Dirofilaria immitis and Wolbachia pipientis: a thorough investigation of the symbiosis responsible for canine heartworm disease

McHaffie, Jake

doi:10.1007/s00436-011-2644-5

Cited by 14 publications

(8 citation statements)

References 13 publications

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“…The administration of antibiotics (doxycycline or minocycline) is considered of great value in order to impair the eventual development of the circulating microfilariae to adult worms in a new host, although further confirmation of this effect should be generated [59]. This is the result of removing the filarial endosymbiont Wolbachia pipientis which is critical for the survival, development and reproduction of D. immitis [60]. Furthermore, the elimination of W. pipientis results in reduced lung inflammation during the course of adulticide treatment [61,62].…”

Section: What To Expect and How To Monitormentioning

confidence: 99%

Concern for <em>Dirofilaria immitis</em> and Macrocyclic Lactone Loss of Efficacy: Current Situation in the USA and Europe, and Future Scenarios

Diakou¹,

Prichard²

2021

Preprint

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Dirofilaria immitis infection is one of the most severe parasitic diseases of dogs. Prevention is achieved by the administration of drugs containing macrocyclic lactones (MLs). These products are very safe and highly effective, targeting the third and fourth larval stages (L3, L4) of the parasite. Until 2011, claims of ineffectiveness of MLs, reported as “Lack of Efficacy” (LOE), were generally attributed to owners’ non-compliance, or other reason for inadequate preventative coverage. There was solid argumentation that a resistance problem is not likely to occur because of i) the great extent of refugia, ii) the complexity of resistance development to MLs, and iii) the possible big number of genes involved in resistance selection. Nevertheless, today it is unequivocally proven that ML resistant D. immitis strains exist, at least in the Lower Mississippi region, USA. Accordingly, tools have been developed, to evaluate and confirm the susceptibility status of D. immitis strains. A simple, in-clinic, microfilariae suppression test, 14-28 days after ML administration, and a “decision tree” (algorithm), including compliance and preventatives’ purchase history, and testing gaps, may be applied for assessing any resistant nature of the parasite. On the molecular level, specific SNPs may be used as markers of ML resistance, offering a basis for validation of clinically suspected resistant strains. In Europe, no LOE/resistance claims have been reported so far, and the existing conditions (stray dogs, rich wildlife, majority of owned dogs not on preventive MLs treatment) do not favor selection pressure on the parasites. Considering the genetic basis of resistance and the epizootiological characteristics of D. immitis, ML resistance neither establishes easily nor spreads quickly, a fact confirmed by the current known dispersion of the problem, which is limited. Nevertheless, ML resistance may propagate from an initial geographical point, via animal and vector mobility, to other regions, while it can also emerge as an independent evolutionary process in a new area. For these reasons and considering the current chemoprophylaxis recommendations and increasing use of ML endectoparasiticides as a potential selection pressure, it is important to remain vigilant for timely detection of any ML LOE/resistance, in all continents where D. immitis is enzootic.

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Section: What To Expect and How To Monitormentioning

confidence: 99%

Concern for <em>Dirofilaria immitis</em> and Macrocyclic Lactone Loss of Efficacy: Current Situation in the USA and Europe, and Future Scenarios

Diakou¹,

Prichard²

2021

Preprint

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“…The exact function of Wolbachia in heartworm is unknown but it is required for normal parasite development, fertility, and long-time survival of Dirofilaria. Therefore, preventing the expansion of the Wolbachia population is believed to prevent heartworm development (McCall et al, 2008;McHaffie, 2012).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of different dosages of doxycycline during the adulticide treatment of heartworm (Dirofilaria immitis) in dogs

Carretón

Morchón

Falcón-Cordón

et al. 2020

Veterinary Parasitology

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The endosymbiont bacteria Wolbachia plays an important role in the pathogenesis and inflammatory immune response to heartworm (Dirofilaria immitis) infection in dogs. Doxycycline is used to reduce Wolbachia from all life stages of heartworm to avoid large releases of the bacteria during the death of the worms. However, the dose and duration currently recommended have been extrapolated from the treatment of other rickettsial infections. Therefore, the aim was to study the dynamics of Wolbachia IgG antibodies in heartworm-infected dogs under adulticide treatment using different dosages of doxycycline. Forty-nine heartworm-infected dogs were recruited. On day 0 (diagnosis), monthly ivermectin (6 μg/kg) was prescribed, as well as daily doxycycline for 30 days, at 10 mg/kg/12 h (n = 13), 5 mg/kg/12 h (n = 19), and 10 mg/kg/24 h (n = 17). Dogs underwent adulticide treatment and blood samples were collected on days 0, 30, 90, and 120. All dogs had antibodies against recombinant Wolbachia surface protein (rWSP), confirming the important role of the bacteria in heartworm. No significant differences were found in anti-rWSP response by presence/absence of microfilariae, or by parasite burden on day 0. In all treated groups, the anti-rWSP antibody response was not significantly different between days 0 and 30 but was significantly lower between days 0 and 120 (p < 0.05). The results of the present study suggest that the administration of a lower dose than currently recommended is sufficient to achieve a significant reduction of Wolbachia in dogs infected by D. immitis.

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“…may be useful in treatment of heartworm disease in dogs through decreasing the number of endogenous Wolbachia and consequently the microfilarial load, inhibition of the larval stage and also worm infertility. Typically, application of antimicrobial substances against Wolbachia may be useful as a complementary anti-filarial therapy strategy in canine and feline dirofilariasis, but further studies are needed to substitute these novel methods for anti-parasite drugs (11). In this regard, doxycycline is an effective treatment against Wolbachia , and in combination with ivermectin has been shown to have adulticidal efficiency for heartworm treatments in dogs (12–15).…”

Section: Introductionmentioning

confidence: 99%

“…Elimination of Wolbachia by antimicrobial agents can exert a preventive effect on embryogenesis of D. immitis and could have potential application in sterilization of the female worms and consequently control and treatment of dirofilariasis (16). Interfering of this obligate relationship has been used in novel therapeutic strategies; for example, a combination of antimicrobial therapy using doxycycline and ivermectin, as a macrocyclic lactone can destroy nematodes (8, 11, 14). Overall, due to the zoonotic potential and the increasing number of D. immitis and D. repens infections in non-endemic areas, xenomonitoring of this bacterium may be useful (20).…”

Section: Introductionmentioning

confidence: 99%

Molecular Detection and Phylogenetic Analysis of Endosymbiont Wolbachia pipientis (Rickettsiales: Anaplasmataceae) Isolated from Dirofilaria immitis in Northwest of Iran

Khanmohammadi¹,

Falak²,

Meamar³

et al. 2019

JAD

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Background: The purpose of this study was molecular detection and phylogenetic analysis of Wolbachia species of Dirofilaria immitis. Methods: Adult filarial nematodes were collected from the cardiovascular and pulmonary arterial systems of naturally infected dogs, which caught in different geographical areas of Meshkin Shahr in Ardabil Province, Iran, during 2017. Dirofilaria immitis genomic DNA were extracted. Phylogenetic analysis for proofing of D. immitis was carried out using cytochrome oxidase I (COI) gene. Afterward, the purified DNA was used to determine the molecular pattern of the Wolbachia surface protein (WSP) gene sequence by PCR. Results: Phylogeny and homology studies showed high consistency of the COI gene with the previously-registered sequences for D. immitis. Comparison of DNA sequences revealed no nucleotide variation between them. PCR showed that all of the collected parasites were infected with W. pipientis. The sequence of the WSP gene in Wolbachia species from D. immitis was significantly different from other species of Dirofilaria as well as other filarial species. The maximum homology was observed with the Wolbachia isolated from D. immitis. The greatest distance between WSP nucleotides of Wolbachia species found between D. immitis and those isolated from Onchocerca lupi. Conclusion: PCR could be a simple but suitable method for detection of Wolbachia species. There is a pattern of host specificity between Wolbachia and Dirofilaria that can be related to ancestral evolutions. The results of this phylogenetic analysis and molecular characterization may help us for better identification of Wolbachia species and understanding of their coevolution.

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Dirofilaria immitis and Wolbachia pipientis: a thorough investigation of the symbiosis responsible for canine heartworm disease

Cited by 14 publications

References 13 publications

Concern for <em>Dirofilaria immitis</em> and Macrocyclic Lactone Loss of Efficacy: Current Situation in the USA and Europe, and Future Scenarios

Concern for <em>Dirofilaria immitis</em> and Macrocyclic Lactone Loss of Efficacy: Current Situation in the USA and Europe, and Future Scenarios

Evaluation of different dosages of doxycycline during the adulticide treatment of heartworm (Dirofilaria immitis) in dogs

Molecular Detection and Phylogenetic Analysis of Endosymbiont Wolbachia pipientis (Rickettsiales: Anaplasmataceae) Isolated from Dirofilaria immitis in Northwest of Iran

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