Cross-genera amplification and identification of Colpodella sp. with Cryptosporidium primers in fecal samples of zoo felids from northeast China

First Detection and Molecular Characterization of Colpodella in Goats, Foxes, and Birds

PURPOSE

This study aimed to evaluate the prevalence of Colpodella sp. in domestic and wild animals in Cyprus. To the authors' knowledge, this is the first study to report the detection of Colpodella sp. in foxes (Cyprus red fox Vulpes vulpes indutus), wild birds (Eurasian coot Fulica atra, duck Anas spp.) and goats (Capra hircus) worldwide.

METHODS

A total of 180 faecal samples (29 foxes, 48 Eurasian coot, 20 Eurasian teal Anas crecca, 7 duck, 44 goats - 10 from a farm and 34 free-living individuals - and 32 sheep Ovis aries) were analyzed for the parasite by nested PCR and sequencing.

RESULTS

Four samples were positive (4/180 = 2.2%), including one goat from a farm (1/10 = 10%), one fox (1/29 = 3.4%), one Eurasian coot (1/48 = 2.1%) and one duck (1/7 = 14.3%).

CONCLUSION

The results of this study support the evidence that Colpodella sp. can infect mammals and birds, as well as livestock and wildlife, which could act as zoonotic reservoirs of the parasite and potentially pose a risk to human and animal health.

Molecular identification of tick-borne Rickettsia, Anaplasma, Ehrlichia, Babesia, and Colpodella in confiscated Malayan pangolins

The traditional concept of "tonic food" and demand for traditional Chinese medicine make pangolins the largest population of illegally smuggled mammals in the world. Illegal hunting and trade are not only responsible for the sharp decline in pangolin populations but also provide conditions for pathogenic transmission. In 2021, we rescued 21 confiscated unhealthy Malayan pangolins, none of which survived. This study aimed to investigate the reasons for their unexpected deaths and the potential pathogens that may be transmitted during smuggling. Physical examination found that more than 80% pangolins were parasitized with A. javanense ticks. Autopsy and pathological staining analysis revealed multiple organ damage in the deceased pangolins. Pathogens nucleic acid detection of 33 tick samples showed that the positive rate of Rickettsia spp., Anaplasma spp., Ehrlichia spp. Babesia spp., and Colpodella spp. were 90.91%, 6.06%, 6.06%, 15.15% and 18.18%, respectively. Furthermore, pangolin samples were positive for Rickettsia spp. (42.86%, 9/21), Ehrlichia sp. (4.76%, 1/21), and Babesia sp. (4.76%, 1/21). This study confirmed that spotted fever triggered by Rickettsia spp. from A. javanense might accelerate the most death of confiscated pangolins, while Ehrlichia sp., and Babesia sp. infection potentially accelerating a few deaths. Of note, A. javanense ticks carrying Colpodella spp. were detected for the first time in Malayan pangolins. However, whether Colpodella spp. are pathogenic to pangolins is unknown. Further research on the diagnosis, treatment, surveillance, and elimination of ticks and tick-borne diseases in humans, livestock, and wildlife should provide insight into wildlife conservation and zoonotic disease prevention.

Are Colpodella Species Pathogenic? Nutrient Uptake and Approaches to Diagnose Infections

Colpodella species are free-living protists phylogenetically related to apicomplexans. Colpodella sp. have been detected in human and animal tissues, as well as in ticks and biting flies. The trophozoite and cyst stages of Colpodella species can be distinguished from stages of the prey Parabodo caudatus using Sam-Yellowe's trichrome staining. Colpodella species obtain nutrients by attaching to their prey, aspirating the prey's cytoplasmic contents into a posterior food vacuole and encysting. It is unclear whether both trophozoite and cyst stages are present in human and animal tissues. Molecular techniques have detected Colpodella species in human blood, cerebrospinal fluid, and in ticks and flies. However, no morphological information was reported to aid life-cycle stage identification of Colpodella species. This review discusses the increased reports of Colpodella species detection in animals and in arthropods and the need to identify stages present in human and animal tissues. We previously used Sam-Yellowe's trichrome staining to identify life-cycle stages of Colpodella sp. In this review, we examine the reports of Colpodella species detection in human and animal tissues to determine whether the identification of Colpodella species represents true infections or contaminations of samples collected during routine surveillance of piroplasm infections in animals and arthropods. This review also aims to provide insights regarding Colpodella, nutrient uptake, and the survival of Colpodella sp. within humans, animals, and arthropods, as well as whether the attachment of trophozoites to cells occurs in tissues leading to myzocytosis and endocytosis.

Ultrastructure of Myzocytosis and Cyst Formation, and the Role of Actin in Tubular Tether Formation in Colpodella sp. (ATCC 50594)

Free-living relatives of the Apicomplexa such as Colpodella species, Alphamonas species, and Voromonas pontica are predators that prey on ciliate, bodonid, and algal prey using the process of myzocytosis. During myzocytosis, the pseudoconoid is used to attach to the prey leading to aspiration of cytoplasmic contents of the prey into a posterior food vacuole formed in the predator, aided by secretions from the apical complex organelles. The conoid and associated proteins are conserved among the apicomplexa. However, the organization and function of the pseudoconoid during myzocytosis are not well understood. In this study, we investigated the morphology and ultrastructure of Colpodella sp. (ATCC 50594) during the stages of myzocytosis and cyst formation in the life cycle using light microscopy and transmission electron microscopy (TEM) in order to identify the organization of the tubular tether involved in nutrient aspiration by Colpodella sp. Tubular tethers of varying lengths were identified by light microscopy. We report that initial contact by Colpodella sp. trophozoites with Parabodo caudatus prey is by an area posterior to the apical tip of the rostrum that engulfs the membrane of the prey pulling it into the cytoplasm of the predator. The tubular tether that forms contains membranes of both predator and prey and is facilitated by microtubule organization and the cytoskeleton at the point of contact. Cytochalasin D treatment of diprotist cultures resulted in morphological distortions of trophozoites and the tubular tether suggesting a role of actin in the formation of the tubular tether. This mechanism of predation may provide insight into the mode of invasion observed in pathogenic apicomplexan zoites during host cell entry.