Prevalence of Ticks Infesting Dairy Cattle and the Pathogens They Harbour in Smallholder Farms in Peri-Urban Areas of Nairobi, Kenya

Prevalence, trend comparisons, and identification of ixodid ticks (Acari: Ixodoidea) among cattle in Ethiopia: A systematic review and meta-analysis

Ticks and tick-borne pathogens are the main challenge to livestock production and productivity in sub-Saharan Africa, particularly in Ethiopia, where favorable conditions exist for the activity of various parasites due to its geographical location, climate, and biological and cultural characteristics. This study was to provide pooled estimates for individually available data on ixodid ticks, their trend comparisons, and ixodid tick grouping among cattle in Ethiopia. Cochrane's Q, I2, sensitivity analysis, funnel plot, Begg, and Egger regression tests were used to check heterogeneity and publication bias. A random effect model was used to calculate the pooled magnitude of ixodid ticks among cattle. A total of 17,161 cattle from 41 studies were included. The pooled prevalence of ixodid ticks among cattle was 64.42% (95% CI = 57.13-71.71). A total of 82,804 adult ticks belonging to three different genera of ixodid ticks, namely Rhipicephalus (Boophilus) (47.53%), Amblyomma (46.10%), and Hyalomma (6.37%), were recorded from the included studies. The general trend for the prevalence of ixodid tick infestation among cattle has decreased, from 68.65% in 2010-2015 to 60.13% in 2021-2023. In the present scenario, ixodid tick infestation range from 59.21 to 89.58% and are higher in Gambella region.

Recent Advances in Tick Antigen Discovery and Anti-Tick Vaccine Development

Ticks can seriously affect human and animal health around the globe, causing significant economic losses each year. Chemical acaricides are widely used to control ticks, which negatively impact the environment and result in the emergence of acaricide-resistant tick populations. A vaccine is considered as one of the best alternative approaches to control ticks and tick-borne diseases, as it is less expensive and more effective than chemical controls. Many antigen-based vaccines have been developed as a result of current advances in transcriptomics, genomics, and proteomic techniques. A few of these (e.g., Gavac^® and TickGARD^®) are commercially available and are commonly used in different countries. Furthermore, a significant number of novel antigens are being investigated with the perspective of developing new anti-tick vaccines. However, more research is required to develop new and more efficient antigen-based vaccines, including on assessing the efficiency of various epitopes against different tick species to confirm their cross-reactivity and their high immunogenicity. In this review, we discuss the recent advancements in the development of antigen-based vaccines (traditional and RNA-based) and provide a brief overview of recent discoveries of novel antigens, along with their sources, characteristics, and the methods used to test their efficiency.

Metagenomic Investigation of Ticks From Kenyan Wildlife Reveals Diverse Microbial Pathogens and New Country Pathogen Records

Focusing on the utility of ticks as xenosurveillance sentinels to expose circulating pathogens in Kenyan drylands, host-feeding ticks collected from wild ungulates [buffaloes, elephants, giraffes, hartebeest, impala, rhinoceros (black and white), zebras (Grévy’s and plains)], carnivores (leopards, lions, spotted hyenas, wild dogs), as well as regular domestic and Boran cattle were screened for pathogens using metagenomics. A total of 75 host-feeding ticks [Rhipicephalus (97.3%) and Amblyomma (2.7%)] collected from 15 vertebrate taxa were sequenced in 46 pools. Fifty-six pathogenic bacterial species were detected in 35 pools analyzed for pathogens and relative abundances of major phyla. The most frequently observed species was Escherichia coli (62.8%), followed by Proteus mirabilis (48.5%) and Coxiella burnetii (45.7%). Francisella tularemia and Jingmen tick virus (JMTV) were detected in 14.2 and 13% of the pools, respectively, in ticks collected from wild animals and cattle. This is one of the first reports of JMTV in Kenya, and phylogenetic reconstruction revealed significant divergence from previously known isolates and related viruses. Eight fungal species with human pathogenicity were detected in 5 pools (10.8%). The vector-borne filarial pathogens (Brugia malayi, Dirofilaria immitis, Loa loa), protozoa (Plasmodium spp., Trypanosoma cruzi), and environmental and water-/food-borne pathogens (Entamoeba histolytica, Encephalitozoon intestinalis, Naegleria fowleri, Schistosoma spp., Toxoplasma gondii, and Trichinella spiralis) were detected. Documented viruses included human mastadenovirus C, Epstein-Barr virus and bovine herpesvirus 5, Trinbago virus, and Guarapuava tymovirus-like virus 1. Our findings confirmed that host-feeding ticks are an efficient sentinel for xenosurveillance and demonstrate clear potential for wildlife-livestock-human pathogen transfer in the Kenyan landscape.