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Lau DCW, Power RI, Šlapeta J. Exploring multiplex qPCR as a diagnostic tool for detecting microfilarial DNA in dogs infected with Dirofilaria immitis: A comparative analysis with the modified Knott's test. Vet Parasitol 2024; 325:110097. [PMID: 38104431 DOI: 10.1016/j.vetpar.2023.110097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/10/2023] [Accepted: 12/11/2023] [Indexed: 12/19/2023]
Abstract
Current recommendations to diagnose cardiopulmonary dirofilariosis in dogs caused by Dirofilaria immitis involves tandem antigen and circulating microfilariae tests. The modified Knott's test is an important tool in heartworm diagnosis, allowing identification of circulating microfilariae. However, the subjective nature of the modified Knott's test affects its accuracy and diagnostic laboratories usually do not provide a quantitative outcome. Quantitative enumeration of microfilariae enables clinicians to track treatment progress and acts as a proxy for detecting emerging macrocyclic lactone resistance. There is a need for better diagnostic tools suitable for routine use to efficiently and accurately quantify the presence of D. immitis microfilaremia. The aim of this study was to determine whether the quantitative modified Knott's test can be substituted by multiplex quantitative polymerase chain reaction (qPCR) targeting D. immitis and associated Wolbachia endosymbiont DNA in canine blood samples. To do this, genomic DNA samples (n = 161) from Australian dogs, collected as part of a previous 2021 study, were assessed in a TaqMan qPCR targeting DNA of D. immitis, Wolbachia sp. and Canis lupus familiaris. Of the 161 genomic DNA samples, eight were considered positive for D. immitis microfilariae. The qPCR assay demonstrated good efficiency (E = 90 to 110%, R2 > 0.94). Considering the performance and efficient use of bench time, this TaqMan qPCR assay is a suitable alternative to the modified Knott's test for quantitative enumeration of microfilariae (Cohen's kappa coefficient [κ]: κ = 1 using D. immitis qPCR marker, κ = 0.93 using Wolbachia qPCR marker). The qPCR data demonstrated a comparable result to that of the quantitative modified Knott's test in a 2022 survey of D. immitis in Australian dogs (n = 23) before and after macrocyclic lactone (ML) administration. Improving the detection and diagnosis of canine heartworm infections will assist veterinarians in better managing and controlling disease outcomes and will be valuable for tracking the spread of ML resistance in Australia.
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Affiliation(s)
- Daisy Ching-Wai Lau
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, New South Wales 2006, Australia
| | - Rosemonde Isabella Power
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, New South Wales 2006, Australia
| | - Jan Šlapeta
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, New South Wales 2006, Australia; The University of Sydney Institute for Infectious Diseases, New South Wales 2006, Australia.
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Dantas-Torres F, Ketzis J, Pérez Tort G, Mihalca AD, Baneth G, Otranto D, Watanabe M, Linh BK, Inpankaew T, Borrás P, Arumugam S, Penzhorn BL, Ybañez AP, Irwin P, Traub RJ. Heartworm adulticide treatment: a tropical perspective. Parasit Vectors 2023; 16:148. [PMID: 37106364 PMCID: PMC10141906 DOI: 10.1186/s13071-023-05690-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 02/02/2023] [Indexed: 04/29/2023] Open
Abstract
Dirofilaria immitis (the canine heartworm) is widespread in the tropics, with prevalence surpassing 30% in high-risk areas. In addition to the suitable climatic conditions that favour mosquito abundance and filarial larva development, there is low compliance with the recommended year-round use of preventives in these transmission hotspots. This represents a major concern, considering that melarsomine (first-line heartworm adulticide) is unavailable in several tropical countries, resulting in the so-called slow-kill protocol being the only available adulticide treatment option. In this article, the members of TroCCAP (Tropical Council for Companion Animal Parasites) review the current distribution of heartworm in the tropics and the availability of melarsomine, and discuss alternatives for the management of heartworm infections in dogs.
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Affiliation(s)
- Filipe Dantas-Torres
- Instituto Aggeu Magalhães, Fundação Oswaldo Cruz (Fiocruz), Recife, Pernambuco, Brazil.
| | - Jennifer Ketzis
- Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis
| | - Gabriela Pérez Tort
- University of Buenos Aires and Virreyes Veterinary Hospital, Buenos Aires, Argentina
| | - Andrei Daniel Mihalca
- University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, Cluj-Napoca, Romania
| | - Gad Baneth
- The Hebrew University of Jerusalem, Rehovot, Israel
| | | | | | - Bui Khanh Linh
- Vietnam National University of Agriculture, Hanoi, Vietnam
| | | | - Pablo Borrás
- Administración Nacional de Laboratorios e Institutos de Salud Dr. Carlos G. Malbrán, Buenos Aires, Argentina
| | - Sangaran Arumugam
- Madras Veterinary College, Tamil Nadu Veterinary and Animal Sciences University, Chennai, India
| | | | | | | | - Rebecca J Traub
- Melbourne Veterinary School, University of Melbourne, Parkville, VIC, Australia
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Latrofa MS, Varotto-Boccazzi I, Louzada-Flores VN, Iatta R, Mendoza-Roldan JA, Roura X, Zatelli A, Epis S, Bandi C, Otranto D. Interaction between Wolbachia pipientis and Leishmania infantum in heartworm infected dogs. Parasit Vectors 2023; 16:77. [PMID: 36850014 PMCID: PMC9972713 DOI: 10.1186/s13071-023-05662-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 01/10/2023] [Indexed: 03/01/2023] Open
Abstract
BACKGROUND Wolbachia is a Gram-negative endosymbiont associated with several species of arthropods and filarioid nematodes, including Dirofilaria immitis. This endosymbiont may elicit a Th1 response, which is a component of the immunity against Leishmania infantum. METHODS To investigate the interactions between Wolbachia of D. immitis and L. infantum in naturally infected dogs and cytokine circulation, dogs without clinical signs (n = 187) were selected. Dogs were tested for microfilariae (mfs) by Knott, for female antigens of D. immitis by SNAP, and for anti-L. infantum antibodies by IFAT and assigned to four groups. Dogs of group 1 (G1) and 2 (G2) were positive for D. immitis and positive or negative to L. infantum, respectively. Dogs of group 3 (G3) and 4 (G4) were negative to D. immitis and positive or negative to L. infantum, respectively. Wolbachia and L. infantum DNA was quantified by real-time PCR (qPCR) in dog blood samples. A subset of dogs (n = 65) was examined to assess pro- and anti-inflammatory cytokine production using an ELISA test. RESULTS Of 93 dogs positive to D. immitis with circulating mfs, 85% were positive to Wolbachia, with the highest amount of DNA detected in G1 and the lowest in dogs with low mfs load in G1 and G2. Among dogs positive to L. infantum, 66% from G1 showed low antibody titer, while 48.9% from G3 had the highest antibody titer. Of 37 dogs positive to Wolbachia from G1, 26 (70.3%) had low antibody titers to L. infantum (1:160). Among cytokines, TNFα showed the highest mean concentration in G1 (246.5 pg/ml), IFNγ being the one most represented (64.3%). IL-10 (1809.5 pg/ml) and IL-6 (123.5 pg/ml) showed the highest mean concentration in dogs from G1. A lower percentage of dogs producing IL-4 was observed in all groups examined, with the highest mean concentration (2794 pg/ml) recorded in G2. CONCLUSION Results show the association of D. immitis and Wolbachia with the lower antibody titers of L. infantum in co-infected dogs, suggesting the hypothesis that the endosymbiont may affect the development of the patent leishmaniosis. However, due to the limitations associated with the heterogeneity of naturally infected dogs in field conditions, results should be validated by investigation on experimental models.
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Affiliation(s)
- Maria Stefania Latrofa
- grid.7644.10000 0001 0120 3326Department of Veterinary Medicine, University of Bari, Bari, Italy
| | | | | | - Roberta Iatta
- grid.7644.10000 0001 0120 3326Interdisciplinary Department of Medicine, University of Bari, Bari, Italy
| | | | - Xavier Roura
- grid.7080.f0000 0001 2296 0625Hospital Clínic Veterinari, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Andrea Zatelli
- grid.7644.10000 0001 0120 3326Department of Veterinary Medicine, University of Bari, Bari, Italy
| | - Sara Epis
- grid.4708.b0000 0004 1757 2822Department of Biosciences, University of Milan, Milan, Italy ,grid.4708.b0000 0004 1757 2822Pediatric CRC ‘Fondazione Romeo ed Enrica Invernizzi’, University of Milan, Milan, Italy
| | - Claudio Bandi
- grid.4708.b0000 0004 1757 2822Department of Biosciences, University of Milan, Milan, Italy ,grid.4708.b0000 0004 1757 2822Pediatric CRC ‘Fondazione Romeo ed Enrica Invernizzi’, University of Milan, Milan, Italy
| | - Domenico Otranto
- Department of Veterinary Medicine, University of Bari, Bari, Italy. .,Faculty of Veterinary Sciences, Bu-Ali Sina University, Hamedan, Iran.
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Ciuca L, Vismarra A, Constanza D, Di Loria A, Meomartino L, Ciaramella P, Cringoli G, Genchi M, Rinaldi L, Kramer L. Efficacy of oral, topical and extended-release injectable formulations of moxidectin combined with doxycycline in Dirofilaria immitis naturally infected dogs. Parasit Vectors 2023; 16:54. [PMID: 36740705 PMCID: PMC9901089 DOI: 10.1186/s13071-023-05673-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/16/2023] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Several studies in both experimentally and naturally infected dogs have reported the adulticide effect of a combination of macrocyclic lactones and doxycycline against Dirofilaria immitis, showing that these protocols can be used as an alternative to melarsomine. The present study evaluated the efficacy of oral, topical and extended-release injectable formulations of moxidectin when combined with doxycycline in dogs naturally infected with D. immitis from a shelter located in southern Italy. METHODS Thirty dogs with naturally acquired D. immitis infection were divided in three groups (G) and treated with oral moxidectin (G1) once a month for 9 consecutive months, topical moxidectin (G2) once a month for 9 consecutive months or extended release moxidectin injectable (G3) at enrolment and again at 6 months (Day 180). All treatment groups received doxycycline for the first 30 days. Microfilarial concentrations in 1 ml (mff/ml) blood were determined monthly for 9 months with the modified Knott's test. A clinical scoring system was employed for each dog enrolled in the study based on thoracic radiography and cardiac ultrasound (CU) examinations performed at Day - 15 (before treatment) and at Day 180. RESULTS Results from the present study suggest that the majority of dogs from all treatment groups became antigen negative, as evaluated at Day 270: 9/10 dogs (90.0%) from G1, 6/10 dogs (60.0%) from G2 and 8/10 dogs (80.0%) from G3. Improvement of radiographic alterations was observed in all treatment groups, and almost all dogs were cleared of pulmonary abnormalities by 6 months from the beginning of treatment (P = 0.000). Cardiac ultrasound examination showed a progressive improvement of cardiac function in a limited number of animals (4/30). CONCLUSIONS The combination of doxycycline and three different formulations of moxidectin leads to antigen-negative status in naturally infected dogs.
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Affiliation(s)
- Lavinia Ciuca
- grid.4691.a0000 0001 0790 385XDepartment of Veterinary Medicine and Animal Production, University of Naples Federico II, Via Federico Delpino 1, 80137 Naples, Italy
| | - Alice Vismarra
- grid.10383.390000 0004 1758 0937Department of Veterinary Medicine Sciences, University of Parma, Strada del Taglio, 10, 43126 Parma, Italy
| | - Dario Constanza
- grid.4691.a0000 0001 0790 385XDepartment of Veterinary Medicine and Animal Production, University of Naples Federico II, Via Federico Delpino 1, 80137 Naples, Italy
| | - Antonio Di Loria
- grid.4691.a0000 0001 0790 385XDepartment of Veterinary Medicine and Animal Production, University of Naples Federico II, Via Federico Delpino 1, 80137 Naples, Italy
| | - Leonardo Meomartino
- grid.4691.a0000 0001 0790 385XDepartment of Veterinary Medicine and Animal Production, University of Naples Federico II, Via Federico Delpino 1, 80137 Naples, Italy
| | - Paolo Ciaramella
- grid.4691.a0000 0001 0790 385XDepartment of Veterinary Medicine and Animal Production, University of Naples Federico II, Via Federico Delpino 1, 80137 Naples, Italy
| | - Giuseppe Cringoli
- grid.4691.a0000 0001 0790 385XDepartment of Veterinary Medicine and Animal Production, University of Naples Federico II, Via Federico Delpino 1, 80137 Naples, Italy
| | - Marco Genchi
- grid.10383.390000 0004 1758 0937Department of Veterinary Medicine Sciences, University of Parma, Strada del Taglio, 10, 43126 Parma, Italy
| | - Laura Rinaldi
- grid.4691.a0000 0001 0790 385XDepartment of Veterinary Medicine and Animal Production, University of Naples Federico II, Via Federico Delpino 1, 80137 Naples, Italy
| | - Laura Kramer
- grid.10383.390000 0004 1758 0937Department of Veterinary Medicine Sciences, University of Parma, Strada del Taglio, 10, 43126 Parma, Italy
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Bezerra-Santos MA, Dantas-Torres F, Benelli G, Otranto D. Emerging parasites and vectors in a rapidly changing world: from ecology to management. Acta Trop 2023; 238:106746. [PMID: 36403676 DOI: 10.1016/j.actatropica.2022.106746] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/05/2022] [Accepted: 10/28/2022] [Indexed: 11/18/2022]
Abstract
Global changes have influenced our societies in several ways with both positive (e.g., technology, transportation, and food security), and negative impacts (e.g., mental health problems, spread of diseases, and pandemics). Overall, these changes have affected the distribution patterns of parasites and arthropod vectors with the introduction and spreading of alien species in new geographical areas, eventually posing new challenges in public health. In this framework, the Acta Tropica Special Issue "Emerging parasites and vectors in a rapidly changing world: from ecology to management" provides a focus on the biology, ecology and management of emerging parasites and vectors of human and veterinary importance. Herein we review and discuss novel studies dealing with interactions of parasites and vectors with animals in changing environmental settings. In our opinion, a special focus on the implementation of management strategies of parasitic diseases to face anthropogenic environmental changes still represent a priority for public health. In the final section, key research challenges in this rapidly changing scenario are outlined.
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Affiliation(s)
- Marcos Antonio Bezerra-Santos
- Department of Veterinary Medicine, University of Bari Aldo Moro, Str. prov. per Casamassima km 3, Valenzano, Bari 70010, Italy
| | | | - Giovanni Benelli
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy
| | - Domenico Otranto
- Department of Veterinary Medicine, University of Bari Aldo Moro, Str. prov. per Casamassima km 3, Valenzano, Bari 70010, Italy; Faculty of Veterinary Sciences, Bu-Ali Sina University, Hamedan, Iran.
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Power RI, Šlapeta J. Exploration of the sensitivity to macrocyclic lactones in the canine heartworm (Dirofilaria immitis) in Australia using phenotypic and genotypic approaches. Int J Parasitol Drugs Drug Resist 2022; 20:145-158. [PMID: 36417831 PMCID: PMC9772245 DOI: 10.1016/j.ijpddr.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 11/08/2022] [Accepted: 11/08/2022] [Indexed: 11/18/2022]
Abstract
Canine heartworm disease is a potentially deadly cardiopulmonary disease caused by the mosquito-borne filarial nematode Dirofilaria immitis. In Australia, the administration of macrocyclic lactone (ML) drugs has successfully reduced the prevalence of D. immitis infection. However, the recent re-emergence of D. immitis in dogs in Queensland, Australia and the identification of ML-resistant isolates in the USA poses an important question of whether ML-resistance has emerged in this parasite in Australia. The aim of this study was to utilise phenotypic and genotypic approaches to examine the sensitivity to ML drugs in D. immitis in Australia. To do this, we surveyed 45 dogs from Queensland and New South Wales across 3 years (2019-2022) for the presence of D. immitis infection using an antigen test, quantitative Modified Knott's test, and qPCR targeting both D. immitis and the D. immitis symbiont Wolbachia. A phenotype observed by utilising sequential quantification of microfilariae for 23/45 dogs was coupled with genetic testing of filtered microfilariae for SNPs previously associated with ML-resistance in isolates from the USA. Sixteen (16/45) dogs tested positive for D. immitis infection despite reportedly receiving 'rigorous' heartworm prevention for 12 months prior to the study, according to the owners' assessment. The phenotype and genotypic assays in this study did not unequivocally demonstrate the presence of ML-resistant D. immitis in Australia. Although the failure of 16 dogs to reduce microfilaremia by >90% after ML treatment was considered a suspect phenotype of ML-resistance, no genotypic evidence was discovered using the genetic SNP analysis. The traditional quantitative Modified Knott's test can be substituted by qPCR targeting D. immitis or associated Wolbachia endosymbiont DNA for a more rapid measurement of microfilariae levels. More definitive phenotypic evidence of resistance is critically needed before the usefulness of SNPs for the detection of ML-resistance in Australia can be properly assessed.
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Affiliation(s)
- Rosemonde Isabella Power
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, New South Wales, 2006, Australia
| | - Jan Šlapeta
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, New South Wales, 2006, Australia,The University of Sydney Institute for Infectious Diseases, New South Wales, 2006, Australia,Corresponding author. Sydney School of Veterinary Science, Faculty of Science, University of Sydney, New South Wales, 2006, Australia.
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