Knowledge of the tick fauna of continental Southeast Asia is either patchy or, in some cases, for example Cambodia and Myanmar, poor. Nevertheless, 97 species have been recorded from this region, making it one of the most diverse for ticks worldwide. Throughout Southeast Asia, work on tick-borne diseases of stock and companion animals, as well as of humans, is in its infancy, and the medical, veterinary and socio-economic importance of these diseases is largely unknown. Here we review current knowledge of Southeast Asian ticks and tick-borne diseases, with the aim of stimulating further research on this subject.

The diagnosis of strongyloidiasis by coprological methods has a low sensitivity, underestimating the prevalence of Strongyloides stercoralis in endemic areas. Serodiagnostic tests for strongyloidiasis have shown robust diagnostic properties. However, these methods require a blood draw, an invasive and labor-intensive sample collection method, especially in the resource-limited settings where S. stercoralis is endemic. Our study examines a urine-based assay for strongyloidiasis and compares its diagnostic accuracy with coprological and serological methods. Receiver operating characteristic (ROC) curve analyses determined the diagnostic sensitivity (D-Sn) and specificity (D-Sp) of the urine ELISA, as well as estimates its positive predictive value and diagnostic risk. The likelihood ratios of obtaining a positive test result (LR+) or a negative test result (LR-) were calculated for each diagnostic positivity threshold. The urine ELISA assay correlated significantly with the serological ELISA assay for strongyloidiasis, with a D-Sn of 92.7% and a D-Sp of 40.7%, when compared to coprological methods. Moreover, the urine ELISA IgG test had a detection rate of 69%, which far exceeds the coprological method (28%). The likelihood of a positive diagnosis of strongyloidiasis by the urine ELISA IgG test increased significantly with increasing units of IgG detected in urine. The urine ELISA IgG assay for strongyloidiasis assay has a diagnostic accuracy comparable to serological assay, both of which are more sensitive than coprological methods. Since the collection of urine is easy and non-invasive, the urine ELISA IgG assay for strongyloidiasis could be used to screen populations at risk for strongyloidiasis in S. stercoralis endemic areas.

The use of Strongyloides ratti as heterologous antigen for serodiagnosis of strongyloidiasis is preferable to Strongyloides from humans due to the ease and safety of antigen preparation. In Southeast Asia where Opisthorchis viverrini coexists with Strongyloides stercoralis, there has been no report in using S. ratti for serodiagnosis of S. stercoralis. In this study, performance of an enzyme-linked immunosorbent assay (ELISA) based on S. ratti was compared with that based on S. stercoralis for diagnosis of strongyloidiasis in areas where O. viverrini is co-endemic in Thailand. Of the 107 individuals, 50 (46.7 %) were positive for S. stercoralis by agar culture method and by ELISA; 82 (76.6 %) and 81 (75.7 %) were seropositive using S. ratti and S. stercoralis antigens, respectively. The levels of parasite-specific IgG to S. ratti and S. stercoralis antigen were significantly proportionally correlated (P < 0.001). Mixed infections with O. viverrini have little effect on diagnosis of strongyloidiasis. Of 42 subjects who were infected with other parasites, there were no cross-reaction with Angiostrongylus cantonensis, Taenia spp., hookworms, Paragonimus spp., Clonorchis sinensis, Ascaris lumbricoides except for Fasciola spp. (1 of 5), and Opisthorchis viverrini (5 of 20). In spite of cross-reactivities, the results suggest that the S. ratti antigen provides an useful option for diagnosis of strongyloidiasis in an endemic area of opisthorchiasis with high sensitivity comparable to the S. stercoralis antigen and provide a basis for effective control strategies for strongyloidiasis.

This study was aimed at describing two (2) intestinal nematodes from naturally infected native breed of goats (Capra hircus) in Bangladesh, identified as Oesophagostomum columbianum (Curtice, 1890) Stossich 1899 and Haemonchus contortus (Rudolphi, 1803) Cobb, 1898. The identification was made based on morphometric features and was confirmed by amplifying internal transcribed spacer (ITS) and cytochrome c oxidase (cox1) gene. Well-developed lateral alae, distinct cervical papillae anteriorly to esophageal expansion, and male spicule length (0.73-0.79 mm, n = 2 ) were characteristically observed in O. columbianum. At the same time, male spicule length (0.40-0.46 mm, n = 2 ) and position of female vulvar flap (4.30-4.54 mm from posterior end, n = 3 ) were observed in H. contortus. DNA sequence homology of the ITS and cox1 gene of both specimens revealed the same results, showing similarity to the GenBank sequences of O. columbianum (GenBank No. KC715827; JX188470) and H. contortus (GenBank No. KJ724377; HQ389229). Phylogenetic analysis computed by maximum livelihood (ML) from the ITS nucleotide sequences revealed that the O. columbianum and H. contortus isolates identified in this study were clustered in the same clade with isolates from China and Iran, respectively. This study, for the first time, illustrates the characteristics of O. columbianum and H. contortus in Bangladesh, combining both morphological and molecular data. The universal primer-based polymerase chain reaction (PCR) protocol could be an economical and efficient option for researchers from poor resource settings for precise identification of nematodes. The information generated in this study may contribute to formulating effective control strategies against these nematodes.

Introduction: Endoparasites in captive wildlife might pose a threat to public health; however, very few studies have been conducted on this issue, and much remains to be learned, especially in limited-resource settings. This study aimed to investigate endoparasites of captive wildlife in Bangladesh. Perception and understanding of veterinarians regarding one health and zoonoses were also assessed. Materials and Methods: A cross-sectional study was conducted from October 2019 to August 2020. A total of 45 fecal samples from 18 different species of wild animals (i.e., 11 species of mammals: herbivores, carnivores, and omnivores, six birds, and a single reptile species) were collected randomly. Parasitological assessments were done by modified formalin ether sedimentation technique and rechecked by Sheather’s sugar floatation technique. Molecular identification of Spirometra spp. was conducted by amplifying the cytochrome c oxidase 1 (cox1) gene. Questionnaire surveys among 15 veterinarians and an in-depth interview (IDI) with a zoo officer were conducted. Results: Helminths (Spirometra sp., Capillaria sp., Ascaridia/Heterakis, opisthorchiid, strongyles, acuariid, hookworms, roundworms, and unidentified nematode larvae) and protozoa (coccidian oocyst) were identified, and the overall prevalence was 48.9% (22/45). The cox1 sequences (341 bp) of the Bangladesh-origin Spirometra species from lion showed 99.3–99.7% similarity to the reference sequences of Spirometra decipiens (GenBank No: KJ599679.1; MT122766). The majority of study participants (86.6%) agreed about the importance of endoparasite control in zoo animals, and 73.3% expressed that the one health concept should be promoted in Bangladesh. Only 6.7% of veterinarians perceived confidence in diagnosing parasitic diseases and preventing antiparasiticidal resistance. Conclusions: In the present survey, we found a considerable prevalence of endoparasites in captive wildlife. For the first time, zoonotically important S. decipiens from lion was molecularly characterized in Bangladesh. Veterinarian training is required to improve parasite control knowledge and practice. This study highlights the need for routine parasitological assessment, promotion of one health, and improvement of the implementation of current parasite control strategies in zoo animals.