Background: Ticks and fleas are considered amongst the most important arthropod vectors of medical and veterinary concern due to their ability to transmit pathogens to a range of animal species including dogs, cats and humans. By sharing a common environment with humans, companion animal-associated parasitic arthropods may potentially transmit zoonotic vector-borne pathogens (VBPs). This study aimed to molecularly detect pathogens from ticks and fleas from companion dogs and cats in East and Southeast Asia.Methods: A total of 392 ticks and 248 fleas were collected from 401 infested animals (i.e. 271 dogs and 130 cats) from China, Taiwan, Indonesia, Malaysia, Singapore, Thailand, the Philippines and Vietnam, and molecularly screened for the presence of pathogens. Ticks were tested forRickettsiaspp.,Anaplasmaspp.,Ehrlichiaspp.,Babesiaspp. andHepatozoonspp. while fleas were screened for the presence ofRickettsiaspp. andBartonellaspp.Result: Of the 392 ticks tested, 37 (9.4%) scored positive for at least one pathogen withHepatozoon canisbeing the most prevalent (5.4%), followed byEhrlichia canis(1.8%),Babesia vogeli(1%),Anaplasma platys(0.8%) andRickettsiaspp. (1%) [includingRickettsiasp. (0.5%),Rickettsia asembonensis(0.3%) andRickettsia felis(0.3%)]. Out of 248 fleas tested, 106 (42.7%) were harboring at least one pathogen withR. felisbeing the most common (19.4%), followed byBartonellaspp. (16.5%),Rickettsia asembonensis(10.9%) and “CandidatusRickettsia senegalensis” (0.4%). Furthermore, 35Rhipicephalus sanguineusticks were subjected to phylogenetic analysis, of which 34 ticks belonged to the tropical and only one belonged to the temperate lineage (Rh. sanguineus(sensu stricto)).Conclusion: Our data reveals the circulation of different VBPs in ticks and fleas of dogs and cats from Asia, including zoonotic agents, which may represent a potential risk to animal and human health.

An opisthorchiid liver fluke was recently reported from ducks (Anas platyrhynchos) in Binh Dinh Province of Central Vietnam, and referred to as “Opisthorchis viverrini-like”. This species uses common cyprinoid fishes as second intermediate hosts as does Opisthorchis viverrini, with which it is sympatric in this province. In this study, we refer to the liver fluke from ducks as “Opisthorchis sp. BD2013”, and provide new sequence data from the mitochondrial (mt) genome and the nuclear ribosomal transcription unit. A phylogenetic analysis was conducted to clarify the basal taxonomic position of this species from ducks within the genus Opisthorchis (Digenea: Opisthorchiidae). Adults and eggs of liver flukes were collected from ducks, metacercariae from fishes (Puntius brevis, Rasbora aurotaenia, Esomus metallicus) and cercariae from snails (Bithynia funiculata) in different localities in Binh Dinh Province. From four developmental life stage samples (adults, eggs, metacercariae and cercariae), the complete cytochrome b (cob), nicotinamide dehydrogenase subunit 1 (nad1) and cytochrome c oxidase subunit 1 (cox1) genes, and near-complete 18S and partial 28S ribosomal DNA (rDNA) sequences were obtained by PCR-coupled sequencing. The alignments of nucleotide sequences of concatenated cob + nad1 + cox1, and of concatenated 18S + 28S were separately subjected to phylogenetic analyses. Homologous sequences from other trematode species were included in each alignment. Phylogenetic trees were inferred from concatenated (cob + nad1 + cox1) nucleotide sequences and combined 18S + 28S nucleotide sequences of five Opisthorchis sp. BD2013 samples and additional reference taxa. Both trees demonstrated the anticipated clustering of taxa within the superfamily Opisthorchioidea, the paraphyly of the genus Opisthorchis and the sister-species relationship of Opisthorchis sp. BD2013 with O. viverrini. While it is likely that Opisthorchis sp. BD2013 is distinct from O. viverrini, it is clearly a sister taxon of O. viverrini within the limited number of Opisthorchis species for which appropriate sequence data are available. The new sequences provided here will assist the diagnosis and the taxonomic clarification of the opisthorchiid species.

Background and Aim: Stray cats are a reservoir for various zoonotic diseases relevant to public health in Thailand. The vector-borne infection, hemoplasmosis, also known as infectious anemia, is one such disease carried by domestic and wild felids. This study focuses on molecular characterization and phylogenetic analysis of hemoplasma in semi-domesticated cats in Bangkok, Thailand. Materials and Methods: In total, 473 blood samples were collected from 53 temple communities in 34 metropolitan districts and assayed using polymerase chain reaction (PCR) to amplify partial 16S rRNA genes for hemoplasma detection. Risk factors for hemoplasma infection (gender, age, free-roaming, and ectoparasite exposure) were analyzed using Chi-square tests, logistic regression, and odds ratios (OR) with 95% confidence intervals (95% CI) using R software (version 3.6.1). A phylogenetic tree was established from genetic characterization of hemoplasmas. Results: In total, 180 samples (38.05%) were positive for hemoplasma. Of half of the positive sequenced samples, 83.33% were infected with Candidatus Mycoplasma haemominutum (CMhm), 13.33% with Mycoplasma haemofelis (Mhf), and 3.33% with Candidatus Mycoplasma turicensis (CMt). Cats over 5 years old were more likely to be infected than younger cats (p<0.005, OR=3.8, 95% CI=1.64-4.78). Cats were diagnosed as positive based on PCR assays in 97% (33/34) of districts surveyed. The phylogenetic tree showed two majority clusters with three clades of feline hemotropic mycoplasma. Conclusion: Overall, the survey shows the prevalence (38.05%) and distribution of feline hemoplasma in semi-domesticated cats. This information will contribute to effective prevention and control strategies to minimize infections by feline vector-borne pathogens in Thailand.

Histomoniasis, commonly known as blackhead disease, is a parasitic disease in poultry caused by the protozoan Histomonas meleagridis. The availability of various compounds for chemotherapy in the 1970s resulted in the successful control of blackhead disease. Since the ban of antihistomonal drugs in the European Union, the disease has re-emerged, resulting in up to 100% mortality in turkey flocks. This has renewed the interest of scientists with numerous publications focusing on prophylactic strategies. This review summarizes the literature on the preventive and curative options for the control and treatment of histomoniasis. Two main approaches to the prophylaxis of the disease were found, which included chemotherapies and plant substrate products. Histostat-50 and paromomycin were the only available drugs that showed antihistomonal activity despite some concern about their threat to human health and antibiotic resistance. None of the plant substrate products provided potential protection to birds against blackhead disease. The use of attenuated histomonads could be an alternative for the prevention of the disease, but the production of this vaccine prototype is still challenging due to advanced technique requirements.

This study was conducted to detect Ascaris suum, Toxocara canis, and Toxocara cati in naturally infected chicken livers, and then to provide information related to ascarid infections in humans. Ninety-four chicken liver samples collected at a fresh market were used for this study. DNA was extracted from each minced liver sample (500 mg) by the alkaline lysis method using NaOH 50mM and Tris-HCl (pH 8.0). The nested multiplex PCR assay using ascarid universal primers was applied to amplify the ITS1 ribosomal RNA gene of A. suum, Toxocara canis, and Toxocara cati in all the liver samples. Then, species specific-primers were used to discriminate between A. suum and Toxocara spp. The results showed that 2 of the 94 chicken liver samples detected positive for the presence of A. suum DNA. This study provided useful information and evidence about A. suum infection in humans via exposure to contaminated soil or eating raw/undercooked chicken livers in Vietnam.

Ticks and fleas are considered amongst the most important arthropod vectors of medical and veterinary concern due to their ability to transmit pathogens to a range of animal species including dogs, cats and humans. By sharing a common environment with humans, companion animal-associated parasitic arthropods may potentially transmit zoonotic vector-borne pathogens (VBPs). This study aimed to molecularly detect pathogens from ticks ( n = 392) and fleas ( n = 248) collected from companion dogs and cats in East and Southeast Asia. Of the 392 ticks tested, 37 (9.4%) scored positive for at least one pathogen with Hepatozoon canis being the most prevalent (5.4%), followed by Ehrlichia canis (1.8%), Babesia vogeli (1%), Anaplasma platys (0.8%) and Rickettsia spp. (1%) [including Rickettsia sp. (0.5%), Rickettsia asembonensis (0.3%), Rickettsia felis (0.3%)]. Out of 248 fleas tested, 106 (42.7%) were harboring at least one pathogen with R. felis being the most common (19.4%), followed by Bartonella spp. (16.5%), Rickettsia asembonensis (10.9%) and Candidatus Rickettsia senegalensis (0.4%). Furthermore, 35 Rhipicephalus sanguineus sensu lato ticks were subjected to phylogenetic analysis, of which 34 ticks belonged to the tropical and only one belonged to the temperate lineage ( Rh. sanguineus sensu stricto). Our data reveals the circulation of different VBPs in ticks and fleas of dogs and cats from Asia, including zoonotic agents, which may represent a potential risk to animal and human health. Author summary: Ticks and fleas are among the most important vectors of pathogens infesting many animal species including humans worldwide. Although a number of vector-borne pathogens have been detected in dogs and cats from East and Southeast Asia, investigation in ticks and fleas collected from them are scant. In order to provide an overview of the pathogens circulating in ticks and fleas from companion dogs and cats in Asia, ticks ( n = 392) and fleas ( n = 248) were collected from privately-owned dogs and cats from China, Taiwan, Indonesia, Malaysia, Singapore, Thailand, Philippines and Vietnam and molecularly screened for the presence of pathogens. Overall, multiple pathogens were found in ticks (i.e., Babesia vogeli , Hepatozoon canis , Ehrlichia canis , Anaplasma platys and Rickettsia spp.) and fleas (i.e., Rickettsia spp. and Bartonella spp.) from the sampling areas. Of the ticks tested, 9.4% scored positive for at least one pathogen and of fleas 42.7% harbored at least one pathogen with Rickettsia felis being the most common (19.4%). Overall, of the detected pathogens, R. felis stood out as the most important due to its zoonotic potential. The result of this study should increase awareness among pet owners and veterinary practitioners regarding the importance of ticks and fleas, and their transmitted pathogens.