Evaluation of live-attenuated Histomonas meleagridis isolates as vaccine candidates against wild-type challenge

Beer, L.C.; Graham, Brittany D.; Barros, Thaina L.; Latorre, Juan D.; Téllez-Isaías, Guillermo; Fuller, Alberta L.; Hargis, Billy M.; Vuong, Christine N.

doi:10.1016/j.psj.2021.101656

Cited by 6 publications

(7 citation statements)

References 59 publications

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“…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). More research remains necessary for histomonosis vaccine development and to elucidate practical methods for industry application.…”

Section: Attempted Vaccination With Attenuated Isolatessupporting

confidence: 88%

“…Repeated intracloacal passaging of H. meleagridis in turkeys produced an isolate of low virulence which was successfully used to induce protection against a virulent strain (206). 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).…”

Section: Attempted Vaccination With Attenuated Isolatessupporting

confidence: 86%

“…Oral challenge with virulent histomonads on day-of-hatch has previously induced histomonosis in turkeys (31), although the oral route in absence of vectors remains somewhat controversial in older birds. Recently, challenge with wild-type H. meleagridis before feeding on day-of-hatch induced disease regardless of oral or cloacal route, presumably due to the near-neutral pH in the proventriculus-ventriculus region allowing the histomonads to survive and parasitize the ceca (101). Interestingly, oral challenge with virulent H. meleagridis at day 21 did not induce histomonosis, further suggesting that the cloacal route rather than the oral route is the primary method for transmitting unprotected histomonads in older birds; however, the oral route should not be disregarded for young birds (101).…”

Section: Pathogenesismentioning

confidence: 99%

“…Vaccination attempts for histomonosis have yielded some success in controlled experimental conditions, but a histomonosis vaccine has not yet been developed for commercial application (91,101,164,183,194,(201)(202)(203). A clonal in vitro attenuated strain of H. administered cloacally as a vaccine at day 14 protected turkeys which were subsequently challenged on day 42 with a virulent strain; in-contact turkeys from the vaccination were also resistant to subsequent infection (183).…”

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: 88%

Section: Attempted Vaccination With Attenuated Isolatessupporting

confidence: 86%

Section: Pathogenesismentioning

confidence: 99%

Section: Attempted Vaccination With Attenuated Isolatesmentioning

confidence: 99%

See 2 more Smart Citations

Histomonosis in Poultry: A Comprehensive Review

et al. 2022

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show abstract

“…to alleviate its negative effects. These models use various approaches to infect the birds, including intracloacal inoculation of all experimental birds with either H. meleagridis or Heterakis gallinarum eggs, which are the vectors for H. meleagridis ( Hauck and Hafez, 2013 ; Beer et al, 2022 ).…”

Section: Introductionmentioning

confidence: 99%