Veterinary Biosciences - Research Publications
Permanent URI for this collection
Search Results
1 - 5 of 5
-
ItemNo Preview AvailableAn Integrated Coproscopic and Molecular Method Provides Insights into the Epidemiology of Zoonotic Intestinal Helminths of Dogs across Cambodia(WILEY-HINDAWI, 2023-08-22)Introduction. In Cambodia, a limited number of focal surveys targeting dogs in rural communities have reported intestinal helminths of potential zoonotic risk as highly endemic. In this study, we investigated the prevalence, diversity, distribution, and risk predictors associated with zoonotic intestinal helminths infecting pet, community, and pagoda dogs across rural and urban settings in Cambodia through an integrated coproscopic and molecular approach. Methods. Faecal samples, demographic, and clinical data were collected from 457 dogs across Cambodia. Faeces were screened for gastroenteric parasites using sodium nitrate faecal floatation (1.30 SpGr) and multiplex TaqMan-based quantitative polymerase chain reaction (qPCR) assays for differentiation of canine hookworm species (Ancylostoma ceylanicum, Ancylostoma braziliense, Ancylostoma caninum, and Uncinaria stenocephala) and for Strongyloides spp. Conventional polymerase chain reaction (PCR) and DNA sequencing was used to further characterise eggs resembling zoonotic helminths that could not be designated to a species level by light microscopy alone. In addition, infection intensities for hookworms and Toxocara as eggs per gram of faeces were estimated to assess the dog age-dependent contribution of these zoonotic parasites in the environment. Finally, multiple logistic regression analyses were performed to identify risk predictors for gastrointestinal parasitoses. Results. Using combined coproscopic and molecular methods, we detected at least one helminth in 79% of the sampled dogs. Of these, 78.8% were infected with at least one zoonotic species, with A. ceylanicum (50%) and A. caninum (50%) constituting the most common parasites followed by A. braziliense (20%), Toxocara canis (15%), Strongyloides spp. (5%), Dipylidium caninum (2%), and Eucoleus spp. (2%). The indirect zoonotic helminths Spirometra erinaceieuropaei, Spirometra mansoni, and Haplorchis yokogawai contributed to 14% of the total infections in dogs. Dogs were also found mechanically passing eggs of large trematodes such as Fischoederius elongatus, Schistosoma spp., Paramphistomatidae, and Gastrothylax crumenifer. Contradictory to previous reports, the prevalence of T. canis was highest in adult dogs with egg shedding intensity peaking in dogs more than 7 years of age. Finally, we found that pale mucous membranes and low total protein were predictors of hookworm infection in dogs ( p < 0.05 ). Conclusion. Dogs within both rural and urban settings across Cambodia are highly infected with a large diversity of zoonotic gastroenteric helminths. This study reports the presence of A. braziliense, the aetiological agent of hookworm-related “creeping eruptions” for the first time in Cambodia. Moreover, infection intensity data suggest that adult dogs should also be targeted by deworming campaigns to reduce the prevalence of zoonotic hookworm and T. canis infections within the country. These results highlight the need for an integrated approach to canine population management and parasite control in dogs across urban and rural settings in Cambodia to mitigate the public health risks and impacts posed by these helminths.
-
ItemAncylostoma ceylanicum Hookworms in Dogs, Grenada, West Indies(CENTERS DISEASE CONTROL & PREVENTION, 2022-09)Ancylostoma ceylanicum hookworms are recognized agents of human infection in the Asia-Pacific region. We investigated prevalence of zoonotic hookworm infections in dogs in Grenada in 2021; 40.8% were infected by hookworms, including Ancylostoma ceylanicum. Surveillance of this parasite in dogs and humans is needed in tropical/subtropical countries in the Americas.
-
ItemZoonotic Soil-Transmitted Helminths in Free-Roaming Dogs, Kiribati(CENTERS DISEASE CONTROL & PREVENTION, 2021-08)Soil-transmitted helminths are highly prevalent in the Asia-Pacific region. We report a 96.5% prevalence of zoonotic soil-transmitted helminths in dogs in Kiribati. We advocate for urgent implementation of treatment and prevention programs for these zoonotic pathogens, in line with the Kiribati-World Health Organization Cooperation Strategy 2018-2022.
-
ItemComparison of the egg recovery rates and limit of detection for soil-transmitted helminths using the Kato-Katz thick smear, faecal flotation and quantitative real-time PCR in human stool(PUBLIC LIBRARY SCIENCE, 2021-05)BACKGROUND: Monitoring the success of soil-transmitted helminth (STH) control programs relies on accurate diagnosis and quantitative assessment of infection prevalence and intensity. As preventative chemotherapeutic program coverage for STH expands, the necessity of gaining insights into the relative or comparative sensitivities, in terms of limits of detection (LOD) and egg-recovery-rates (ERR) for microscopy and quantitative polymerase chain reaction qPCR-based diagnostic techniques becomes imperative to inform suitability for their intended use for large scale STH monitoring and treatment efficacy studies. METHODOLOGY/PRINCIPAL FINDINGS: The diagnostic performance in terms of ERR and LOD of the Kato-Katz (KK) thick smear technique, sodium nitrate (NaNO3) faecal floatation (FF) and qPCR for the accurate detection and enumeration of STH eggs were calculated and expressed in eggs per gram (EPG), by experimentally seeding parasite-free human faeces with Ascaris spp., Trichuris spp. and Necator americanus eggs representing low, medium and high intensity infections. The efficiency of NaNO3 flotation was also calculated over a range of specific gravities (SpGr) for the optimum recovery of STH eggs. FF of SpGr 1.30 recovered 62.7%, 11% and 8.7% more Trichuris spp., Necator americanus and Ascaris spp. eggs respectively, than the recommended SpGr of 1.20. All diagnostic methods demonstrated strong direct correlation to the intensity of seeded EPG. KK and FF (SpGr 1.30) resulted in significant lower ERRs compared to qPCR (p <0.05). qPCR demonstrated significantly (p <0.05) greater sensitivity with an ability to detect as little as 5 EPG for all three STH, compared to 50 EPG by KK and FF (SpGr 1.30). CONCLUSIONS/SIGNIFICANCE: This study compares the diagnostic parameters in terms of LOD and ERRs of STHs for the KK, FF and qPCR. These results indicate that the diagnostic performance of qPCR assays should be considered by control programs in the phase that aims to seek confirmation of transmission break and cessation of preventive chemotherapy in low-transmission settings, in line with the control targets of the WHO neglected tropical diseases 2030 Roadmap.
-
ItemHigh-throughput multiplex qPCRs for the surveillance of zoonotic species of canine hookworms(PUBLIC LIBRARY SCIENCE, 2020-06)The canine hookworms Ancylostoma braziliense, Ancylostoma ceylanicum, Ancylostoma caninum and Uncinaria stenocephala are not only capable of producing morbidity and mortality in dogs but are also neglected tropical zoonoses. Each hookworm species differs considerably in its geographical distribution, life cycle, biology, pathogenic impacts on both canine and human hosts, zoonotic potential, and response to treatment with anthelminthics. Here we describe the development and validation of two Taq-Man based multiplex PCR assays capable of detecting and differentiating all four canine hookworm species in faeces of naturally infected dogs. The analytical sensitivity of both assays was assessed using 10-fold serial dilutions of synthetic gene block fragments containing individual sequence targets of each hookworm species. The sensitivity of the assays and ability to detect mixed species infections were compared to a conventional PCR-Restriction Fragment Length Polymorphism based-approach when applied to laboratory and field samples from endemic areas. The qPCRs detected at least one species of hookworms in 82.4% of PCR-RFLP-negative but microscopy-positive samples. The qPCRs detected an additional 68% mixed infections with different species of canine hookworms, and additional single species infection with A. caninum (47%), U. stenocephala (33%) and A. ceylanicum (0.02%) that were missed by PCR-RFLP. These multiplex qPCR assays will assist field based epidemiological surveillance studies towards an accurate and sensitive monitoring of canine hookworm infections in dogs, to inform their species-specific zoonotic risks to populations living in endemic areas, globally.