Histomonas meleagridis isolates compared by virulence and gene expression

Wei, Zehui; Abraham, Mathew; Chadwick, Elle; Beckstead, Robert B.

doi:10.1016/j.vetpar.2020.109233

Cited by 7 publications

(9 citation statements)

References 28 publications

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“…Candidate vaccination isolates have been shown distinctly attenuated as indicated by lowered mortalities (p < 0.05), lowered lesion scores (p < 0.05), and similar body weight gain (BWG) (p > 0.05) as the non-challenged controls during vaccination phases (101). This information is consistent with previous research indicating attenuation of H. meleagridis following repeated in vitro passage (102,131,179,196). Importantly, administration of non-clonal vaccination isolates on day 14 has conferred protection against challenge with homologous and heterologous virulent isolates; moreover, these conditions potentially better portrayed the field environment where turkeys are exposed to multiple isolates (101).…”

Section: Attempted Vaccination With Attenuated Isolatessupporting

confidence: 87%

“…Humoral immune response to H. meleagridis α-actinin1 and α-actinin3 was higher and induced sooner in specific-pathogen-free layer-type chickens as compared to meat-type chickens (68). Shotgun proteomics has been utilized to compare virulent and attenuated monoeukaryotic monoxenic H. meleagridis; cysteine proteases were the predominant lytic molecules in the virulent exoproteome as compared to the attenuated isolate (130,131). Mazumdar et al ( 132) completed a de novo transcriptome sequencing study utilizing single-cell cloned virulent and attenuated isolates, demonstrating different gene families.…”

Section: Phylogenetic and Molecular Characterizationsmentioning

confidence: 99%

“…Serial in vivo passaging of the Hm-L1 attenuated strain from chicken-to-chicken or turkey-to-turkey restored the strain to original virulence (198,199). Differences in virulence have been found within H. meleagridis isolates obtained from different geographical locations, in addition to varied loss of pathogenicity following repeated passaging (131). Furthermore, subpopulations of serially passaged monocultures originating from the same parental isolate have shown a marked difference in virulence, supporting the idea of genetic mutation through repeated serial passaging in vitro (131).…”

Section: Attempted Vaccination With Attenuated Isolatesmentioning

confidence: 99%

“…Differences in virulence have been found within H. meleagridis isolates obtained from different geographical locations, in addition to varied loss of pathogenicity following repeated passaging (131). Furthermore, subpopulations of serially passaged monocultures originating from the same parental isolate have shown a marked difference in virulence, supporting the idea of genetic mutation through repeated serial passaging in vitro (131). Long-term passaging in vitro (>290 serial passages) resulted in a phenotype shift toward greater tenacity of histomonad survival at lower temperatures and improved growth rates (37).…”

Section: Attempted Vaccination With Attenuated Isolatesmentioning

confidence: 99%

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Histomonosis in Poultry: A Comprehensive Review

et al. 2022

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Histomonas meleagridis, the etiological agent of histomonosis, is a poultry parasite primarily detrimental to turkeys. Characteristic lesions occur in the liver and ceca, with mortalities in turkey flocks often reaching 80–100%. Chickens and other gallinaceous birds can be susceptible but the disease was primarily considered sub-clinical until recent years. Treating and preventing H. meleagridis infection have become more difficult since 2015, when nitarsone was voluntarily removed from the market, leaving the poultry industry with no approved prophylactics, therapeutics, or vaccines to combat histomonosis. Phytogenic compounds evaluated for chemoprophylaxis of histomonosis have varied results with in vitro and in vivo experiments. Some recent research successes are encouraging for the pursuit of antihistomonal compounds derived from plants. Turkeys and chickens exhibit a level of resistance to re-infection when recovered from H. meleagridis infection, but no commercial vaccines are yet available, despite experimental successes. Safety and stability of live-attenuated isolates have been demonstrated; furthermore, highly efficacious protection has been conferred in experimental settings with administration of these isolates without harming performance. Taken together, these research advancements are encouraging for vaccine development, but further investigation is necessary to evaluate proper administration age, dose, and route. A summary of the published research is provided in this review.

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Section: Attempted Vaccination With Attenuated Isolatessupporting

confidence: 87%

Section: Phylogenetic and Molecular Characterizationsmentioning

confidence: 99%

Section: Attempted Vaccination With Attenuated Isolatesmentioning

confidence: 99%

Section: Attempted Vaccination With Attenuated Isolatesmentioning

confidence: 99%

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Histomonosis in Poultry: A Comprehensive Review

et al. 2022

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“…Factors behind the variability in disease manifestation and incidence are unknown. Previous studies have reported the existence of two distinct clusters of H. meleagridis differing in prevalence in geographical locations and pathology ( 7 ) and variation in the expression of virulence factors and pathogenicity of different field isolates ( 8 ). Nevertheless, as far as we are aware, the impact of different isolates of H. meleagridis or the feed composition of the diet in the horizontal transmission of the disease has not been investigated.…”

Section: Introductionmentioning

confidence: 99%

Feed Composition and Isolate of Histomonas meleagridis Alter Horizontal Transmission of Histomonosis in Turkeys. Proof of Concept

et al. 2022

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Outbreaks of histomonosis in turkeys are typically initiated by the ingestion of contaminated embryonated eggs of Heterakis gallinarum, potentially present in earthworms and mechanical vectors. Once an outbreak is started, infected turkeys can transmit the disease by horizontal transmission. Factors influencing horizontal transmission of histomonosis are poorly understood. Replication of horizontal transmission in experimental conditions has not been consistent, presenting an obstacle in searching for alternatives to prevent or treat the disease. Two pilot experiments and three validation experiments were conducted in the present study. In pilot experiment 1, one isolate of Histomonas meleagridis (named Buford) was used. Turkeys were fed a low-nutrient density diet corn-soy based (LOW-CS) and raised in floor pens. In pilot experiment 2, another isolate of H. meleagridis was used (named PHL). Turkeys were fed a low-nutrient density diet with the addition of wheat middlings (LOW-WM) and raised in floor pens. In experiment 3, conducted on floor pens, both isolates and diets were used in different groups. In experiment 4, turkeys were raised on battery cages and only the PHL isolate was used. Both diets (LOW-WM and LOW-CS) were used, in addition to a diet surpassing the nutritional needs of young poults (turkey starter, TS). In experiment 5, conducted in battery cages, only the PHL isolate was used, and the LOW-WM and TS diets were in different groups. The horizontal transmission was achieved only with the PHL isolate from all experiments. The transmission rate varied among experimental diets, with the TS diet having the lowest transmission rate in experiments 4 and 5. Variation was observed between experiments and within experimental groups.

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