New Chemotherapeutic Agents in Enterohepatitis (Blackhead) of Turkeys

Waletzky, E.; Clark, J.H.; Marson, H. W.

doi:10.1126/science.111.2896.720

Cited by 17 publications

(3 citation statements)

References 2 publications

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“…An important finding was the identification of Heterakis gallinarum as a vector for H. meleagridis, implicating practical suggestions on the prevention of histomonosis by aspects of biosecurity and worm control (Graybill & Smith, 1920). Later on, experimental studies demonstrated arsenicals and nitroheterocyclics to be effective against histomonosis (Tyzzer, 1923;Waletzky et al, 1950). Hence, those drugs became commercially available and by their use, outbreaks of the disease in turkeys and chickens could be effectively prevented or treated.…”

Section: Emphasis Of the Reviewmentioning

confidence: 99%

Histomonosis in poultry: previous and current strategies for prevention and therapy

et al. 2016

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Histomonosis is a parasitic disease of poultry with worldwide prevalence. The disease can cause morbidity and mortality in chicken and turkey flocks entailing severe economic losses. In the first half of the last century, there was a high demand to control histomonosis as the turkey industry was severely affected by the disease. Consequently, numerous chemical compounds were tested for their efficacy against Histomonas meleagridis with varying outcomes, that are summarized and specified in this review. At the same time, preliminary attempts to protect birds with cultured histomonads indicated the possibility of vaccination. Several years ago antihistomonal drugs were banned in countries with tight regulations on pharmaceuticals in order to comply with the demand of consumer protection. As a consequence, outbreaks of histomonosis in poultry flocks increased and the disease became endemic again. New approaches to prevent and treat histomonosis are, therefore, needed and recently performed studies focused on various areas to combat the disease, from alternative chemotherapeutic substances to plant-derived compounds until vaccination, altogether reviewed here. Considering existing regulations and the overall outcome of experimental studies, it can be concluded that vaccination is very promising, despite the fact that various challenges need to be addressed until the first ever developed vaccine based upon live flagellates in human or bird medicine can be marketed.

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Section: Emphasis Of the Reviewmentioning

confidence: 99%

Histomonosis in poultry: previous and current strategies for prevention and therapy

et al. 2016

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“…'G'NHEPTIN (2-amino, 5-nitrothiazole) -'-' has been rather widely used in the control of infectious enterohepatitis since the discovery of the drug by Waletzky et al (1950). The preventive action of the drug also has been confirmed experimentally by McGregor (1949), Jungherr andWinn (1950), andDeVolt et al (1951).…”

mentioning

confidence: 90%

“…Several investigators including Waletzky et al (1950) and Jungherr and Winn (1950) have noted the tendency of blackhead to recur after cessation of enheptm treatment. In the experience of the writers, the ailment has recurred on some occasions but has failed to recur in other instances after treatment with the drug was stopped.…”

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confidence: 96%

An Investigation to Determine Whether Immunity to Infectious Enterohepatitis (Blackhead) of Turkeys Develops during Enheptin Treatment

1954

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Experimental infections with the protozoan parasite Histomonas meleagridis: a review

Hauck

Hafez

2012

Parasitol Res

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In recent years, a number of studies about Histomonas meleagridis, and more specifically about experiments in vivo involving H. meleagridis to investigate the pathogenicity and efficacy of drugs or vaccines, have been published. Together with older publications, a considerable amount of information about experimental infections with H. meleagridis exist, which is helpful for planning future animal studies and can reduce the number of birds used in such studies toward better animal welfare. One hundred sixty-seven publications describing experimental infections with H. meleagridis were published in scientific journals between 1920 and 2012. One hundred forty-two of these publications describe infections of turkeys (Meleagris gallopavo) and 52 infections of chickens (Gallus gallus). In 18 studies, experiments involving other species were done. The most popular routes of infection were the intracloacal application of histomonal trophozoites from culture material, from lesions or from feces of infected birds, or using larvae of the cecal worm Heterakis gallinarum (83 studies) and the oral application of eggs or other stages of the cecal worm containing histomonal stages (83 studies). During the last 10 years, intracloacal application of trophozoites has become the most popular way to experimentally infect birds with H. meleagridis due to its high reproducibility and reliability. In most studies, infection doses of several 10,000 or 100,000 histomonal trophozoites were used for infection, and the resulting mortality in turkeys was more than 70 %. First mortality can occur as early as 6 days p.i.; peak mortality usually is 13-15 days p.i. Lower infection doses may delay mortality about 2 days. In chickens infected by the intracloacal route, mortality and clinical signs are rare, but infection rates are similar. Cecal lesions can be observed from 3 to 4 days p.i., lesions up to 3 weeks p.i.; liver lesions may be lacking completely or be present only in a small number of birds. In most studies infecting birds with Heterakis eggs containing histomonal stages, several 100 to 1,000 Heterakis eggs were used. However, lower doses might be sufficient, as infection with as few as 58 eggs per bird caused a mortality up to 90 % in turkeys. Clinical symptoms start 9 days p.i., and first mortality occurs after 12 days, while most of the infected birds die between 19 and 21 days p.i. The infectivity of Heterakis eggs containing histomonal stages for chickens is similar as for turkeys, but mortality and clinical signs are rare. Further infection was done by oral application of histomonal trophozoites either grown in culture or using lesions or feces of infected birds (26 studies). These yielded very mixed results, with infection rates between 0 and more than 80 % in turkeys and chickens. After successful oral infection of turkeys, mortality occurs at roughly the same time as after intracloacal infection. Further 18 studies employed seeder birds to infect in-contact birds. Other means of infection were exposure to contaminated soil or...

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New Chemotherapeutic Agents in Enterohepatitis (Blackhead) of Turkeys

Cited by 17 publications

References 2 publications

Histomonosis in poultry: previous and current strategies for prevention and therapy

Histomonosis in poultry: previous and current strategies for prevention and therapy

An Investigation to Determine Whether Immunity to Infectious Enterohepatitis (Blackhead) of Turkeys Develops during Enheptin Treatment

Experimental infections with the protozoan parasite Histomonas meleagridis: a review

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