Guardians of the Herd: Molecular Surveillance of Tick Vectors Uncovers Theileriosis Perils in Large Ruminants

Theileria sp. (Piroplasmida: Theileriidae) is one of the most widely known infections transmitted by hard ticks (Acari: Ixodidae) and has been linked to significant economic losses across the globe. The study's main emphasis was theileriosis, a disease that is common in Pakistan and has an incidence ranging from 0.6% to 33%. Through DNA screening of the vector ticks and host blood, this study sought to determine the risk of tick-borne theileriosis in populations of buffalos (Bubalus bubalis) and cattle (Bos indicus) in Toba Tek Singh district of Punjab, Pakistan. Identified tick species include Hyalomma anatolicum (35.4%), Rhipicephalus (Boophilus) microplus (30.2%), and R. sanguineus (25%). Tick specimens were collected from animals and their respective microenvironments. PCR assays targeting Theileria annulata were used to investigate the infection in the DNA extracted from the collected blood samples from large ruminants and salivary glands (SGs) of the Hyalomma ticks. The 18S rRNA of T. annulata was amplified using specific primers. Positive T. annulata amplicons were sequenced and verified using BLAST analysis. Overall, 50% of SGs contained T. annulate DNA. Female ticks, and those collected from cattle and from riverine environments had significantly higher (p < 0.05) rates of Theileria infection in their acini. Overall prevalence of Theileria infection was 35.9% in blood collected from large ruminants. Cattle had a substantially greater frequency of bovine theileriosis (43.2%) than buffalos (28.7%). Age and sex of large ruminants were significantly positively associated (p < 0.05) with Theileria infection. Furthermore, compared to non-riverine cattle (35%) and buffalo (19.5%), riverine cattle (52.2%) and buffalo (36.2%) showed a considerably higher prevalence. The results of this study, which is the first in Pakistan to examine the blood of large ruminants and vectorial function of Ixodid ticks in the transmission of T. annulata along with associated risk factors, offer an important insight for risk assessment of Theileria infection in livestock using vectorial infectivity.

Fins infestation induced by Myxobolus xiantaoensis in yellow catfish Tachysurus fulvidraco Richardson, 1846: Some pathophysiological and molecular insights

The myxozoan parasite Myxobolus xiantaoensis is a fin pathogen of commercially important yellow catfish Tachysurus fulvidraco Richardson, 1846, in the freshwater ponds of China. In the present work, four geographical isolates of M. xiantaoensis were sampled from the fins of yellow catfish. It was found that the spores of four isolates exhibited few markable differences in morphometrics. The small subunit ribosomal DNA (SSU rDNA) sequences of four isolates were conspecific to the SSU rDNA sequence of M. xiantaoensis. No genetic level variation was observed, even in the characteristically more variable internal transcribed spacer (ITS) region. This absence of variability suggests high gene flow as a result of panmixia in the parasitic populations. ITS phylogeny placed four isolates of M. xiantaoensis in a clade together with myxozoans species infecting Siluriformes. The M. xiantaoensis infection inflicted severe hemorrhages on epidermis of ray-fins, which grew into inflammatory epithelial hyperplasia and lytic cartilage signs. The histochemical analysis of infected fins biopsies is characterized by damage of collagen components of cartilage, resulting in weakness, breaks, and missing fin rays. These tissue sections also had a remarkable inflammatory response around the fin cartilage, with the absence of mature spores and chondrocytes. These results indicate that the fin cartilage damage appeared before the development of tissue inflammation and the parasitic infestation of the fins. The present four geographical isolates of M. xiantaoensis were identified by a holistic approach of species characterization based on biological, morphological, and molecular evidence. These four isolates showed some morphological and genetic variations but within the intraspecific range.

Ultrastructures of Epibiotic Suctorian, Tokophrya huangmeiensis

Tokophrya species are either free-living or facultative ectosymbiotic suctorians associated with copepods, isopods, mysids, decapods and amphipods. Tokophrya huangmeiensis in particular is found to be epizoic with the redclaw crayfish Cherax quadricarinatus Von Martens, 1868, which has been observed as part of an ongoing investigation of freshwater ciliates biodiversity in Huanggang, Hubei, China (Tahir et al. 2017). This first study on T. huangmeiensis based on morphological features using light microscopy and small subunit ribosomal DNA sequence (Tahir et al. 2017), suggested that more detailed descriptions on the physiological and structural changes of this species should be done. Thus, in this study, we looked at the ultrastructures of T. huangmeiensis using electron microscopy, including both scanning (SEM) and transmission electron microscopy (TEM).

First record of a new epibionts suctorian ciliate Tokophrya huangmeiensis sp.n. (Ciliophora, Phyllopharyngea) from redclaw crayfish Cherax quadricarinatus von Martens 1868

A new suctorian ciliate, Tokophrya huangmeiensis sp. n. was isolated from the carapace of redclaw crayfish Cherax quadricarinatus, during investigation of fish ciliates diversity in freshwater aquaculture of Hubei, China. The zooids of newly isolated ciliate were found aggregated into colonies on stalks of another ciliate Epistylis. The adults of this newly found species were characterized by an elongated pyramidal shaped and corrugated cell body with two fascicles of tentacles on the apical part of cell body. Stalks were hollow and transparent with longitudinal striations. The single contractile vacuole was located in the apical region and an elongated ρ-shaped macronucleus was situated along the long axis of cell body. Phylogenetic analyses showed that the subclass Suctoria is monophyletic and comprises the groups Exogenina, Evaginogenina and Endogenina, where Exogenina is the earliest branching lineage among these three groups. Tokophrya huangmeiensis sp. n. clustered with the other Tokophrya species and within the Endogenina subgroup as expected.