the 16SrRNA gene and Sanger sequencing. The predominant tick species collected was Amblyomma variegatum (62.98%). From the 491 tick pools screened, 34 (6.92%) were positive for Ehrlichia and Anaplasma. The pathogens identified were Ehrlichia canis (4.28%), Ehrlichia minasensis (1.63%), Anaplasma capra (0.81%) and Anaplasma marginale (0.20%). This study reports the first molecular identification of the above-mentioned Ehrlichia and Anaplasma species in ticks from Ghana. With the association of human infections with the zoonotic pathogen A. capra, livestock owners are at risk of infections, calling for the development of effective control measures.

A Preliminary Study to Compare Recombinase Polymerase Amplification-Lateral Flow and Quantitative PCR in the Detection of Cutaneous Leishmania in Communities from the Volta Region of Ghana.

Background: Leishmaniasis is a parasitic disease that mostly affects populations in tropical and subtropical countries. In Ghana, cutaneous leishmaniasis (CL) is the most common form of the disease affecting communities of the Volta Region. Conventional parasitological method (microscopy) is the commonly used test for CL diagnosis in many endemic countries, but has low sensitivity in chronic cases. Therefore, there is a clear need for a sensitive and easy-to-use point-of-care diagnostic method like an isothermal recombinase polymerase amplification-lateral flow (RPA-LF) test, suitable for use in austere and low-resource settings for the identification of CL cases. This study compared the efficacy of RPA-LF test with quantitative PCR (qPCR) in detecting Leishmania in suspected CL cases from the Volta Region. Methods: Twenty-five participants between 5 and 14 years were enrolled in the study from whom a total of 26 samples were obtained. Lesion samples were collected using FTA® filter papers applied to ulcerated lesions for molecular diagnosis. DNA isolated from filter papers was used for both the RPA-LF test and qPCR. Results: Twenty-two participants (88%) presented with one or two ulcerated active lesions per individual, while the rest of them had plaques or dried lesions. Among the 26 samples, 19/26 (73%) had concordant results when comparing the two diagnostic methods. Conclusion: Data from this study suggest that the RPA-LF test can be used in addition to a conventional parasitological diagnostic test (microscopy) to detect CL cases in communities of the Volta Region.

Ticks and prevalence of tick-borne pathogens from domestic animals in Ghana.

BACKGROUND: Ticks are important vectors of various pathogenic protozoa, bacteria and viruses that cause serious and life-threatening illnesses in humans and animals worldwide. Estimating tick-borne pathogen prevalence in tick populations is necessary to delineate how geographical differences, environmental variability and host factors influence pathogen prevalence and transmission. This study identified ticks and tick-borne pathogens in samples collected from June 2016 to December 2017 at seven sites within the Coastal, Sudan and Guinea savanna ecological zones of Ghana. METHODS: A total of 2016 ticks were collected from domestic animals including cattle, goats and dogs. Ticks were morphologically identified and analysed for pathogens such as Crimean-Congo haemorrhagic fever virus (CCHFV), Alkhurma haemorrhagic fever virus (AHFV), Rickettsia spp. and Coxiella burnetii using polymerase chain reaction assays (PCR) and sequence analysis. RESULTS: Seven species were identified, with Amblyomma variegatum (60%) most frequently found, followed by Rhipicephalus sanguineus sensu lato (21%), Rhipicephalus spp. (9%), Hyalomma truncatum (6%), Hyalomma rufipes (3%), Rhipicephalus evertsi (1%) and Rhipicephalus (Boophilus) sp. (0.1%). Out of 912 pools of ticks tested, Rickettsia spp. and Coxiella burnetii DNA was found in 45.6% and 16.7% of pools, respectively, whereas no CCHFV or AHFV RNA were detected. Co-infection of bacterial DNA was identified in 9.6% of tick pools, with no statistical difference among the ecozones studied. CONCLUSIONS: Based on these data, humans and animals in these ecological zones are likely at the highest risk of exposure to rickettsiosis, since ticks infected with Rickettsia spp. displayed the highest rates of infection and co-infection with C. burnetii, compared to other tick-borne pathogens in Ghana.

Chikungunya viruses containing the A226V mutation detected retrospectively in Cameroon form a new geographical subclade.

BACKGROUND: Chikungunya virus (CHIKV) is a re-emerging arbovirus associated with sporadic outbreaks in Cameroon since 2006. Viral whole genomes were generated to analyze the origins of evolutionary lineages, the potential of emergence/re-emergence, and to infer transmission dynamics of recent Cameroon CHIKV outbreak strains. METHODS: Samples collected between 2016 and 2019 during CHIKV outbreaks in Cameroon were screened for CHIKV using reverse transcription PCR (RT-PCR), followed by whole genome sequencing of positive samples. RESULTS: Three coding-complete CHIKV genomes were obtained from samples, which belong to an emerging sub-lineage of the East/Central/South African genotype and formed a monophyletic taxon with previous Central African strains. This clade, which we have named the new Central African clade, appears to be evolving at 3.0 × 10-4 nucleotide substitutions per site per year (95% highest posterior density (HPD) interval of 1.94 × 10-4 to 4.1 × 10-4). Notably, mutations in the envelope proteins (E1-A226V, E2-L210Q, and E2-I211T), which are known to enhance CHIKV adaptability and infectious potential in Aedes albopictus, were present in all strains and mapped to established high-density Ae. albopictus populations. CONCLUSIONS: These new CHIKV strains constitute a conserved genomic pool of an emerging sub-lineage, reflecting a putative vector host adaptation to Ae. albopictus, which has practically displaced Aedes aegypti from select regions of Cameroon.

Whole Genome Sequencing and Antimicrobial Resistance of Staphylococcus aureus from Surgical Site Infections in Ghana.

Staphylococcus aureus (S. aureus) is a common cause of surgical site infections (SSIs) globally. Data on the occurrence of methicillin-susceptible S. aureus (MSSA) as well as methicillin-resistant S. aureus (MRSA) among patients with surgical site infections (SSIs) in sub-Saharan African are scarce. We characterized S. aureus from SSIs in Ghana using molecular methods and antimicrobial susceptibility testing (AST). Wound swabs or aspirate samples were collected from subjects with SSIs. S. aureus was identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS); AST was performed by Kirby-Bauer disk diffusion, and results were interpreted according to the Clinical and Laboratory Standards Institute (CLSI) guideline. Detection of spa, mecA, and pvl genes was performed by polymerase chain reaction (PCR). Whole-genome sequencing (WGS) was done using the Illumina MiSeq platform. Samples were collected from 112 subjects, with 13 S. aureus isolates recovered. Of these, 92% were sensitive to co-trimoxazole, 77% to clindamycin, and 54% to erythromycin. Multi-drug resistance was detected in 5 (38%) isolates. The four mecA gene-positive MRSA isolates detected belonged to ST152 (n = 3) and ST5 (n = 1). In total, 62% of the isolates were positive for the Panton-Valentine leukocidin (pvl) toxin gene. This study reports, for the first time, a pvl-positive ST152-t355 MRSA clone from SSIs in Ghana. The occurrence of multi-drug-resistant S. aureus epidemic clones suggests that continuous surveillance is required to monitor the spread and resistance trends of S. aureus in hospital settings in the country.