In silico and phylogenetic analyses of partial BbRAP-1, BbCP2, BbSBP-4 and BbβTUB gene sequences of Babesia bovis isolates from cattle in South Africa

Current Status and Challenges Associated with Tick-Borne Pathogens and Diseases: Where Do We Stand?

Lyme Borreliosis (LB), caused by Borrelia burgdorferi sensu lato (s [...].

Epidemiology of Ticks and Tick-Borne Pathogens in Domestic Ruminants across Southern African Development Community (SADC) Region from 1980 until 2021: A Systematic Review and Meta-Analysis

Ticks are hematophagous ectoparasites that are capable of infesting a wide range of mammals, including domestic animals, ruminants, wildlife, and humans across the world, and they transmit disease-causing pathogens. Numerous individual epidemiological studies have been conducted on the distribution and prevalence of ticks and tick-borne diseases (TBDs) in the Southern African Developing Community (SADC) region, but no effort has been undertaken to synchronize findings, which would be helpful in the implementation of consolidated tick control measures. With the aim of generating consolidated pooled prevalence estimates of ticks and TBDs in the SADC region, we performed a systematic review and meta-analysis of published articles using the PRISMA 2020 guidelines. A deep search was performed on five electronic databases, namely, PubMed, ScienceDirect, Google Scholar, AJOL, and Springer Link. Of the 347 articles identified, only 61 of the articles were eligible for inclusion. In total, 18,355 tick specimens were collected, belonging to the genera Amblyomma, Haemaphysalis, Hyalomma, and Rhipicephalus (including Boophilus) across several countries, including South Africa (n = 8), Tanzania (n = 3), Zambia (n = 2), Zimbabwe (n = 2), Madagascar (n = 2), Angola (n = 2), Mozambique (n = 1), and Comoros (n = 1). The overall pooled prevalence estimate (PPE) of TBPs in livestock was 52.2%, with the highest PPE in cattle [51.2%], followed by sheep [45.4%], and goats [29.9%]. For bacteria-like and rickettsial TBPs, Anaplasma marginale had the highest PPE of 45.9%, followed by A. centrale [14.7%], A. phagocytophilum [2.52%], and A. bovis [0.88%], whilst Ehrlichia ruminantium had a PPE of 4.2%. For piroplasmids, Babesia bigemina and B. bovis had PPEs of 20.8% and 20.3%, respectively. Theileria velifera had the highest PPE of 43.0%, followed by T. mutans [29.1%], T. parva [25.0%], and other Theileria spp. [14.06%]. Findings from this study suggest the need for a consolidated scientific approach in the investigation of ticks, TBPs, and TBDs in the whole SADC region, as most of the TBDs are transboundary and require a regional control strategy.

A descriptive study of parasites detected in ticks of domestic animals in Lesotho

Ticks are medically important and significant vectors of diseases affecting livestock, humans, and companion animals than any other arthropod vectors. In the absence of information on the relationship of tick species and piroplasms parasites in Lesotho, the current study was aimed at detecting piroplasms parasites of economic importance from ticks of domestic animals. A total of 322 pooled tick DNA samples were subjected to PCR screening for the presence of piroplasms. The overall infection rate of piroplasms was 7% with Babesia bigemina at 3.4% (11/322), B. bovis 0.3% (1/322), B. ovis 2.8% (9/322) and 0.6% (2/322) for B. motasi. DNA extracted from the Lesotho Rhipicephalus decoloratus and R. evertsi evertsi tested positive for the presence of B. bigemina with a 15% and 3% infection rate, respectively. Otobius megnini tested positive for only B. bovis at a 12.5% infection rate. Rhipicephalus e. evertsi was the only tick species PCR positive for ovine babesiosis with 3.2% for B. ovis and 0.7% for B. motasi. Equine piroplasm (Theileria equi and B. caballi) and Theileria (T. parva and T. ovis) parasites were not detected in the current study. The PCR-positive samples were confirmed by direct sequencing of the product. This study is the first to report on a relationship of Babesia parasites with tick species in Lesotho and it is evident that vector-borne diseases are present in ticks of domestic animals in this country. Research findings in this study require a joint effort from both veterinary and medical sectors to unite and conduct more epidemiological studies of tick-borne diseases in both animals and humans and to also determine the role played by tick species in the transmission of the detected parasites in domestic animals of Lesotho. This information provides a baseline knowledge of important piroplasms parasites and raising awareness of their prevalence in Lesotho.

Use of molecular markers can help to understand the genetic diversity of Babesia bovis

Cattle babesiosis is a tick-borne disease responsible for significant losses for the livestock industries in tropical areas of the world. These piroplasms are under constant control of the host immune system, which lead to a strong selective pressure for arising more virulent or attenuated phenotypes. Aiming to better understand the most critical genetic modifications in Babesia bovis genome, related to virulence, an in silico analysis was performed using DNA sequences from GenBank. Fourteen genes (sbp-2, sbp-4, trap, msa-1, msa-2b, msa-2c, Bv80 (or Bb-1), 18S rRNA, acs-1, ama-1, β-tub, cp-2, p0, rap-1a) related to parasite infection and immunogenicity and ITS region were selected for alignment and comparison of several isolates of Babesia bovis from different geographic regions around the world. Among the 15 genes selected for the study of diversity, only 7 genes (sbp-2, sbp-4, trap, msa-1, msa-2b, msa-2c, Bv80) and the ITS region presented sufficient genetic variation for the studies of phylogeny. Despite this genetic diversity observed into groups, there was not sufficient information available to associate molecular markers with virulence of isolates. However, some genetic groups no were correlated with geographic region what could indicate some typical evolutionary characteristics in the relation between parasite-host. Further studies using these genes in herds presenting diverse clinical conditions are required. The better understanding of evolutionary mechanisms of the parasite may contribute to improve prophylactic and therapeutic measures. In this way, we suggest that genes used in our study are potential markers of virulence and attenuation and have to be analyzed with the use of sequences from animals that present clinical signs of babesiosis and asymptomatic carriers.