ABSTRACT
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.
Subject(s)
Amblyomma , Hemorrhagic Fever Virus, Crimean-Congo , Animals , Hemorrhagic Fever Virus, Crimean-Congo/genetics , Ghana , Phylogeny , Biological AssayABSTRACT
Ticks are competent vectors of a wide range of pathogens. They are of veterinary and public health importance as they affect both animal and human health. Transhumance and the transboundary movements of cattle within the West African Sub-region have facilitated the spread of ticks which threatens the introduction of invasive species. Currently, Rhipicephalus microplus have been identified in the Upper East Region of Ghana which could mean a wider distribution of the species across the country due to livestock trade. This study focused on three sites in the Greater Accra Region, which serves as the gateway to receiving most of the cattle transported from the northern regions of Ghana. Ticks were sampled from August 2022 in the wet season to January 2023 in the dry season. Three tick genera were identified: Amblyomma (19.5%), Hyalomma (1.1%), and Rhipicephalus (79.3%) from the 1,489 feeding ticks collected from cattle. Furthermore, Rhipicephalus microplus, Hyalomma rufipes and Amblyomma variegatum were identified molecularly using primers that target the mitochondrial COI gene. There was a significant association between the tick species and seasons (p < 0.001). Finding R. microplus in this study indicates the extent of the spread of this invasive tick species in Ghana and highlights the need for efficient surveillance systems and control measures within the country.
Subject(s)
Cattle Diseases , Ixodidae , Rhipicephalus , Tick Infestations , Humans , Cattle , Animals , Rhipicephalus/genetics , Tick Infestations/epidemiology , Tick Infestations/veterinary , Ghana , Cattle Diseases/epidemiology , Ixodidae/genetics , Introduced SpeciesABSTRACT
Ticks are important vectors involved in the transmission of pathogens of zoonotic and veterinary importance. In this study, ticks were collected from cattle in Navrongo, Kintampo, and Kumasi and screened for pathogen DNA using PCR and Sanger sequencing. A total of 454 ticks were collected, morphologically identified and confirmed using primers that target the 660-bp segment of the mitochondrial COI gene. The predominant tick species was Amblyomma variegatum (70.26%). DNA was extracted from 85 tick pools and screened for the presence of Rickettsia DNA based on the 639 bp of the outer membrane protein A (ompA) gene, Ehrlichia/Anaplasma DNA based on the 345 bp fragment of the 16SrRNA gene and Babesia/ Theileria DNA based on the 560 bp fragment of the ssrRNA gene. From the 85 tick pools, the DNA of pathogens detected were Rickettsia africae (36.47%), Rickettsia aeschlimannii (16.47%), Ehrlichia canis (2.35%), Babesia occultans (1.18%), Theileria velifera (1.18%) and a symbiont Candidatus Midichloria mitochondrii (8.24%). This study reports the first molecular detection of Candidatus Cryptoplasma californiense (1.18%) in Ghana. Coinfections were recorded in 8.24% of the tick pools. The findings of this study highlight the importance of tick species in Ghana and the need to adopt effective control measures to prevent pathogen spread.
Subject(s)
Cattle Diseases , Rhipicephalus , Rickettsia , Theileria , Tick-Borne Diseases , Animals , Cattle , Ghana/epidemiology , Tick-Borne Diseases/epidemiology , Tick-Borne Diseases/veterinary , Tick-Borne Diseases/microbiology , Cattle Diseases/epidemiology , Cattle Diseases/microbiology , Rickettsia/genetics , Rhipicephalus/genetics , Theileria/genetics , DNAABSTRACT
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.
ABSTRACT
Vector-borne diseases emergence, particularly malaria, present a significant public health challenge worldwide. Anophelines are predominant malaria vectors, with varied distribution, and influenced by environment and climate. This study, in Ghana, modelled environmental suitability for Anopheles stephensi, a potential vector that may threaten advances in malaria and vector control. Understanding this vector's distribution and dynamics ensures effective malaria and vector control programmes implementation. We explored the MaxEnt ecological modelling method to forecast An. stephensi's potential hotspots and niches. We analysed environmental and climatic variables to predict spatial distribution and ecological niches of An. stephensi with a spatial resolution of approximately 5 km2. Analysing geospatial and species occurrence data, we identified optimal environmental conditions and important factors for its presence. The model's most important variables guided hotspot prediction across several ecological zones aside from urban and peri-urban regions. Considering the vector's complex bionomics, these areas provide varying and adaptable conditions for the vector to colonise and establish. This is shown by the AUC = 0.943 prediction accuracy of the model, which is considered excellent. Based on our predictions, this vector species would thrive in the Greater Accra, Ashanti Central, Upper East, Northern, and North East regions. Forecasting its environmental suitability by ecological niche modelling supports proactive surveillance and focused malaria management strategies. Public health officials can act to reduce the risk of malaria transmission by identifying areas where mosquitoes may breed, which will ultimately improve health outcomes and disease control.